x86: Rewrite exit-to-userspace code

This is the first big batch of x86 asm-to-C conversion patches.

The exit-to-usermode code is copied in several places and is written in a nasty combination of asm and C. It's not at all clear what it's supposed to do, and the way it's structured makes it very hard to work with. For example, it's not even clear why syscall exit hooks are called only once per syscall right now. (It seems to be a side effect of the way that rdi and rdx are handled in the asm loop, and it seems reliable, but it's still pointlessly complicated.) The existing code also makes context tracking overly complicated and hard to understand. Finally, it's nearly impossible for anyone to change what happens on exit to usermode, since the existing code is so fragile.

I tried to clean it up incrementally, but I decided it was too hard. Instead, this series just replaces the code. It seems to work.

Context tracking in particular works very differently now. The low-level entry code checks that we're in CONTEXT_USER and switches to CONTEXT_KERNEL. The exit code does the reverse. There is no need to track what CONTEXT_XYZ state we came from, because we already know. Similarly, SCHEDULE_USER is gone, since we can reschedule if needed by simply calling schedule() from C code.

The main things that are missing are that I haven't done the 32-bit parts (anyone want to help?) and therefore I haven't deleted the old C code. I also think this may break UML for trivial reasons.

IRQ context tracking is still messy. One the cleanup progresses to the point that we can enter CONTEXT_KERNEL in syscalls before enabling interrupts, we can fully clean up IRQ context tracking.

Once these land, I'll send some more :)

Note: we might want to backport patches 1 and 2.

Changes from v4:
- Remove now-unused SAVE_EXTRA_REGS_RBP macro
- Fix comment at the top of common.c
- Decorate internal labels in error_entry with .L
- Fix two mis-formatted asm lines
- Undo inadvertent removal of R11 initialization in the sysexit path

I didn't rename the error_entry labels.

Changes from v3:
- Add the syscall_arg_fault_32 test.
- Fix a pre-existing bad syscall arg buglet.
- Fix an asm glitch due to a bad rebase.
- Fix a CONFIG_PROVE_LOCKDEP warning.
Borislav: the end result of this series differs from the v3.91 that I only in the removal of a single trailing tab. The badarg patch is in a different place now, though, since we might want to backport it.

Changes from v2: Misplaced the actual list -- sorry.

Changes from v1:
- Fix bisection failure by squashing the 64-bit native and compat syscall conversions together. The intermediate state didn't built, and fixing it isn't worthwhile (the results will be harder to understand).
- Replace context_tracking_assert_state with CT_WARN_ON and ct_state.
- The last two patches are now. I incorrectly thought that we weren't ready for them yet on 32-bit kernels, but I was wrong.

Andy Lutomirski (16):
selftests/x86: Add a test for 32-bit fast syscall arg faults x86/entry/64/compat: Fix bad fast syscall arg failure path
context_tracking: Add ct_state and CT_WARN_ON
notifiers: Assert that RCU is watching in notify_die
x86: Move C entry and exit code to arch/x86/entry/common.c x86/traps: Assert that we're in CONTEXT_KERNEL in exception entries x86/entry: Add enter_from_user_mode and use it in syscalls x86/entry: Add new, comprehensible entry and exit hooks x86/entry/64: Really create an error-entry-from-usermode code path x86/entry/64: Migrate 64-bit and compat syscalls to new exit hooks x86/asm/entry/64: Save all regs on interrupt entry x86/asm/entry/64: Simplify irq stack pt_regs handling x86/asm/entry/64: Migrate error and interrupt exit work to C x86/entry: Remove exception_enter from most trap handlers x86/entry: Remove SCHEDULE_USER and asm/context-tracking.h x86/irq: Document how IRQ context tracking works and add an assertion

Ingo Molnar (1):
uml: Fix do_signal() prototype

 arch/um/include/shared/kern_util.h              |   3 +-
 arch/um/kernel/process.c                        |   6 +-
 arch/um/kernel/signal.c                         |   8 +-
 arch/um/kernel/tlb.c                            |   2 +-
 arch/um/kernel/trap.c                           |   2 +-
 arch/x86/entry/Makefile                         |   1 +
 arch/x86/entry/calling.h                        |   3 -
 arch/x86/entry/common.c                         | 374 ++++++++++++++++++++++++
 arch/x86/entry/entry_64.S                       | 197 ++++---------
 arch/x86/entry/entry_64_compat.S                |  46 ++-
 arch/x86/include/asm/context_tracking.h         |  10 -
 arch/x86/include/asm/signal.h                   |   1 +
 arch/x86/include/asm/traps.h                    |   4 +-
 arch/x86/kernel/cpu/mcheck/mce.c                |   5 +-
 arch/x86/kernel/cpu/mcheck/p5.c                 |   5 +-
 arch/x86/kernel/cpu/mcheck/winchip.c            |   4 +-
 arch/x86/kernel/irq.c                           |  15 +
 arch/x86/kernel/ptrace.c                        | 202 +------------
 arch/x86/kernel/signal.c                        |  28 +-
 arch/x86/kernel/traps.c                         |  87 ++----
 include/linux/context_tracking.h                |  15 +
 include/linux/context_tracking_state.h          |   1 +
 kernel/notifier.c                               |   2 +
 tools/testing/selftests/x86/Makefile            |   2 +-
 tools/testing/selftests/x86/syscall_arg_fault.c | 130 ++++++++
 25 files changed, 681 insertions(+), 472 deletions(-)
 create mode 100644 arch/x86/entry/common.c
 delete mode 100644 arch/x86/include/asm/context_tracking.h
 create mode 100644 tools/testing/selftests/x86/syscall_arg_fault.c

2.4.3

From: Ingo Molnar <[email protected]>

Once x86 exports its do_signal(), the prototypes will clash.

Fix the clash and also improve the code a bit: remove the unnecessary kern_do_signal() indirection. This allows interrupt_end() to share the 'regs' parameter calculation.

Also remove the unused return code to match x86.

Minimally build and boot tested.

---
 arch/um/include/shared/kern_util.h | 3 ++-
 arch/um/kernel/process.c           | 6 ++++--
 arch/um/kernel/signal.c            | 8 +-------
 arch/um/kernel/tlb.c               | 2 +-
 arch/um/kernel/trap.c              | 2 +-
 5 files changed, 9 insertions(+), 12 deletions(-)

index 83a91f976330..35ab97e4bb9b 100644
@@ -22,7 +22,8 @@ extern int kmalloc_ok;
 extern unsigned long alloc_stack(int order, int atomic);
 extern void free_stack(unsigned long stack, int order);
 
-extern int do_signal(void);
+struct pt_regs;
+extern void do_signal(struct pt_regs *regs);
 extern void interrupt_end(void);
 extern void relay_signal(int sig, struct siginfo *si, struct uml_pt_regs *regs);
 

index 68b9119841cd..a6d922672b9f 100644
@@ -90,12 +90,14 @@ void *__switch_to(struct task_struct *from, struct task_struct *to)
 
 void interrupt_end(void)
 {
+	struct pt_regs *regs = &current->thread.regs;
+
 	if (need_resched())
 		schedule();
 	if (test_thread_flag(TIF_SIGPENDING))
-		do_signal();
+		do_signal(regs);
 	if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
-		tracehook_notify_resume(&current->thread.regs);
+		tracehook_notify_resume(regs);
 }
 
 void exit_thread(void)

index 4f60e4aad790..57acbd67d85d 100644
@@ -64,7 +64,7 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 	signal_setup_done(err, ksig, singlestep);
 }
 
-static int kern_do_signal(struct pt_regs *regs)
+void do_signal(struct pt_regs *regs)
 {
 	struct ksignal ksig;
 	int handled_sig = 0;

@@ -110,10 +110,4 @@ static int kern_do_signal(struct pt_regs *regs)
 	 */
 	if (!handled_sig)
 		restore_saved_sigmask();
-	return handled_sig;
-}
-
-int do_signal(void)
-{
-	return kern_do_signal(&current->thread.regs);
 }

index f1b3eb14b855..2077248e8a72 100644
@@ -291,7 +291,7 @@ void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
 		/* We are under mmap_sem, release it such that current can terminate */
 		up_write(&current->mm->mmap_sem);
 		force_sig(SIGKILL, current);
-		do_signal();
+		do_signal(&current->thread.regs);
 	}
 }
 

index 47ff9b7f3e5d..1b0f5c59d522 100644
@@ -173,7 +173,7 @@ static void bad_segv(struct faultinfo fi, unsigned long ip)
 void fatal_sigsegv(void)
 {
 	force_sigsegv(SIGSEGV, current);
-	do_signal();
+	do_signal(&current->thread.regs);
 	/*
 	 * This is to tell gcc that we're not returning - do_signal
 	 * can, in general, return, but in this case, it's not, since

2.4.3

If user code does SYSCALL32 or SYSENTER without a valid stack, then our attempt to determine the syscall args will result in a failed uaccess fault. Previously, we would try to recover by jumping to the syscall exit code, but we'd run the syscall exit work even though we never made it to the syscall entry work.

Clean it up by treating the failure path as a non-syscall entry and exit pair.

This fixes strace's output when running the syscall_arg_fault test. Without this fix, strace would get out of sync and would fail to associate syscall entries with syscall exits.

---
 arch/x86/entry/entry_64.S        |  2 +-
 arch/x86/entry/entry_64_compat.S | 35 +++++++++++++++++++++++++++++++++--
 2 files changed, 34 insertions(+), 3 deletions(-)

index 3bb2c4302df1..141a5d49dddc 100644
@@ -613,7 +613,7 @@ ret_from_intr:
 	testb	$3, CS(%rsp)
 	jz	retint_kernel
 	/* Interrupt came from user space */
-retint_user:
+GLOBAL(retint_user)
 	GET_THREAD_INFO(%rcx)
 
 	/* %rcx: thread info. Interrupts are off. */

index bb187a6a877c..efe0b1e499fa 100644
@@ -425,8 +425,39 @@ cstar_tracesys:
 END(entry_SYSCALL_compat)
 
 ia32_badarg:
-	ASM_CLAC
-	movq	$-EFAULT, RAX(%rsp)
+	/*
+	 * So far, we've entered kernel mode, set AC, turned on IRQs, and
+	 * saved C regs except r8-r11.  We haven't done any of the other
+	 * standard entry work, though.  We want to bail, but we shouldn't
+	 * treat this as a syscall entry since we don't even know what the
+	 * args are.  Instead, treat this as a non-syscall entry, finish
+	 * the entry work, and immediately exit after setting AX = -EFAULT.
+	 *
+	 * We're really just being polite here.  Killing the task outright
+	 * would be a reasonable action, too.  Given that the only valid
+	 * way to have gotten here is through the vDSO, and we already know
+	 * that the stack pointer is bad, the task isn't going to survive
+	 * for long no matter what we do.
+	 */
+
+	ASM_CLAC			/* undo STAC */
+	movq	$-EFAULT, RAX(%rsp)	/* return -EFAULT if possible */
+
+	/* Fill in the rest of pt_regs */
+	xorl	%eax, %eax
+	movq	%rax, R11(%rsp)
+	movq	%rax, R10(%rsp)
+	movq	%rax, R9(%rsp)
+	movq	%rax, R8(%rsp)
+	SAVE_EXTRA_REGS
+
+	/* Turn IRQs back off. */
+	DISABLE_INTERRUPTS(CLBR_NONE)
+	TRACE_IRQS_OFF
+
+	/* And exit again. */
+	jmp retint_user
+
 ia32_ret_from_sys_call:
 	xorl	%eax, %eax		/* Do not leak kernel information */
 	movq	%rax, R11(%rsp)

2.4.3

This test passes on 4.0 and fails on some newer kernels. Fortunately, the failure is likely not a big deal. This test will make sure that we don't break it further (e.g. OOPSing) as we clean up the entry code and that we eventually fix the regression.

There's arguably no need to preserve the old ABI here -- anything that makes it into a fast (vDSO) syscall with a bad stack is about to crash no matter what we do.

---
 tools/testing/selftests/x86/Makefile            |   2 +-
 tools/testing/selftests/x86/syscall_arg_fault.c | 130 ++++++++++++++++++++++++
 2 files changed, 131 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/x86/syscall_arg_fault.c

index caa60d56d7d1..e8df47e6326c 100644
@@ -5,7 +5,7 @@ include ../lib.mk
 .PHONY: all all_32 all_64 warn_32bit_failure clean
 
 TARGETS_C_BOTHBITS := sigreturn single_step_syscall sysret_ss_attrs
-TARGETS_C_32BIT_ONLY := entry_from_vm86
+TARGETS_C_32BIT_ONLY := entry_from_vm86 syscall_arg_fault
 
 TARGETS_C_32BIT_ALL := $(TARGETS_C_BOTHBITS) $(TARGETS_C_32BIT_ONLY)
 BINARIES_32 := $(TARGETS_C_32BIT_ALL:%=%_32)

2.4.3

This will let us sprinkle sanity checks around the kernel without making too much of a mess.

---
 include/linux/context_tracking.h       | 15 +++++++++++++++
 include/linux/context_tracking_state.h |  1 +
 2 files changed, 16 insertions(+)

index b96bd299966f..008fc67d0d96 100644
@@ -49,13 +49,28 @@ static inline void exception_exit(enum ctx_state prev_ctx)
 	}
 }
 
+
+/**
+ * ct_state() - return the current context tracking state if known
+ *
+ * Returns the current cpu's context tracking state if context tracking
+ * is enabled.  If context tracking is disabled, returns
+ * CONTEXT_DISABLED.  This should be used primarily for debugging.
+ */
+static inline enum ctx_state ct_state(void)
+{
+	return context_tracking_is_enabled() ?
+		this_cpu_read(context_tracking.state) : CONTEXT_DISABLED;
+}
 #else
 static inline void user_enter(void) { }
 static inline void user_exit(void) { }
 static inline enum ctx_state exception_enter(void) { return 0; }
 static inline void exception_exit(enum ctx_state prev_ctx) { }
+static inline enum ctx_state ct_state(void) { return CONTEXT_DISABLED; }
 #endif /* !CONFIG_CONTEXT_TRACKING */
 
+#define CT_WARN_ON(cond) WARN_ON(context_tracking_is_enabled() && (cond))
 
 #ifdef CONFIG_CONTEXT_TRACKING_FORCE
 extern void context_tracking_init(void);

index 678ecdf90cf6..ee956c528fab 100644
@@ -14,6 +14,7 @@ struct context_tracking {
 	bool active;
 	int recursion;
 	enum ctx_state {
+		CONTEXT_DISABLED = -1,	/* returned by ct_state() if unknown */
 		CONTEXT_KERNEL = 0,
 		CONTEXT_USER,
 		CONTEXT_GUEST,

2.4.3

---
 arch/x86/kernel/irq.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

index 88b366487b0e..6233de046c08 100644
@@ -216,8 +216,23 @@ __visible unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
 	unsigned vector = ~regs->orig_ax;
 	unsigned irq;
 
+	/*
+	 * NB: Unlike exception entries, IRQ entries do not reliably
+	 * handle context tracking in the low-level entry code.  This is
+	 * because syscall entries execute briefly with IRQs on before
+	 * updating context tracking state, so we can take an IRQ from
+	 * kernel mode with CONTEXT_USER.  The low-level entry code only
+	 * updates the context if we came from user mode, so we won't
+	 * switch to CONTEXT_KERNEL.  We'll fix that once the syscall
+	 * code is cleaned up enough that we can cleanly defer enabling
+	 * IRQs.
+	 */
+
 	entering_irq();
 
+	/* entering_irq() tells RCU that we're not quiescent.  Check it. */
+	rcu_lockdep_assert(rcu_is_watching(), "IRQ failed to wake up RCU");
+
 	irq = __this_cpu_read(vector_irq[vector]);
 
 	if (!handle_irq(irq, regs)) {

2.4.3

SCHEDULE_USER is no longer used, and asm/context-tracking.h contained nothing else. Remove the header entirely

---
 arch/x86/entry/entry_64.S               |  1 -
 arch/x86/include/asm/context_tracking.h | 10 ----------
 2 files changed, 11 deletions(-)
 delete mode 100644 arch/x86/include/asm/context_tracking.h

index 168ee264c345..041a37a643e1 100644
@@ -33,7 +33,6 @@
 #include <asm/paravirt.h>
 #include <asm/percpu.h>
 #include <asm/asm.h>
-#include <asm/context_tracking.h>
 #include <asm/smap.h>
 #include <asm/pgtable_types.h>
 #include <linux/err.h>

deleted file mode 100644
index 1fe49704b146..000000000000
@@ -1,10 +0,0 @@
-#ifndef _ASM_X86_CONTEXT_TRACKING_H
-#define _ASM_X86_CONTEXT_TRACKING_H
-
-#ifdef CONFIG_CONTEXT_TRACKING
-# define SCHEDULE_USER call schedule_user
-#else
-# define SCHEDULE_USER call schedule
-#endif
-
-#endif

2.4.3

On 64-bit kernels, we don't need it any more: we handle context tracking directly on entry from user mode and exit to user mode. On 32-bit kernels, we don't support context tracking at all, so these hooks had no effect.

This doesn't change do_page_fault. Before we do that, we need to make sure that there is no code that can page fault from kernel mode with CONTEXT_USER. The 32-bit fast system call stack argument code is the only offender I'm aware of right now.

---
 arch/x86/include/asm/traps.h         |  4 +-
 arch/x86/kernel/cpu/mcheck/mce.c     |  5 +--
 arch/x86/kernel/cpu/mcheck/p5.c      |  5 +--
 arch/x86/kernel/cpu/mcheck/winchip.c |  4 +-
 arch/x86/kernel/traps.c              | 78 +++++++++---------------------------
 5 files changed, 27 insertions(+), 69 deletions(-)

index c5380bea2a36..c3496619740a 100644
@@ -112,8 +112,8 @@ asmlinkage void smp_threshold_interrupt(void);
 asmlinkage void smp_deferred_error_interrupt(void);
 #endif
 
-extern enum ctx_state ist_enter(struct pt_regs *regs);
-extern void ist_exit(struct pt_regs *regs, enum ctx_state prev_state);
+extern void ist_enter(struct pt_regs *regs);
+extern void ist_exit(struct pt_regs *regs);
 extern void ist_begin_non_atomic(struct pt_regs *regs);
 extern void ist_end_non_atomic(void);
 

index df919ff103c3..dc87973098dc 100644
@@ -1029,7 +1029,6 @@ void do_machine_check(struct pt_regs *regs, long error_code)
 {
 	struct mca_config *cfg = &mca_cfg;
 	struct mce m, *final;
-	enum ctx_state prev_state;
 	int i;
 	int worst = 0;
 	int severity;

@@ -1055,7 +1054,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
 	int flags = MF_ACTION_REQUIRED;
 	int lmce = 0;
 
-	prev_state = ist_enter(regs);
+	ist_enter(regs);
 
 	this_cpu_inc(mce_exception_count);
 

@@ -1227,7 +1226,7 @@ out:
 	local_irq_disable();
 	ist_end_non_atomic();
 done:
-	ist_exit(regs, prev_state);
+	ist_exit(regs);
 }
 EXPORT_SYMBOL_GPL(do_machine_check);
 

index 737b0ad4e61a..12402e10aeff 100644
@@ -19,10 +19,9 @@ int mce_p5_enabled __read_mostly;
 /* Machine check handler for Pentium class Intel CPUs: */
 static void pentium_machine_check(struct pt_regs *regs, long error_code)
 {
-	enum ctx_state prev_state;
 	u32 loaddr, hi, lotype;
 
-	prev_state = ist_enter(regs);
+	ist_enter(regs);
 
 	rdmsr(MSR_IA32_P5_MC_ADDR, loaddr, hi);
 	rdmsr(MSR_IA32_P5_MC_TYPE, lotype, hi);

@@ -39,7 +38,7 @@ static void pentium_machine_check(struct pt_regs *regs, long error_code)
 
 	add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
 
-	ist_exit(regs, prev_state);
+	ist_exit(regs);
 }
 
 /* Set up machine check reporting for processors with Intel style MCE: */

index 44f138296fbe..01dd8702880b 100644
@@ -15,12 +15,12 @@
 /* Machine check handler for WinChip C6: */
 static void winchip_machine_check(struct pt_regs *regs, long error_code)
 {
-	enum ctx_state prev_state = ist_enter(regs);
+	ist_enter(regs);
 
 	printk(KERN_EMERG "CPU0: Machine Check Exception.\n");
 	add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
 
-	ist_exit(regs, prev_state);
+	ist_exit(regs);
 }
 
 /* Set up machine check reporting on the Winchip C6 series */

2.4.3

---
 arch/x86/entry/entry_64.S        | 64 +++++++++++-----------------------------
 arch/x86/entry/entry_64_compat.S |  5 ++++
 2 files changed, 23 insertions(+), 46 deletions(-)

index 83eb63d31da4..168ee264c345 100644
@@ -508,7 +508,16 @@ END(irq_entries_start)
 
 	testb	$3, CS(%rsp)
 	jz	1f
+
+	/*
+	 * IRQ from user mode.  Switch to kernel gsbase and inform context
+	 * tracking that we're in kernel mode.
+	 */
 	SWAPGS
+#ifdef CONFIG_CONTEXT_TRACKING
+	call enter_from_user_mode
+#endif
+
 1:
 	/*
 	 * Save previous stack pointer, optionally switch to interrupt stack.

@@ -547,26 +556,13 @@ ret_from_intr:
 
 	testb	$3, CS(%rsp)
 	jz	retint_kernel
-	/* Interrupt came from user space */
-GLOBAL(retint_user)
-	GET_THREAD_INFO(%rcx)
 
-	/* %rcx: thread info. Interrupts are off. */
-retint_with_reschedule:
-	movl	$_TIF_WORK_MASK, %edi
-retint_check:
+	/* Interrupt came from user space */
 	LOCKDEP_SYS_EXIT_IRQ
-	movl	TI_flags(%rcx), %edx
-	andl	%edi, %edx
-	jnz	retint_careful
-
-retint_swapgs:					/* return to user-space */
-	/*
-	 * The iretq could re-enable interrupts:
-	 */
-	DISABLE_INTERRUPTS(CLBR_ANY)
+GLOBAL(retint_user)
+	mov	%rsp,%rdi
+	call	prepare_exit_to_usermode
 	TRACE_IRQS_IRETQ
-
 	SWAPGS
 	jmp	restore_regs_and_iret
 

@@ -644,35 +640,6 @@ native_irq_return_ldt:
 	popq	%rax
 	jmp	native_irq_return_iret
 #endif
-
-	/* edi: workmask, edx: work */
-retint_careful:
-	bt	$TIF_NEED_RESCHED, %edx
-	jnc	retint_signal
-	TRACE_IRQS_ON
-	ENABLE_INTERRUPTS(CLBR_NONE)
-	pushq	%rdi
-	SCHEDULE_USER
-	popq	%rdi
-	GET_THREAD_INFO(%rcx)
-	DISABLE_INTERRUPTS(CLBR_NONE)
-	TRACE_IRQS_OFF
-	jmp	retint_check
-
-retint_signal:
-	testl	$_TIF_DO_NOTIFY_MASK, %edx
-	jz	retint_swapgs
-	TRACE_IRQS_ON
-	ENABLE_INTERRUPTS(CLBR_NONE)
-	movq	$-1, ORIG_RAX(%rsp)
-	xorl	%esi, %esi			/* oldset */
-	movq	%rsp, %rdi			/* &pt_regs */
-	call	do_notify_resume
-	DISABLE_INTERRUPTS(CLBR_NONE)
-	TRACE_IRQS_OFF
-	GET_THREAD_INFO(%rcx)
-	jmp	retint_with_reschedule
-
 END(common_interrupt)
 
 /*

@@ -1088,7 +1055,12 @@ ENTRY(error_entry)
 	SWAPGS
 
 .Lerror_entry_from_usermode_after_swapgs:
+#ifdef CONFIG_CONTEXT_TRACKING
+	call enter_from_user_mode
+#endif
+
 .Lerror_entry_done:
+
 	TRACE_IRQS_OFF
 	ret
 

index 204528cf4359..55fa85837da2 100644
@@ -455,6 +455,11 @@ ia32_badarg:
 	DISABLE_INTERRUPTS(CLBR_NONE)
 	TRACE_IRQS_OFF
 
+	/* Now finish entering normal kernel mode. */
+#ifdef CONFIG_CONTEXT_TRACKING
+	call enter_from_user_mode
+#endif
+
 	/* And exit again. */
 	jmp retint_user
 

2.4.3

There's no need for both rsi and rdi to point to the original stack.

---
 arch/x86/entry/entry_64.S | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

index 65029f48bcc4..83eb63d31da4 100644
@@ -506,8 +506,6 @@ END(irq_entries_start)
 	SAVE_C_REGS
 	SAVE_EXTRA_REGS
 
-	movq	%rsp,%rdi	/* arg1 for \func (pointer to pt_regs) */
-
 	testb	$3, CS(%rsp)
 	jz	1f
 	SWAPGS

@@ -519,14 +517,14 @@ END(irq_entries_start)
 	 * a little cheaper to use a separate counter in the PDA (short of
 	 * moving irq_enter into assembly, which would be too much work)
 	 */
-	movq	%rsp, %rsi
+	movq	%rsp, %rdi
 	incl	PER_CPU_VAR(irq_count)
 	cmovzq	PER_CPU_VAR(irq_stack_ptr), %rsp
-	pushq	%rsi
+	pushq	%rdi
 	/* We entered an interrupt context - irqs are off: */
 	TRACE_IRQS_OFF
 
-	call	\func
+	call	\func	/* rdi points to pt_regs */
 	.endm
 
 	/*

2.4.3

To prepare for the big rewrite of the error and interrupt exit paths, we will need pt_regs completely filled in. It's already completely filled in when error_exit runs, so rearrange interrupt handling to match it. This will slow down interrupt handling very slightly (eight instructions), but the simplification it enables will be more than worth it.

---
 arch/x86/entry/calling.h  |  3 ---
 arch/x86/entry/entry_64.S | 29 +++++++++--------------------
 2 files changed, 9 insertions(+), 23 deletions(-)

index f4e6308c4200..f5eda6ecbca3 100644
@@ -135,9 +135,6 @@ For 32-bit we have the following conventions - kernel is built with
 	movq %rbp, 4*8+\offset(%rsp)
 	movq %rbx, 5*8+\offset(%rsp)
 	.endm
-	.macro SAVE_EXTRA_REGS_RBP offset=0
-	movq %rbp, 4*8+\offset(%rsp)
-	.endm
 
 	.macro RESTORE_EXTRA_REGS offset=0
 	movq 0*8+\offset(%rsp), %r15

index 4ca5b782ed70..65029f48bcc4 100644
@@ -502,21 +502,13 @@ END(irq_entries_start)
 /* 0(%rsp): ~(interrupt number) */
 	.macro interrupt func
 	cld
-	/*
-	 * Since nothing in interrupt handling code touches r12...r15 members
-	 * of "struct pt_regs", and since interrupts can nest, we can save
-	 * four stack slots and simultaneously provide
-	 * an unwind-friendly stack layout by saving "truncated" pt_regs
-	 * exactly up to rbp slot, without these members.
-	 */
-	ALLOC_PT_GPREGS_ON_STACK -RBP
-	SAVE_C_REGS -RBP
-	/* this goes to 0(%rsp) for unwinder, not for saving the value: */
-	SAVE_EXTRA_REGS_RBP -RBP
+	ALLOC_PT_GPREGS_ON_STACK
+	SAVE_C_REGS
+	SAVE_EXTRA_REGS
 
-	leaq	-RBP(%rsp), %rdi		/* arg1 for \func (pointer to pt_regs) */
+	movq	%rsp,%rdi	/* arg1 for \func (pointer to pt_regs) */
 
-	testb	$3, CS-RBP(%rsp)
+	testb	$3, CS(%rsp)
 	jz	1f
 	SWAPGS
 1:

@@ -553,9 +545,7 @@ ret_from_intr:
 	decl	PER_CPU_VAR(irq_count)
 
 	/* Restore saved previous stack */
-	popq	%rsi
-	/* return code expects complete pt_regs - adjust rsp accordingly: */
-	leaq	-RBP(%rsi), %rsp
+	popq	%rsp
 
 	testb	$3, CS(%rsp)
 	jz	retint_kernel

@@ -580,7 +570,7 @@ retint_swapgs:					/* return to user-space */
 	TRACE_IRQS_IRETQ
 
 	SWAPGS
-	jmp	restore_c_regs_and_iret
+	jmp	restore_regs_and_iret
 
 /* Returning to kernel space */
 retint_kernel:

@@ -604,6 +594,8 @@ retint_kernel:
  * At this label, code paths which return to kernel and to user,
  * which come from interrupts/exception and from syscalls, merge.
  */
+restore_regs_and_iret:
+	RESTORE_EXTRA_REGS
 restore_c_regs_and_iret:
 	RESTORE_C_REGS
 	REMOVE_PT_GPREGS_FROM_STACK 8

@@ -674,12 +666,10 @@ retint_signal:
 	jz	retint_swapgs
 	TRACE_IRQS_ON
 	ENABLE_INTERRUPTS(CLBR_NONE)
-	SAVE_EXTRA_REGS
 	movq	$-1, ORIG_RAX(%rsp)
 	xorl	%esi, %esi			/* oldset */
 	movq	%rsp, %rdi			/* &pt_regs */
 	call	do_notify_resume
-	RESTORE_EXTRA_REGS
 	DISABLE_INTERRUPTS(CLBR_NONE)
 	TRACE_IRQS_OFF
 	GET_THREAD_INFO(%rcx)

@@ -1160,7 +1150,6 @@ END(error_entry)
  */
 ENTRY(error_exit)
 	movl	%ebx, %eax
-	RESTORE_EXTRA_REGS
 	DISABLE_INTERRUPTS(CLBR_NONE)
 	TRACE_IRQS_OFF
 	testl	%eax, %eax

2.4.3

These need to be migrated together, as the compat case used to jump into the middle of the 64-bit exit code.

---
 arch/x86/entry/entry_64.S        | 69 +++++-----------------------------------
 arch/x86/entry/entry_64_compat.S |  6 ++--
 2 files changed, 11 insertions(+), 64 deletions(-)

index ccfcba90de6e..4ca5b782ed70 100644
@@ -229,6 +229,11 @@ entry_SYSCALL_64_fastpath:
 	 */
 	USERGS_SYSRET64
 
+GLOBAL(int_ret_from_sys_call_irqs_off)
+	TRACE_IRQS_ON
+	ENABLE_INTERRUPTS(CLBR_NONE)
+	jmp int_ret_from_sys_call
+
 	/* Do syscall entry tracing */
 tracesys:
 	movq	%rsp, %rdi

@@ -272,69 +277,11 @@ tracesys_phase2:
  * Has correct iret frame.
  */
 GLOBAL(int_ret_from_sys_call)
-	DISABLE_INTERRUPTS(CLBR_NONE)
-int_ret_from_sys_call_irqs_off: /* jumps come here from the irqs-off SYSRET path */
-	TRACE_IRQS_OFF
-	movl	$_TIF_ALLWORK_MASK, %edi
-	/* edi:	mask to check */
-GLOBAL(int_with_check)
-	LOCKDEP_SYS_EXIT_IRQ
-	GET_THREAD_INFO(%rcx)
-	movl	TI_flags(%rcx), %edx
-	andl	%edi, %edx
-	jnz	int_careful
-	andl	$~TS_COMPAT, TI_status(%rcx)
-	jmp	syscall_return
-
-	/*
-	 * Either reschedule or signal or syscall exit tracking needed.
-	 * First do a reschedule test.
-	 * edx:	work, edi: workmask
-	 */
-int_careful:
-	bt	$TIF_NEED_RESCHED, %edx
-	jnc	int_very_careful
-	TRACE_IRQS_ON
-	ENABLE_INTERRUPTS(CLBR_NONE)
-	pushq	%rdi
-	SCHEDULE_USER
-	popq	%rdi
-	DISABLE_INTERRUPTS(CLBR_NONE)
-	TRACE_IRQS_OFF
-	jmp	int_with_check
-
-	/* handle signals and tracing -- both require a full pt_regs */
-int_very_careful:
-	TRACE_IRQS_ON
-	ENABLE_INTERRUPTS(CLBR_NONE)
 	SAVE_EXTRA_REGS
-	/* Check for syscall exit trace */
-	testl	$_TIF_WORK_SYSCALL_EXIT, %edx
-	jz	int_signal
-	pushq	%rdi
-	leaq	8(%rsp), %rdi			/* &ptregs -> arg1 */
-	call	syscall_trace_leave
-	popq	%rdi
-	andl	$~(_TIF_WORK_SYSCALL_EXIT|_TIF_SYSCALL_EMU), %edi
-	jmp	int_restore_rest
-
-int_signal:
-	testl	$_TIF_DO_NOTIFY_MASK, %edx
-	jz	1f
-	movq	%rsp, %rdi			/* &ptregs -> arg1 */
-	xorl	%esi, %esi			/* oldset -> arg2 */
-	call	do_notify_resume
-1:	movl	$_TIF_WORK_MASK, %edi
-int_restore_rest:
+	movq	%rsp, %rdi
+	call	syscall_return_slowpath	/* returns with IRQs disabled */
 	RESTORE_EXTRA_REGS
-	DISABLE_INTERRUPTS(CLBR_NONE)
-	TRACE_IRQS_OFF
-	jmp	int_with_check
-
-syscall_return:
-	/* The IRETQ could re-enable interrupts: */
-	DISABLE_INTERRUPTS(CLBR_ANY)
-	TRACE_IRQS_IRETQ
+	TRACE_IRQS_IRETQ		/* we're about to change IF */
 
 	/*
 	 * Try to use SYSRET instead of IRET if we're returning to

index efe0b1e499fa..204528cf4359 100644
@@ -209,10 +209,10 @@ sysexit_from_sys_call:
 	.endm
 
 	.macro auditsys_exit exit
-	testl	$(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
-	jnz	ia32_ret_from_sys_call
 	TRACE_IRQS_ON
 	ENABLE_INTERRUPTS(CLBR_NONE)
+	testl	$(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
+	jnz	ia32_ret_from_sys_call
 	movl	%eax, %esi		/* second arg, syscall return value */
 	cmpl	$-MAX_ERRNO, %eax	/* is it an error ? */
 	jbe	1f

@@ -231,7 +231,7 @@ sysexit_from_sys_call:
 	movq	%rax, R10(%rsp)
 	movq	%rax, R9(%rsp)
 	movq	%rax, R8(%rsp)
-	jmp	int_with_check
+	jmp	int_ret_from_sys_call_irqs_off
 	.endm
 
 sysenter_auditsys:

2.4.3

In 539f51136500 ("x86/asm/entry/64: Disentangle error_entry/exit gsbase/ebx/usermode code"), I arranged the code slightly wrong -- IRET faults would skip the code path that was intended to execute on all error entries from user mode. Fix it up.

While we're at it, make all the labels in error_entry local.

This does not fix a bug, but we'll need it, and it slightly shrinks the code.

---
 arch/x86/entry/entry_64.S | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

index 141a5d49dddc..ccfcba90de6e 100644
@@ -1143,12 +1143,17 @@ ENTRY(error_entry)
 	SAVE_EXTRA_REGS 8
 	xorl	%ebx, %ebx
 	testb	$3, CS+8(%rsp)
-	jz	error_kernelspace
+	jz	.Lerror_kernelspace
 
-	/* We entered from user mode */
+.Lerror_entry_from_usermode_swapgs:
+	/*
+	 * We entered from user mode or we're pretending to have entered
+	 * from user mode due to an IRET fault.
+	 */
 	SWAPGS
 
-error_entry_done:
+.Lerror_entry_from_usermode_after_swapgs:
+.Lerror_entry_done:
 	TRACE_IRQS_OFF
 	ret
 

@@ -1158,31 +1163,30 @@ error_entry_done:
 	 * truncated RIP for IRET exceptions returning to compat mode. Check
 	 * for these here too.
 	 */
-error_kernelspace:
+.Lerror_kernelspace:
 	incl	%ebx
 	leaq	native_irq_return_iret(%rip), %rcx
 	cmpq	%rcx, RIP+8(%rsp)
-	je	error_bad_iret
+	je	.Lerror_bad_iret
 	movl	%ecx, %eax			/* zero extend */
 	cmpq	%rax, RIP+8(%rsp)
-	je	bstep_iret
+	je	.Lbstep_iret
 	cmpq	$gs_change, RIP+8(%rsp)
-	jne	error_entry_done
+	jne	.Lerror_entry_done
 
 	/*
 	 * hack: gs_change can fail with user gsbase.  If this happens, fix up
 	 * gsbase and proceed.  We'll fix up the exception and land in
 	 * gs_change's error handler with kernel gsbase.
 	 */
-	SWAPGS
-	jmp	error_entry_done
+	jmp	.Lerror_entry_from_usermode_swapgs
 
-bstep_iret:
+.Lbstep_iret:
 	/* Fix truncated RIP */
 	movq	%rcx, RIP+8(%rsp)
 	/* fall through */
 
-error_bad_iret:
+.Lerror_bad_iret:
 	/*
 	 * We came from an IRET to user mode, so we have user gsbase.
 	 * Switch to kernel gsbase:

@@ -1198,7 +1202,7 @@ error_bad_iret:
 	call	fixup_bad_iret
 	mov	%rax, %rsp
 	decl	%ebx
-	jmp	error_entry_done
+	jmp	.Lerror_entry_from_usermode_after_swapgs
 END(error_entry)
 
 

2.4.3

The current entry and exit code is incomprehensible, appears to work primary by luck, and is very difficult to incrementally improve. Add new code in preparation for simply deleting the old code.

prepare_exit_to_usermode is a new function that will handle all slow path exits to user mode. It is called with IRQs disabled and it leaves us in a state in which it is safe to immediately return to user mode. IRQs must not be re-enabled at any point after prepare_exit_to_usermode returns and user mode is actually entered. (We can, of course, fail to enter user mode and treat that failure as a fresh entry to kernel mode.) All callers of do_notify_resume will be migrated to call prepare_exit_to_usermode instead; prepare_exit_to_usermode needs to do everything that do_notify_resume does, but it also takes care of scheduling and context tracking. Unlike do_notify_resume, it does not need to be called in a loop.

syscall_return_slowpath is exactly what it sounds like. It will be called on any syscall exit slow path. It will replaces syscall_trace_leave and it calls prepare_exit_to_usermode on the way out.

---
 arch/x86/entry/common.c | 112 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 111 insertions(+), 1 deletion(-)

index 9a327ee24eef..febc53086a69 100644
@@ -207,6 +207,7 @@ long syscall_trace_enter(struct pt_regs *regs)
 		return syscall_trace_enter_phase2(regs, arch, phase1_result);
 }
 
+/* Deprecated. */
 void syscall_trace_leave(struct pt_regs *regs)
 {
 	bool step;

@@ -237,8 +238,117 @@ void syscall_trace_leave(struct pt_regs *regs)
 	user_enter();
 }
 
+static struct thread_info *pt_regs_to_thread_info(struct pt_regs *regs)
+{
+	unsigned long top_of_stack =
+		(unsigned long)(regs + 1) + TOP_OF_KERNEL_STACK_PADDING;
+	return (struct thread_info *)(top_of_stack - THREAD_SIZE);
+}
+
+/* Called with IRQs disabled. */
+__visible void prepare_exit_to_usermode(struct pt_regs *regs)
+{
+	if (WARN_ON(!irqs_disabled()))
+		local_irq_disable();
+
+	/*
+	 * In order to return to user mode, we need to have IRQs off with
+	 * none of _TIF_SIGPENDING, _TIF_NOTIFY_RESUME, _TIF_USER_RETURN_NOTIFY,
+	 * _TIF_UPROBE, or _TIF_NEED_RESCHED set.  Several of these flags
+	 * can be set at any time on preemptable kernels if we have IRQs on,
+	 * so we need to loop.  Disabling preemption wouldn't help: doing the
+	 * work to clear some of the flags can sleep.
+	 */
+	while (true) {
+		u32 cached_flags =
+			READ_ONCE(pt_regs_to_thread_info(regs)->flags);
+
+		if (!(cached_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME |
+				      _TIF_UPROBE | _TIF_NEED_RESCHED)))
+			break;
+
+		/* We have work to do. */
+		local_irq_enable();
+
+		if (cached_flags & _TIF_NEED_RESCHED)
+			schedule();
+
+		if (cached_flags & _TIF_UPROBE)
+			uprobe_notify_resume(regs);
+
+		/* deal with pending signal delivery */
+		if (cached_flags & _TIF_SIGPENDING)
+			do_signal(regs);
+
+		if (cached_flags & _TIF_NOTIFY_RESUME) {
+			clear_thread_flag(TIF_NOTIFY_RESUME);
+			tracehook_notify_resume(regs);
+		}
+
+		if (cached_flags & _TIF_USER_RETURN_NOTIFY)
+			fire_user_return_notifiers();
+
+		/* Disable IRQs and retry */
+		local_irq_disable();
+	}
+
+	user_enter();
+}
+
+/*
+ * Called with IRQs on and fully valid regs.  Returns with IRQs off in a
+ * state such that we can immediately switch to user mode.
+ */
+__visible void syscall_return_slowpath(struct pt_regs *regs)
+{
+	struct thread_info *ti = pt_regs_to_thread_info(regs);
+	u32 cached_flags = READ_ONCE(ti->flags);
+	bool step;
+
+	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
+
+	if (WARN(irqs_disabled(), "syscall %ld left IRQs disabled",
+		 regs->orig_ax))
+		local_irq_enable();
+
+	/*
+	 * First do one-time work.  If these work items are enabled, we
+	 * want to run them exactly once per syscall exit with IRQs on.
+	 */
+	if (cached_flags & (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT |
+			    _TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT)) {
+		audit_syscall_exit(regs);
+
+		if (cached_flags & _TIF_SYSCALL_TRACEPOINT)
+			trace_sys_exit(regs, regs->ax);
+
+		/*
+		 * If TIF_SYSCALL_EMU is set, we only get here because of
+		 * TIF_SINGLESTEP (i.e. this is PTRACE_SYSEMU_SINGLESTEP).
+		 * We already reported this syscall instruction in
+		 * syscall_trace_enter().
+		 */
+		step = unlikely(
+			(cached_flags & (_TIF_SINGLESTEP | _TIF_SYSCALL_EMU))
+			== _TIF_SINGLESTEP);
+		if (step || cached_flags & _TIF_SYSCALL_TRACE)
+			tracehook_report_syscall_exit(regs, step);
+	}
+
+#ifdef CONFIG_COMPAT
+	/*
+	 * Compat syscalls set TS_COMPAT.  Make sure we clear it before
+	 * returning to user mode.
+	 */
+	ti->status &= ~TS_COMPAT;
+#endif
+
+	local_irq_disable();
+	prepare_exit_to_usermode(regs);
+}
+
 /*
- * notification of userspace execution resumption
+ * Deprecated notification of userspace execution resumption
  * - triggered by the TIF_WORK_MASK flags
  */
 __visible void

2.4.3

Changing the x86 context tracking hooks is dangerous because there are no good checks that we track our context correctly. Add a helper to check that we're actually in CONTEXT_USER when we enter from user mode and wire it up for syscall entries.

Subsequent patches will wire this up for all non-NMI entries as well. NMIs are their own special beast and cannot currently switch overall context tracking state. Instead, they have their own special RCU hooks.

This is a tiny speedup if !CONFIG_CONTEXT_TRACKING (removes a branch) and a tiny slowdown if CONFIG_CONTEXT_TRACING (adds a layer of indirection). Eventually, we should fix up the core context tracking code to supply a function that does what we want (and can be much simpler than user_exit), which will enable us to get rid of the extra call.

---
 arch/x86/entry/common.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

index 917d0c3cb851..9a327ee24eef 100644
@@ -28,6 +28,15 @@
 #define CREATE_TRACE_POINTS
 #include <trace/events/syscalls.h>
 
+#ifdef CONFIG_CONTEXT_TRACKING
+/* Called on entry from user mode with IRQs off. */
+__visible void enter_from_user_mode(void)
+{
+	CT_WARN_ON(ct_state() != CONTEXT_USER);
+	user_exit();
+}
+#endif
+
 static void do_audit_syscall_entry(struct pt_regs *regs, u32 arch)
 {
 #ifdef CONFIG_X86_64

@@ -65,14 +74,16 @@ unsigned long syscall_trace_enter_phase1(struct pt_regs *regs, u32 arch)
 	work = ACCESS_ONCE(current_thread_info()->flags) &
 		_TIF_WORK_SYSCALL_ENTRY;
 
+#ifdef CONFIG_CONTEXT_TRACKING
 	/*
 	 * If TIF_NOHZ is set, we are required to call user_exit() before
 	 * doing anything that could touch RCU.
 	 */
 	if (work & _TIF_NOHZ) {
-		user_exit();
+		enter_from_user_mode();
 		work &= ~_TIF_NOHZ;
 	}
+#endif
 
 #ifdef CONFIG_SECCOMP
 	/*

2.4.3

Other than the super-atomic exception entries, all exception entries are supposed to switch our context tracking state to CONTEXT_KERNEL. Assert that they do. These assertions appear trivial at this point, as exception_enter is the function responsible for switching context, but I'm planning on reworking x86's exception context tracking, and these assertions will help make sure that all of this code keeps working.

---
 arch/x86/kernel/traps.c | 9 +++++++++
 1 file changed, 9 insertions(+)

index f5791927aa64..2a783c4fe0e9 100644
@@ -292,6 +292,8 @@ static void do_error_trap(struct pt_regs *regs, long error_code, char *str,
 	enum ctx_state prev_state = exception_enter();
 	siginfo_t info;
 
+	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
+
 	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) !=
 			NOTIFY_STOP) {
 		conditional_sti(regs);

@@ -376,6 +378,7 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
 	siginfo_t *info;
 
 	prev_state = exception_enter();
+	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
 	if (notify_die(DIE_TRAP, "bounds", regs, error_code,
 			X86_TRAP_BR, SIGSEGV) == NOTIFY_STOP)
 		goto exit;

@@ -457,6 +460,7 @@ do_general_protection(struct pt_regs *regs, long error_code)
 	enum ctx_state prev_state;
 
 	prev_state = exception_enter();
+	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
 	conditional_sti(regs);
 
 	if (v8086_mode(regs)) {

@@ -514,6 +518,7 @@ dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code)
 		return;
 
 	prev_state = ist_enter(regs);
+	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
 	if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
 				SIGTRAP) == NOTIFY_STOP)

@@ -750,6 +755,7 @@ dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
 	enum ctx_state prev_state;
 
 	prev_state = exception_enter();
+	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
 	math_error(regs, error_code, X86_TRAP_MF);
 	exception_exit(prev_state);
 }

@@ -760,6 +766,7 @@ do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
 	enum ctx_state prev_state;
 
 	prev_state = exception_enter();
+	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
 	math_error(regs, error_code, X86_TRAP_XF);
 	exception_exit(prev_state);
 }

@@ -776,6 +783,7 @@ do_device_not_available(struct pt_regs *regs, long error_code)
 	enum ctx_state prev_state;
 
 	prev_state = exception_enter();
+	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
 	BUG_ON(use_eager_fpu());
 
 #ifdef CONFIG_MATH_EMULATION

@@ -805,6 +813,7 @@ dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
 	enum ctx_state prev_state;
 
 	prev_state = exception_enter();
+	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
 	local_irq_enable();
 
 	info.si_signo = SIGILL;

2.4.3

The entry and exit C helpers were confusingly scattered between ptrace.c and signal.c, even though they aren't specific to ptrace or signal handling. Move them together in a new file.

This change just moves code around. It doesn't change anything.

---
 arch/x86/entry/Makefile       |   1 +
 arch/x86/entry/common.c       | 253 ++++++++++++++++++++++++++++++++++++++++++
 arch/x86/include/asm/signal.h |   1 +
 arch/x86/kernel/ptrace.c      | 202 +--------------------------------
 arch/x86/kernel/signal.c      |  28 +----
 5 files changed, 257 insertions(+), 228 deletions(-)
 create mode 100644 arch/x86/entry/common.c

index 7a144971db79..bd55dedd7614 100644
@@ -2,6 +2,7 @@
 # Makefile for the x86 low level entry code
 #
 obj-y				:= entry_$(BITS).o thunk_$(BITS).o syscall_$(BITS).o
+obj-y				+= common.o
 
 obj-y				+= vdso/
 obj-y				+= vsyscall/

index 31eab867e6d3..b42408bcf6b5 100644
@@ -30,6 +30,7 @@ typedef sigset_t compat_sigset_t;
 #endif /* __ASSEMBLY__ */
 #include <uapi/asm/signal.h>
 #ifndef __ASSEMBLY__
+extern void do_signal(struct pt_regs *regs);
 extern void do_notify_resume(struct pt_regs *, void *, __u32);
 
 #define __ARCH_HAS_SA_RESTORER

index 206996c1669d..197c44e8ff8b 100644
@@ -701,7 +701,7 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs)
  * want to handle. Thus you cannot kill init even with a SIGKILL even by
  * mistake.
  */
-static void do_signal(struct pt_regs *regs)
+void do_signal(struct pt_regs *regs)
 {
 	struct ksignal ksig;
 

@@ -736,32 +736,6 @@ static void do_signal(struct pt_regs *regs)
 	restore_saved_sigmask();
 }
 
-/*
- * notification of userspace execution resumption
- * - triggered by the TIF_WORK_MASK flags
- */
-__visible void
-do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
-{
-	user_exit();
-
-	if (thread_info_flags & _TIF_UPROBE)
-		uprobe_notify_resume(regs);
-
-	/* deal with pending signal delivery */
-	if (thread_info_flags & _TIF_SIGPENDING)
-		do_signal(regs);
-
-	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
-		clear_thread_flag(TIF_NOTIFY_RESUME);
-		tracehook_notify_resume(regs);
-	}
-	if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
-		fire_user_return_notifiers();
-
-	user_enter();
-}
-
 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
 {
 	struct task_struct *me = current;

2.4.3

Low-level arch entries often call notify_die, and it's easy for arch code to fail to exit an RCU quiescent state first. Assert that we're not quiescent in notify_die.

---
 kernel/notifier.c | 2 ++
 1 file changed, 2 insertions(+)

index ae9fc7cc360e..980e4330fb59 100644
@@ -544,6 +544,8 @@ int notrace notify_die(enum die_val val, const char *str,
 		.signr	= sig,
 
 	};
+	rcu_lockdep_assert(rcu_is_watching(),
+			   "notify_die called but RCU thinks we're quiescent");
 	return atomic_notifier_call_chain(&die_chain, val, &args);
 }
 NOKPROBE_SYMBOL(notify_die);

2.4.3

So this looks mostly problem free on my boxen, except this warning triggers:

Adding 3911820k swap on /dev/sda2. Priority:-1 extents:1 across:3911820k
capability: warning: `dbus-daemon' uses 32-bit capabilities (legacy support in use)

------------[ cut here ]------------
WARNING: CPU: 1 PID: 2445 at arch/x86/entry/common.c:311 syscall_return_slowpath+0x4c/0x270()
syscall 6 left IRQs disabled
Modules linked in:
CPU: 1 PID: 2445 Comm: distccd Not tainted 4.2.0-rc1-01597-gaecd781-dirty #18
 0000000000000000 00000000776afac2 ffff880035413e58 ffffffff81c8915f
 0000000000000000 ffff880035413eb0 ffff880035413e98 ffffffff810a8d82
 ffff880035413e78 ffff880035413f58 0000000020020002 ffff880035410000
Call Trace:
 [<ffffffff81c8915f>] dump_stack+0x4f/0x7b
 [<ffffffff810a8d82>] warn_slowpath_common+0xa2/0xc0
 [<ffffffff810a8df5>] warn_slowpath_fmt+0x55/0x70
 [<ffffffff81001ddc>] syscall_return_slowpath+0x4c/0x270
 [<ffffffff81c96471>] int_ret_from_sys_call+0x25/0x9f
---[ end trace 083efc734e089d37 ]---

device: 'vcs2': device_add
PM: Adding info for No Bus:vcs2
device: 'vcsa2': device_add

with ancient user-space, running the attached .config.

The system booted up fine otherwise. The warning corresponds to:

        if (WARN(irqs_disabled(), "syscall %ld left IRQs disabled",
                 regs->orig_ax))
                local_irq_enable();

and this was just the regular startup of the distccd daemon during bootup, nothing particularly fancy.

Note that 'distccd' is a 32-bit ELF binary - and this is a 64-bit kernel.

Syscall 6 would be:

arch/x86/entry/syscalls/syscall_32.tbl:6 i386 close sys_close

Thanks,

Ingo

#
# Automatically generated file; DO NOT EDIT.
# Linux/x86_64 4.2.0-rc1 Kernel Configuration
#
CONFIG_64BIT=y
CONFIG_X86_64=y
CONFIG_X86=y
CONFIG_INSTRUCTION_DECODER=y
CONFIG_OUTPUT_FORMAT="elf64-x86-64"
CONFIG_ARCH_DEFCONFIG="arch/x86/configs/x86_64_defconfig"
CONFIG_LOCKDEP_SUPPORT=y
CONFIG_STACKTRACE_SUPPORT=y
CONFIG_HAVE_LATENCYTOP_SUPPORT=y
CONFIG_MMU=y
CONFIG_NEED_DMA_MAP_STATE=y
CONFIG_NEED_SG_DMA_LENGTH=y
CONFIG_GENERIC_ISA_DMA=y
CONFIG_GENERIC_BUG=y
CONFIG_GENERIC_BUG_RELATIVE_POINTERS=y
CONFIG_GENERIC_HWEIGHT=y
CONFIG_ARCH_MAY_HAVE_PC_FDC=y
CONFIG_RWSEM_XCHGADD_ALGORITHM=y
CONFIG_GENERIC_CALIBRATE_DELAY=y
CONFIG_ARCH_HAS_CPU_RELAX=y
CONFIG_ARCH_HAS_CACHE_LINE_SIZE=y
CONFIG_HAVE_SETUP_PER_CPU_AREA=y
CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK=y
CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK=y
CONFIG_ARCH_HIBERNATION_POSSIBLE=y
CONFIG_ARCH_SUSPEND_POSSIBLE=y
CONFIG_ARCH_WANT_HUGE_PMD_SHARE=y
CONFIG_ARCH_WANT_GENERAL_HUGETLB=y
CONFIG_ZONE_DMA32=y
CONFIG_AUDIT_ARCH=y
CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING=y
CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC=y
CONFIG_X86_64_SMP=y
CONFIG_ARCH_HWEIGHT_CFLAGS="-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" CONFIG_BOOTPARAM_SUPPORT_NOT_WANTED=y
CONFIG_ARCH_SUPPORTS_UPROBES=y
CONFIG_FIX_EARLYCON_MEM=y
CONFIG_PGTABLE_LEVELS=4
CONFIG_DEFCONFIG_LIST="/lib/modules/$UNAME_RELEASE/.config"
CONFIG_IRQ_WORK=y
CONFIG_BUILDTIME_EXTABLE_SORT=y

#
# General setup
#
CONFIG_BROKEN_BOOT_ALLOWED4=y
# CONFIG_BROKEN_BOOT_ALLOWED3 is not set
# CONFIG_BROKEN_BOOT_DISALLOWED is not set
CONFIG_BROKEN_BOOT_EUROPE=y
CONFIG_BROKEN_BOOT_TITAN=y
CONFIG_INIT_ENV_ARG_LIMIT=32
CONFIG_CROSS_COMPILE=""
CONFIG_COMPILE_TEST=y
CONFIG_LOCALVERSION=""
CONFIG_LOCALVERSION_AUTO=y
CONFIG_HAVE_KERNEL_GZIP=y
CONFIG_HAVE_KERNEL_BZIP2=y
CONFIG_HAVE_KERNEL_LZMA=y
CONFIG_HAVE_KERNEL_XZ=y
CONFIG_HAVE_KERNEL_LZO=y
CONFIG_HAVE_KERNEL_LZ4=y
# CONFIG_KERNEL_GZIP is not set
CONFIG_KERNEL_BZIP2=y
# CONFIG_KERNEL_LZMA is not set
# CONFIG_KERNEL_XZ is not set
# CONFIG_KERNEL_LZO is not set
# CONFIG_KERNEL_LZ4 is not set
CONFIG_DEFAULT_HOSTNAME="(none)"
CONFIG_SWAP=y
CONFIG_SYSVIPC=y
# CONFIG_POSIX_MQUEUE is not set
# CONFIG_CROSS_MEMORY_ATTACH is not set
# CONFIG_FHANDLE is not set
# CONFIG_USELIB is not set
# CONFIG_AUDIT is not set
CONFIG_HAVE_ARCH_AUDITSYSCALL=y

#
# IRQ subsystem
#
CONFIG_GENERIC_IRQ_PROBE=y
CONFIG_GENERIC_IRQ_SHOW=y
CONFIG_GENERIC_PENDING_IRQ=y
CONFIG_GENERIC_IRQ_CHIP=y
CONFIG_IRQ_DOMAIN=y
CONFIG_IRQ_DOMAIN_HIERARCHY=y
CONFIG_IRQ_DOMAIN_DEBUG=y
CONFIG_IRQ_FORCED_THREADING=y
CONFIG_SPARSE_IRQ=y
CONFIG_CLOCKSOURCE_WATCHDOG=y
CONFIG_ARCH_CLOCKSOURCE_DATA=y
CONFIG_CLOCKSOURCE_VALIDATE_LAST_CYCLE=y
CONFIG_GENERIC_TIME_VSYSCALL=y
CONFIG_GENERIC_CLOCKEVENTS=y
CONFIG_GENERIC_CLOCKEVENTS_BROADCAST=y
CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST=y
CONFIG_GENERIC_CMOS_UPDATE=y

#
# Timers subsystem
#
CONFIG_TICK_ONESHOT=y
CONFIG_NO_HZ_COMMON=y
# CONFIG_HZ_PERIODIC is not set
CONFIG_NO_HZ_IDLE=y
# CONFIG_NO_HZ_FULL is not set
CONFIG_NO_HZ=y
CONFIG_HIGH_RES_TIMERS=y

#
# CPU/Task time and stats accounting
#
# CONFIG_TICK_CPU_ACCOUNTING is not set
# CONFIG_VIRT_CPU_ACCOUNTING_GEN is not set
CONFIG_IRQ_TIME_ACCOUNTING=y
CONFIG_BSD_PROCESS_ACCT=y
CONFIG_BSD_PROCESS_ACCT_V3=y
CONFIG_TASKSTATS=y
CONFIG_TASK_DELAY_ACCT=y
CONFIG_TASK_XACCT=y
CONFIG_TASK_IO_ACCOUNTING=y

#
# RCU Subsystem
#
CONFIG_PREEMPT_RCU=y
CONFIG_RCU_EXPERT=y
CONFIG_SRCU=y
# CONFIG_TASKS_RCU is not set
CONFIG_RCU_STALL_COMMON=y
CONFIG_RCU_FANOUT=64
CONFIG_RCU_FANOUT_LEAF=16
# CONFIG_RCU_FAST_NO_HZ is not set
CONFIG_TREE_RCU_TRACE=y
CONFIG_RCU_BOOST=y
CONFIG_RCU_KTHREAD_PRIO=1
CONFIG_RCU_BOOST_DELAY=500
# CONFIG_RCU_NOCB_CPU is not set
# CONFIG_RCU_EXPEDITE_BOOT is not set
CONFIG_BUILD_BIN2C=y
CONFIG_IKCONFIG=y
CONFIG_IKCONFIG_PROC=y
CONFIG_LOG_BUF_SHIFT=20
CONFIG_LOG_CPU_MAX_BUF_SHIFT=12
CONFIG_HAVE_UNSTABLE_SCHED_CLOCK=y
CONFIG_ARCH_SUPPORTS_NUMA_BALANCING=y
CONFIG_ARCH_SUPPORTS_INT128=y
CONFIG_CGROUPS=y
CONFIG_CGROUP_DEBUG=y
CONFIG_CGROUP_FREEZER=y
CONFIG_CGROUP_DEVICE=y
CONFIG_CPUSETS=y
CONFIG_PROC_PID_CPUSET=y
# CONFIG_CGROUP_CPUACCT is not set
CONFIG_PAGE_COUNTER=y
CONFIG_MEMCG=y
CONFIG_MEMCG_SWAP=y
# CONFIG_MEMCG_SWAP_ENABLED is not set
CONFIG_MEMCG_KMEM=y
# CONFIG_CGROUP_PERF is not set
CONFIG_CGROUP_SCHED=y
# CONFIG_FAIR_GROUP_SCHED is not set
# CONFIG_RT_GROUP_SCHED is not set
# CONFIG_BLK_CGROUP is not set
CONFIG_CHECKPOINT_RESTORE=y
# CONFIG_NAMESPACES is not set
# CONFIG_SCHED_AUTOGROUP is not set
CONFIG_SYSFS_DEPRECATED=y
CONFIG_SYSFS_DEPRECATED_V2=y
CONFIG_RELAY=y
CONFIG_BLK_DEV_INITRD=y
CONFIG_INITRAMFS_SOURCE=""
CONFIG_RD_GZIP=y
CONFIG_RD_BZIP2=y
# CONFIG_RD_LZMA is not set
# CONFIG_RD_XZ is not set
# CONFIG_RD_LZO is not set
CONFIG_RD_LZ4=y
# CONFIG_CC_OPTIMIZE_FOR_SIZE is not set
CONFIG_ANON_INODES=y
CONFIG_HAVE_UID16=y
CONFIG_SYSCTL_EXCEPTION_TRACE=y
CONFIG_HAVE_PCSPKR_PLATFORM=y
CONFIG_BPF=y
CONFIG_EXPERT=y
# CONFIG_UID16 is not set
CONFIG_MULTIUSER=y
# CONFIG_SGETMASK_SYSCALL is not set
# CONFIG_SYSFS_SYSCALL is not set
CONFIG_KALLSYMS=y
CONFIG_KALLSYMS_ALL=y
CONFIG_PRINTK=y
CONFIG_BUG=y
# CONFIG_ELF_CORE is not set
CONFIG_PCSPKR_PLATFORM=y
CONFIG_BASE_FULL=y
CONFIG_FUTEX=y
# CONFIG_EPOLL is not set
# CONFIG_SIGNALFD is not set
# CONFIG_TIMERFD is not set
CONFIG_EVENTFD=y
CONFIG_BPF_SYSCALL=y
# CONFIG_SHMEM is not set
CONFIG_AIO=y
CONFIG_ADVISE_SYSCALLS=y
# CONFIG_PCI_QUIRKS is not set
CONFIG_EMBEDDED=y
CONFIG_HAVE_PERF_EVENTS=y

#
# Kernel Performance Events And Counters
#
CONFIG_PERF_EVENTS=y
# CONFIG_DEBUG_PERF_USE_VMALLOC is not set
CONFIG_VM_EVENT_COUNTERS=y
# CONFIG_COMPAT_BRK is not set
CONFIG_SLAB=y
# CONFIG_SLUB is not set
# CONFIG_SLOB is not set
CONFIG_SYSTEM_TRUSTED_KEYRING=y
# CONFIG_PROFILING is not set
CONFIG_TRACEPOINTS=y
CONFIG_HAVE_OPROFILE=y
CONFIG_OPROFILE_NMI_TIMER=y
# CONFIG_KPROBES is not set
CONFIG_JUMP_LABEL=y
CONFIG_UPROBES=y
# CONFIG_HAVE_64BIT_ALIGNED_ACCESS is not set
CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS=y
CONFIG_ARCH_USE_BUILTIN_BSWAP=y
CONFIG_USER_RETURN_NOTIFIER=y
CONFIG_HAVE_IOREMAP_PROT=y
CONFIG_HAVE_KPROBES=y
CONFIG_HAVE_KRETPROBES=y
CONFIG_HAVE_OPTPROBES=y
CONFIG_HAVE_KPROBES_ON_FTRACE=y
CONFIG_HAVE_ARCH_TRACEHOOK=y
CONFIG_HAVE_DMA_ATTRS=y
CONFIG_HAVE_DMA_CONTIGUOUS=y
CONFIG_GENERIC_SMP_IDLE_THREAD=y
CONFIG_HAVE_REGS_AND_STACK_ACCESS_API=y
CONFIG_HAVE_DMA_API_DEBUG=y
CONFIG_HAVE_HW_BREAKPOINT=y
CONFIG_HAVE_MIXED_BREAKPOINTS_REGS=y
CONFIG_HAVE_USER_RETURN_NOTIFIER=y
CONFIG_HAVE_PERF_EVENTS_NMI=y
CONFIG_HAVE_PERF_REGS=y
CONFIG_HAVE_PERF_USER_STACK_DUMP=y
CONFIG_HAVE_ARCH_JUMP_LABEL=y
CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG=y
CONFIG_HAVE_CMPXCHG_LOCAL=y
CONFIG_HAVE_CMPXCHG_DOUBLE=y
CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION=y
CONFIG_ARCH_WANT_OLD_COMPAT_IPC=y
CONFIG_HAVE_ARCH_SECCOMP_FILTER=y
CONFIG_SECCOMP_FILTER=y
CONFIG_HAVE_CC_STACKPROTECTOR=y
CONFIG_CC_STACKPROTECTOR=y
# CONFIG_CC_STACKPROTECTOR_NONE is not set
# CONFIG_CC_STACKPROTECTOR_REGULAR is not set
CONFIG_CC_STACKPROTECTOR_STRONG=y
CONFIG_HAVE_CONTEXT_TRACKING=y
CONFIG_HAVE_VIRT_CPU_ACCOUNTING_GEN=y
CONFIG_HAVE_IRQ_TIME_ACCOUNTING=y
CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE=y
CONFIG_HAVE_ARCH_HUGE_VMAP=y
CONFIG_HAVE_ARCH_SOFT_DIRTY=y
CONFIG_MODULES_USE_ELF_RELA=y
CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK=y
CONFIG_ARCH_HAS_PGD_INIT_LATE=y
CONFIG_ARCH_HAS_ELF_RANDOMIZE=y
CONFIG_HAVE_COPY_THREAD_TLS=y
CONFIG_OLD_SIGSUSPEND3=y
CONFIG_COMPAT_OLD_SIGACTION=y

#
# GCOV-based kernel profiling
#
CONFIG_ARCH_HAS_GCOV_PROFILE_ALL=y
# CONFIG_HAVE_GENERIC_DMA_COHERENT is not set
CONFIG_SLABINFO=y
CONFIG_RT_MUTEXES=y
CONFIG_BASE_SMALL=0
CONFIG_MODULES=y
# CONFIG_MODULE_FORCE_LOAD is not set
# CONFIG_MODULE_UNLOAD is not set
CONFIG_MODVERSIONS=y
# CONFIG_MODULE_SRCVERSION_ALL is not set
CONFIG_MODULE_SIG=y
# CONFIG_MODULE_SIG_FORCE is not set
CONFIG_MODULE_SIG_ALL=y
# CONFIG_MODULE_SIG_SHA1 is not set
CONFIG_MODULE_SIG_SHA224=y
# CONFIG_MODULE_SIG_SHA256 is not set
# CONFIG_MODULE_SIG_SHA384 is not set
# CONFIG_MODULE_SIG_SHA512 is not set
CONFIG_MODULE_SIG_HASH="sha224"
CONFIG_MODULE_COMPRESS=y
CONFIG_MODULE_COMPRESS_GZIP=y
# CONFIG_MODULE_COMPRESS_XZ is not set
CONFIG_MODULES_TREE_LOOKUP=y
CONFIG_STOP_MACHINE=y
CONFIG_BLOCK=y
CONFIG_BLK_DEV_BSG=y
CONFIG_BLK_DEV_BSGLIB=y
CONFIG_BLK_DEV_INTEGRITY=y
CONFIG_BLK_CMDLINE_PARSER=y

#
# Partition Types
#
CONFIG_PARTITION_ADVANCED=y
CONFIG_ACORN_PARTITION=y
CONFIG_ACORN_PARTITION_CUMANA=y
CONFIG_ACORN_PARTITION_EESOX=y
CONFIG_ACORN_PARTITION_ICS=y
CONFIG_ACORN_PARTITION_ADFS=y
CONFIG_ACORN_PARTITION_POWERTEC=y
CONFIG_ACORN_PARTITION_RISCIX=y
# CONFIG_AIX_PARTITION is not set
CONFIG_OSF_PARTITION=y
# CONFIG_AMIGA_PARTITION is not set
# CONFIG_ATARI_PARTITION is not set
# CONFIG_MAC_PARTITION is not set
CONFIG_MSDOS_PARTITION=y
CONFIG_BSD_DISKLABEL=y
# CONFIG_MINIX_SUBPARTITION is not set
CONFIG_SOLARIS_X86_PARTITION=y
# CONFIG_UNIXWARE_DISKLABEL is not set
# CONFIG_LDM_PARTITION is not set
CONFIG_SGI_PARTITION=y
CONFIG_ULTRIX_PARTITION=y
# CONFIG_SUN_PARTITION is not set
# CONFIG_KARMA_PARTITION is not set
CONFIG_EFI_PARTITION=y
CONFIG_SYSV68_PARTITION=y
CONFIG_CMDLINE_PARTITION=y
CONFIG_BLOCK_COMPAT=y

#
# IO Schedulers
#
CONFIG_IOSCHED_NOOP=y
CONFIG_IOSCHED_DEADLINE=m
CONFIG_IOSCHED_CFQ=m
CONFIG_DEFAULT_NOOP=y
CONFIG_DEFAULT_IOSCHED="noop"
CONFIG_PREEMPT_NOTIFIERS=y
CONFIG_PADATA=y
CONFIG_ASN1=y
CONFIG_UNINLINE_SPIN_UNLOCK=y
CONFIG_ARCH_SUPPORTS_ATOMIC_RMW=y
CONFIG_RWSEM_SPIN_ON_OWNER=y
CONFIG_LOCK_SPIN_ON_OWNER=y
CONFIG_ARCH_USE_QUEUED_SPINLOCKS=y
CONFIG_QUEUED_SPINLOCKS=y
CONFIG_ARCH_USE_QUEUED_RWLOCKS=y
CONFIG_QUEUED_RWLOCKS=y
CONFIG_FREEZER=y

#
# Processor type and features
#
# CONFIG_ZONE_DMA is not set
# CONFIG_SMP_SUPPORT is not set
CONFIG_X86_FEATURE_NAMES=y
CONFIG_X86_MPPARSE=y
# CONFIG_X86_EXTENDED_PLATFORM is not set
CONFIG_IOSF_MBI=m
CONFIG_IOSF_MBI_DEBUG=y
# CONFIG_SCHED_OMIT_FRAME_POINTER is not set
# CONFIG_KVMTOOL_TEST_ENABLE is not set
# CONFIG_HYPERVISOR_GUEST is not set
CONFIG_NO_BOOTMEM=y
# CONFIG_MK8 is not set
# CONFIG_MPSC is not set
# CONFIG_MCORE2 is not set
CONFIG_GENERIC_CPU=y
CONFIG_X86_INTERNODE_CACHE_SHIFT=6
CONFIG_X86_L1_CACHE_SHIFT=6
CONFIG_X86_TSC=y
CONFIG_X86_CMPXCHG64=y
CONFIG_X86_CMOV=y
CONFIG_X86_MINIMUM_CPU_FAMILY=64
CONFIG_X86_DEBUGCTLMSR=y
CONFIG_PROCESSOR_SELECT=y
# CONFIG_CPU_SUP_INTEL is not set
CONFIG_CPU_SUP_AMD=y
CONFIG_CPU_SUP_CENTAUR=y
CONFIG_HPET_TIMER=y
# CONFIG_DMI is not set
CONFIG_GART_IOMMU=y
CONFIG_CALGARY_IOMMU=y
CONFIG_CALGARY_IOMMU_ENABLED_BY_DEFAULT=y
CONFIG_SWIOTLB=y
CONFIG_IOMMU_HELPER=y
# CONFIG_MAXSMP is not set
CONFIG_NR_CPUS=64
# CONFIG_SCHED_SMT is not set
# CONFIG_SCHED_MC is not set
# CONFIG_PREEMPT_NONE is not set
# CONFIG_PREEMPT_VOLUNTARY is not set
CONFIG_PREEMPT=y
CONFIG_PREEMPT_COUNT=y
CONFIG_X86_LOCAL_APIC=y
CONFIG_X86_IO_APIC=y
CONFIG_X86_REROUTE_FOR_BROKEN_BOOT_IRQS=y
# CONFIG_X86_MCE is not set
CONFIG_X86_16BIT=y
CONFIG_X86_ESPFIX64=y
CONFIG_X86_VSYSCALL_EMULATION=y
# CONFIG_I8K is not set
CONFIG_MICROCODE=y
CONFIG_MICROCODE_INTEL=y
# CONFIG_MICROCODE_AMD is not set
CONFIG_MICROCODE_OLD_INTERFACE=y
# CONFIG_MICROCODE_EARLY is not set
# CONFIG_X86_MSR is not set
# CONFIG_X86_CPUID is not set
# CONFIG_UP_WANTED_1 is not set
CONFIG_SMP=y
CONFIG_ARCH_PHYS_ADDR_T_64BIT=y
CONFIG_ARCH_DMA_ADDR_T_64BIT=y
CONFIG_NUMA=y
CONFIG_AMD_NUMA=y
# CONFIG_NUMA_EMU is not set
CONFIG_NODES_SHIFT=6
CONFIG_ARCH_SPARSEMEM_ENABLE=y
CONFIG_ARCH_SPARSEMEM_DEFAULT=y
CONFIG_ARCH_SELECT_MEMORY_MODEL=y
CONFIG_ILLEGAL_POINTER_VALUE=0xdead000000000000
CONFIG_SELECT_MEMORY_MODEL=y
CONFIG_SPARSEMEM_MANUAL=y
CONFIG_SPARSEMEM=y
CONFIG_NEED_MULTIPLE_NODES=y
CONFIG_HAVE_MEMORY_PRESENT=y
CONFIG_SPARSEMEM_EXTREME=y
CONFIG_SPARSEMEM_VMEMMAP_ENABLE=y
CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER=y
# CONFIG_SPARSEMEM_VMEMMAP is not set
CONFIG_HAVE_MEMBLOCK=y
CONFIG_HAVE_MEMBLOCK_NODE_MAP=y
CONFIG_ARCH_DISCARD_MEMBLOCK=y
CONFIG_MOVABLE_NODE=y
# CONFIG_HAVE_BOOTMEM_INFO_NODE is not set
# CONFIG_MEMORY_HOTPLUG is not set
CONFIG_PAGEFLAGS_EXTENDED=y
CONFIG_SPLIT_PTLOCK_CPUS=4
CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK=y
CONFIG_MEMORY_BALLOON=y
# CONFIG_COMPACTION is not set
# CONFIG_MIGRATION is not set
CONFIG_PHYS_ADDR_T_64BIT=y
CONFIG_ZONE_DMA_FLAG=0
CONFIG_NEED_BOUNCE_POOL=y
CONFIG_VIRT_TO_BUS=y
CONFIG_MMU_NOTIFIER=y
CONFIG_KSM=y
CONFIG_DEFAULT_MMAP_MIN_ADDR=4096
# CONFIG_TRANSPARENT_HUGEPAGE is not set
# CONFIG_CLEANCACHE is not set
# CONFIG_FRONTSWAP is not set
# CONFIG_CMA is not set
# CONFIG_MEM_SOFT_DIRTY is not set
CONFIG_ZPOOL=y
# CONFIG_ZBUD is not set
CONFIG_ZSMALLOC=y
CONFIG_PGTABLE_MAPPING=y
CONFIG_ZSMALLOC_STAT=y
CONFIG_GENERIC_EARLY_IOREMAP=y
CONFIG_ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT=y
# CONFIG_X86_PMEM_LEGACY is not set
# CONFIG_X86_CHECK_BIOS_CORRUPTION is not set
CONFIG_X86_RESERVE_LOW=64
CONFIG_MTRR=y
# CONFIG_MTRR_SANITIZER is not set
CONFIG_X86_PAT=y
CONFIG_ARCH_USES_PG_UNCACHED=y
# CONFIG_ARCH_RANDOM is not set
CONFIG_X86_SMAP=y
CONFIG_SECCOMP=y
# CONFIG_HZ_100 is not set
CONFIG_HZ_250=y
# CONFIG_HZ_300 is not set
# CONFIG_HZ_1000 is not set
CONFIG_HZ=250
CONFIG_SCHED_HRTICK=y
# CONFIG_KEXEC is not set
# CONFIG_CRASH_DUMP is not set
CONFIG_PHYSICAL_START=0x1000000
CONFIG_RELOCATABLE=y
CONFIG_RANDOMIZE_BASE=y
CONFIG_RANDOMIZE_BASE_MAX_OFFSET=0x40000000
CONFIG_X86_NEED_RELOCS=y
CONFIG_PHYSICAL_ALIGN=0x200000
CONFIG_HOTPLUG_CPU=y
CONFIG_BOOTPARAM_HOTPLUG_CPU0=y
CONFIG_DEBUG_HOTPLUG_CPU0=y
# CONFIG_COMPAT_VDSO is not set
CONFIG_CMDLINE_BOOL=y
CONFIG_CMDLINE=""
CONFIG_HAVE_LIVEPATCH=y
CONFIG_LIVEPATCH=y
CONFIG_ARCH_ENABLE_MEMORY_HOTPLUG=y
CONFIG_USE_PERCPU_NUMA_NODE_ID=y

#
# Power management and ACPI options
#
CONFIG_ARCH_HIBERNATION_HEADER=y
# CONFIG_SUSPEND is not set
CONFIG_HIBERNATE_CALLBACKS=y
CONFIG_HIBERNATION=y
CONFIG_PM_STD_PARTITION=""
CONFIG_PM_SLEEP=y
CONFIG_PM_SLEEP_SMP=y
# CONFIG_PM_AUTOSLEEP is not set
# CONFIG_PM_WAKELOCKS is not set
CONFIG_PM=y
CONFIG_PM_DEBUG=y
# CONFIG_PM_ADVANCED_DEBUG is not set
CONFIG_PM_SLEEP_DEBUG=y
CONFIG_DPM_WATCHDOG=y
CONFIG_DPM_WATCHDOG_TIMEOUT=60
# CONFIG_PM_TRACE_RTC is not set
CONFIG_WQ_POWER_EFFICIENT_DEFAULT=y
# CONFIG_ACPI is not set
CONFIG_SFI=y

#
# CPU Frequency scaling
#
CONFIG_CPU_FREQ=y CONFIG_CPU_FREQ_GOV_COMMON=y CONFIG_CPU_FREQ_STAT=y
# CONFIG_CPU_FREQ_STAT_DETAILS is not set
# CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE is not set # CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE is not set # CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE is not set # CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND is not set CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE=y CONFIG_CPU_FREQ_GOV_PERFORMANCE=y
# CONFIG_CPU_FREQ_GOV_POWERSAVE is not set
# CONFIG_CPU_FREQ_GOV_USERSPACE is not set CONFIG_CPU_FREQ_GOV_ONDEMAND=m CONFIG_CPU_FREQ_GOV_CONSERVATIVE=y

#
# CPU frequency scaling drivers
#
# CONFIG_X86_INTEL_PSTATE is not set
# CONFIG_X86_P4_CLOCKMOD is not set

#

# shared options
#
# CONFIG_X86_SPEEDSTEP_LIB is not set

#
# CPU Idle
#
# CONFIG_CPU_IDLE is not set
# CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED is not set

#
# Memory power savings
#
# CONFIG_I7300_IDLE is not set

#
# Bus options (PCI etc.)
#
CONFIG_PCI=y
CONFIG_PCI_DIRECT=y
CONFIG_PCI_DOMAINS=y
# CONFIG_PCI_CNB20LE_QUIRK is not set
# CONFIG_PCIEPORTBUS is not set
CONFIG_PCI_BUS_ADDR_T_64BIT=y
# CONFIG_PCI_MSI is not set
CONFIG_PCI_DEBUG=y
# CONFIG_PCI_REALLOC_ENABLE_AUTO is not set
# CONFIG_PCI_STUB is not set
CONFIG_HT_IRQ=y
CONFIG_PCI_ATS=y
CONFIG_PCI_IOV=y
# CONFIG_PCI_PRI is not set
CONFIG_PCI_PASID=y

#
# PCI host controller drivers
#
CONFIG_ISA_DMA_API=y
CONFIG_AMD_NB=y
CONFIG_PCCARD=y
CONFIG_PCMCIA=y
CONFIG_PCMCIA_LOAD_CIS=y
CONFIG_CARDBUS=y

#
# PC-card bridges
#
# CONFIG_YENTA is not set
CONFIG_PD6729=y
CONFIG_I82092=y
CONFIG_PCCARD_NONSTATIC=y
CONFIG_HOTPLUG_PCI=y
CONFIG_HOTPLUG_PCI_CPCI=y
# CONFIG_HOTPLUG_PCI_CPCI_ZT5550 is not set
CONFIG_HOTPLUG_PCI_CPCI_GENERIC=y
CONFIG_HOTPLUG_PCI_SHPC=y
CONFIG_RAPIDIO=y
CONFIG_RAPIDIO_DISC_TIMEOUT=30
# CONFIG_RAPIDIO_ENABLE_RX_TX_PORTS is not set
CONFIG_RAPIDIO_DMA_ENGINE=y
# CONFIG_RAPIDIO_DEBUG is not set
CONFIG_RAPIDIO_ENUM_BASIC=m

#
# RapidIO Switch drivers
#
CONFIG_RAPIDIO_TSI57X=y
CONFIG_RAPIDIO_CPS_XX=y
CONFIG_RAPIDIO_TSI568=y
# CONFIG_RAPIDIO_CPS_GEN2 is not set
# CONFIG_X86_SYSFB is not set

#
# Executable file formats / Emulations
#
CONFIG_BINFMT_ELF=y
CONFIG_COMPAT_BINFMT_ELF=y
# CONFIG_BINFMT_SCRIPT is not set
# CONFIG_HAVE_AOUT is not set
CONFIG_BINFMT_MISC=m
CONFIG_COREDUMP=y
CONFIG_IA32_EMULATION=y
CONFIG_IA32_AOUT=m
# CONFIG_X86_X32 is not set
CONFIG_COMPAT=y
CONFIG_COMPAT_FOR_U64_ALIGNMENT=y
CONFIG_SYSVIPC_COMPAT=y
CONFIG_KEYS_COMPAT=y
CONFIG_X86_DEV_DMA_OPS=y
CONFIG_PMC_ATOM=y
CONFIG_NET=y
CONFIG_NET_INGRESS=y

#
# Networking options
#
CONFIG_PACKET=y
CONFIG_PACKET_DIAG=m
CONFIG_UNIX=y
# CONFIG_UNIX_DIAG is not set
CONFIG_XFRM=y
CONFIG_XFRM_ALGO=m
# CONFIG_XFRM_USER is not set
CONFIG_XFRM_SUB_POLICY=y
CONFIG_XFRM_MIGRATE=y
CONFIG_XFRM_STATISTICS=y
# CONFIG_NET_KEY is not set
CONFIG_INET=y
CONFIG_IP_MULTICAST=y
CONFIG_IP_ADVANCED_ROUTER=y
CONFIG_IP_FIB_TRIE_STATS=y
# CONFIG_IP_MULTIPLE_TABLES is not set
CONFIG_IP_ROUTE_MULTIPATH=y
# CONFIG_IP_ROUTE_VERBOSE is not set
CONFIG_IP_ROUTE_CLASSID=y
# CONFIG_IP_PNP is not set
CONFIG_NET_IPIP=m
CONFIG_NET_IPGRE_DEMUX=y
CONFIG_NET_IP_TUNNEL=y
CONFIG_NET_IPGRE=m
# CONFIG_NET_IPGRE_BROADCAST is not set
CONFIG_IP_MROUTE=y
CONFIG_IP_MROUTE_MULTIPLE_TABLES=y
CONFIG_IP_PIMSM_V1=y
# CONFIG_IP_PIMSM_V2 is not set
# CONFIG_SYN_COOKIES is not set
CONFIG_NET_IPVTI=m
CONFIG_NET_UDP_TUNNEL=y
CONFIG_NET_FOU=m
CONFIG_NET_FOU_IP_TUNNELS=y
CONFIG_GENEVE_CORE=y
CONFIG_INET_AH=m
# CONFIG_INET_ESP is not set
# CONFIG_INET_IPCOMP is not set
# CONFIG_INET_XFRM_TUNNEL is not set
CONFIG_INET_TUNNEL=m
# CONFIG_INET_XFRM_MODE_TRANSPORT is not set
CONFIG_INET_XFRM_MODE_TUNNEL=m
# CONFIG_INET_XFRM_MODE_BEET is not set
CONFIG_INET_LRO=m
CONFIG_INET_DIAG=m
CONFIG_INET_TCP_DIAG=m
CONFIG_INET_UDP_DIAG=m
# CONFIG_TCP_CONG_ADVANCED is not set
CONFIG_TCP_CONG_CUBIC=y
CONFIG_DEFAULT_TCP_CONG="cubic"
# CONFIG_TCP_MD5SIG is not set
# CONFIG_NETLABEL is not set
CONFIG_NETWORK_SECMARK=y
CONFIG_NET_PTP_CLASSIFY=y
# CONFIG_NETWORK_PHY_TIMESTAMPING is not set
CONFIG_NETFILTER=y
# CONFIG_NETFILTER_DEBUG is not set
CONFIG_NETFILTER_ADVANCED=y
CONFIG_BRIDGE_NETFILTER=m

#
# Core Netfilter Configuration
#
CONFIG_NETFILTER_INGRESS=y
CONFIG_NETFILTER_NETLINK=y
CONFIG_NETFILTER_NETLINK_ACCT=y
CONFIG_NETFILTER_NETLINK_QUEUE=y
CONFIG_NETFILTER_NETLINK_LOG=y
# CONFIG_NF_CONNTRACK is not set
CONFIG_NF_LOG_COMMON=y
CONFIG_NF_TABLES=y
CONFIG_NF_TABLES_NETDEV=y
CONFIG_NFT_EXTHDR=m
CONFIG_NFT_META=y
# CONFIG_NFT_RBTREE is not set
CONFIG_NFT_HASH=y
CONFIG_NFT_COUNTER=m
# CONFIG_NFT_LOG is not set
CONFIG_NFT_LIMIT=m
CONFIG_NFT_QUEUE=y
CONFIG_NFT_REJECT=y
CONFIG_NFT_COMPAT=m
CONFIG_NETFILTER_XTABLES=y

#
# Xtables combined modules
#
CONFIG_NETFILTER_XT_MARK=y

#
# Xtables targets
#
# CONFIG_NETFILTER_XT_TARGET_CHECKSUM is not set
CONFIG_NETFILTER_XT_TARGET_CLASSIFY=m
CONFIG_NETFILTER_XT_TARGET_DSCP=m
CONFIG_NETFILTER_XT_TARGET_HL=m
CONFIG_NETFILTER_XT_TARGET_HMARK=y
CONFIG_NETFILTER_XT_TARGET_IDLETIMER=y
CONFIG_NETFILTER_XT_TARGET_LOG=y
# CONFIG_NETFILTER_XT_TARGET_MARK is not set
CONFIG_NETFILTER_XT_TARGET_NFLOG=m
# CONFIG_NETFILTER_XT_TARGET_NFQUEUE is not set
CONFIG_NETFILTER_XT_TARGET_RATEEST=y
# CONFIG_NETFILTER_XT_TARGET_TEE is not set
CONFIG_NETFILTER_XT_TARGET_TPROXY=m
# CONFIG_NETFILTER_XT_TARGET_TRACE is not set
# CONFIG_NETFILTER_XT_TARGET_SECMARK is not set
# CONFIG_NETFILTER_XT_TARGET_TCPMSS is not set
CONFIG_NETFILTER_XT_TARGET_TCPOPTSTRIP=m

#
# Xtables matches
#
CONFIG_NETFILTER_XT_MATCH_ADDRTYPE=m
CONFIG_NETFILTER_XT_MATCH_BPF=m
CONFIG_NETFILTER_XT_MATCH_CGROUP=y
CONFIG_NETFILTER_XT_MATCH_COMMENT=y
# CONFIG_NETFILTER_XT_MATCH_CPU is not set
CONFIG_NETFILTER_XT_MATCH_DCCP=m
# CONFIG_NETFILTER_XT_MATCH_DEVGROUP is not set
CONFIG_NETFILTER_XT_MATCH_DSCP=m
CONFIG_NETFILTER_XT_MATCH_ECN=m
CONFIG_NETFILTER_XT_MATCH_ESP=y
CONFIG_NETFILTER_XT_MATCH_HASHLIMIT=m
# CONFIG_NETFILTER_XT_MATCH_HL is not set
CONFIG_NETFILTER_XT_MATCH_IPCOMP=y
CONFIG_NETFILTER_XT_MATCH_IPRANGE=m
# CONFIG_NETFILTER_XT_MATCH_L2TP is not set
CONFIG_NETFILTER_XT_MATCH_LENGTH=m
CONFIG_NETFILTER_XT_MATCH_LIMIT=m
CONFIG_NETFILTER_XT_MATCH_MAC=m
# CONFIG_NETFILTER_XT_MATCH_MARK is not set
# CONFIG_NETFILTER_XT_MATCH_MULTIPORT is not set
CONFIG_NETFILTER_XT_MATCH_NFACCT=m
CONFIG_NETFILTER_XT_MATCH_OSF=y
# CONFIG_NETFILTER_XT_MATCH_OWNER is not set
CONFIG_NETFILTER_XT_MATCH_POLICY=y
# CONFIG_NETFILTER_XT_MATCH_PHYSDEV is not set
CONFIG_NETFILTER_XT_MATCH_PKTTYPE=m
# CONFIG_NETFILTER_XT_MATCH_QUOTA is not set
CONFIG_NETFILTER_XT_MATCH_RATEEST=y
CONFIG_NETFILTER_XT_MATCH_REALM=m
CONFIG_NETFILTER_XT_MATCH_RECENT=y
CONFIG_NETFILTER_XT_MATCH_SCTP=y
CONFIG_NETFILTER_XT_MATCH_SOCKET=m
CONFIG_NETFILTER_XT_MATCH_STATISTIC=m
CONFIG_NETFILTER_XT_MATCH_STRING=y
CONFIG_NETFILTER_XT_MATCH_TCPMSS=y
CONFIG_NETFILTER_XT_MATCH_TIME=y
# CONFIG_NETFILTER_XT_MATCH_U32 is not set
# CONFIG_IP_SET is not set
CONFIG_IP_VS=y
CONFIG_IP_VS_DEBUG=y
CONFIG_IP_VS_TAB_BITS=12

#
# IPVS transport protocol load balancing support
#
# CONFIG_IP_VS_PROTO_TCP is not set
# CONFIG_IP_VS_PROTO_UDP is not set
CONFIG_IP_VS_PROTO_AH_ESP=y
# CONFIG_IP_VS_PROTO_ESP is not set
CONFIG_IP_VS_PROTO_AH=y
CONFIG_IP_VS_PROTO_SCTP=y

#
# IPVS scheduler
#
CONFIG_IP_VS_RR=y
CONFIG_IP_VS_WRR=m
CONFIG_IP_VS_LC=y
CONFIG_IP_VS_WLC=y
# CONFIG_IP_VS_FO is not set
CONFIG_IP_VS_LBLC=m
CONFIG_IP_VS_LBLCR=y
CONFIG_IP_VS_DH=m
CONFIG_IP_VS_SH=m
# CONFIG_IP_VS_SED is not set
CONFIG_IP_VS_NQ=y

#
# IPVS SH scheduler
#
CONFIG_IP_VS_SH_TAB_BITS=8

#
# IPVS application helper
#

#
# IP: Netfilter Configuration
#
CONFIG_NF_DEFRAG_IPV4=m
CONFIG_NF_TABLES_IPV4=m
CONFIG_NFT_CHAIN_ROUTE_IPV4=m
CONFIG_NFT_REJECT_IPV4=m
CONFIG_NF_TABLES_ARP=m
CONFIG_NF_LOG_ARP=y
CONFIG_NF_LOG_IPV4=y
CONFIG_NF_REJECT_IPV4=m
CONFIG_IP_NF_IPTABLES=m
CONFIG_IP_NF_MATCH_AH=m
CONFIG_IP_NF_MATCH_ECN=m
CONFIG_IP_NF_MATCH_RPFILTER=m
# CONFIG_IP_NF_MATCH_TTL is not set
CONFIG_IP_NF_FILTER=m
CONFIG_IP_NF_TARGET_REJECT=m
CONFIG_IP_NF_MANGLE=m
CONFIG_IP_NF_TARGET_ECN=m
# CONFIG_IP_NF_TARGET_TTL is not set
CONFIG_IP_NF_RAW=m
CONFIG_IP_NF_SECURITY=m
CONFIG_IP_NF_ARPTABLES=y
CONFIG_IP_NF_ARPFILTER=m
CONFIG_IP_NF_ARP_MANGLE=m

#
# DECnet: Netfilter Configuration
#
# CONFIG_DECNET_NF_GRABULATOR is not set
CONFIG_NF_TABLES_BRIDGE=m
CONFIG_NFT_BRIDGE_META=m
CONFIG_NF_LOG_BRIDGE=m
CONFIG_BRIDGE_NF_EBTABLES=m
CONFIG_BRIDGE_EBT_BROUTE=m
# CONFIG_BRIDGE_EBT_T_FILTER is not set
CONFIG_BRIDGE_EBT_T_NAT=m
CONFIG_BRIDGE_EBT_802_3=m
CONFIG_BRIDGE_EBT_AMONG=m
CONFIG_BRIDGE_EBT_ARP=m
CONFIG_BRIDGE_EBT_IP=m
# CONFIG_BRIDGE_EBT_LIMIT is not set
CONFIG_BRIDGE_EBT_MARK=m
CONFIG_BRIDGE_EBT_PKTTYPE=m
# CONFIG_BRIDGE_EBT_STP is not set
CONFIG_BRIDGE_EBT_VLAN=m
CONFIG_BRIDGE_EBT_ARPREPLY=m
CONFIG_BRIDGE_EBT_DNAT=m
CONFIG_BRIDGE_EBT_MARK_T=m
# CONFIG_BRIDGE_EBT_REDIRECT is not set
# CONFIG_BRIDGE_EBT_SNAT is not set
# CONFIG_BRIDGE_EBT_LOG is not set
# CONFIG_BRIDGE_EBT_NFLOG is not set
CONFIG_IP_DCCP=y
CONFIG_INET_DCCP_DIAG=m

#
# DCCP CCIDs Configuration
#
# CONFIG_IP_DCCP_CCID2_DEBUG is not set
# CONFIG_IP_DCCP_CCID3 is not set

#
# DCCP Kernel Hacking
#
CONFIG_IP_DCCP_DEBUG=y
CONFIG_IP_SCTP=m
CONFIG_SCTP_DBG_OBJCNT=y
# CONFIG_SCTP_DEFAULT_COOKIE_HMAC_MD5 is not set
# CONFIG_SCTP_DEFAULT_COOKIE_HMAC_SHA1 is not set
CONFIG_SCTP_DEFAULT_COOKIE_HMAC_NONE=y
# CONFIG_SCTP_COOKIE_HMAC_MD5 is not set
CONFIG_SCTP_COOKIE_HMAC_SHA1=y
# CONFIG_TIPC is not set
CONFIG_ATM=m
# CONFIG_ATM_CLIP is not set
CONFIG_ATM_LANE=m
CONFIG_ATM_MPOA=m
# CONFIG_ATM_BR2684 is not set
# CONFIG_L2TP is not set
CONFIG_STP=m
CONFIG_BRIDGE=m
CONFIG_BRIDGE_IGMP_SNOOPING=y
CONFIG_HAVE_NET_DSA=y
# CONFIG_VLAN_8021Q is not set
CONFIG_DECNET=m
CONFIG_DECNET_ROUTER=y
CONFIG_LLC=y
CONFIG_LLC2=m
CONFIG_IPX=y
CONFIG_IPX_INTERN=y
# CONFIG_ATALK is not set
# CONFIG_X25 is not set
# CONFIG_LAPB is not set
CONFIG_PHONET=y
CONFIG_IEEE802154=m
# CONFIG_IEEE802154_SOCKET is not set
CONFIG_MAC802154=m
CONFIG_NET_SCHED=y