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riscv: Add GENERIC_ENTRY, irq stack support

PATCH Superseded [email protected] 3 participants 15 messages Sep 6, 2022 – Sep 7, 2022

Subsystems (3)

v3 of 17 Superseded Latest is v17 →

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#0 lore raw

v3 cover riscv: Add GENERIC_ENTRY, irq stack support

From: Guo Ren <[email protected]>

The patches convert riscv to use the generic entry infrastructure from kernel/entry/*. Add independent irq stacks (IRQ_STACKS) for percpu to prevent kernel stack overflows. Add the HAVE_SOFTIRQ_ON_OWN_STACK feature for the IRQ_STACKS config. You can try it directly with [1].

[1] https://github.com/guoren83/linux/tree/generic_entry_v3

V3:
- Fixup CONFIG_COMPAT=n compile error
- Add THREAD_SIZE_ORDER config
- Optimize elf_kexec.c warning fixup
- Add static to irq_stack_ptr definition

V2:

- Fixup compile error by include "riscv: ptrace: Remove duplicate operation"
- Fixup compile warning

- Add test repo link in cover letter

V1:

Guo Ren (7):
riscv: elf_kexec: Fixup compile warning
riscv: compat_syscall_table: Fixup compile warning
riscv: ptrace: Remove duplicate operation
riscv: convert to generic entry
riscv: Support HAVE_IRQ_EXIT_ON_IRQ_STACK
riscv: Support HAVE_SOFTIRQ_ON_OWN_STACK
riscv: Add config of thread stack size

 arch/riscv/Kconfig                    |  19 ++
 arch/riscv/include/asm/csr.h          |   1 -
 arch/riscv/include/asm/entry-common.h |   8 +
 arch/riscv/include/asm/irq.h          |   3 +
 arch/riscv/include/asm/ptrace.h       |  10 +-
 arch/riscv/include/asm/stacktrace.h   |   5 +
 arch/riscv/include/asm/syscall.h      |   6 +
 arch/riscv/include/asm/thread_info.h  |  19 +-
 arch/riscv/include/asm/vmap_stack.h   |  28 +++
 arch/riscv/kernel/Makefile            |   1 +
 arch/riscv/kernel/elf_kexec.c         |   2 +-
 arch/riscv/kernel/entry.S             | 255 +++++---------------------
 arch/riscv/kernel/irq.c               |  75 ++++++++
 arch/riscv/kernel/ptrace.c            |  41 -----
 arch/riscv/kernel/signal.c            |  21 +--
 arch/riscv/kernel/sys_riscv.c         |  27 +++
 arch/riscv/kernel/traps.c             |  11 ++
 arch/riscv/mm/fault.c                 |  12 +-
 18 files changed, 259 insertions(+), 285 deletions(-)
 create mode 100644 arch/riscv/include/asm/entry-common.h
 create mode 100644 arch/riscv/include/asm/vmap_stack.h
Signature · 1 line
2.36.1
#1 lore raw

PATCH v3 1/7 riscv: elf_kexec: Fixup compile warning

From: Guo Ren <[email protected]>

If CRYTPO or CRYPTO_SHA256 or KEXE_FILE is not enabled, then:

COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash arch/riscv/

../arch/riscv/kernel/elf_kexec.c: In function 'elf_kexec_load':
../arch/riscv/kernel/elf_kexec.c:185:23: warning: variable 'kernel_start' set but not used [-Wunused-but-set-variable]

  185 |         unsigned long kernel_start;
      |                       ^~~~~~~~~~~~
Fixes 838b3e28488f ("RISC-V: Load purgatory in kexec_file")
---
 arch/riscv/kernel/elf_kexec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
arch/riscv/kernel/elf_kexec.c +1 -1
index 0cb94992c15b..4b9264340b78 100644
@@ -198,7 +198,7 @@ static void *elf_kexec_load(struct kimage *image, char *kernel_buf,
 	if (ret)
 		goto out;
 	kernel_start = image->start;
-	pr_notice("The entry point of kernel at 0x%lx\n", image->start);
+	pr_notice("The entry point of kernel at 0x%lx\n", kernel_start);
 
 	/* Add the kernel binary to the image */
 	ret = riscv_kexec_elf_load(image, &ehdr, &elf_info,
Signature · 1 line
2.36.1
#2 lore raw

PATCH v3 2/7 riscv: compat_syscall_table: Fixup compile warning

In reply to [email protected]

From: Guo Ren <[email protected]>

../arch/riscv/kernel/compat_syscall_table.c:12:41: warning: initialized field overwritten [-Woverride-init]
12 | #define __SYSCALL(nr, call) [nr] = (call),
| ^
../include/uapi/asm-generic/unistd.h:567:1: note: in expansion of macro '__SYSCALL'
567 | __SYSCALL(__NR_semget, sys_semget)

Fixes 59c10c52f573 ("riscv: compat: syscall: Add compat_sys_call_table implementation")
---
 arch/riscv/kernel/Makefile | 1 +
 1 file changed, 1 insertion(+)
arch/riscv/kernel/Makefile +1 -0
index 33bb60a354cd..01da14e21019 100644
@@ -9,6 +9,7 @@ CFLAGS_REMOVE_patch.o	= $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_sbi.o	= $(CC_FLAGS_FTRACE)
 endif
 CFLAGS_syscall_table.o	+= $(call cc-option,-Wno-override-init,)
+CFLAGS_compat_syscall_table.o += $(call cc-option,-Wno-override-init,)
 
 ifdef CONFIG_KEXEC
 AFLAGS_kexec_relocate.o := -mcmodel=medany $(call cc-option,-mno-relax)
Signature · 1 line
2.36.1
#3 lore raw

PATCH v3 3/7 riscv: ptrace: Remove duplicate operation

In reply to [email protected]

From: Guo Ren <[email protected]>

The TIF_SYSCALL_TRACE is controlled by a common code, see kernel/ptrace.c and include/linux/thread.h.

clear_task_syscall_work(child, SYSCALL_TRACE);

---
 arch/riscv/kernel/ptrace.c | 1 -
 1 file changed, 1 deletion(-)
arch/riscv/kernel/ptrace.c +0 -1
index 2ae8280ae475..44f4b1ca315d 100644
@@ -212,7 +212,6 @@ unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
 
 void ptrace_disable(struct task_struct *child)
 {
-	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 }
 
 long arch_ptrace(struct task_struct *child, long request,
Signature · 7 lines
2.36.1


_______________________________________________
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[email protected]
http://lists.infradead.org/mailman/listinfo/linux-riscv
#4 lore raw

PATCH v3 4/7 riscv: convert to generic entry

In reply to [email protected]

From: Guo Ren <[email protected]>

This patch converts riscv to use the generic entry infrastructure from kernel/entry/*. The generic entry makes maintainers' work easier and codes more elegant. Here are the changes than before:

- More clear entry.S with handle_exception and ret_from_exception
- Get rid of complex custom signal implementation
- More readable syscall procedure
- Little modification on ret_from_fork & ret_from_kernel_thread
- Wrap with irqentry_enter/exit and syscall_enter/exit_from_user_mode
- Use the standard preemption code instead of custom

---
 arch/riscv/Kconfig                    |   1 +
 arch/riscv/include/asm/csr.h          |   1 -
 arch/riscv/include/asm/entry-common.h |   8 +
 arch/riscv/include/asm/ptrace.h       |  10 +-
 arch/riscv/include/asm/stacktrace.h   |   5 +
 arch/riscv/include/asm/syscall.h      |   6 +
 arch/riscv/include/asm/thread_info.h  |  13 +-
 arch/riscv/kernel/entry.S             | 228 +++-----------------------
 arch/riscv/kernel/irq.c               |  15 ++
 arch/riscv/kernel/ptrace.c            |  40 -----
 arch/riscv/kernel/signal.c            |  21 +--
 arch/riscv/kernel/sys_riscv.c         |  27 +++
 arch/riscv/kernel/traps.c             |  11 ++
 arch/riscv/mm/fault.c                 |  12 +-
 14 files changed, 117 insertions(+), 281 deletions(-)
 create mode 100644 arch/riscv/include/asm/entry-common.h
arch/riscv/Kconfig +1 -0
index ed66c31e4655..a07bb3b73b5b 100644
@@ -56,6 +56,7 @@ config RISCV
 	select GENERIC_ATOMIC64 if !64BIT
 	select GENERIC_CLOCKEVENTS_BROADCAST if SMP
 	select GENERIC_EARLY_IOREMAP
+	select GENERIC_ENTRY
 	select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO
 	select GENERIC_IDLE_POLL_SETUP
 	select GENERIC_IOREMAP if MMU
arch/riscv/include/asm/csr.h +0 -1
index 0e571f6483d9..7c2b8cdb7b77 100644
@@ -40,7 +40,6 @@
 #define SR_UXL		_AC(0x300000000, UL) /* XLEN mask for U-mode */
 #define SR_UXL_32	_AC(0x100000000, UL) /* XLEN = 32 for U-mode */
 #define SR_UXL_64	_AC(0x200000000, UL) /* XLEN = 64 for U-mode */
-#define SR_UXL_SHIFT	32
 #endif
 
 /* SATP flags */
arch/riscv/include/asm/entry-common.h new file +8 -0
new file mode 100644
index 000000000000..1636ac2af28e
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _ASM_RISCV_ENTRY_COMMON_H
+#define _ASM_RISCV_ENTRY_COMMON_H
+
+#include <asm/stacktrace.h>
+
+#endif /* _ASM_RISCV_ENTRY_COMMON_H */
arch/riscv/include/asm/ptrace.h +8 -2
index 6ecd461129d2..4e46a611f255 100644
@@ -53,6 +53,9 @@ struct pt_regs {
 	unsigned long orig_a0;
 };
 
+#define PTRACE_SYSEMU			0x1f
+#define PTRACE_SYSEMU_SINGLESTEP	0x20
+
 #ifdef CONFIG_64BIT
 #define REG_FMT "%016lx"
 #else
@@ -121,8 +124,6 @@ extern unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
 
 void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
 			   unsigned long frame_pointer);
-int do_syscall_trace_enter(struct pt_regs *regs);
-void do_syscall_trace_exit(struct pt_regs *regs);
 
 /**
  * regs_get_register() - get register value from its offset
@@ -172,6 +173,11 @@ static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs,
 	return 0;
 }
 
+static inline int regs_irqs_disabled(struct pt_regs *regs)
+{
+	return !(regs->status & SR_IE);
+}
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_RISCV_PTRACE_H */
arch/riscv/include/asm/stacktrace.h +5 -0
index 3450c1912afd..f7e8ef2418b9 100644
@@ -16,4 +16,9 @@ extern void notrace walk_stackframe(struct task_struct *task, struct pt_regs *re
 extern void dump_backtrace(struct pt_regs *regs, struct task_struct *task,
 			   const char *loglvl);
 
+static inline bool on_thread_stack(void)
+{
+	return !(((unsigned long)(current->stack) ^ current_stack_pointer) & ~(THREAD_SIZE - 1));
+}
+
 #endif /* _ASM_RISCV_STACKTRACE_H */
arch/riscv/include/asm/syscall.h +6 -0
index 384a63b86420..6c573f18030b 100644
@@ -74,5 +74,11 @@ static inline int syscall_get_arch(struct task_struct *task)
 #endif
 }
 
+static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
+{
+	return false;
+}
+
 asmlinkage long sys_riscv_flush_icache(uintptr_t, uintptr_t, uintptr_t);
+asmlinkage void do_sys_ecall_u(struct pt_regs *regs);
 #endif	/* _ASM_RISCV_SYSCALL_H */
arch/riscv/include/asm/thread_info.h +1 -12
index 67322f878e0d..7de4fb96f0b5 100644
@@ -66,6 +66,7 @@ struct thread_info {
 	long			kernel_sp;	/* Kernel stack pointer */
 	long			user_sp;	/* User stack pointer */
 	int			cpu;
+	unsigned long		syscall_work;	/* SYSCALL_WORK_ flags */
 };
 
 /*
@@ -88,26 +89,18 @@ struct thread_info {
  * - pending work-to-be-done flags are in lowest half-word
  * - other flags in upper half-word(s)
  */
-#define TIF_SYSCALL_TRACE	0	/* syscall trace active */
 #define TIF_NOTIFY_RESUME	1	/* callback before returning to user */
 #define TIF_SIGPENDING		2	/* signal pending */
 #define TIF_NEED_RESCHED	3	/* rescheduling necessary */
 #define TIF_RESTORE_SIGMASK	4	/* restore signal mask in do_signal() */
 #define TIF_MEMDIE		5	/* is terminating due to OOM killer */
-#define TIF_SYSCALL_TRACEPOINT  6       /* syscall tracepoint instrumentation */
-#define TIF_SYSCALL_AUDIT	7	/* syscall auditing */
-#define TIF_SECCOMP		8	/* syscall secure computing */
 #define TIF_NOTIFY_SIGNAL	9	/* signal notifications exist */
 #define TIF_UPROBE		10	/* uprobe breakpoint or singlestep */
 #define TIF_32BIT		11	/* compat-mode 32bit process */
 
-#define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
 #define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
 #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
 #define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
-#define _TIF_SYSCALL_TRACEPOINT	(1 << TIF_SYSCALL_TRACEPOINT)
-#define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
-#define _TIF_SECCOMP		(1 << TIF_SECCOMP)
 #define _TIF_NOTIFY_SIGNAL	(1 << TIF_NOTIFY_SIGNAL)
 #define _TIF_UPROBE		(1 << TIF_UPROBE)
 
@@ -115,8 +108,4 @@ struct thread_info {
 	(_TIF_NOTIFY_RESUME | _TIF_SIGPENDING | _TIF_NEED_RESCHED | \
 	 _TIF_NOTIFY_SIGNAL | _TIF_UPROBE)
 
-#define _TIF_SYSCALL_WORK \
-	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_AUDIT | \
-	 _TIF_SECCOMP)
-
 #endif /* _ASM_RISCV_THREAD_INFO_H */
arch/riscv/kernel/entry.S +22 -206

312 lines not on this page · raw message

arch/riscv/kernel/irq.c +15 -0
index 7207fa08d78f..24c2e1bd756a 100644
@@ -5,6 +5,7 @@
  * Copyright (C) 2018 Christoph Hellwig
  */
 
+#include <linux/entry-common.h>
 #include <linux/interrupt.h>
 #include <linux/irqchip.h>
 #include <linux/seq_file.h>
@@ -22,3 +23,17 @@ void __init init_IRQ(void)
 	if (!handle_arch_irq)
 		panic("No interrupt controller found.");
 }
+
+asmlinkage void noinstr do_riscv_irq(struct pt_regs *regs)
+{
+	struct pt_regs *old_regs;
+	irqentry_state_t state = irqentry_enter(regs);
+
+	irq_enter_rcu();
+	old_regs = set_irq_regs(regs);
+	handle_arch_irq(regs);
+	set_irq_regs(old_regs);
+	irq_exit_rcu();
+
+	irqentry_exit(regs, state);
+}
arch/riscv/kernel/ptrace.c +0 -40
index 44f4b1ca315d..4caed6c683e4 100644
@@ -228,46 +228,6 @@ long arch_ptrace(struct task_struct *child, long request,
 	return ret;
 }
 
-/*
- * Allows PTRACE_SYSCALL to work.  These are called from entry.S in
- * {handle,ret_from}_syscall.
- */
-__visible int do_syscall_trace_enter(struct pt_regs *regs)
-{
-	if (test_thread_flag(TIF_SYSCALL_TRACE))
-		if (ptrace_report_syscall_entry(regs))
-			return -1;
-
-	/*
-	 * Do the secure computing after ptrace; failures should be fast.
-	 * If this fails we might have return value in a0 from seccomp
-	 * (via SECCOMP_RET_ERRNO/TRACE).
-	 */
-	if (secure_computing() == -1)
-		return -1;
-
-#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
-	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
-		trace_sys_enter(regs, syscall_get_nr(current, regs));
-#endif
-
-	audit_syscall_entry(regs->a7, regs->a0, regs->a1, regs->a2, regs->a3);
-	return 0;
-}
-
-__visible void do_syscall_trace_exit(struct pt_regs *regs)
-{
-	audit_syscall_exit(regs);
-
-	if (test_thread_flag(TIF_SYSCALL_TRACE))
-		ptrace_report_syscall_exit(regs, 0);
-
-#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
-	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
-		trace_sys_exit(regs, regs_return_value(regs));
-#endif
-}
-
 #ifdef CONFIG_COMPAT
 static int compat_riscv_gpr_get(struct task_struct *target,
 				const struct user_regset *regset,
arch/riscv/kernel/signal.c +2 -19
index 5a2de6b6f882..5871eccbbd94 100644
@@ -12,6 +12,7 @@
 #include <linux/syscalls.h>
 #include <linux/resume_user_mode.h>
 #include <linux/linkage.h>
+#include <linux/entry-common.h>
 
 #include <asm/ucontext.h>
 #include <asm/vdso.h>
@@ -272,7 +273,7 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 	signal_setup_done(ret, ksig, 0);
 }
 
-static void do_signal(struct pt_regs *regs)
+void arch_do_signal_or_restart(struct pt_regs *regs)
 {
 	struct ksignal ksig;
 
@@ -309,21 +310,3 @@ static void do_signal(struct pt_regs *regs)
 	 */
 	restore_saved_sigmask();
 }
-
-/*
- * notification of userspace execution resumption
- * - triggered by the _TIF_WORK_MASK flags
- */
-asmlinkage __visible void do_notify_resume(struct pt_regs *regs,
-					   unsigned long thread_info_flags)
-{
-	if (thread_info_flags & _TIF_UPROBE)
-		uprobe_notify_resume(regs);
-
-	/* Handle pending signal delivery */
-	if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
-		do_signal(regs);
-
-	if (thread_info_flags & _TIF_NOTIFY_RESUME)
-		resume_user_mode_work(regs);
-}
arch/riscv/kernel/sys_riscv.c +27 -0
index 571556bb9261..41cc1c4bccb3 100644
@@ -5,8 +5,10 @@
  * Copyright (C) 2017 SiFive
  */
 
+#include <linux/entry-common.h>
 #include <linux/syscalls.h>
 #include <asm/unistd.h>
+#include <asm/syscall.h>
 #include <asm/cacheflush.h>
 #include <asm-generic/mman-common.h>
 
@@ -72,3 +74,28 @@ SYSCALL_DEFINE3(riscv_flush_icache, uintptr_t, start, uintptr_t, end,
 
 	return 0;
 }
+
+typedef long (*syscall_t)(ulong, ulong, ulong, ulong, ulong, ulong, ulong);
+
+asmlinkage void do_sys_ecall_u(struct pt_regs *regs)
+{
+	syscall_t syscall;
+	ulong nr = regs->a7;
+
+	regs->epc += 4;
+	regs->orig_a0 = regs->a0;
+	regs->a0 = -ENOSYS;
+
+	nr = syscall_enter_from_user_mode(regs, nr);
+#ifdef CONFIG_COMPAT
+	if ((regs->status & SR_UXL) == SR_UXL_32)
+		syscall = compat_sys_call_table[nr];
+	else
+#endif
+		syscall = sys_call_table[nr];
+
+	if (nr < NR_syscalls)
+		regs->a0 = syscall(regs->orig_a0, regs->a1, regs->a2,
+				   regs->a3, regs->a4, regs->a5, regs->a6);
+	syscall_exit_to_user_mode(regs);
+}
arch/riscv/kernel/traps.c +11 -0
index 635e6ec26938..751745de10c5 100644
@@ -17,6 +17,7 @@
 #include <linux/module.h>
 #include <linux/irq.h>
 #include <linux/kexec.h>
+#include <linux/entry-common.h>
 
 #include <asm/asm-prototypes.h>
 #include <asm/bug.h>
@@ -99,7 +100,9 @@ static void do_trap_error(struct pt_regs *regs, int signo, int code,
 #define DO_ERROR_INFO(name, signo, code, str)				\
 asmlinkage __visible __trap_section void name(struct pt_regs *regs)	\
 {									\
+	irqentry_state_t state = irqentry_enter(regs);			\
 	do_trap_error(regs, signo, code, regs->epc, "Oops - " str);	\
+	irqentry_exit(regs, state);					\
 }
 
 DO_ERROR_INFO(do_trap_unknown,
@@ -123,18 +126,22 @@ int handle_misaligned_store(struct pt_regs *regs);
 
 asmlinkage void __trap_section do_trap_load_misaligned(struct pt_regs *regs)
 {
+	irqentry_state_t state = irqentry_enter(regs);
 	if (!handle_misaligned_load(regs))
 		return;
 	do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
 		      "Oops - load address misaligned");
+	irqentry_exit(regs, state);
 }
 
 asmlinkage void __trap_section do_trap_store_misaligned(struct pt_regs *regs)
 {
+	irqentry_state_t state = irqentry_enter(regs);
 	if (!handle_misaligned_store(regs))
 		return;
 	do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
 		      "Oops - store (or AMO) address misaligned");
+	irqentry_exit(regs, state);
 }
 #endif
 DO_ERROR_INFO(do_trap_store_fault,
@@ -158,6 +165,8 @@ static inline unsigned long get_break_insn_length(unsigned long pc)
 
 asmlinkage __visible __trap_section void do_trap_break(struct pt_regs *regs)
 {
+	irqentry_state_t state = irqentry_enter(regs);
+
 #ifdef CONFIG_KPROBES
 	if (kprobe_single_step_handler(regs))
 		return;
@@ -185,6 +194,8 @@ asmlinkage __visible __trap_section void do_trap_break(struct pt_regs *regs)
 		regs->epc += get_break_insn_length(regs->epc);
 	else
 		die(regs, "Kernel BUG");
+
+	irqentry_exit(regs, state);
 }
 NOKPROBE_SYMBOL(do_trap_break);
 
arch/riscv/mm/fault.c +11 -1
index f2fbd1400b7c..45cd200114b1 100644
@@ -15,6 +15,7 @@
 #include <linux/uaccess.h>
 #include <linux/kprobes.h>
 #include <linux/kfence.h>
+#include <linux/entry-common.h>
 
 #include <asm/ptrace.h>
 #include <asm/tlbflush.h>
@@ -203,7 +204,7 @@ static inline bool access_error(unsigned long cause, struct vm_area_struct *vma)
  * This routine handles page faults.  It determines the address and the
  * problem, and then passes it off to one of the appropriate routines.
  */
-asmlinkage void do_page_fault(struct pt_regs *regs)
+static void __do_page_fault(struct pt_regs *regs)
 {
 	struct task_struct *tsk;
 	struct vm_area_struct *vma;
@@ -350,4 +351,13 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
 	}
 	return;
 }
+
+asmlinkage void do_page_fault(struct pt_regs *regs)
+{
+	irqentry_state_t state = irqentry_enter(regs);
+
+	__do_page_fault(regs);
+
+	irqentry_exit(regs, state);
+}
 NOKPROBE_SYMBOL(do_page_fault);
Signature · 7 lines
2.36.1


_______________________________________________
linux-riscv mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/linux-riscv
#5 lore raw

Re: [PATCH V3 4/7] riscv: convert to generic entry

arch/riscv/kernel/irq.c void __init init_IRQ(void) · line 39

Quoted 13 lines · On Mon, Sep 05, 2022 at 11:54:20PM -0400, [email protected] wrote:
arch/riscv/kernel/irq.c +13 -0
+asmlinkage void noinstr do_riscv_irq(struct pt_regs *regs)
+{
+	struct pt_regs *old_regs;
+	irqentry_state_t state = irqentry_enter(regs);
+
+	irq_enter_rcu();
+	old_regs = set_irq_regs(regs);
+	handle_arch_irq(regs);
+	set_irq_regs(old_regs);
+	irq_exit_rcu();
+
+	irqentry_exit(regs, state);
+}

The above is right in that everything that calls irqentry_enter() should be noinstr; however all the below instances get it wrong:

Quoted 49 lines

#define DO_ERROR_INFO(name, signo, code, str) \
asmlinkage __visible __trap_section void name(struct pt_regs *regs) \
{ \

arch/riscv/kernel/traps.c +10 -0
+	irqentry_state_t state = irqentry_enter(regs);			\
 	do_trap_error(regs, signo, code, regs->epc, "Oops - " str);	\
+	irqentry_exit(regs, state);					\
 }
 
 DO_ERROR_INFO(do_trap_unknown,
@@ -123,18 +126,22 @@ int handle_misaligned_store(struct pt_regs *regs);
 
 asmlinkage void __trap_section do_trap_load_misaligned(struct pt_regs *regs)
 {
+	irqentry_state_t state = irqentry_enter(regs);
 	if (!handle_misaligned_load(regs))
 		return;
 	do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
 		      "Oops - load address misaligned");
+	irqentry_exit(regs, state);
 }
 
 asmlinkage void __trap_section do_trap_store_misaligned(struct pt_regs *regs)
 {
+	irqentry_state_t state = irqentry_enter(regs);
 	if (!handle_misaligned_store(regs))
 		return;
 	do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
 		      "Oops - store (or AMO) address misaligned");
+	irqentry_exit(regs, state);
 }
 #endif
 DO_ERROR_INFO(do_trap_store_fault,
@@ -158,6 +165,8 @@ static inline unsigned long get_break_insn_length(unsigned long pc)
 
 asmlinkage __visible __trap_section void do_trap_break(struct pt_regs *regs)
 {
+	irqentry_state_t state = irqentry_enter(regs);
+
 #ifdef CONFIG_KPROBES
 	if (kprobe_single_step_handler(regs))
 		return;
@@ -185,6 +194,8 @@ asmlinkage __visible __trap_section void do_trap_break(struct pt_regs *regs)
 		regs->epc += get_break_insn_length(regs->epc);
 	else
 		die(regs, "Kernel BUG");
+
+	irqentry_exit(regs, state);
 }
 NOKPROBE_SYMBOL(do_trap_break);

arch/riscv/kernel/traps.c asmlinkage __visible __trap_section void do_trap_break(struct pt_regs *regs)

Quoted 10 lines
arch/riscv/kernel/traps.c +8 -0
 
+asmlinkage void do_page_fault(struct pt_regs *regs)
+{
+	irqentry_state_t state = irqentry_enter(regs);
+
+	__do_page_fault(regs);
+
+	irqentry_exit(regs, state);
+}
 NOKPROBE_SYMBOL(do_page_fault);

Without noinstr the compiler is free to insert instrumentation (think all the k*SAN, KCov, GCov, ftrace etc..) which can call code we're not yet ready to run this early in the entry path, for instance it could rely on RCU which isn't on yet, or expect lockdep state.

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author
#6 lore raw

Re: [PATCH V3 4/7] riscv: convert to generic entry

Quoted 70 lines · Peter Zijlstra

arch/riscv/kernel/irq.c void __init init_IRQ(void) · line 39

Quoted 13 lines · On Mon, Sep 05, 2022 at 11:54:20PM -0400, [email protected] wrote:
arch/riscv/kernel/irq.c +13 -0
+asmlinkage void noinstr do_riscv_irq(struct pt_regs *regs)
+{
+     struct pt_regs *old_regs;
+     irqentry_state_t state = irqentry_enter(regs);
+
+     irq_enter_rcu();
+     old_regs = set_irq_regs(regs);
+     handle_arch_irq(regs);
+     set_irq_regs(old_regs);
+     irq_exit_rcu();
+
+     irqentry_exit(regs, state);
+}

The above is right in that everything that calls irqentry_enter() should be noinstr; however all the below instances get it wrong:

Quoted 49 lines

#define DO_ERROR_INFO(name, signo, code, str) \
asmlinkage __visible __trap_section void name(struct pt_regs *regs) \
{ \

arch/riscv/kernel/traps.c +10 -0
+     irqentry_state_t state = irqentry_enter(regs);                  \
      do_trap_error(regs, signo, code, regs->epc, "Oops - " str);     \
+     irqentry_exit(regs, state);                                     \
 }
 
 DO_ERROR_INFO(do_trap_unknown,
@@ -123,18 +126,22 @@ int handle_misaligned_store(struct pt_regs *regs);
 
 asmlinkage void __trap_section do_trap_load_misaligned(struct pt_regs *regs)
 {
+     irqentry_state_t state = irqentry_enter(regs);
      if (!handle_misaligned_load(regs))
              return;
      do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
                    "Oops - load address misaligned");
+     irqentry_exit(regs, state);
 }
 
 asmlinkage void __trap_section do_trap_store_misaligned(struct pt_regs *regs)
 {
+     irqentry_state_t state = irqentry_enter(regs);
      if (!handle_misaligned_store(regs))
              return;
      do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
                    "Oops - store (or AMO) address misaligned");
+     irqentry_exit(regs, state);
 }
 #endif
 DO_ERROR_INFO(do_trap_store_fault,
@@ -158,6 +165,8 @@ static inline unsigned long get_break_insn_length(unsigned long pc)
 
 asmlinkage __visible __trap_section void do_trap_break(struct pt_regs *regs)
 {
+     irqentry_state_t state = irqentry_enter(regs);
+
 #ifdef CONFIG_KPROBES
      if (kprobe_single_step_handler(regs))
              return;
@@ -185,6 +194,8 @@ asmlinkage __visible __trap_section void do_trap_break(struct pt_regs *regs)
              regs->epc += get_break_insn_length(regs->epc);
      else
              die(regs, "Kernel BUG");
+
+     irqentry_exit(regs, state);
 }
 NOKPROBE_SYMBOL(do_trap_break);
Quoted 14 lines

arch/riscv/mm/fault.c asmlinkage void do_page_fault(struct pt_regs *regs) · line 363

Quoted 9 lines
arch/riscv/mm/fault.c +8 -0
+asmlinkage void do_page_fault(struct pt_regs *regs)
+{
+     irqentry_state_t state = irqentry_enter(regs);
+
+     __do_page_fault(regs);
+
+     irqentry_exit(regs, state);
+}
 NOKPROBE_SYMBOL(do_page_fault);

Without noinstr the compiler is free to insert instrumentation (think all the k*SAN, KCov, GCov, ftrace etc..) which can call code we're not yet ready to run this early in the entry path, for instance it could rely on RCU which isn't on yet, or expect lockdep state.

I'll add a patch to fix it in the next version. Thx for pointing it out.

Quoted 2 lines
Signature · 2 lines
Best Regards
 Guo Ren
#7 lore raw

PATCH v3 5/7 riscv: Support HAVE_IRQ_EXIT_ON_IRQ_STACK

In reply to [email protected]

From: Guo Ren <[email protected]>

Add independent irq stacks for percpu to prevent kernel stack overflows. It is also compatible with VMAP_STACK by implementing arch_alloc_vmap_stack. Many architectures have supported HAVE_IRQ_EXIT_ON_IRQ_STACK, riscv should follow up.

---
 arch/riscv/Kconfig                   |  8 +++++
 arch/riscv/include/asm/irq.h         |  3 ++
 arch/riscv/include/asm/thread_info.h |  2 ++
 arch/riscv/include/asm/vmap_stack.h  | 28 ++++++++++++++++
 arch/riscv/kernel/entry.S            | 27 ++++++++++++++++
 arch/riscv/kernel/irq.c              | 48 ++++++++++++++++++++++++++--
 6 files changed, 114 insertions(+), 2 deletions(-)
 create mode 100644 arch/riscv/include/asm/vmap_stack.h
arch/riscv/Kconfig +8 -0
index a07bb3b73b5b..a8a12b4ba1a9 100644
@@ -433,6 +433,14 @@ config FPU
 
 	  If you don't know what to do here, say Y.
 
+config IRQ_STACKS
+	bool "Independent irq stacks"
+	default y
+	select HAVE_IRQ_EXIT_ON_IRQ_STACK
+	help
+	  Add independent irq stacks for percpu to prevent kernel stack overflows.
+	  We may save some memory footprint by disabling IRQ_STACKS.
+
 endmenu # "Platform type"
 
 menu "Kernel features"
arch/riscv/include/asm/irq.h +3 -0
index e4c435509983..205e1c693dfd 100644
@@ -13,5 +13,8 @@
 #include <asm-generic/irq.h>
 
 extern void __init init_IRQ(void);
+asmlinkage void call_on_stack(struct pt_regs *regs, ulong *sp,
+				     void (*fn)(struct pt_regs *), ulong tmp);
+asmlinkage void noinstr do_riscv_irq(struct pt_regs *regs);
 
 #endif /* _ASM_RISCV_IRQ_H */
arch/riscv/include/asm/thread_info.h +2 -0
index 7de4fb96f0b5..043da8ccc7e6 100644
@@ -40,6 +40,8 @@
 #define OVERFLOW_STACK_SIZE     SZ_4K
 #define SHADOW_OVERFLOW_STACK_SIZE (1024)
 
+#define IRQ_STACK_SIZE		THREAD_SIZE
+
 #ifndef __ASSEMBLY__
 
 extern long shadow_stack[SHADOW_OVERFLOW_STACK_SIZE / sizeof(long)];
arch/riscv/include/asm/vmap_stack.h new file +28 -0
new file mode 100644
index 000000000000..3fbf481abf4f
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+// Copied from arch/arm64/include/asm/vmap_stack.h.
+#ifndef _ASM_RISCV_VMAP_STACK_H
+#define _ASM_RISCV_VMAP_STACK_H
+
+#include <linux/bug.h>
+#include <linux/gfp.h>
+#include <linux/kconfig.h>
+#include <linux/vmalloc.h>
+#include <linux/pgtable.h>
+#include <asm/thread_info.h>
+
+/*
+ * To ensure that VMAP'd stack overflow detection works correctly, all VMAP'd
+ * stacks need to have the same alignment.
+ */
+static inline unsigned long *arch_alloc_vmap_stack(size_t stack_size, int node)
+{
+	void *p;
+
+	BUILD_BUG_ON(!IS_ENABLED(CONFIG_VMAP_STACK));
+
+	p = __vmalloc_node(stack_size, THREAD_ALIGN, THREADINFO_GFP, node,
+			__builtin_return_address(0));
+	return kasan_reset_tag(p);
+}
+
+#endif /* _ASM_RISCV_VMAP_STACK_H */
arch/riscv/kernel/entry.S +27 -0
index 5f49517cd3a2..551ce4c25698 100644
@@ -332,6 +332,33 @@ ENTRY(ret_from_kernel_thread)
 	tail syscall_exit_to_user_mode
 ENDPROC(ret_from_kernel_thread)
 
+#ifdef CONFIG_IRQ_STACKS
+ENTRY(call_on_stack)
+	/* Create a frame record to save our ra and fp */
+	addi	sp, sp, -RISCV_SZPTR
+	REG_S	ra, (sp)
+	addi	sp, sp, -RISCV_SZPTR
+	REG_S	fp, (sp)
+
+	/* Save sp in fp */
+	move	fp, sp
+
+	/* Move to the new stack and call the function there */
+	la	a3, IRQ_STACK_SIZE
+	add	sp, a1, a3
+	jalr	a2
+
+	/*
+	 * Restore sp from prev fp, and fp, ra from the frame
+	 */
+	move	sp, fp
+	REG_L	fp, (sp)
+	addi	sp, sp, RISCV_SZPTR
+	REG_L	ra, (sp)
+	addi	sp, sp, RISCV_SZPTR
+	ret
+ENDPROC(call_on_stack)
+#endif
 
 /*
  * Integer register context switch
arch/riscv/kernel/irq.c +46 -2

73 lines not on this page · raw message

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#8 lore raw

PATCH v3 6/7 riscv: Support HAVE_SOFTIRQ_ON_OWN_STACK

In reply to [email protected]

From: Guo Ren <[email protected]>

Add the HAVE_SOFTIRQ_ON_OWN_STACK feature for the IRQ_STACKS config. The irq and softirq use the same independent irq_stack of percpu by time division multiplexing.

---
 arch/riscv/Kconfig      |  7 ++++---
 arch/riscv/kernel/irq.c | 16 ++++++++++++++++
 2 files changed, 20 insertions(+), 3 deletions(-)
arch/riscv/Kconfig +4 -3
index a8a12b4ba1a9..da548ed7d107 100644
@@ -434,12 +434,13 @@ config FPU
 	  If you don't know what to do here, say Y.
 
 config IRQ_STACKS
-	bool "Independent irq stacks"
+	bool "Independent irq & softirq stacks"
 	default y
 	select HAVE_IRQ_EXIT_ON_IRQ_STACK
+	select HAVE_SOFTIRQ_ON_OWN_STACK
 	help
-	  Add independent irq stacks for percpu to prevent kernel stack overflows.
-	  We may save some memory footprint by disabling IRQ_STACKS.
+	  Add independent irq & softirq stacks for percpu to prevent kernel stack
+	  overflows. We may save some memory footprint by disabling IRQ_STACKS.
 
 endmenu # "Platform type"
 
arch/riscv/kernel/irq.c +16 -0
index 5ad4952203c5..c09cd4d28308 100644
@@ -11,6 +11,7 @@
 #include <linux/seq_file.h>
 #include <asm/smp.h>
 #include <asm/vmap_stack.h>
+#include <asm/softirq_stack.h>
 
 #ifdef CONFIG_IRQ_STACKS
 static DEFINE_PER_CPU(ulong *, irq_stack_ptr);
@@ -38,6 +39,21 @@ static void init_irq_stacks(void)
 		per_cpu(irq_stack_ptr, cpu) = per_cpu(irq_stack, cpu);
 }
 #endif /* CONFIG_VMAP_STACK */
+
+#ifndef CONFIG_PREEMPT_RT
+static void do_riscv_softirq(struct pt_regs *regs)
+{
+	__do_softirq();
+}
+
+void do_softirq_own_stack(void)
+{
+	ulong *sp = per_cpu(irq_stack_ptr, smp_processor_id());
+
+	call_on_stack(NULL, sp, do_riscv_softirq, 0);
+}
+#endif /* CONFIG_PREEMPT_RT */
+
 #else
 static void init_irq_stacks(void) {}
 #endif /* CONFIG_IRQ_STACKS */
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#9 lore raw

PATCH v3 7/7 riscv: Add config of thread stack size

In reply to [email protected]

From: Guo Ren <[email protected]>

0cac21b02ba5 ("risc v: use 16KB kernel stack on 64-bit") increase the thread size mandatory, but some scenarios, such as D1 with a small memory footprint, would suffer from that. After independent irq stack support, let's give users a choice to determine their custom stack size.

---
 arch/riscv/Kconfig                   | 9 +++++++++
 arch/riscv/include/asm/thread_info.h | 4 ++--
 2 files changed, 11 insertions(+), 2 deletions(-)
arch/riscv/Kconfig +9 -0
index da548ed7d107..e436b5793ab6 100644
@@ -442,6 +442,15 @@ config IRQ_STACKS
 	  Add independent irq & softirq stacks for percpu to prevent kernel stack
 	  overflows. We may save some memory footprint by disabling IRQ_STACKS.
 
+config THREAD_SIZE_ORDER
+	int "Pages of thread stack size (as a power of 2)"
+	range 1 4
+	default "1" if 32BIT
+	default "2" if 64BIT
+	help
+	  Specify the Pages of thread stack size (from 8KB to 64KB), which also
+	  affects irq stack size, which is equal to thread stack size.
+
 endmenu # "Platform type"
 
 menu "Kernel features"
arch/riscv/include/asm/thread_info.h +2 -2
index 043da8ccc7e6..c64d995df6e1 100644
@@ -19,9 +19,9 @@
 
 /* thread information allocation */
 #ifdef CONFIG_64BIT
-#define THREAD_SIZE_ORDER	(2 + KASAN_STACK_ORDER)
+#define THREAD_SIZE_ORDER	(CONFIG_THREAD_SIZE_ORDER + KASAN_STACK_ORDER)
 #else
-#define THREAD_SIZE_ORDER	(1 + KASAN_STACK_ORDER)
+#define THREAD_SIZE_ORDER	(CONFIG_THREAD_SIZE_ORDER + KASAN_STACK_ORDER)
 #endif
 #define THREAD_SIZE		(PAGE_SIZE << THREAD_SIZE_ORDER)
 
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#10 lore raw
In reply to [email protected]
Quoted 6 lines · On 06/09/2022 04:54, [email protected] wrote:

From: Guo Ren <[email protected]>

The patches convert riscv to use the generic entry infrastructure from kernel/entry/*. Add independent irq stacks (IRQ_STACKS) for percpu to prevent kernel stack overflows. Add the HAVE_SOFTIRQ_ON_OWN_STACK feature for the IRQ_STACKS config. You can try it directly with [1].

Hey Guo Ren,
I applied this patchset to v6.0-rc4 & ran into a build error:
/stuff/linux/arch/riscv/kernel/entry.S:347:9: error: operand must be a bare symbol name
la a3, ((1 << (12)) << (2 + 0))

        ^

CC arch/riscv/kernel/process.o
make[5]: *** [/stuff/linux/scripts/Makefile.build:322: arch/riscv/kernel/entry.o] Error 1 make[5]: *** Waiting for unfinished jobs....

Thanks,
Conor.

Quoted 42 lines

[1] https://github.com/guoren83/linux/tree/generic_entry_v3

V3:
- Fixup CONFIG_COMPAT=n compile error
- Add THREAD_SIZE_ORDER config
- Optimize elf_kexec.c warning fixup
- Add static to irq_stack_ptr definition

V2:

- Fixup compile error by include "riscv: ptrace: Remove duplicate operation"
- Fixup compile warning

- Add test repo link in cover letter

V1:

Guo Ren (7):
riscv: elf_kexec: Fixup compile warning
riscv: compat_syscall_table: Fixup compile warning
riscv: ptrace: Remove duplicate operation
riscv: convert to generic entry
riscv: Support HAVE_IRQ_EXIT_ON_IRQ_STACK
riscv: Support HAVE_SOFTIRQ_ON_OWN_STACK
riscv: Add config of thread stack size

 arch/riscv/Kconfig                    |  19 ++
 arch/riscv/include/asm/csr.h          |   1 -
 arch/riscv/include/asm/entry-common.h |   8 +
 arch/riscv/include/asm/irq.h          |   3 +
 arch/riscv/include/asm/ptrace.h       |  10 +-
 arch/riscv/include/asm/stacktrace.h   |   5 +
 arch/riscv/include/asm/syscall.h      |   6 +
 arch/riscv/include/asm/thread_info.h  |  19 +-
 arch/riscv/include/asm/vmap_stack.h   |  28 +++
 arch/riscv/kernel/Makefile            |   1 +
 arch/riscv/kernel/elf_kexec.c         |   2 +-
 arch/riscv/kernel/entry.S             | 255 +++++---------------------
 arch/riscv/kernel/irq.c               |  75 ++++++++
Quoted 9 lines
 arch/riscv/kernel/ptrace.c            |  41 -----
 arch/riscv/kernel/signal.c            |  21 +--
 arch/riscv/kernel/sys_riscv.c         |  27 +++
 arch/riscv/kernel/traps.c             |  11 ++
 arch/riscv/mm/fault.c                 |  12 +-
 18 files changed, 259 insertions(+), 285 deletions(-)
 create mode 100644 arch/riscv/include/asm/entry-common.h
 create mode 100644 arch/riscv/include/asm/vmap_stack.h

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author
#11 lore raw
Quoted 9 lines · On Wed, Sep 7, 2022 at 1:42 AM <[email protected]> wrote:
Quoted 6 lines · On 06/09/2022 04:54, [email protected] wrote:

From: Guo Ren <[email protected]>

The patches convert riscv to use the generic entry infrastructure from kernel/entry/*. Add independent irq stacks (IRQ_STACKS) for percpu to prevent kernel stack overflows. Add the HAVE_SOFTIRQ_ON_OWN_STACK feature for the IRQ_STACKS config. You can try it directly with [1].

Quoted 4 lines

Hey Guo Ren,
I applied this patchset to v6.0-rc4 & ran into a build error:
/stuff/linux/arch/riscv/kernel/entry.S:347:9: error: operand must be a bare symbol name
la a3, ((1 << (12)) << (2 + 0))

Yes, please try:

-       la      a3, IRQ_STACK_SIZE
+       li      a3, IRQ_STACK_SIZE

la is for the symbol, not immediate. But why does my toolchain not report the error?

➜ linux git:(generic_entry_v3) make ARCH=riscv CROSS_COMPILE=riscv64-unknown-linux-gnu- EXTRA_CFLAGS+=-g O=../build-riscv/ -kj62 all -kj
➜ linux git:(generic_entry_v3) riscv64-unknown-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=riscv64-unknown-linux-gnu-gcc COLLECT_LTO_WRAPPER=/opt/riscv/libexec/gcc/riscv64-unknown-linux-gnu/11.1.0/lto-wrapper
Target: riscv64-unknown-linux-gnu
Configured with:
/home/guoren/source/riscv-gnu-toolchain/riscv-gcc/configure --target=riscv64-unknown-linux-gnu --prefix=/opt/riscv --with-sysroot=/opt/riscv/sysroot --with-pkgversion=g5964b5cd7272 --with-system-zlib --enable-shared --enable-tls --enable-languages=c,c++,fortran --disable-libmudflap --disable-libssp --disable-libquadmath --disable-libsanitizer --disable-nls --disable-bootstrap --src=.././riscv-gcc --enable-multilib --with-abi=lp64d --with-arch=rv64imafdc --with-tune=rocket
--with-isa-spec=2.2 'CFLAGS_FOR_TARGET=-O2 -mcmodel=medlow'
'CXXFLAGS_FOR_TARGET=-O2 -mcmodel=medlow'
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 11.1.0 (g5964b5cd7272)

Quoted 58 lines
        ^

CC arch/riscv/kernel/process.o
make[5]: *** [/stuff/linux/scripts/Makefile.build:322: arch/riscv/kernel/entry.o] Error 1 make[5]: *** Waiting for unfinished jobs....

Thanks,
Conor.

Quoted 51 lines

[1] https://github.com/guoren83/linux/tree/generic_entry_v3

V3:
- Fixup CONFIG_COMPAT=n compile error
- Add THREAD_SIZE_ORDER config
- Optimize elf_kexec.c warning fixup
- Add static to irq_stack_ptr definition

V2:

- Fixup compile error by include "riscv: ptrace: Remove duplicate operation"
- Fixup compile warning

- Add test repo link in cover letter

V1:

Guo Ren (7):
riscv: elf_kexec: Fixup compile warning
riscv: compat_syscall_table: Fixup compile warning
riscv: ptrace: Remove duplicate operation
riscv: convert to generic entry
riscv: Support HAVE_IRQ_EXIT_ON_IRQ_STACK
riscv: Support HAVE_SOFTIRQ_ON_OWN_STACK
riscv: Add config of thread stack size

 arch/riscv/Kconfig                    |  19 ++
 arch/riscv/include/asm/csr.h          |   1 -
 arch/riscv/include/asm/entry-common.h |   8 +
 arch/riscv/include/asm/irq.h          |   3 +
 arch/riscv/include/asm/ptrace.h       |  10 +-
 arch/riscv/include/asm/stacktrace.h   |   5 +
 arch/riscv/include/asm/syscall.h      |   6 +
 arch/riscv/include/asm/thread_info.h  |  19 +-
 arch/riscv/include/asm/vmap_stack.h   |  28 +++
 arch/riscv/kernel/Makefile            |   1 +
 arch/riscv/kernel/elf_kexec.c         |   2 +-
 arch/riscv/kernel/entry.S             | 255 +++++---------------------
 arch/riscv/kernel/irq.c               |  75 ++++++++
 arch/riscv/kernel/ptrace.c            |  41 -----
 arch/riscv/kernel/signal.c            |  21 +--
 arch/riscv/kernel/sys_riscv.c         |  27 +++
 arch/riscv/kernel/traps.c             |  11 ++
 arch/riscv/mm/fault.c                 |  12 +-
 18 files changed, 259 insertions(+), 285 deletions(-)
 create mode 100644 arch/riscv/include/asm/entry-common.h
 create mode 100644 arch/riscv/include/asm/vmap_stack.h
Signature · 2 lines
Best Regards
 Guo Ren
author
#12 lore raw

Hi Conor,

I've found the root cause, you are using llvm:

$ grep "bare sym" llvm -rn |grep RISCV
llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp:1296: return
Error(ErrorLoc, "operand must be a bare symbol name");
llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp:1304: return
Error(ErrorLoc, "operand must be a bare symbol name");

That means we could fix up Binutils with a warning at least.

Thx for pointing it out.

Quoted 111 lines · Guo Ren
Quoted 9 lines · On Wed, Sep 7, 2022 at 1:42 AM <[email protected]> wrote:
Quoted 6 lines · On 06/09/2022 04:54, [email protected] wrote:

From: Guo Ren <[email protected]>

The patches convert riscv to use the generic entry infrastructure from kernel/entry/*. Add independent irq stacks (IRQ_STACKS) for percpu to prevent kernel stack overflows. Add the HAVE_SOFTIRQ_ON_OWN_STACK feature for the IRQ_STACKS config. You can try it directly with [1].

Quoted 4 lines

Hey Guo Ren,
I applied this patchset to v6.0-rc4 & ran into a build error:
/stuff/linux/arch/riscv/kernel/entry.S:347:9: error: operand must be a bare symbol name
la a3, ((1 << (12)) << (2 + 0))

Yes, please try:

(quoted diff) +1 -1
-       la      a3, IRQ_STACK_SIZE
+       li      a3, IRQ_STACK_SIZE

la is for the symbol, not immediate. But why does my toolchain not report the error?

➜ linux git:(generic_entry_v3) make ARCH=riscv CROSS_COMPILE=riscv64-unknown-linux-gnu- EXTRA_CFLAGS+=-g O=../build-riscv/ -kj62 all -kj
➜ linux git:(generic_entry_v3) riscv64-unknown-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=riscv64-unknown-linux-gnu-gcc COLLECT_LTO_WRAPPER=/opt/riscv/libexec/gcc/riscv64-unknown-linux-gnu/11.1.0/lto-wrapper
Target: riscv64-unknown-linux-gnu
Configured with:
/home/guoren/source/riscv-gnu-toolchain/riscv-gcc/configure --target=riscv64-unknown-linux-gnu --prefix=/opt/riscv --with-sysroot=/opt/riscv/sysroot --with-pkgversion=g5964b5cd7272 --with-system-zlib --enable-shared --enable-tls --enable-languages=c,c++,fortran --disable-libmudflap --disable-libssp --disable-libquadmath --disable-libsanitizer --disable-nls --disable-bootstrap --src=.././riscv-gcc --enable-multilib --with-abi=lp64d --with-arch=rv64imafdc --with-tune=rocket
--with-isa-spec=2.2 'CFLAGS_FOR_TARGET=-O2 -mcmodel=medlow'
'CXXFLAGS_FOR_TARGET=-O2 -mcmodel=medlow'
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 11.1.0 (g5964b5cd7272)

Quoted 58 lines
        ^

CC arch/riscv/kernel/process.o
make[5]: *** [/stuff/linux/scripts/Makefile.build:322: arch/riscv/kernel/entry.o] Error 1 make[5]: *** Waiting for unfinished jobs....

Thanks,
Conor.

Quoted 51 lines

[1] https://github.com/guoren83/linux/tree/generic_entry_v3

V3:
- Fixup CONFIG_COMPAT=n compile error
- Add THREAD_SIZE_ORDER config
- Optimize elf_kexec.c warning fixup
- Add static to irq_stack_ptr definition

V2:

- Fixup compile error by include "riscv: ptrace: Remove duplicate operation"
- Fixup compile warning

- Add test repo link in cover letter

V1:

Guo Ren (7):
riscv: elf_kexec: Fixup compile warning
riscv: compat_syscall_table: Fixup compile warning
riscv: ptrace: Remove duplicate operation
riscv: convert to generic entry
riscv: Support HAVE_IRQ_EXIT_ON_IRQ_STACK
riscv: Support HAVE_SOFTIRQ_ON_OWN_STACK
riscv: Add config of thread stack size

 arch/riscv/Kconfig                    |  19 ++
 arch/riscv/include/asm/csr.h          |   1 -
 arch/riscv/include/asm/entry-common.h |   8 +
 arch/riscv/include/asm/irq.h          |   3 +
 arch/riscv/include/asm/ptrace.h       |  10 +-
 arch/riscv/include/asm/stacktrace.h   |   5 +
 arch/riscv/include/asm/syscall.h      |   6 +
 arch/riscv/include/asm/thread_info.h  |  19 +-
 arch/riscv/include/asm/vmap_stack.h   |  28 +++
 arch/riscv/kernel/Makefile            |   1 +
 arch/riscv/kernel/elf_kexec.c         |   2 +-
 arch/riscv/kernel/entry.S             | 255 +++++---------------------
 arch/riscv/kernel/irq.c               |  75 ++++++++
 arch/riscv/kernel/ptrace.c            |  41 -----
 arch/riscv/kernel/signal.c            |  21 +--
 arch/riscv/kernel/sys_riscv.c         |  27 +++
 arch/riscv/kernel/traps.c             |  11 ++
 arch/riscv/mm/fault.c                 |  12 +-
 18 files changed, 259 insertions(+), 285 deletions(-)
 create mode 100644 arch/riscv/include/asm/entry-common.h
 create mode 100644 arch/riscv/include/asm/vmap_stack.h

--
Best Regards
Guo Ren

Signature · 2 lines
Best Regards
 Guo Ren
#13 lore raw
Quoted 5 lines · Guo Ren

EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe

Hi Conor,

I've found the root cause, you are using llvm:

Yup, probably should have specified - sorry. I didn't realise that that was something GCC wouldn't complain about. It was an LLVM=1 build with clang-15.

I usually do builds with clang while testing patches as it seems to be lesser used.

Thanks,
Conor.

Quoted 129 lines
$ grep "bare sym" llvm -rn |grep RISCV
llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp:1296: return
Error(ErrorLoc, "operand must be a bare symbol name");
llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp:1304: return
Error(ErrorLoc, "operand must be a bare symbol name");

That means we could fix up Binutils with a warning at least.

Thx for pointing it out.

Quoted 108 lines · Guo Ren
Quoted 9 lines · On Wed, Sep 7, 2022 at 1:42 AM <[email protected]> wrote:
Quoted 6 lines · On 06/09/2022 04:54, [email protected] wrote:

From: Guo Ren <[email protected]>

The patches convert riscv to use the generic entry infrastructure from kernel/entry/*. Add independent irq stacks (IRQ_STACKS) for percpu to prevent kernel stack overflows. Add the HAVE_SOFTIRQ_ON_OWN_STACK feature for the IRQ_STACKS config. You can try it directly with [1].

Quoted 4 lines

Hey Guo Ren,
I applied this patchset to v6.0-rc4 & ran into a build error:
/stuff/linux/arch/riscv/kernel/entry.S:347:9: error: operand must be a bare symbol name
la a3, ((1 << (12)) << (2 + 0))

Yes, please try:

(quoted diff) +1 -1
-       la      a3, IRQ_STACK_SIZE
+       li      a3, IRQ_STACK_SIZE

la is for the symbol, not immediate. But why does my toolchain not report the error?

➜ linux git:(generic_entry_v3) make ARCH=riscv CROSS_COMPILE=riscv64-unknown-linux-gnu- EXTRA_CFLAGS+=-g O=../build-riscv/ -kj62 all -kj
➜ linux git:(generic_entry_v3) riscv64-unknown-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=riscv64-unknown-linux-gnu-gcc COLLECT_LTO_WRAPPER=/opt/riscv/libexec/gcc/riscv64-unknown-linux-gnu/11.1.0/lto-wrapper
Target: riscv64-unknown-linux-gnu
Configured with:
/home/guoren/source/riscv-gnu-toolchain/riscv-gcc/configure --target=riscv64-unknown-linux-gnu --prefix=/opt/riscv --with-sysroot=/opt/riscv/sysroot --with-pkgversion=g5964b5cd7272 --with-system-zlib --enable-shared --enable-tls --enable-languages=c,c++,fortran --disable-libmudflap --disable-libssp --disable-libquadmath --disable-libsanitizer --disable-nls --disable-bootstrap --src=.././riscv-gcc --enable-multilib --with-abi=lp64d --with-arch=rv64imafdc --with-tune=rocket
--with-isa-spec=2.2 'CFLAGS_FOR_TARGET=-O2 -mcmodel=medlow'
'CXXFLAGS_FOR_TARGET=-O2 -mcmodel=medlow'
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 11.1.0 (g5964b5cd7272)

Quoted 58 lines
         ^

CC arch/riscv/kernel/process.o
make[5]: *** [/stuff/linux/scripts/Makefile.build:322: arch/riscv/kernel/entry.o] Error 1 make[5]: *** Waiting for unfinished jobs....

Thanks,
Conor.

Quoted 51 lines

[1] https://github.com/guoren83/linux/tree/generic_entry_v3

V3:
- Fixup CONFIG_COMPAT=n compile error
- Add THREAD_SIZE_ORDER config
- Optimize elf_kexec.c warning fixup
- Add static to irq_stack_ptr definition

V2:

- Fixup compile error by include "riscv: ptrace: Remove duplicate operation"
- Fixup compile warning

- Add test repo link in cover letter

V1:

Guo Ren (7):
riscv: elf_kexec: Fixup compile warning
riscv: compat_syscall_table: Fixup compile warning
riscv: ptrace: Remove duplicate operation
riscv: convert to generic entry
riscv: Support HAVE_IRQ_EXIT_ON_IRQ_STACK
riscv: Support HAVE_SOFTIRQ_ON_OWN_STACK
riscv: Add config of thread stack size

  arch/riscv/Kconfig                    |  19 ++
  arch/riscv/include/asm/csr.h          |   1 -
  arch/riscv/include/asm/entry-common.h |   8 +
  arch/riscv/include/asm/irq.h          |   3 +
  arch/riscv/include/asm/ptrace.h       |  10 +-
  arch/riscv/include/asm/stacktrace.h   |   5 +
  arch/riscv/include/asm/syscall.h      |   6 +
  arch/riscv/include/asm/thread_info.h  |  19 +-
  arch/riscv/include/asm/vmap_stack.h   |  28 +++
  arch/riscv/kernel/Makefile            |   1 +
  arch/riscv/kernel/elf_kexec.c         |   2 +-
  arch/riscv/kernel/entry.S             | 255 +++++---------------------
  arch/riscv/kernel/irq.c               |  75 ++++++++
  arch/riscv/kernel/ptrace.c            |  41 -----
  arch/riscv/kernel/signal.c            |  21 +--
  arch/riscv/kernel/sys_riscv.c         |  27 +++
  arch/riscv/kernel/traps.c             |  11 ++
  arch/riscv/mm/fault.c                 |  12 +-
  18 files changed, 259 insertions(+), 285 deletions(-)

create mode 100644 arch/riscv/include/asm/entry-common.h create mode 100644 arch/riscv/include/asm/vmap_stack.h

Quoted 3 lines

--
Best Regards
Guo Ren

--
Best Regards
Guo Ren

author
#14 lore raw
Quoted 9 lines · On Wed, Sep 7, 2022 at 2:23 PM <[email protected]> wrote:
Quoted 5 lines · Guo Ren

EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe

Hi Conor,

I've found the root cause, you are using llvm:

Yup, probably should have specified - sorry. I didn't realise that

It's my typo bug. You reminded me of using clang.

Quoted 139 lines

that was something GCC wouldn't complain about. It was an LLVM=1 build with clang-15.

I usually do builds with clang while testing patches as it seems to be lesser used.

Thanks,
Conor.

Quoted 129 lines
$ grep "bare sym" llvm -rn |grep RISCV
llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp:1296: return
Error(ErrorLoc, "operand must be a bare symbol name");
llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp:1304: return
Error(ErrorLoc, "operand must be a bare symbol name");

That means we could fix up Binutils with a warning at least.

Thx for pointing it out.

Quoted 108 lines · Guo Ren
Quoted 9 lines · On Wed, Sep 7, 2022 at 1:42 AM <[email protected]> wrote:
Quoted 6 lines · On 06/09/2022 04:54, [email protected] wrote:

From: Guo Ren <[email protected]>

The patches convert riscv to use the generic entry infrastructure from kernel/entry/*. Add independent irq stacks (IRQ_STACKS) for percpu to prevent kernel stack overflows. Add the HAVE_SOFTIRQ_ON_OWN_STACK feature for the IRQ_STACKS config. You can try it directly with [1].

Quoted 4 lines

Hey Guo Ren,
I applied this patchset to v6.0-rc4 & ran into a build error:
/stuff/linux/arch/riscv/kernel/entry.S:347:9: error: operand must be a bare symbol name
la a3, ((1 << (12)) << (2 + 0))

Yes, please try:

(quoted diff) +1 -1
-       la      a3, IRQ_STACK_SIZE
+       li      a3, IRQ_STACK_SIZE

la is for the symbol, not immediate. But why does my toolchain not report the error?

➜ linux git:(generic_entry_v3) make ARCH=riscv CROSS_COMPILE=riscv64-unknown-linux-gnu- EXTRA_CFLAGS+=-g O=../build-riscv/ -kj62 all -kj
➜ linux git:(generic_entry_v3) riscv64-unknown-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=riscv64-unknown-linux-gnu-gcc COLLECT_LTO_WRAPPER=/opt/riscv/libexec/gcc/riscv64-unknown-linux-gnu/11.1.0/lto-wrapper
Target: riscv64-unknown-linux-gnu
Configured with:
/home/guoren/source/riscv-gnu-toolchain/riscv-gcc/configure --target=riscv64-unknown-linux-gnu --prefix=/opt/riscv --with-sysroot=/opt/riscv/sysroot --with-pkgversion=g5964b5cd7272 --with-system-zlib --enable-shared --enable-tls --enable-languages=c,c++,fortran --disable-libmudflap --disable-libssp --disable-libquadmath --disable-libsanitizer --disable-nls --disable-bootstrap --src=.././riscv-gcc --enable-multilib --with-abi=lp64d --with-arch=rv64imafdc --with-tune=rocket
--with-isa-spec=2.2 'CFLAGS_FOR_TARGET=-O2 -mcmodel=medlow'
'CXXFLAGS_FOR_TARGET=-O2 -mcmodel=medlow'
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 11.1.0 (g5964b5cd7272)

Quoted 58 lines
         ^

CC arch/riscv/kernel/process.o
make[5]: *** [/stuff/linux/scripts/Makefile.build:322: arch/riscv/kernel/entry.o] Error 1 make[5]: *** Waiting for unfinished jobs....

Thanks,
Conor.

Quoted 51 lines

[1] https://github.com/guoren83/linux/tree/generic_entry_v3

V3:
- Fixup CONFIG_COMPAT=n compile error
- Add THREAD_SIZE_ORDER config
- Optimize elf_kexec.c warning fixup
- Add static to irq_stack_ptr definition

V2:

- Fixup compile error by include "riscv: ptrace: Remove duplicate operation"
- Fixup compile warning

- Add test repo link in cover letter

V1:

Guo Ren (7):
riscv: elf_kexec: Fixup compile warning
riscv: compat_syscall_table: Fixup compile warning
riscv: ptrace: Remove duplicate operation
riscv: convert to generic entry
riscv: Support HAVE_IRQ_EXIT_ON_IRQ_STACK
riscv: Support HAVE_SOFTIRQ_ON_OWN_STACK
riscv: Add config of thread stack size

  arch/riscv/Kconfig                    |  19 ++
  arch/riscv/include/asm/csr.h          |   1 -
  arch/riscv/include/asm/entry-common.h |   8 +
  arch/riscv/include/asm/irq.h          |   3 +
  arch/riscv/include/asm/ptrace.h       |  10 +-
  arch/riscv/include/asm/stacktrace.h   |   5 +
  arch/riscv/include/asm/syscall.h      |   6 +
  arch/riscv/include/asm/thread_info.h  |  19 +-
  arch/riscv/include/asm/vmap_stack.h   |  28 +++
  arch/riscv/kernel/Makefile            |   1 +
  arch/riscv/kernel/elf_kexec.c         |   2 +-
  arch/riscv/kernel/entry.S             | 255 +++++---------------------
  arch/riscv/kernel/irq.c               |  75 ++++++++
  arch/riscv/kernel/ptrace.c            |  41 -----
  arch/riscv/kernel/signal.c            |  21 +--
  arch/riscv/kernel/sys_riscv.c         |  27 +++
  arch/riscv/kernel/traps.c             |  11 ++
  arch/riscv/mm/fault.c                 |  12 +-
  18 files changed, 259 insertions(+), 285 deletions(-)

create mode 100644 arch/riscv/include/asm/entry-common.h create mode 100644 arch/riscv/include/asm/vmap_stack.h

Quoted 3 lines

--
Best Regards
Guo Ren

--
Best Regards
Guo Ren

Signature · 2 lines
Best Regards
 Guo Ren