irq: Make irqentry text section unconditional
Subsystems (5)
PATCH v6 1/2 irq: Make irqentry text section unconditional
Generate irqentry and softirqentry text sections without any configs. This will add above extra sections, but no performace impact.
Signed-off-by Masami Hiramatsu <[email protected]>
Suggested-by Ingo Molnar <[email protected]>
--- arch/arm/include/asm/traps.h | 7 ------- arch/arm64/include/asm/traps.h | 7 ------- arch/x86/entry/entry_64.S | 9 ++------- include/asm-generic/sections.h | 4 ++++ include/asm-generic/vmlinux.lds.h | 8 -------- include/linux/interrupt.h | 14 +------------- 6 files changed, 7 insertions(+), 42 deletions(-)
arch/arm/include/asm/traps.h +0 -7
@@ -18,7 +18,6 @@ struct undef_hook {void register_undef_hook (struct undef_hook *hook);void unregister_undef_hook (struct undef_hook *hook); -#ifdef CONFIG_FUNCTION_GRAPH_TRACER static inline int __in_irqentry_text (unsigned long ptr) {extern char __irqentry_text_start[];
@@ -27,12 +26,6 @@ static inline int __in_irqentry_text(unsigned long ptr)return ptr >= (unsigned long )&__irqentry_text_start && ptr < (unsigned long )&__irqentry_text_end; } -#else -static inline int __in_irqentry_text (unsigned long ptr) -{ -return 0 ; -} -#endif static inline int in_exception_text (unsigned long ptr) {
arch/arm64/include/asm/traps.h +0 -7
@@ -37,18 +37,11 @@ void unregister_undef_hook(struct undef_hook *hook);void arm64_notify_segfault (struct pt_regs *regs,unsigned long addr); -#ifdef CONFIG_FUNCTION_GRAPH_TRACER static inline int __in_irqentry_text (unsigned long ptr) {return ptr >= (unsigned long )&__irqentry_text_start && ptr < (unsigned long )&__irqentry_text_end; } -#else -static inline int __in_irqentry_text (unsigned long ptr) -{ -return 0 ; -} -#endif static inline int in_exception_text (unsigned long ptr) {
arch/x86/entry/entry_64.S +2 -7
@@ -766,13 +766,8 @@ apicinterrupt3 \num trace(\sym) smp_trace(\sym) #endif /* Make sure APIC interrupt handlers end up in the irqentry section: */ -#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN) -# define PUSH_SECTION_IRQENTRY .pushsection .irqentry.text, "ax" -# define POP_SECTION_IRQENTRY .popsection -#else -# define PUSH_SECTION_IRQENTRY -# define POP_SECTION_IRQENTRY -#endif +#define PUSH_SECTION_IRQENTRY .pushsection .irqentry.text, "ax" +#define POP_SECTION_IRQENTRY .popsection .macro apicinterrupt num sym do_sym PUSH_SECTION_IRQENTRY
include/asm-generic/sections.h +4 -0
@@ -27,6 +27,8 @@* __kprobes_text_start, __kprobes_text_end * __entry_text_start, __entry_text_end * __ctors_start, __ctors_end +* __irqentry_text_start, __irqentry_text_end +* __softirqentry_text_start, __softirqentry_text_end */ extern char _text[], _stext[], _etext[];extern char _data[], _sdata[], _edata[];
@@ -39,6 +41,8 @@ extern char __per_cpu_load[], __per_cpu_start[], __per_cpu_end[];extern char __kprobes_text_start[], __kprobes_text_end[];extern char __entry_text_start[], __entry_text_end[];extern char __start_rodata[], __end_rodata[]; +extern char __irqentry_text_start[], __irqentry_text_end[]; +extern char __softirqentry_text_start[], __softirqentry_text_end[];/* Start and end of .ctors section - used for constructor calls. */ extern char __ctors_start[], __ctors_end[];
include/asm-generic/vmlinux.lds.h +0 -8
@@ -483,25 +483,17 @@ *(.entry.text) \ VMLINUX_SYMBOL(__entry_text_end) = .; -#if defined(CONFIG_FUNCTION_GRAPH_TRACER ) || defined(CONFIG_KASAN )#define IRQENTRY_TEXT \ ALIGN_FUNCTION(); \ VMLINUX_SYMBOL(__irqentry_text_start) = .; \ *(.irqentry.text) \ VMLINUX_SYMBOL(__irqentry_text_end) = .; -#else -#define IRQENTRY_TEXT -#endif -#if defined(CONFIG_FUNCTION_GRAPH_TRACER ) || defined(CONFIG_KASAN )#define SOFTIRQENTRY_TEXT \ ALIGN_FUNCTION(); \ VMLINUX_SYMBOL(__softirqentry_text_start) = .; \ *(.softirqentry.text) \ VMLINUX_SYMBOL(__softirqentry_text_end) = .; -#else -#define SOFTIRQENTRY_TEXT -#endif /* Section used for early init (in .S files) */ #define HEAD_TEXT *(.head.text)
include/linux/interrupt.h +1 -13
@@ -18,6 +18,7 @@#include <linux/atomic.h> #include <asm/ptrace.h> #include <asm/irq.h> +#include <asm/sections.h> /* * These correspond to the IORESOURCE_IRQ_* defines in
@@ -726,7 +727,6 @@ extern int early_irq_init(void);extern int arch_probe_nr_irqs (void );extern int arch_early_irq_init (void ); -#if defined(CONFIG_FUNCTION_GRAPH_TRACER ) || defined(CONFIG_KASAN )/* * We want to know which function is an entrypoint of a hardirq or a softirq. */
@@ -734,16 +734,4 @@ extern int arch_early_irq_init(void);#define __softirq_entry \ __attribute__((__section__(".softirqentry.text"))) -/* Limits of hardirq entrypoints */ -extern char __irqentry_text_start[]; -extern char __irqentry_text_end[]; -/* Limits of softirq entrypoints */ -extern char __softirqentry_text_start[]; -extern char __softirqentry_text_end[]; - -#else -#define __irq_entry -#define __softirq_entry -#endif -#endif
PATCH v6 2/2 kprobes/x86: Do not jump-optimize kprobes on irq entry code
Since the kernel segment registers are not prepared at the entry of irq-entry code, if a kprobe on such code is jump-optimized, accessing per-cpu variables may cause kernel panic.
However, if the kprobe is not optimized, it kicks int3 exception and set segment registers correctly.
This checks probe-address and if it is in irq-entry code, it prohibits optimizing such kprobes. This means we can continuously probing such interrupt handlers by kprobes but it is not optimized anymore.
Signed-off-by Masami Hiramatsu <[email protected]>
Reported-by Francis Deslauriers <[email protected]>
Tested-by Francis Deslauriers <[email protected]>
---
Changes in v6:
- Update for unconditional irqentry.
--- arch/x86/kernel/kprobes/opt.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
arch/x86/kernel/kprobes/opt.c +6 -3
@@ -39,6 +39,7 @@#include <asm/insn.h> #include <asm/debugreg.h> #include <asm/set_memory.h> +#include <asm/sections.h> #include "common.h"
@@ -251,10 +252,12 @@ static int can_optimize(unsigned long paddr)/* * Do not optimize in the entry code due to the unstable -* stack handling. +* stack handling and registers setup. */ -if ((paddr >= (unsigned long )__entry_text_start) && - (paddr < (unsigned long )__entry_text_end)) +if (((paddr >= (unsigned long )__entry_text_start) && + (paddr < (unsigned long )__entry_text_end)) || + ((paddr >= (unsigned long )__irqentry_text_start) && + (paddr < (unsigned long )__irqentry_text_end)))return 0 ;/* Check there is enough space for a relative jump. */
Quoted 6 lines · On Fri, 28 Jul 2017 21:24:54 +0900 Masami Hiramatsu <[email protected]> wrote:
Generate irqentry and softirqentry text sections without any configs. This will add above extra sections, but no performace impact.
Signed-off-by Masami Hiramatsu <[email protected]>Suggested-by Ingo Molnar <[email protected]>
Quoted 8 lines
--- arch/arm/include/asm/traps.h | 7 ------- arch/arm64/include/asm/traps.h | 7 ------- arch/x86/entry/entry_64.S | 9 ++------- include/asm-generic/sections.h | 4 ++++ include/asm-generic/vmlinux.lds.h | 8 -------- include/linux/interrupt.h | 14 +------------- 6 files changed, 7 insertions(+), 42 deletions(-)
Oops, I forgot to fix x86 unwind code.
I'll update this to fix in_entry_code() unconditional.
Thanks,
Quoted 159 lines
arch/arm/include/asm/traps.h +0
-7@@ -18,7 +18,6 @@ struct undef_hook {void register_undef_hook (struct undef_hook *hook);void unregister_undef_hook (struct undef_hook *hook); -#ifdef CONFIG_FUNCTION_GRAPH_TRACER static inline int __in_irqentry_text (unsigned long ptr) {extern char __irqentry_text_start[];@@ -27,12 +26,6 @@ static inline int __in_irqentry_text(unsigned long ptr)return ptr >= (unsigned long )&__irqentry_text_start && ptr < (unsigned long )&__irqentry_text_end; } -#else -static inline int __in_irqentry_text (unsigned long ptr) -{ -return 0 ; -} -#endif static inline int in_exception_text (unsigned long ptr) {arch/arm64/include/asm/traps.h +0
-7@@ -37,18 +37,11 @@ void unregister_undef_hook(struct undef_hook *hook);void arm64_notify_segfault (struct pt_regs *regs,unsigned long addr); -#ifdef CONFIG_FUNCTION_GRAPH_TRACER static inline int __in_irqentry_text (unsigned long ptr) {return ptr >= (unsigned long )&__irqentry_text_start && ptr < (unsigned long )&__irqentry_text_end; } -#else -static inline int __in_irqentry_text (unsigned long ptr) -{ -return 0 ; -} -#endif static inline int in_exception_text (unsigned long ptr) {arch/x86/entry/entry_64.S +2
-7@@ -766,13 +766,8 @@ apicinterrupt3 \num trace(\sym) smp_trace(\sym) #endif /* Make sure APIC interrupt handlers end up in the irqentry section: */ -#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN) -# define PUSH_SECTION_IRQENTRY .pushsection .irqentry.text, "ax" -# define POP_SECTION_IRQENTRY .popsection -#else -# define PUSH_SECTION_IRQENTRY -# define POP_SECTION_IRQENTRY -#endif +#define PUSH_SECTION_IRQENTRY .pushsection .irqentry.text, "ax" +#define POP_SECTION_IRQENTRY .popsection .macro apicinterrupt num sym do_sym PUSH_SECTION_IRQENTRYinclude/asm-generic/sections.h +4
-0@@ -27,6 +27,8 @@* __kprobes_text_start, __kprobes_text_end * __entry_text_start, __entry_text_end * __ctors_start, __ctors_end +* __irqentry_text_start, __irqentry_text_end +* __softirqentry_text_start, __softirqentry_text_end */ extern char _text[], _stext[], _etext[];extern char _data[], _sdata[], _edata[];@@ -39,6 +41,8 @@ extern char __per_cpu_load[], __per_cpu_start[], __per_cpu_end[];extern char __kprobes_text_start[], __kprobes_text_end[];extern char __entry_text_start[], __entry_text_end[];extern char __start_rodata[], __end_rodata[]; +extern char __irqentry_text_start[], __irqentry_text_end[]; +extern char __softirqentry_text_start[], __softirqentry_text_end[];/* Start and end of .ctors section - used for constructor calls. */ extern char __ctors_start[], __ctors_end[];include/asm-generic/vmlinux.lds.h +0
-8@@ -483,25 +483,17 @@ *(.entry.text) \ VMLINUX_SYMBOL(__entry_text_end) = .; -#if defined(CONFIG_FUNCTION_GRAPH_TRACER ) || defined(CONFIG_KASAN )#define IRQENTRY_TEXT \ ALIGN_FUNCTION(); \ VMLINUX_SYMBOL(__irqentry_text_start) = .; \ *(.irqentry.text) \ VMLINUX_SYMBOL(__irqentry_text_end) = .; -#else -#define IRQENTRY_TEXT -#endif -#if defined(CONFIG_FUNCTION_GRAPH_TRACER ) || defined(CONFIG_KASAN )#define SOFTIRQENTRY_TEXT \ ALIGN_FUNCTION(); \ VMLINUX_SYMBOL(__softirqentry_text_start) = .; \ *(.softirqentry.text) \ VMLINUX_SYMBOL(__softirqentry_text_end) = .; -#else -#define SOFTIRQENTRY_TEXT -#endif /* Section used for early init (in .S files) */ #define HEAD_TEXT *(.head.text)include/linux/interrupt.h +1
-13@@ -18,6 +18,7 @@#include <linux/atomic.h> #include <asm/ptrace.h> #include <asm/irq.h> +#include <asm/sections.h> /* * These correspond to the IORESOURCE_IRQ_* defines in @@ -726,7 +727,6 @@ extern int early_irq_init(void);extern int arch_probe_nr_irqs (void );extern int arch_early_irq_init (void ); -#if defined(CONFIG_FUNCTION_GRAPH_TRACER ) || defined(CONFIG_KASAN )/* * We want to know which function is an entrypoint of a hardirq or a softirq. */ @@ -734,16 +734,4 @@ extern int arch_early_irq_init(void);#define __softirq_entry \ __attribute__((__section__(".softirqentry.text"))) -/* Limits of hardirq entrypoints */ -extern char __irqentry_text_start[]; -extern char __irqentry_text_end[]; -/* Limits of softirq entrypoints */ -extern char __softirqentry_text_start[]; -extern char __softirqentry_text_end[]; - -#else -#define __irq_entry -#define __softirq_entry -#endif -#endif
Signature · 1 line
Masami Hiramatsu <[email protected]>