diff options
| -rw-r--r-- | arch/sh/Kconfig.debug | 11 | ||||
| -rw-r--r-- | arch/sh/kernel/asm-offsets.c | 1 | ||||
| -rw-r--r-- | arch/sh/lib/mcount.S | 85 |
3 files changed, 97 insertions, 0 deletions
diff --git a/arch/sh/Kconfig.debug b/arch/sh/Kconfig.debug index 39224b57c6e..52a132c24aa 100644 --- a/arch/sh/Kconfig.debug +++ b/arch/sh/Kconfig.debug @@ -123,4 +123,15 @@ config SH64_SR_WATCH bool "Debug: set SR.WATCH to enable hardware watchpoints and trace" depends on SUPERH64 +config STACK_DEBUG + bool "Enable diagnostic checks of the kernel stack" + depends on FUNCTION_TRACER + select DEBUG_STACKOVERFLOW + default n + help + This option allows checks to be performed on the kernel stack + at runtime. Saying Y here will add overhead to every function + call and will therefore incur a major performance hit. Most + users should say N. + endmenu diff --git a/arch/sh/kernel/asm-offsets.c b/arch/sh/kernel/asm-offsets.c index 99aceb28ee2..d218e808294 100644 --- a/arch/sh/kernel/asm-offsets.c +++ b/arch/sh/kernel/asm-offsets.c @@ -26,6 +26,7 @@ int main(void) DEFINE(TI_CPU, offsetof(struct thread_info, cpu)); DEFINE(TI_PRE_COUNT, offsetof(struct thread_info, preempt_count)); DEFINE(TI_RESTART_BLOCK,offsetof(struct thread_info, restart_block)); + DEFINE(TI_SIZE, sizeof(struct thread_info)); #ifdef CONFIG_HIBERNATION DEFINE(PBE_ADDRESS, offsetof(struct pbe, address)); diff --git a/arch/sh/lib/mcount.S b/arch/sh/lib/mcount.S index 71e87f9b4fd..8596483f7b4 100644 --- a/arch/sh/lib/mcount.S +++ b/arch/sh/lib/mcount.S @@ -9,6 +9,8 @@ * for more details. */ #include <asm/ftrace.h> +#include <asm/thread_info.h> +#include <asm/asm-offsets.h> #define MCOUNT_ENTER() \ mov.l r4, @-r15; \ @@ -28,6 +30,55 @@ rts; \ mov.l @r15+, r4 +#ifdef CONFIG_STACK_DEBUG +/* + * Perform diagnostic checks on the state of the kernel stack. + * + * Check for stack overflow. If there is less than 1KB free + * then it has overflowed. + * + * Make sure the stack pointer contains a valid address. Valid + * addresses for kernel stacks are anywhere after the bss + * (after _ebss) and anywhere in init_thread_union (init_stack). + */ +#define STACK_CHECK() \ + mov #(THREAD_SIZE >> 10), r0; \ + shll8 r0; \ + shll2 r0; \ + \ + /* r1 = sp & (THREAD_SIZE - 1) */ \ + mov #-1, r1; \ + add r0, r1; \ + and r15, r1; \ + \ + mov #TI_SIZE, r3; \ + mov #(STACK_WARN >> 8), r2; \ + shll8 r2; \ + add r3, r2; \ + \ + /* Is the stack overflowing? */ \ + cmp/hi r2, r1; \ + bf stack_panic; \ + \ + /* If sp > _ebss then we're OK. */ \ + mov.l .L_ebss, r1; \ + cmp/hi r1, r15; \ + bt 1f; \ + \ + /* If sp < init_stack, we're not OK. */ \ + mov.l .L_init_thread_union, r1; \ + cmp/hs r1, r15; \ + bf stack_panic; \ + \ + /* If sp > init_stack && sp < _ebss, not OK. */ \ + add r0, r1; \ + cmp/hs r1, r15; \ + bt stack_panic; \ +1: +#else +#define STACK_CHECK() +#endif /* CONFIG_STACK_DEBUG */ + .align 2 .globl _mcount .type _mcount,@function @@ -41,6 +92,8 @@ mcount: tst r0, r0 bf ftrace_stub #endif + STACK_CHECK() + MCOUNT_ENTER() #ifdef CONFIG_DYNAMIC_FTRACE @@ -73,6 +126,8 @@ ftrace_caller: tst r0, r0 bf ftrace_stub + STACK_CHECK() + MCOUNT_ENTER() .globl ftrace_call @@ -100,6 +155,36 @@ ftrace_stub: rts nop +#ifdef CONFIG_STACK_DEBUG + .globl stack_panic +stack_panic: + mov.l .Ldump_stack, r0 + jsr @r0 + nop + + mov.l .Lpanic, r0 + jsr @r0 + mov.l .Lpanic_s, r4 + + rts + nop + .align 2 .Lfunction_trace_stop: .long function_trace_stop +.L_ebss: + .long _ebss +.L_init_thread_union: + .long init_thread_union +.Lpanic: + .long panic +.Lpanic_s: + .long .Lpanic_str +.Ldump_stack: + .long dump_stack + + .section .rodata + .align 2 +.Lpanic_str: + .string "Stack error" +#endif /* CONFIG_STACK_DEBUG */ |