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| author | Matt Fleming <matt@console-pimps.org> | 2009-07-11 01:00:23 +0000 |
|---|---|---|
| committer | Paul Mundt <lethal@linux-sh.org> | 2009-07-11 10:07:58 +0900 |
| commit | b99610fb9cdf390965c62c22322596d961591160 (patch) | |
| tree | 0c836b4390370b4848f151e3b3cbe27e6d8b48e2 /arch/sh/lib | |
| parent | c652d780c9cf7f860141de232b37160fe013feca (diff) | |
| download | linux-b99610fb9cdf390965c62c22322596d961591160.tar.gz | |
sh: Provide diagnostic kernel stack checks
Enable kernel stack checking code in both the dynamic ftrace and mcount code paths. Check the stack to see if it's overflowing and make sure that the stack pointer contains an address that's either in init_stack or after the bss. Signed-off-by: Matt Fleming <matt@console-pimps.org> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh/lib')
| -rw-r--r-- | arch/sh/lib/mcount.S | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/arch/sh/lib/mcount.S b/arch/sh/lib/mcount.S index 71e87f9b4fda..8596483f7b41 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 */ |