aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--arch/sh/Kconfig.debug11
-rw-r--r--arch/sh/kernel/asm-offsets.c1
-rw-r--r--arch/sh/lib/mcount.S85
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 */