Commit 467e6b7a authored by Mitsuo Hayasaka's avatar Mitsuo Hayasaka Committed by Ingo Molnar

x86: Clean up the range of stack overflow checking

The overflow checking of kernel stack checks if the stack
pointer points to the available kernel stack range, which is
derived from the original overflow checking.

It is clear that curbase address is always less than low
boundary of available kernel stack. So, this patch removes the
first condition that checks if the pointer is higher than
curbase.
Signed-off-by: default avatarMitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com>
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Randy Dunlap <rdunlap@xenotime.net>
Link: http://lkml.kernel.org/r/20111129060845.11076.40916.stgit@ltc219.sdl.hitachi.co.jpSigned-off-by: default avatarIngo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
parent 55af7796
...@@ -46,10 +46,9 @@ static inline void stack_overflow_check(struct pt_regs *regs) ...@@ -46,10 +46,9 @@ static inline void stack_overflow_check(struct pt_regs *regs)
if (user_mode_vm(regs)) if (user_mode_vm(regs))
return; return;
if (regs->sp >= curbase && if (regs->sp >= curbase + sizeof(struct thread_info) +
regs->sp <= curbase + THREAD_SIZE && sizeof(struct pt_regs) + 128 &&
regs->sp >= curbase + sizeof(struct thread_info) + regs->sp <= curbase + THREAD_SIZE)
sizeof(struct pt_regs) + 128)
return; return;
irq_stack_top = (u64)__get_cpu_var(irq_stack_union.irq_stack); irq_stack_top = (u64)__get_cpu_var(irq_stack_union.irq_stack);
......
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