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xtensa: Implement "current_stack_pointer"

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To follow the existing per-arch conventions replace open-coded uses
of asm "sp" as "current_stack_pointer". This will let it be used in
non-arch places (like HARDENED_USERCOPY).

Cc: Chris Zankel <chris@zankel.net>
Cc: Marc Zyngier <maz@kernel.org>
Cc: linux-xtensa@linux-xtensa.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Link: https://lore.kernel.org/lkml/CAMo8BfJFJE-n3=AF+pb9_6oF3gzxX7a+7aBrASHjjNX5byqDqw@mail.gmail.com
This commit is contained in:
Kees Cook 2022-02-19 17:26:00 -08:00
parent 2792d84e6d
commit 92652cf986
4 changed files with 8 additions and 6 deletions
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1
arch/xtensa/Kconfig
View file

@ -3,6 +3,7 @@ config XTENSA
def_bool y
select ARCH_32BIT_OFF_T
select ARCH_HAS_BINFMT_FLAT if !MMU
select ARCH_HAS_CURRENT_STACK_POINTER
select ARCH_HAS_DMA_PREP_COHERENT if MMU
select ARCH_HAS_SYNC_DMA_FOR_CPU if MMU
select ARCH_HAS_SYNC_DMA_FOR_DEVICE if MMU

2
arch/xtensa/include/asm/current.h
View file

@ -26,6 +26,8 @@ static inline struct task_struct *get_current(void)
#define current get_current()
register unsigned long current_stack_pointer __asm__("a1");
#else
#define GET_CURRENT(reg,sp) \

8
arch/xtensa/include/asm/stacktrace.h
View file

@ -19,14 +19,14 @@ struct stackframe {
static __always_inline unsigned long *stack_pointer(struct task_struct *task)
{
unsigned long *sp;
unsigned long sp;
if (!task || task == current)
__asm__ __volatile__ ("mov %0, a1\n" : "=a"(sp));
sp = current_stack_pointer;
else
sp = (unsigned long *)task->thread.sp;
sp = task->thread.sp;
return sp;
return (unsigned long *)sp;
}
void walk_stackframe(unsigned long *sp,

3
arch/xtensa/kernel/irq.c
View file

@ -36,9 +36,8 @@ asmlinkage void do_IRQ(int hwirq, struct pt_regs *regs)
#ifdef CONFIG_DEBUG_STACKOVERFLOW
/* Debugging check for stack overflow: is there less than 1KB free? */
{
unsigned long sp;
unsigned long sp = current_stack_pointer;
__asm__ __volatile__ ("mov %0, a1\n" : "=a" (sp));
sp &= THREAD_SIZE - 1;
if (unlikely(sp < (sizeof(thread_info) + 1024)))