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powerpc/32: Implement validation of emergency stack

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VMAP stack added an emergency stack on powerpc/32 for when there is
a stack overflow, but failed to add stack validation for that
emergency stack. That validation is required for show stack.

Implement it.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/2439d50b019f758db4a6d7b238b06441ab109799.1724156805.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2024-08-20 14:26:54 +02:00 committed by Michael Ellerman
parent 062e825a33
commit dca5b1d69a
2 changed files with 22 additions and 2 deletions
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4
arch/powerpc/include/asm/thread_info.h
View File

@ -226,6 +226,10 @@ static inline int arch_within_stack_frames(const void * const stack,
return BAD_STACK;
}
#ifdef CONFIG_PPC32
extern void *emergency_ctx[];
#endif
#endif /* !__ASSEMBLY__ */
#endif /* __KERNEL__ */

20
arch/powerpc/kernel/process.c
View File

@ -2175,10 +2175,10 @@ static inline int valid_irq_stack(unsigned long sp, struct task_struct *p,
return 0;
}
#ifdef CONFIG_PPC64
static inline int valid_emergency_stack(unsigned long sp, struct task_struct *p,
unsigned long nbytes)
{
#ifdef CONFIG_PPC64
unsigned long stack_page;
unsigned long cpu = task_cpu(p);
@ -2205,11 +2205,27 @@ static inline int valid_emergency_stack(unsigned long sp, struct task_struct *p,
stack_page = (unsigned long)paca_ptrs[cpu]->mc_emergency_sp - THREAD_SIZE;
if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
return 1;
# endif
# endif
return 0;
}
#else
static inline int valid_emergency_stack(unsigned long sp, struct task_struct *p,
unsigned long nbytes)
{
unsigned long stack_page;
unsigned long cpu = task_cpu(p);
if (!IS_ENABLED(CONFIG_VMAP_STACK))
return 0;
stack_page = (unsigned long)emergency_ctx[cpu] - THREAD_SIZE;
if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
return 1;
return 0;
}
#endif
/*
* validate the stack frame of a particular minimum size, used for when we are