Commit dca5b1d6 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/32: Implement validation of emergency stack 



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: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/2439d50b019f758db4a6d7b238b06441ab109799.1724156805.git.christophe.leroy@csgroup.eu
parent 062e825a

arch/powerpc/include/asm/thread_info.h

+4 −0
Original line number Diff line number Diff line
@@ -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__ */

arch/powerpc/kernel/process.c

+18 −2
Original line number Diff line number Diff line
@@ -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);
@@ -2206,10 +2206,26 @@ static inline int valid_emergency_stack(unsigned long sp, struct task_struct *p, 
	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