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powerpc/32: Statically initialise first emergency context

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[ Upstream commit a4719f5bb6 ]

The check of the emergency context initialisation in
vmap_stack_overflow is buggy for the SMP case, as it
compares r1 with 0 while in the SMP case r1 is offseted
by the CPU id.

Instead of fixing it, just perform static initialisation
of the first emergency context.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/4a67ba422be75713286dca0c86ee0d3df2eb6dfa.1615552867.git.christophe.leroy@csgroup.eu
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Christophe Leroy 2021-03-12 12:50:25 +00:00 • committed by Greg Kroah-Hartman
commit 286b3ff9fd
2 changed files with 2 additions and 6 deletions
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6
arch/powerpc/kernel/head_32.h
View file

@ -338,11 +338,7 @@ label:
lis r1, emergency_ctx@ha
#endif
lwz r1, emergency_ctx@l(r1)
cmpwi cr1, r1, 0
bne cr1, 1f
lis r1, init_thread_union@ha
addi r1, r1, init_thread_union@l
1: addi r1, r1, THREAD_SIZE - INT_FRAME_SIZE
addi r1, r1, THREAD_SIZE - INT_FRAME_SIZE
EXCEPTION_PROLOG_2
SAVE_NVGPRS(r11)
addi r3, r1, STACK_FRAME_OVERHEAD

2
arch/powerpc/kernel/setup_32.c
View file

@ -164,7 +164,7 @@ void __init irqstack_early_init(void)
}
#ifdef CONFIG_VMAP_STACK
void *emergency_ctx[NR_CPUS] __ro_after_init;
void *emergency_ctx[NR_CPUS] __ro_after_init = {[0] = &init_stack};
void __init emergency_stack_init(void)
{