Messages in this thread Patch in this message | | | From | Heyi Guo <> | Subject | [PATCH] arm64/kernel/entry: refine comment of stack overflow check | Date | Mon, 2 Dec 2019 19:37:02 +0800 |
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Stack overflow checking can be done by testing sp & (1 << THREAD_SHIFT) only for the stacks are aligned to (2 << THREAD_SHIFT) with size of (1 << THREAD_SIZE), and this is the case when CONFIG_VMAP_STACK is set.
Fix the code comment to avoid confusion.
Signed-off-by: Heyi Guo <guoheyi@huawei.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> --- arch/arm64/kernel/entry.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index cf3bd2976e57..9e8ba507090f 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -76,7 +76,8 @@ alternative_else_nop_endif #ifdef CONFIG_VMAP_STACK /* * Test whether the SP has overflowed, without corrupting a GPR. - * Task and IRQ stacks are aligned to (1 << THREAD_SHIFT). + * Task and IRQ stacks are aligned to (2 << THREAD_SHIFT) with size of + * (1 << THREAD_SHIFT). */ add sp, sp, x0 // sp' = sp + x0 sub x0, sp, x0 // x0' = sp' - x0 = (sp + x0) - x0 = sp -- 2.19.1
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