2023-07-16 00:19:57

by Guo Ren

Subject: [PATCH V2 1/2] riscv: stack: Fixup independent irq stack for CONFIG_FRAME_POINTER=n

From: Guo Ren <[email protected]>

The independent irq stack uses s0 to save & restore sp, but s0 would be
corrupted when CONFIG_FRAME_POINTER=n. So add s0 in the clobber list to
fix the problem.

Fixes: 163e76cc6ef4 ("riscv: stack: Support HAVE_IRQ_EXIT_ON_IRQ_STACK")
Cc: [email protected]
Reported-by: Zhangjin Wu <[email protected]>
Signed-off-by: Guo Ren <[email protected]>
Signed-off-by: Guo Ren <[email protected]>
---
arch/riscv/kernel/traps.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index f910dfccbf5d..927347a19847 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -372,6 +372,9 @@ asmlinkage void noinstr do_irq(struct pt_regs *regs)
: [sp] "r" (sp), [regs] "r" (regs)
: "a0", "a1", "a2", "a3", "a4", "a5", "a6", "a7",
"t0", "t1", "t2", "t3", "t4", "t5", "t6",
+#ifndef CONFIG_FRAME_POINTER
+ "s0",
+#endif
"memory");
} else
#endif
--
2.36.1

2023-07-16 11:22:41

by Rémi Denis-Courmont

Subject: Re: [PATCH V2 1/2] riscv: stack: Fixup independent irq stack for CONFIG_FRAME_POINTER=n

Le sunnuntaina 16. heinäkuuta 2023, 3.15.05 EEST [email protected] a écrit :
> From: Guo Ren <[email protected]>
>
> The independent irq stack uses s0 to save & restore sp, but s0 would be
> corrupted when CONFIG_FRAME_POINTER=n. So add s0 in the clobber list to
> fix the problem.

Isn't it *always* corrupted? Shouldn't the clobber be always there? Am I
guessing that the compiler whine that you can't mark the frame pointer as
clobbered? If so, it would be worth mentioning in the commit log, IMO.

> Fixes: 163e76cc6ef4 ("riscv: stack: Support HAVE_IRQ_EXIT_ON_IRQ_STACK")
> Cc: [email protected]
> Reported-by: Zhangjin Wu <[email protected]>
> Signed-off-by: Guo Ren <[email protected]>
> Signed-off-by: Guo Ren <[email protected]>
> ---
> arch/riscv/kernel/traps.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
> index f910dfccbf5d..927347a19847 100644
> --- a/arch/riscv/kernel/traps.c
> +++ b/arch/riscv/kernel/traps.c
> @@ -372,6 +372,9 @@ asmlinkage void noinstr do_irq(struct pt_regs *regs)
>
> : [sp] "r" (sp), [regs] "r" (regs)
> : "a0", "a1", "a2", "a3", "a4", "a5", "a6", "a7",
>
> "t0", "t1", "t2", "t3", "t4", "t5", "t6",
> +#ifndef CONFIG_FRAME_POINTER
> + "s0",
> +#endif
> "memory");
> } else
> #endif


--
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