Re: [PATCH 0/2] riscv: stack: Fixup independent softirq/irq stack for CONFIG_FRAME_POINTER=n

Guo Ren
2023-07-16T00:18:41Z

I'm sorry, this patch would break CONFIG_FRAME_POINTER=y, so please abandon it.

I've updated a v2 with the stable@ver.kernel.org tag fixed:
https://lore.kernel.org/linux-riscv/20230716001506.3506041-1-guoren@kernel.org/

On Sat, Jul 15, 2023 at 9:46 PM <guoren@kernel.org> wrote:
>
> From: Guo Ren <guoren@linux.alibaba.com>
>
> The independent softirq/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.
>
> <+0>: addi sp,sp,-32
> <+2>: sd s0,16(sp)
> <+4>: sd s1,8(sp)
> <+6>: sd ra,24(sp)
> <+8>: sd s2,0(sp)
> <+10>: mv s0,a0 --> compiler allocate s0 for a0 when CONFIG_FRAME_POINTER=n
> <+12>: jal ra,0xffffffff800bc0ce <irqentry_enter>
> <+16>: ld a5,56(tp) # 0x38
> <+20>: lui a4,0x4
> <+22>: mv s1,a0
> <+24>: xor a5,a5,sp
> <+28>: bgeu a5,a4,0xffffffff800bc092 <do_irq+88>
> <+32>: auipc s2,0x5d
> <+36>: ld s2,1118(s2) # 0xffffffff801194b8 <irq_stack_ptr>
> <+40>: add s2,s2,a4
> <+42>: addi sp,sp,-8
> <+44>: sd ra,0(sp)
> <+46>: addi sp,sp,-8
> <+48>: sd s0,0(sp)
> <+50>: addi s0,sp,16 --> our code clobber the s0
> <+52>: mv sp,s2
> <+54>: mv a0,s0 --> a0 got wrong value for handle_riscv_irq
> <+56>: jal ra,0xffffffff800bbb3a <handle_riscv_irq>
>
> Guo Ren (2):
> riscv: stack: Fixup independent irq stack for CONFIG_FRAME_POINTER=n
> riscv: stack: Fixup independent softirq stack for
> CONFIG_FRAME_POINTER=n
>
> arch/riscv/kernel/irq.c | 2 +-
> arch/riscv/kernel/traps.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> --
> 2.36.1
>

--
Best Regards

Guo Ren