linux-kernel - Re: [PATCH] riscv: mm: Fixup compat mode boot failure

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Date: Thu, 21 Dec 2023 19:18:42 -0500
From: Guo Ren <guoren@...nel.org>
To: linux-kernel@...r.kernel.org, paul.walmsley@...ive.com,
	palmer@...belt.com, alexghiti@...osinc.com, charlie@...osinc.com,
	xiao.w.wang@...el.com, david@...hat.com, panqinglin2020@...as.ac.cn,
	rick.p.edgecombe@...el.com, willy@...radead.org
Cc: linux-riscv@...ts.infradead.org, Guo Ren <guoren@...ux.alibaba.com>
Subject: Re: [PATCH] riscv: mm: Fixup compat mode boot failure

On Tue, Dec 19, 2023 at 06:17:01AM -0500, guoren@...nel.org wrote:
> From: Guo Ren <guoren@...ux.alibaba.com>
> 
> In COMPAT mode, the STACK_TOP is 0x80000000, but the TASK_SIZE is
> 0x7fff000. When the user stack is upon 0x7fff000, it will cause a user
> segment fault. Sometimes, it would cause boot failure when the whole
> rootfs is rv32.
> 
> Freeing unused kernel image (initmem) memory: 2236K
> Run /sbin/init as init process
> Starting init: /sbin/init exists but couldn't execute it (error -14)
> Run /etc/init as init process
> ...
> 
> Fixes: add2cc6b6515 ("RISC-V: mm: Restrict address space for sv39,sv48,sv57")
> Signed-off-by: Guo Ren <guoren@...ux.alibaba.com>
> Signed-off-by: Guo Ren <guoren@...nel.org>
Abandon this patch, and here is the v2:
https://lore.kernel.org/linux-riscv/20231221154702.2267684-1-guoren@kernel.org/


> ---
>  arch/riscv/include/asm/pgtable.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
> index ab00235b018f..d2ec5e6fa331 100644
> --- a/arch/riscv/include/asm/pgtable.h
> +++ b/arch/riscv/include/asm/pgtable.h
> @@ -881,7 +881,7 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte)
>  #define TASK_SIZE_MIN	(PGDIR_SIZE_L3 * PTRS_PER_PGD / 2)
>  
>  #ifdef CONFIG_COMPAT
> -#define TASK_SIZE_32	(_AC(0x80000000, UL) - PAGE_SIZE)
> +#define TASK_SIZE_32	(UL(1) << (MMAP_VA_BITS - 1))
>  #define TASK_SIZE	(test_thread_flag(TIF_32BIT) ? \
>  			 TASK_SIZE_32 : TASK_SIZE_64)
>  #else
> -- 
> 2.40.1
> 
> 
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv
>

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