[PATCH][makedumpfile] 2/2 riscv64: Fix huge page translation in vtop_riscv64()

[HAGIO KAZUHITO(萩尾 一仁)]

On 2026/05/06 20:57, Rui Qi wrote:
> When a page table entry has _PAGE_LEAF set at PGD/P4D/PUD/PMD level,
> the current code incorrectly falls through to the next level instead
> of computing the correct physical address. Fix this by calculating
> the paddr with the proper level shift and returning directly.
> 
> Co-developed-by: Rui Qi <qirui.001 at bytedance.com>
> Signed-off-by: Shuan He <heshuan at bytedance.com>
> ---
>   arch/riscv64.c | 26 ++++++++++++++++++--------
>   1 file changed, 18 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/riscv64.c b/arch/riscv64.c
> index 28365fa0cc5b..67755331de24 100644
> --- a/arch/riscv64.c
> +++ b/arch/riscv64.c
> @@ -107,8 +107,12 @@ vtop_riscv64(pgd_t * pgd, unsigned long vaddr, long va_bits)
>   
>   	pt_phys = (pt_val >> _PAGE_PFN_SHIFT) << PAGESHIFT();
>   
> -	if (pt_val & _PAGE_LEAF)
> -		goto out;

the following warning is observed:

cc  -g -O2 -Wall -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D__riscv64__ -U__x86_64__ -c -o ./arch/riscv64.o arch/riscv64.c
arch/riscv64.c: In function 'vtop_riscv64':
arch/riscv64.c:203:1: warning: label 'out' defined but not used [-Wunused-label]
  out:
  ^~~

> +	if (pt_val & _PAGE_LEAF) {
> +		unsigned long shift = (va_bits == VA_BITS_SV57) ? PGD_SHIFT_L5 :
> +				      (va_bits == VA_BITS_SV48) ? PGD_SHIFT_L4 : PGD_SHIFT_L3;
> +		paddr = (pt_phys & ~((1ULL << shift) - 1)) + (vaddr & ((1ULL << shift) - 1));
> +		goto invalid;

just a style point, if this path is not invalid, please do no use the 'invalid'
label and better to return here instead.

Thanks,
Kazu

> +	}
>   
>   	if (va_bits == VA_BITS_SV57)
>   		goto p4d;
> @@ -133,8 +137,10 @@ p4d:
>   
>   	pt_phys = (pt_val >> _PAGE_PFN_SHIFT) << PAGESHIFT();
>   
> -	if (pt_val & _PAGE_LEAF)
> -		goto out;
> +	if (pt_val & _PAGE_LEAF) {
> +		paddr = (pt_phys & ~((1ULL << P4D_SHIFT) - 1)) + (vaddr & ((1ULL << P4D_SHIFT) - 1));
> +		goto invalid;
> +	}
>   pud:
>   	/* PUD */
>   	puda = (pud_t *)(pt_phys) + pud_index(vaddr);
> @@ -152,8 +158,10 @@ pud:
>   
>   	pt_phys = (pt_val >> _PAGE_PFN_SHIFT) << PAGESHIFT();
>   
> -	if(pt_val & _PAGE_LEAF)
> -		goto out;
> +	if (pt_val & _PAGE_LEAF) {
> +		paddr = (pt_phys & ~((1ULL << PUD_SHIFT) - 1)) + (vaddr & ((1ULL << PUD_SHIFT) - 1));
> +		goto invalid;
> +	}
>   pmd:
>   	/* PMD */
>   	pmda = (pmd_t *)(pt_phys) + pmd_index(vaddr);
> @@ -171,8 +179,10 @@ pmd:
>   
>   	pt_phys = (pt_val >> _PAGE_PFN_SHIFT) << PAGESHIFT();
>   
> -	if (pt_val & _PAGE_LEAF)
> -		goto out;
> +	if (pt_val & _PAGE_LEAF) {
> +		paddr = (pt_phys & ~((1ULL << PMD_SHIFT) - 1)) + (vaddr & ((1ULL << PMD_SHIFT) - 1));
> +		goto invalid;
> +	}
>   
>   	/* PTE */
>   	ptea = (pte_t *)(pt_phys) + pte_index(vaddr);