Re: [PATCH] arm64: pgtable: make __pte_to_phys/__phys_to_pte_val inline functions

[Will Deacon]

On Fri, 5 Nov 2021 08:54:03 +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@xxxxxxxx>
> 
> gcc warns about undefined behavior the vmalloc code when building
> with CONFIG_ARM64_PA_BITS_52, when the 'idx++' in the argument to
> __phys_to_pte_val() is evaluated twice:
> 
> mm/vmalloc.c: In function 'vmap_pfn_apply':
> mm/vmalloc.c:2800:58: error: operation on 'data->idx' may be undefined [-Werror=sequence-point]
>  2800 |         *pte = pte_mkspecial(pfn_pte(data->pfns[data->idx++], data->prot));
>       |                                                 ~~~~~~~~~^~
> arch/arm64/include/asm/pgtable-types.h:25:37: note: in definition of macro '__pte'
>    25 | #define __pte(x)        ((pte_t) { (x) } )
>       |                                     ^
> arch/arm64/include/asm/pgtable.h:80:15: note: in expansion of macro '__phys_to_pte_val'
>    80 |         __pte(__phys_to_pte_val((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot))
>       |               ^~~~~~~~~~~~~~~~~
> mm/vmalloc.c:2800:30: note: in expansion of macro 'pfn_pte'
>  2800 |         *pte = pte_mkspecial(pfn_pte(data->pfns[data->idx++], data->prot));
>       |                              ^~~~~~~
> 
> [...]

Applied to arm64 (for-next/core), thanks!

[1/1] arm64: pgtable: make __pte_to_phys/__phys_to_pte_val inline functions
      https://git.kernel.org/arm64/c/c7c386fbc202

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
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