Messages in this thread | | | Date | Mon, 24 Jul 2023 14:35:02 +0800 | Subject | Re: [PATCH -next] arm64: fix -Wundef warning for PUD_SHIFT | From | "zhangjianhua (E)" <> |
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在 2023/7/24 11:26, Anshuman Khandual 写道: > > On 7/24/23 16:00, Zhang Jianhua wrote: >> When building with W=1, the following warning occurs. >> >> arch/arm64/include/asm/kernel-pgtable.h:129:41: error: "PUD_SHIFT" is not defined, evaluates to 0 [-Werror=undef] >> 129 | #define ARM64_MEMSTART_SHIFT PUD_SHIFT >> | ^~~~~~~~~ >> arch/arm64/include/asm/kernel-pgtable.h:142:5: note: in expansion of macro ‘ARM64_MEMSTART_SHIFT’ >> 142 | #if ARM64_MEMSTART_SHIFT < SECTION_SIZE_BITS >> | ^~~~~~~~~~~~~~~~~~~~ >> >> The reason is that PUD_SHIFT isn't defined if CONFIG_PGTABLE_LEVELS == >> 3, and at this time PUD_SHIFT is equal to PGDIR_SHIFT, so define it. > CONFIG_PGTABLE_LEVELS equals 3 only with CONFIG_VA_BITS = 39. > >> Fixes: 06e9bf2fd9b3 ("arm64: choose memstart_addr based on minimum sparsemem section alignment") > This is not a fix, ARM64_MEMSTART_ALIGN would fallback being (1UL << SECTION_SIZE_BITS) > when PUD_SHIFT is undefined (aka 0) but agreed that it's not clean. Yes, it wouldn't be wrong in the end. >> Signed-off-by: Zhang Jianhua <chris.zjh@huawei.com> >> --- >> v2: >> Define PUD_SHIFT before use it instead of judgement >> --- >> --- >> arch/arm64/include/asm/kernel-pgtable.h | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h >> index 577773870b66..996a144e2929 100644 >> --- a/arch/arm64/include/asm/kernel-pgtable.h >> +++ b/arch/arm64/include/asm/kernel-pgtable.h >> @@ -59,6 +59,10 @@ >> #define EARLY_KASLR (0) >> #endif >> >> +#ifndef PUD_SHIFT >> +#define PUD_SHIFT PGDIR_SHIFT >> +#endif > Rather ARM64_MEMSTART_SHIFT block needs to be re-written in a more pgtable levels agnostic > manner ? OR maybe something like this. > > diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h > index 577773870b66..5a83b4b249e8 100644 > --- a/arch/arm64/include/asm/kernel-pgtable.h > +++ b/arch/arm64/include/asm/kernel-pgtable.h > @@ -125,12 +125,14 @@ > * (64k granule), or a multiple that can be mapped using contiguous bits > * in the page tables: 32 * PMD_SIZE (16k granule) > */ > -#if defined(CONFIG_ARM64_4K_PAGES) > +#if defined(CONFIG_ARM64_4K_PAGES) && defined(PUD_SHIFT) > #define ARM64_MEMSTART_SHIFT PUD_SHIFT > -#elif defined(CONFIG_ARM64_16K_PAGES) > +#elif defined(CONFIG_ARM64_16K_PAGES) && defined(CONT_PMD_SHIFT) > #define ARM64_MEMSTART_SHIFT CONT_PMD_SHIFT > -#else > +#elif defined(CONFIG_AR64_64K_PAGES) && defined(PMD_SHIFT) > #define ARM64_MEMSTART_SHIFT PMD_SHIFT > +#else > +#define ARM64_MEMSTART_SHIFT PGDIR_SHIFT > #endif > > The only cases where PUD_SHIFT or PMD_SHIFT (along with CONT_PMD_SHIFT) would not be defined is > when XXX_SHIFT level itself matches PGDIR_SHIFT. Thanks for your reply, this modification seems more comprehensive and appropriate. I will send v2 patch soon. >> + >> #define SPAN_NR_ENTRIES(vstart, vend, shift) \ >> ((((vend) - 1) >> (shift)) - ((vstart) >> (shift)) + 1) >>
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