Messages in this thread | | | Date | Tue, 25 Jul 2023 20:03:40 +0800 | Subject | Re: [PATCH -next v2] arm64: fix build warning for ARM64_MEMSTART_SHIFT | From | "zhangjianhua (E)" <> |
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在 2023/7/25 18:15, Catalin Marinas 写道: > On Tue, Jul 25, 2023 at 04:47:46PM +0800, zhangjianhua (E) wrote: >> 在 2023/7/25 12:22, Anshuman Khandual 写道: >>> On 7/24/23 20:41, Catalin Marinas wrote: >>>> On Mon, Jul 24, 2023 at 05:27:51PM +0000, 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 >>>>> | ^~~~~~~~~~~~~~~~~~~~ >>>> Another thing that's missing here is that the warning is probably when >>>> this file is included from asm-offests.h or some .S file. >>>> >>>>> diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h >>>>> index 577773870b66..51bdce66885d 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 >>>> That's not the correct fix since PUD_SHIFT should always be defined. >>>> When CONFIG_PGTABLE_LEVELS == 3, pgtable-types.h includes >>>> asm-generic/pgtable-nopud.h and this defines PUD_SHIFT. We either got >>> Right, PUD_SHIFT is always defined irrespective of page table levels. >>> >>>> ARM64_MEMSTART_SHIFT defined in the wrong file or kernel-pgtable.h does >>>> not pull the relevant headers (either directly or via an included >>>> header). Even if kernel-pgtable.h ends up including the nopud/nopmd >>>> headers, P*D_SHIFT is guarded by an #indef __ASSEMBLY__ in those files. >>>> >>>> Something like below appears to fix this, though I'm not particularly >>>> fond of guarding the ARM64_MEMSTART_* definitions by #ifndef >>>> __ASSEMBLY__ for no apparent reason (could add a comment though): >>>> >>>> -----------------------8<--------------------------- >>>> diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h >>>> index 577773870b66..fcea7e87a6ca 100644 >>>> --- a/arch/arm64/include/asm/kernel-pgtable.h >>>> +++ b/arch/arm64/include/asm/kernel-pgtable.h >>>> @@ -118,6 +118,8 @@ >>>> #define SWAPPER_RX_MMUFLAGS (SWAPPER_RW_MMUFLAGS | PTE_RDONLY) >>>> #endif >>>> +#ifndef __ASSEMBLY__ >>>> + >>>> /* >>>> * To make optimal use of block mappings when laying out the linear >>>> * mapping, round down the base of physical memory to a size that can >>>> @@ -145,4 +147,6 @@ >>>> #define ARM64_MEMSTART_ALIGN (1UL << ARM64_MEMSTART_SHIFT) >>>> #endif >>>> +#endif /* __ASSEMBLY__ */ >>>> + >>>> #endif /* __ASM_KERNEL_PGTABLE_H */ >>>> diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h >>>> index e4944d517c99..22b36f2d5d93 100644 >>>> --- a/arch/arm64/include/asm/pgtable-hwdef.h >>>> +++ b/arch/arm64/include/asm/pgtable-hwdef.h >>>> @@ -6,6 +6,7 @@ >>>> #define __ASM_PGTABLE_HWDEF_H >>>> #include <asm/memory.h> >>>> +#include <asm/pgtable-types.h> >>>> /* >>>> * Number of page-table levels required to address 'va_bits' wide >>>> diff --git a/arch/arm64/include/asm/pgtable-types.h b/arch/arm64/include/asm/pgtable-types.h >>>> index b8f158ae2527..ae86e66fdb11 100644 >>>> --- a/arch/arm64/include/asm/pgtable-types.h >>>> +++ b/arch/arm64/include/asm/pgtable-types.h >>>> @@ -11,6 +11,8 @@ >>>> #include <asm/types.h> >>>> +#ifndef __ASSEMBLY__ >>>> + >>>> typedef u64 pteval_t; >>>> typedef u64 pmdval_t; >>>> typedef u64 pudval_t; >>>> @@ -44,6 +46,8 @@ typedef struct { pteval_t pgprot; } pgprot_t; >>>> #define pgprot_val(x) ((x).pgprot) >>>> #define __pgprot(x) ((pgprot_t) { (x) } ) >>>> +#endif /* __ASSEMBLY__ */ >>>> + >>>> #if CONFIG_PGTABLE_LEVELS == 2 >>>> #include <asm-generic/pgtable-nopmd.h> >>>> #elif CONFIG_PGTABLE_LEVELS == 3 >>>> -----------------------8<--------------------------- >>>> >>>> To avoid guarding the ARM64_MEMSTART_* definitions, we could instead >>>> move the P*D_SHIFT definitions in asm-generic/pgtable-nop*d.h outside >>>> the #ifndef __ASSEMBLY__ block. >>> OR could ARM64_MEMSTART_SHIFT and ARM64_MEMSTART_ALIGN computation blocks >>> be moved inside arch/arm64/mm/init.c, where it is used exclusively. Seems >>> to be solving the problem as well. > That's fine by me, better than adding the #ifndef __ASSEMBLY__ around > them. > >> This method can avoid the current compilation warning, but does not >> solve the problem that PUD_SHIFT and PMD_SHIFT undefined in fact, and >> it is contrary to XXX_SHIFT should always be defined. Maybe it would >> be more appropriate to solve this issue directly. > For .c files, we can solve this by including asm/pgtable-types.h in > asm/pgtable-hwdef.h. This still leaves P*D_SHIFT undefined for .S files > since the generic nop*d.h headers guard the shifts with !__ASSEMBLY__ > but do we really care about this? I haven't seen any other warning of > P*D_SHIFT not being defined. If you do want to solve these, just go and > change the generic headers to take the shift out of the asm guard. I > don't think it's worth it. OK, agree, I will send a new patch for Anshuman's method.
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