Messages in this thread | | | Date | Tue, 25 Jul 2023 09:52:18 +0530 | Subject | Re: [PATCH -next v2] arm64: fix build warning for ARM64_MEMSTART_SHIFT | From | Anshuman Khandual <> |
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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.
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