[PATCH v7 5/7] powerpc: mm: Add common pud_pfn stub for all platforms
From: Rohan McLure <hidden>
Date: 2023-02-15 02:09:42
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
Prior to this commit, pud_pfn was implemented with BUILD_BUG as the inline function for 64-bit Book3S systems but is never included, as its invocations in generic code are guarded by calls to pud_devmap which return zero on such systems. A future patch will provide support for page table checks, the generic code for which depends on a pud_pfn stub being implemented, even while the patch will not interact with puds directly. Remove the 64-bit Book3S stub and define pud_pfn to warn on all platforms. pud_pfn may be defined properly on a per-platform basis should it grow real usages in future. Signed-off-by: Rohan McLure <redacted> --- V2: Remove conditional BUILD_BUG and BUG. Instead warn on usage. V3: Replace WARN with WARN_ONCE, which should suffice to demonstrate misuse of puds. --- arch/powerpc/include/asm/book3s/64/pgtable.h | 10 ---------- arch/powerpc/include/asm/pgtable.h | 14 ++++++++++++++ 2 files changed, 14 insertions(+), 10 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 589d2dbe3873..df5ee856444d 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h@@ -1327,16 +1327,6 @@ static inline int pgd_devmap(pgd_t pgd) } #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ -static inline int pud_pfn(pud_t pud) -{ - /* - * Currently all calls to pud_pfn() are gated around a pud_devmap() - * check so this should never be used. If it grows another user we - * want to know about it. - */ - BUILD_BUG(); - return 0; -} #define __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION pte_t ptep_modify_prot_start(struct vm_area_struct *, unsigned long, pte_t *); void ptep_modify_prot_commit(struct vm_area_struct *, unsigned long,
diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index 284408829fa3..ad0829f816e9 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h@@ -153,6 +153,20 @@ struct seq_file; void arch_report_meminfo(struct seq_file *m); #endif /* CONFIG_PPC64 */ +/* + * Currently only consumed by page_table_check_pud_{set,clear}. Since clears + * and sets to page table entries at any level are done through + * page_table_check_pte_{set,clear}, provide stub implementation. + */ +#ifndef pud_pfn +#define pud_pfn pud_pfn +static inline int pud_pfn(pud_t pud) +{ + WARN_ONCE(1, "pud: platform does not use pud entries directly"); + return 0; +} +#endif + #endif /* __ASSEMBLY__ */ #endif /* _ASM_POWERPC_PGTABLE_H */
--
2.37.2