[PATCH v2] powerpc/s64: Clarify that radix lacks DEBUG_PAGEALLOC
From: Joel Stanley <joel@jms.id.au>
Date: 2021-10-13 21:35:36
The page_alloc.c code will call into __kernel_map_pages when DEBUG_PAGEALLOC is configured and enabled. As the implementation assumes hash, this should crash spectacularly if not for a bit of luck in __kernel_map_pages. In this function linear_map_hash_count is always zero, the for loop exits without doing any damage. There are no other platforms that determine if they support debug_pagealloc at runtime. Instead of adding code to mm/page_alloc.c to do that, this change turns the map/unmap into a noop when in radix mode and prints a warning once. Signed-off-by: Joel Stanley <joel@jms.id.au> --- v2: Put __kernel_map_pages in pgtable.h arch/powerpc/include/asm/book3s/64/hash.h | 2 ++ arch/powerpc/include/asm/book3s/64/pgtable.h | 11 +++++++++++ arch/powerpc/include/asm/book3s/64/radix.h | 3 +++ arch/powerpc/mm/book3s64/hash_utils.c | 2 +- arch/powerpc/mm/book3s64/radix_pgtable.c | 7 +++++++ 5 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h
index d959b0195ad9..674fe0e890dc 100644
--- a/arch/powerpc/include/asm/book3s/64/hash.h
+++ b/arch/powerpc/include/asm/book3s/64/hash.h@@ -255,6 +255,8 @@ int hash__create_section_mapping(unsigned long start, unsigned long end, int nid, pgprot_t prot); int hash__remove_section_mapping(unsigned long start, unsigned long end); +void hash__kernel_map_pages(struct page *page, int numpages, int enable); + #endif /* !__ASSEMBLY__ */ #endif /* __KERNEL__ */ #endif /* _ASM_POWERPC_BOOK3S_64_HASH_H */
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 5d34a8646f08..265661ded238 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h@@ -1101,6 +1101,17 @@ static inline void vmemmap_remove_mapping(unsigned long start, } #endif +#ifdef CONFIG_DEBUG_PAGEALLOC +static inline void __kernel_map_pages(struct page *page, int numpages, int enable) +{ + if (radix_enabled()) { + radix__kernel_map_pages(page, numpages, enable); + return; + } + hash__kernel_map_pages(page, numpages, enable); +} +#endif + static inline pte_t pmd_pte(pmd_t pmd) { return __pte_raw(pmd_raw(pmd));
diff --git a/arch/powerpc/include/asm/book3s/64/radix.h b/arch/powerpc/include/asm/book3s/64/radix.h
index 59cab558e2f0..d090d9612348 100644
--- a/arch/powerpc/include/asm/book3s/64/radix.h
+++ b/arch/powerpc/include/asm/book3s/64/radix.h@@ -316,5 +316,8 @@ int radix__create_section_mapping(unsigned long start, unsigned long end, int nid, pgprot_t prot); int radix__remove_section_mapping(unsigned long start, unsigned long end); #endif /* CONFIG_MEMORY_HOTPLUG */ + +void radix__kernel_map_pages(struct page *page, int numpages, int enable); + #endif /* __ASSEMBLY__ */ #endif
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
index c145776d3ae5..cfd45245d009 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c@@ -1988,7 +1988,7 @@ static void kernel_unmap_linear_page(unsigned long vaddr, unsigned long lmi) mmu_kernel_ssize, 0); } -void __kernel_map_pages(struct page *page, int numpages, int enable) +void hash__kernel_map_pages(struct page *page, int numpages, int enable) { unsigned long flags, vaddr, lmi; int i;
diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index ae20add7954a..83b33418ad28 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c@@ -920,6 +920,13 @@ void __meminit radix__vmemmap_remove_mapping(unsigned long start, unsigned long #endif #endif +#ifdef CONFIG_DEBUG_PAGEALLOC +void radix__kernel_map_pages(struct page *page, int numpages, int enable) +{ + pr_warn_once("DEBUG_PAGEALLOC not supported in radix mode\n"); +} +#endif + #ifdef CONFIG_TRANSPARENT_HUGEPAGE unsigned long radix__pmd_hugepage_update(struct mm_struct *mm, unsigned long addr,
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2.33.0