From: Christophe Leroy Date: Mon, 17 Feb 2020 09:41:35 +0000 (+0000) Subject: powerpc/mm: Don't kmap_atomic() in pte_offset_map() on PPC32 X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=6453f9ed9d4e4b4cdf201bf34bf460c436bf50ea;p=linux.git powerpc/mm: Don't kmap_atomic() in pte_offset_map() on PPC32 On PPC32, pte_offset_map() does a kmap_atomic() in order to support page tables allocated in high memory, just like ARM and x86/32. But since at least 2008 and commit 8054a3428fbe ("powerpc: Remove dead CONFIG_HIGHPTE"), page tables are never allocated in high memory. When the page is in low mem, kmap_atomic() just returns the page address but still disable preemption and pagefault. And it is not an inlined function, so we suffer function call for no reason. Make pte_offset_map() the same as pte_offset_kernel() and make pte_unmap() void, in the same way as PPC64 which doesn't have HIGHMEM. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/03c97f0f6b3790d164822563be80f2fd4713a955.1581932480.git.christophe.leroy@c-s.fr --- diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h index 5b39c11e884a9..7549393c4c436 100644 --- a/arch/powerpc/include/asm/book3s/32/pgtable.h +++ b/arch/powerpc/include/asm/book3s/32/pgtable.h @@ -366,10 +366,8 @@ static inline void __ptep_set_access_flags(struct vm_area_struct *vma, (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) #define pte_offset_kernel(dir, addr) \ ((pte_t *) pmd_page_vaddr(*(dir)) + pte_index(addr)) -#define pte_offset_map(dir, addr) \ - ((pte_t *)(kmap_atomic(pmd_page(*(dir))) + \ - (pmd_page_vaddr(*(dir)) & ~PAGE_MASK)) + pte_index(addr)) -#define pte_unmap(pte) kunmap_atomic(pte) +#define pte_offset_map(dir, addr) pte_offset_kernel((dir), (addr)) +static inline void pte_unmap(pte_t *pte) { } /* * Encode and decode a swap entry. diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h b/arch/powerpc/include/asm/nohash/32/pgtable.h index 60c4d829152e0..b04ba257fddbc 100644 --- a/arch/powerpc/include/asm/nohash/32/pgtable.h +++ b/arch/powerpc/include/asm/nohash/32/pgtable.h @@ -372,10 +372,8 @@ static inline int pte_young(pte_t pte) #define pte_offset_kernel(dir, addr) \ (pmd_bad(*(dir)) ? NULL : (pte_t *)pmd_page_vaddr(*(dir)) + \ pte_index(addr)) -#define pte_offset_map(dir, addr) \ - ((pte_t *)(kmap_atomic(pmd_page(*(dir))) + \ - (pmd_page_vaddr(*(dir)) & ~PAGE_MASK)) + pte_index(addr)) -#define pte_unmap(pte) kunmap_atomic(pte) +#define pte_offset_map(dir, addr) pte_offset_kernel((dir), (addr)) +static inline void pte_unmap(pte_t *pte) { } /* * Encode and decode a swap entry.