Re: [PATCH v3 7/9] ARM: page: Turn highpage accesses into static inlines
From: Ard Biesheuvel <ardb@kernel.org>
Date: 2024-03-11 12:15:46
Also in:
llvm
On Mon, 11 Mar 2024 at 10:15, Linus Walleij [off-list ref] wrote:
Clearing and copying pages in highmem uses either the cpu_user vtable or the __glue() assembler stubs to call into per-CPU versions of these functions. This is all really confusing for KCFI so wrap these into static inlines and prefix each inline function with __nocfi. __cpu_clear_user_highpage() and __cpu_copy_user_highpage() are exported in arch/arm/mm/proc-syms.c which causes a problem with using static inlines, but it turns out that these exports are completely unused, so we can just delete them. Signed-off-by: Linus Walleij <redacted> --- arch/arm/include/asm/page.h | 36 +++++++++++++++++++++++++++++------- arch/arm/mm/proc-syms.c | 7 +------ 2 files changed, 30 insertions(+), 13 deletions(-)
Are you sure this patch is needed?
quoted hunk ↗ jump to hunk
diff --git a/arch/arm/include/asm/page.h b/arch/arm/include/asm/page.h index 119aa85d1feb..8bf297228627 100644 --- a/arch/arm/include/asm/page.h +++ b/arch/arm/include/asm/page.h@@ -138,17 +138,39 @@ void xscale_mc_clear_user_highpage(struct page *page, unsigned long vaddr); #ifdef MULTI_USER extern struct cpu_user_fns cpu_user; -#define __cpu_clear_user_highpage cpu_user.cpu_clear_user_highpage -#define __cpu_copy_user_highpage cpu_user.cpu_copy_user_highpage +static inline void __nocfi __cpu_clear_user_highpage(struct page *page, + unsigned long vaddr) +{ + cpu_user.cpu_clear_user_highpage(page, vaddr); +} + +static inline void __nocfi __cpu_copy_user_highpage(struct page *to, + struct page *from, unsigned long vaddr, + struct vm_area_struct *vma) +{ + cpu_user.cpu_copy_user_highpage(to, from, vaddr, vma); +} #else -#define __cpu_clear_user_highpage __glue(_USER,_clear_user_highpage) -#define __cpu_copy_user_highpage __glue(_USER,_copy_user_highpage) +/* These turn into function declarations for each per-CPU glue function */ +void __glue(_USER,_clear_user_highpage)(struct page *page, unsigned long vaddr); +void __glue(_USER,_copy_user_highpage)(struct page *to, struct page *from, + unsigned long vaddr, struct vm_area_struct *vma); + +static inline void __nocfi __cpu_clear_user_highpage(struct page *page, + unsigned long vaddr) +{ + __glue(_USER,_clear_user_highpage)(page, vaddr); +} + +static inline void __nocfi __cpu_copy_user_highpage(struct page *to, + struct page *from, unsigned long vaddr, + struct vm_area_struct *vma) +{ + __glue(_USER,_copy_user_highpage)(to, from, vaddr, vma); +} -extern void __cpu_clear_user_highpage(struct page *page, unsigned long vaddr); -extern void __cpu_copy_user_highpage(struct page *to, struct page *from, - unsigned long vaddr, struct vm_area_struct *vma); #endif #define clear_user_highpage(page,vaddr) \diff --git a/arch/arm/mm/proc-syms.c b/arch/arm/mm/proc-syms.c index e21249548e9f..c93fec38d9f4 100644 --- a/arch/arm/mm/proc-syms.c +++ b/arch/arm/mm/proc-syms.c@@ -31,14 +31,9 @@ EXPORT_SYMBOL(__cpuc_flush_dcache_area); EXPORT_SYMBOL(cpu_cache); #endif -#ifdef CONFIG_MMU -#ifndef MULTI_USER -EXPORT_SYMBOL(__cpu_clear_user_highpage); -EXPORT_SYMBOL(__cpu_copy_user_highpage); -#else +#if defined(CONFIG_MMU) && defined(MULTI_USER) EXPORT_SYMBOL(cpu_user); #endif -#endif /* * No module should need to touch the TLB (and currently --2.34.1
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