From fc0e1299da548b32440051f58f08e0c1eb7edd0b Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Tue, 14 Nov 2017 13:58:08 +0000 Subject: [PATCH] arm64: mm: Add arm64_kernel_unmapped_at_el0 helper In order for code such as TLB invalidation to operate efficiently when the decision to map the kernel at EL0 is determined at runtime, this patch introduces a helper function, arm64_kernel_unmapped_at_el0, to determine whether or not the kernel is mapped whilst running in userspace. Currently, this just reports the value of CONFIG_UNMAP_KERNEL_AT_EL0, but will later be hooked up to a fake CPU capability using a static key. Reviewed-by: Mark Rutland Tested-by: Laura Abbott Tested-by: Shanker Donthineni Signed-off-by: Will Deacon --- arch/arm64/include/asm/mmu.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h index 01bfb184f2a8..c07954638658 100644 --- a/arch/arm64/include/asm/mmu.h +++ b/arch/arm64/include/asm/mmu.h @@ -19,6 +19,8 @@ #define MMCF_AARCH32 0x1 /* mm context flag for AArch32 executables */ #define USER_ASID_FLAG (UL(1) << 48) +#ifndef __ASSEMBLY__ + typedef struct { atomic64_t id; void *vdso; @@ -32,6 +34,11 @@ typedef struct { */ #define ASID(mm) ((mm)->context.id.counter & 0xffff) +static inline bool arm64_kernel_unmapped_at_el0(void) +{ + return IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0); +} + extern void paging_init(void); extern void bootmem_init(void); extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt); @@ -42,4 +49,5 @@ extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, extern void *fixmap_remap_fdt(phys_addr_t dt_phys); extern void mark_linear_text_alias_ro(void); +#endif /* !__ASSEMBLY__ */ #endif