From e4193c7e92ab5213ecd536f048497b6546eab23c Mon Sep 17 00:00:00 2001
From: Will Deacon <will.deacon@arm.com>
Date: Tue, 14 Nov 2017 13:58:08 +0000
Subject: [PATCH 12/51] arm64: mm: Add arm64_kernel_unmapped_at_el0 helper
Git-commit: fc0e1299da548b32440051f58f08e0c1eb7edd0b
Patch-mainline: v4.16-rc1
References: bsc#1068032
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 <mark.rutland@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Tested-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
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 9751438cb991..6762f37457bd 100644
--- a/arch/arm64/include/asm/mmu.h
+++ b/arch/arm64/include/asm/mmu.h
@@ -18,6 +18,8 @@
#define USER_ASID_FLAG (UL(1) << 48)
+#ifndef __ASSEMBLY__
+
typedef struct {
atomic64_t id;
void *vdso;
@@ -31,6 +33,11 @@ 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);
@@ -41,4 +48,5 @@ 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
--
2.11.0