Commit 1434f49f authored Nov 14, 2017 by Will Deacon Committed by Greg Kroah-Hartman Jan 05, 2018

FROMLIST: 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 <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>
(cherry picked from git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git


 commit fc0e1299da548b32440051f58f08e0c1eb7edd0b)

Change-Id: I0f48eadf55ee97f09553380a62d9fffe54d9dc83
Signed-off-by: Greg Hackmann <ghackmann@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

parent b7032349

arch/arm64/include/asm/mmu.h

+8 −0

Original line number	Diff line number	Diff line
		@@ -18,6 +18,8 @@

		#define USER_ASID_FLAG (UL(1) << 48)

		#ifndef __ASSEMBLY__

		typedef struct {
		atomic64_t id;
		void *vdso;
		@@ -30,6 +32,11 @@ 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 __iomem *early_io_map(phys_addr_t phys, unsigned long virt);
		extern void init_mem_pgprot(void);
		@@ -37,4 +44,5 @@ extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
		unsigned long virt, phys_addr_t size,
		pgprot_t prot);

		#endif /* !__ASSEMBLY__ */
		#endif