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Commit fc0e1299 authored by Will Deacon's avatar Will Deacon
Browse files

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: default avatarMark Rutland <mark.rutland@arm.com>
Tested-by: default avatarLaura Abbott <labbott@redhat.com>
Tested-by: default avatarShanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 0c8ea531

arch/arm64/include/asm/mmu.h

+8 −0
Original line number Diff line number Diff line
@@ -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