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arm64: mm: Introduce TTBR_ASID_MASK for getting at the ASID in the TTBR 

There are now a handful of open-coded masks to extract the ASID from a
TTBR value, so introduce a TTBR_ASID_MASK and use that instead.

Suggested-by: Mark Rutland <mark.rutland@arm.com>
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>
This commit is contained in:
Will Deacon 2017-12-01 17:33:48 +00:00
parent 7a4a0c1555
commit b519538dfe
4 changed files with 6 additions and 4 deletions
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3
arch/arm64/include/asm/asm-uaccess.h
View File

@ -4,6 +4,7 @@
#include <asm/alternative.h>
#include <asm/kernel-pgtable.h>
#include <asm/mmu.h>
#include <asm/sysreg.h>
#include <asm/assembler.h>
@ -17,7 +18,7 @@
msr ttbr0_el1, \tmp1 // set reserved TTBR0_EL1
isb
sub \tmp1, \tmp1, #SWAPPER_DIR_SIZE
bic \tmp1, \tmp1, #(0xffff << 48)
bic \tmp1, \tmp1, #TTBR_ASID_MASK
msr ttbr1_el1, \tmp1 // set reserved ASID
isb
.endm

1
arch/arm64/include/asm/mmu.h
View File

@ -18,6 +18,7 @@
#define MMCF_AARCH32 0x1 /* mm context flag for AArch32 executables */
#define USER_ASID_FLAG (UL(1) << 48)
#define TTBR_ASID_MASK (UL(0xffff) << 48)
#ifndef __ASSEMBLY__

4
arch/arm64/include/asm/uaccess.h
View File

@ -112,7 +112,7 @@ static inline void __uaccess_ttbr0_disable(void)
write_sysreg(ttbr + SWAPPER_DIR_SIZE, ttbr0_el1);
isb();
/* Set reserved ASID */
ttbr &= ~(0xffffUL << 48);
ttbr &= ~TTBR_ASID_MASK;
write_sysreg(ttbr, ttbr1_el1);
isb();
}
@ -131,7 +131,7 @@ static inline void __uaccess_ttbr0_enable(void)
/* Restore active ASID */
ttbr1 = read_sysreg(ttbr1_el1);
ttbr1 |= ttbr0 & (0xffffUL << 48);
ttbr1 |= ttbr0 & TTBR_ASID_MASK;
write_sysreg(ttbr1, ttbr1_el1);
isb();

2
arch/arm64/kernel/entry.S
View File

@ -205,7 +205,7 @@ alternative_else_nop_endif
.if \el != 0
mrs x21, ttbr1_el1
tst x21, #0xffff << 48 // Check for the reserved ASID
tst x21, #TTBR_ASID_MASK // Check for the reserved ASID
orr x23, x23, #PSR_PAN_BIT // Set the emulated PAN in the saved SPSR
b.eq 1f // TTBR0 access already disabled
and x23, x23, #~PSR_PAN_BIT // Clear the emulated PAN in the saved SPSR