4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Will Deacon <will.deacon@xxxxxxx> Commit b519538dfefc upstream. 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@xxxxxxx> Reviewed-by: Mark Rutland <mark.rutland@xxxxxxx> Tested-by: Laura Abbott <labbott@xxxxxxxxxx> Tested-by: Shanker Donthineni <shankerd@xxxxxxxxxxxxxx> Signed-off-by: Will Deacon <will.deacon@xxxxxxx> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/arm64/include/asm/asm-uaccess.h | 3 ++- arch/arm64/include/asm/mmu.h | 1 + arch/arm64/include/asm/uaccess.h | 4 ++-- arch/arm64/kernel/entry.S | 2 +- 4 files changed, 6 insertions(+), 4 deletions(-) --- a/arch/arm64/include/asm/asm-uaccess.h +++ b/arch/arm64/include/asm/asm-uaccess.h @@ -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 --- a/arch/arm64/include/asm/mmu.h +++ b/arch/arm64/include/asm/mmu.h @@ -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__ --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -112,7 +112,7 @@ static inline void __uaccess_ttbr0_disab 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_enabl /* Restore active ASID */ ttbr1 = read_sysreg(ttbr1_el1); - ttbr1 |= ttbr0 & (0xffffUL << 48); + ttbr1 |= ttbr0 & TTBR_ASID_MASK; write_sysreg(ttbr1, ttbr1_el1); isb(); --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -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