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| author | James Morse <james.morse@arm.com> | 2016-02-05 14:58:48 +0000 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2016-02-18 17:27:04 +0000 |
| commit | 57f4959bad0a154aeca125b7d38d1d9471a12422 (patch) | |
| tree | 6d75f86840bb0bd2d3f4928993f696c44e2033c0 /arch/arm64/include/asm/sysreg.h | |
| parent | 406e308770a92bd33995b2e5b681e86358328bb0 (diff) | |
| download | lwn-57f4959bad0a154aeca125b7d38d1d9471a12422.tar.gz lwn-57f4959bad0a154aeca125b7d38d1d9471a12422.zip | |
arm64: kernel: Add support for User Access Override
'User Access Override' is a new ARMv8.2 feature which allows the
unprivileged load and store instructions to be overridden to behave in
the normal way.
This patch converts {get,put}_user() and friends to use ldtr*/sttr*
instructions - so that they can only access EL0 memory, then enables
UAO when fs==KERNEL_DS so that these functions can access kernel memory.
This allows user space's read/write permissions to be checked against the
page tables, instead of testing addr<USER_DS, then using the kernel's
read/write permissions.
Signed-off-by: James Morse <james.morse@arm.com>
[catalin.marinas@arm.com: move uao_thread_switch() above dsb()]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/sysreg.h')
| -rw-r--r-- | arch/arm64/include/asm/sysreg.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index e9c68e636576..1a78d6e2a78b 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -79,9 +79,12 @@ #define SYS_DCZID_EL0 sys_reg(3, 3, 0, 0, 7) #define REG_PSTATE_PAN_IMM sys_reg(0, 0, 4, 0, 4) +#define REG_PSTATE_UAO_IMM sys_reg(0, 0, 4, 0, 3) #define SET_PSTATE_PAN(x) __inst_arm(0xd5000000 | REG_PSTATE_PAN_IMM |\ (!!x)<<8 | 0x1f) +#define SET_PSTATE_UAO(x) __inst_arm(0xd5000000 | REG_PSTATE_UAO_IMM |\ + (!!x)<<8 | 0x1f) /* SCTLR_EL1 */ #define SCTLR_EL1_CP15BEN (0x1 << 5) |