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authorJames Morse <james.morse@arm.com>2016-02-05 14:58:48 +0000
committerCatalin Marinas <catalin.marinas@arm.com>2016-02-18 17:27:04 +0000
commit57f4959bad0a154aeca125b7d38d1d9471a12422 (patch)
tree6d75f86840bb0bd2d3f4928993f696c44e2033c0 /arch/arm64/lib/copy_from_user.S
parentarm64: add ARMv8.2 id_aa64mmfr2 boiler plate (diff)
downloadlinux-dev-57f4959bad0a154aeca125b7d38d1d9471a12422.tar.xz
linux-dev-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 '')
-rw-r--r--arch/arm64/lib/copy_from_user.S8
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/arm64/lib/copy_from_user.S b/arch/arm64/lib/copy_from_user.S
index 4699cd74f87e..1d982d64f1a7 100644
--- a/arch/arm64/lib/copy_from_user.S
+++ b/arch/arm64/lib/copy_from_user.S
@@ -34,7 +34,7 @@
*/
.macro ldrb1 ptr, regB, val
- USER(9998f, ldrb \ptr, [\regB], \val)
+ uao_user_alternative 9998f, ldrb, ldtrb, \ptr, \regB, \val
.endm
.macro strb1 ptr, regB, val
@@ -42,7 +42,7 @@
.endm
.macro ldrh1 ptr, regB, val
- USER(9998f, ldrh \ptr, [\regB], \val)
+ uao_user_alternative 9998f, ldrh, ldtrh, \ptr, \regB, \val
.endm
.macro strh1 ptr, regB, val
@@ -50,7 +50,7 @@
.endm
.macro ldr1 ptr, regB, val
- USER(9998f, ldr \ptr, [\regB], \val)
+ uao_user_alternative 9998f, ldr, ldtr, \ptr, \regB, \val
.endm
.macro str1 ptr, regB, val
@@ -58,7 +58,7 @@
.endm
.macro ldp1 ptr, regB, regC, val
- USER(9998f, ldp \ptr, \regB, [\regC], \val)
+ uao_ldp 9998f, \ptr, \regB, \regC, \val
.endm
.macro stp1 ptr, regB, regC, val