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authorCatalin Marinas <catalin.marinas@arm.com>2016-07-01 14:58:21 +0100
committerCatalin Marinas <catalin.marinas@arm.com>2016-11-21 17:33:47 +0000
commitbd38967d406fb4f9fca67d612db71b5d74cfb0f5 (patch)
treefbcc9bd2e2f70c40387fe166de6f4e874c0d0bdb /arch/arm64/lib/clear_user.S
parentarm64: Update the synchronous external abort fault description (diff)
downloadlinux-dev-bd38967d406fb4f9fca67d612db71b5d74cfb0f5.tar.xz
linux-dev-bd38967d406fb4f9fca67d612db71b5d74cfb0f5.zip
arm64: Factor out PAN enabling/disabling into separate uaccess_* macros
This patch moves the directly coded alternatives for turning PAN on/off into separate uaccess_{enable,disable} macros or functions. The asm macros take a few arguments which will be used in subsequent patches. Note that any (unlikely) access that the compiler might generate between uaccess_enable() and uaccess_disable(), other than those explicitly specified by the user access code, will not be protected by PAN. Cc: Will Deacon <will.deacon@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Kees Cook <keescook@chromium.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to '')
-rw-r--r--arch/arm64/lib/clear_user.S11
1 files changed, 3 insertions, 8 deletions
diff --git a/arch/arm64/lib/clear_user.S b/arch/arm64/lib/clear_user.S
index 5d1cad3ce6d6..d7150e30438a 100644
--- a/arch/arm64/lib/clear_user.S
+++ b/arch/arm64/lib/clear_user.S
@@ -17,10 +17,7 @@
*/
#include <linux/linkage.h>
-#include <asm/alternative.h>
-#include <asm/assembler.h>
-#include <asm/cpufeature.h>
-#include <asm/sysreg.h>
+#include <asm/uaccess.h>
.text
@@ -33,8 +30,7 @@
* Alignment fixed up by hardware.
*/
ENTRY(__clear_user)
-ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(0)), ARM64_ALT_PAN_NOT_UAO, \
- CONFIG_ARM64_PAN)
+ uaccess_enable_not_uao x2, x3
mov x2, x1 // save the size for fixup return
subs x1, x1, #8
b.mi 2f
@@ -54,8 +50,7 @@ uao_user_alternative 9f, strh, sttrh, wzr, x0, 2
b.mi 5f
uao_user_alternative 9f, strb, sttrb, wzr, x0, 0
5: mov x0, #0
-ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(1)), ARM64_ALT_PAN_NOT_UAO, \
- CONFIG_ARM64_PAN)
+ uaccess_disable_not_uao x2
ret
ENDPROC(__clear_user)