[PATCH AUTOSEL 5.6 299/606] ARM: uaccess: integrate uaccess_save and uaccess_restore

Sasha Levin
2020-06-09T00:19:43Z

From: Russell King <rmk+kernel@armlinux.org.uk>

[ Upstream commit 8ede890b0bcebe8c760aacfe20e934d98c3dc6aa ]

Integrate uaccess_save / uaccess_restore macros into the new
uaccess_entry / uaccess_exit macros respectively.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm/include/asm/uaccess-asm.h | 30 +++++++++++++-----------------
1 file changed, 13 insertions(+), 17 deletions(-)

diff --git a/arch/arm/include/asm/uaccess-asm.h b/arch/arm/include/asm/uaccess-asm.h
index d475e3e8145d..e46468b91eaa 100644
--- a/arch/arm/include/asm/uaccess-asm.h
+++ b/arch/arm/include/asm/uaccess-asm.h
@@ -67,30 +67,23 @@
#endif
.endm

- .macro uaccess_save, tmp
#ifdef CONFIG_CPU_SW_DOMAIN_PAN
- mrc p15, 0, \tmp, c3, c0, 0
- str \tmp, [sp, #SVC_DACR]
-#endif
- .endm
-
- .macro uaccess_restore
-#ifdef CONFIG_CPU_SW_DOMAIN_PAN
- ldr r0, [sp, #SVC_DACR]
- mcr p15, 0, r0, c3, c0, 0
+#define DACR(x...) x
+#else
+#define DACR(x...)
#endif
- .endm

/*
* Save the address limit on entry to a privileged exception and
* if using PAN, save and disable usermode access.
*/
.macro uaccess_entry, tsk, tmp0, tmp1, tmp2, disable
- ldr \tmp0, [\tsk, #TI_ADDR_LIMIT]
- mov \tmp1, #TASK_SIZE
- str \tmp1, [\tsk, #TI_ADDR_LIMIT]
- str \tmp0, [sp, #SVC_ADDR_LIMIT]
- uaccess_save \tmp0
+ ldr \tmp1, [\tsk, #TI_ADDR_LIMIT]
+ mov \tmp2, #TASK_SIZE
+ str \tmp2, [\tsk, #TI_ADDR_LIMIT]
+ DACR( mrc p15, 0, \tmp0, c3, c0, 0)
+ DACR( str \tmp0, [sp, #SVC_DACR])
+ str \tmp1, [sp, #SVC_ADDR_LIMIT]
.if \disable
uaccess_disable \tmp0
.endif
@@ -99,8 +92,11 @@
/* Restore the user access state previously saved by uaccess_entry */
.macro uaccess_exit, tsk, tmp0, tmp1
ldr \tmp1, [sp, #SVC_ADDR_LIMIT]
- uaccess_restore
+ DACR( ldr \tmp0, [sp, #SVC_DACR])
str \tmp1, [\tsk, #TI_ADDR_LIMIT]
+ DACR( mcr p15, 0, \tmp0, c3, c0, 0)
.endm

+#undef DACR
+
#endif /* __ASM_UACCESS_ASM_H__ */
--
2.25.1