linux-kernel - [PATCH AUTOSEL 5.6 299/606] ARM: uaccess: integrate uaccess_save and uaccess

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Date:   Mon,  8 Jun 2020 19:07:04 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Russell King <rmk+kernel@...linux.org.uk>,
        Sasha Levin <sashal@...nel.org>,
        linux-arm-kernel@...ts.infradead.org
Subject: [PATCH AUTOSEL 5.6 299/606] ARM: uaccess: integrate uaccess_save and uaccess_restore

From: Russell King <rmk+kernel@...linux.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@...linux.org.uk>
Signed-off-by: Sasha Levin <sashal@...nel.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