linux-kernel - [PATCH v10 8/9] arm64: armv8_deprecated: convert user

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Message-Id: <20251103163224.818353-9-yeoreum.yun@arm.com>
Date: Mon,  3 Nov 2025 16:32:23 +0000
From: Yeoreum Yun <yeoreum.yun@....com>
To: catalin.marinas@....com,
	will@...nel.org,
	maz@...nel.org,
	broonie@...nel.org,
	oliver.upton@...ux.dev,
	miko.lenczewski@....com,
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	mark.rutland@....com
Cc: linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
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	kvm@...r.kernel.org,
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	Yeoreum Yun <yeoreum.yun@....com>
Subject: [PATCH v10 8/9] arm64: armv8_deprecated: convert user_swpX to inline function

This is preparation patch to apply FEAT_LSUI in
user_swpX operation.
For this, convert user_swpX macro into inline function.
No functional change.

Signed-off-by: Yeoreum Yun <yeoreum.yun@....com>
---
 arch/arm64/kernel/armv8_deprecated.c | 38 +++++++++++++++++-----------
 1 file changed, 23 insertions(+), 15 deletions(-)

diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c
index e737c6295ec7..d15e35f1075c 100644
--- a/arch/arm64/kernel/armv8_deprecated.c
+++ b/arch/arm64/kernel/armv8_deprecated.c
@@ -93,13 +93,18 @@ static unsigned int __maybe_unused aarch32_check_condition(u32 opcode, u32 psr)
 /* Arbitrary constant to ensure forward-progress of the LL/SC loop */
 #define __SWP_LL_SC_LOOPS	4
 
-#define __user_swpX_asm(data, addr, res, temp, temp2, B)	\
-do {								\
+#define LLSC_USER_SWPX(B)					\
+static __always_inline int					\
+__llsc_user_swp##B##_asm(unsigned int *data, unsigned int addr)	\
+{								\
+	int err = 0;						\
+	unsigned int temp, temp2;				\
+								\
 	uaccess_enable_privileged();				\
 	__asm__ __volatile__(					\
 	"	mov		%w3, %w6\n"			\
-	"0:	ldxr"B"		%w2, [%4]\n"			\
-	"1:	stxr"B"		%w0, %w1, [%4]\n"		\
+	"0:	ldxr"#B"	%w2, [%4]\n"			\
+	"1:	stxr"#B"	%w0, %w1, [%4]\n"		\
 	"	cbz		%w0, 2f\n"			\
 	"	sub		%w3, %w3, #1\n"			\
 	"	cbnz		%w3, 0b\n"			\
@@ -110,17 +115,22 @@ do {								\
 	"3:\n"							\
 	_ASM_EXTABLE_UACCESS_ERR(0b, 3b, %w0)			\
 	_ASM_EXTABLE_UACCESS_ERR(1b, 3b, %w0)			\
-	: "=&r" (res), "+r" (data), "=&r" (temp), "=&r" (temp2)	\
+	: "=&r" (err), "+r" (*data), "=&r" (temp), "=&r" (temp2)\
 	: "r" ((unsigned long)addr), "i" (-EAGAIN),		\
 	  "i" (__SWP_LL_SC_LOOPS)				\
 	: "memory");						\
 	uaccess_disable_privileged();				\
-} while (0)
+								\
+	return err;						\
+}
+
+LLSC_USER_SWPX()
+LLSC_USER_SWPX(b)
 
-#define __user_swp_asm(data, addr, res, temp, temp2) \
-	__user_swpX_asm(data, addr, res, temp, temp2, "")
-#define __user_swpb_asm(data, addr, res, temp, temp2) \
-	__user_swpX_asm(data, addr, res, temp, temp2, "b")
+#define __user_swp_asm(data, addr) \
+	__llsc_user_swp_asm(data, addr)
+#define __user_swpb_asm(data, addr) \
+	__llsc_user_swpb_asm(data, addr)
 
 /*
  * Bit 22 of the instruction encoding distinguishes between
@@ -131,7 +141,7 @@ do {								\
 static int emulate_swpX(unsigned int address, unsigned int *data,
 			unsigned int type)
 {
-	unsigned int res = 0;
+	unsigned int res;
 
 	if ((type != TYPE_SWPB) && (address & 0x3)) {
 		/* SWP to unaligned address not permitted */
@@ -140,12 +150,10 @@ static int emulate_swpX(unsigned int address, unsigned int *data,
 	}
 
 	while (1) {
-		unsigned long temp, temp2;
-
 		if (type == TYPE_SWPB)
-			__user_swpb_asm(*data, address, res, temp, temp2);
+			res = __user_swpb_asm(data, address);
 		else
-			__user_swp_asm(*data, address, res, temp, temp2);
+			res = __user_swp_asm(data, address);
 
 		if (likely(res != -EAGAIN) || signal_pending(current))
 			break;
-- 
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}