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From: Ammar Faizi <[email protected]>
To: Willy Tarreau <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>,
	Alviro Iskandar Setiawan <[email protected]>,
	Nugraha <[email protected]>,
	Linux Kernel Mailing List <[email protected]>,
	GNU/Weeb Mailing List <[email protected]>,
	Ammar Faizi <[email protected]>,
	David Laight <[email protected]>
Subject: [PATCH v1 04/11] tools/nolibc: x86-64: Use appropriate register constraints if exist
Date: Thu, 24 Mar 2022 14:30:32 +0700	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

Use appropriate register constraints if exist. Don't use register
variables for all inputs.

Register variables with "r" constraint should be used when we need to
pass data through a specific register to extended inline assembly that
doesn't have a specific register constraint associated with it (anything
outside %rax, %rbx, %rcx, %rdx, %rsi, %rdi).

It also simplifies the macro definition.

Link: https://lore.kernel.org/lkml/[email protected]
Suggested-by: David Laight <[email protected]>
Signed-off-by: Ammar Faizi <[email protected]>
---
 tools/include/nolibc/arch-x86_64.h | 202 +++++++++++++----------------
 1 file changed, 91 insertions(+), 111 deletions(-)

diff --git a/tools/include/nolibc/arch-x86_64.h b/tools/include/nolibc/arch-x86_64.h
index afc50f84a036..3067f553c03c 100644
--- a/tools/include/nolibc/arch-x86_64.h
+++ b/tools/include/nolibc/arch-x86_64.h
@@ -65,129 +65,109 @@ struct sys_stat_struct {
  *
  */
 
-#define my_syscall0(num)                                                      \
-({                                                                            \
-	long _ret;                                                            \
-	register long _num  __asm__("rax") = (num);                           \
-	                                                                      \
-	__asm__ volatile (                                                    \
-		"syscall\n"                                                   \
-		: "=a"(_ret)                                                  \
-		: "0"(_num)                                                   \
-		: "rcx", "r11", "memory", "cc"                                \
-	);                                                                    \
-	_ret;                                                                 \
+#define my_syscall0(num)					\
+({								\
+	long _ret = (num);					\
+	__asm__ volatile (					\
+		"syscall\n"					\
+		: "+a"(_ret)	/* %rax */			\
+		:						\
+		: "rcx", "r11", "memory", "cc"			\
+	);							\
+	_ret;							\
 })
 
-#define my_syscall1(num, arg1)                                                \
-({                                                                            \
-	long _ret;                                                            \
-	register long _num  __asm__("rax") = (num);                           \
-	register long _arg1 __asm__("rdi") = (long)(arg1);                    \
-	                                                                      \
-	__asm__ volatile (                                                    \
-		"syscall\n"                                                   \
-		: "=a"(_ret)                                                  \
-		: "r"(_arg1),                                                 \
-		  "0"(_num)                                                   \
-		: "rcx", "r11", "memory", "cc"                                \
-	);                                                                    \
-	_ret;                                                                 \
+#define my_syscall1(num, arg1)					\
+({								\
+	long _ret = (num);					\
+	__asm__ volatile (					\
+		"syscall\n"					\
+		: "+a"(_ret)	/* %rax */			\
+		: "D"(arg1)	/* %rdi */			\
+		: "rcx", "r11", "memory", "cc"			\
+	);							\
+	_ret;							\
 })
 
-#define my_syscall2(num, arg1, arg2)                                          \
-({                                                                            \
-	long _ret;                                                            \
-	register long _num  __asm__("rax") = (num);                           \
-	register long _arg1 __asm__("rdi") = (long)(arg1);                    \
-	register long _arg2 __asm__("rsi") = (long)(arg2);                    \
-	                                                                      \
-	__asm__ volatile (                                                    \
-		"syscall\n"                                                   \
-		: "=a"(_ret)                                                  \
-		: "r"(_arg1), "r"(_arg2),                                     \
-		  "0"(_num)                                                   \
-		: "rcx", "r11", "memory", "cc"                                \
-	);                                                                    \
-	_ret;                                                                 \
+#define my_syscall2(num, arg1, arg2)				\
+({								\
+	long _ret = (num);					\
+	__asm__ volatile (					\
+		"syscall\n"					\
+		: "+a"(_ret)	/* %rax */			\
+		: "D"(arg1),	/* %rdi */			\
+		  "S"(arg2)	/* %rsi */			\
+		: "rcx", "r11", "memory", "cc"			\
+	);							\
+	_ret;							\
 })
 
-#define my_syscall3(num, arg1, arg2, arg3)                                    \
-({                                                                            \
-	long _ret;                                                            \
-	register long _num  __asm__("rax") = (num);                           \
-	register long _arg1 __asm__("rdi") = (long)(arg1);                    \
-	register long _arg2 __asm__("rsi") = (long)(arg2);                    \
-	register long _arg3 __asm__("rdx") = (long)(arg3);                    \
-	                                                                      \
-	__asm__ volatile (                                                    \
-		"syscall\n"                                                   \
-		: "=a"(_ret)                                                  \
-		: "r"(_arg1), "r"(_arg2), "r"(_arg3),                         \
-		  "0"(_num)                                                   \
-		: "rcx", "r11", "memory", "cc"                                \
-	);                                                                    \
-	_ret;                                                                 \
+#define my_syscall3(num, arg1, arg2, arg3)			\
+({								\
+	long _ret = (num);					\
+	__asm__ volatile (					\
+		"syscall\n"					\
+		: "+a"(_ret)	/* %rax */			\
+		: "D"(arg1),	/* %rdi */			\
+		  "S"(arg2),	/* %rsi */			\
+		  "d"(arg3)	/* %rdx */			\
+		: "rcx", "r11", "memory", "cc"			\
+	);							\
+	_ret;							\
 })
 
-#define my_syscall4(num, arg1, arg2, arg3, arg4)                              \
-({                                                                            \
-	long _ret;                                                            \
-	register long _num  __asm__("rax") = (num);                           \
-	register long _arg1 __asm__("rdi") = (long)(arg1);                    \
-	register long _arg2 __asm__("rsi") = (long)(arg2);                    \
-	register long _arg3 __asm__("rdx") = (long)(arg3);                    \
-	register long _arg4 __asm__("r10") = (long)(arg4);                    \
-	                                                                      \
-	__asm__ volatile (                                                    \
-		"syscall\n"                                                   \
-		: "=a"(_ret)                                                  \
-		: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4),             \
-		  "0"(_num)                                                   \
-		: "rcx", "r11", "memory", "cc"                                \
-	);                                                                    \
-	_ret;                                                                 \
+#define my_syscall4(num, arg1, arg2, arg3, arg4)		\
+({								\
+	long _ret = (num);					\
+	register long _arg4 __asm__("r10") = (long)(arg4);	\
+	__asm__ volatile (					\
+		"syscall\n"					\
+		: "+a"(_ret)	/* %rax */			\
+		: "D"(arg1),	/* %rdi */			\
+		  "S"(arg2),	/* %rsi */			\
+		  "d"(arg3),	/* %rdx */			\
+		  "r"(_arg4)	/* %r10 */			\
+		: "rcx", "r11", "memory", "cc"			\
+	);							\
+	_ret;							\
 })
 
-#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5)                        \
-({                                                                            \
-	long _ret;                                                            \
-	register long _num  __asm__("rax") = (num);                           \
-	register long _arg1 __asm__("rdi") = (long)(arg1);                    \
-	register long _arg2 __asm__("rsi") = (long)(arg2);                    \
-	register long _arg3 __asm__("rdx") = (long)(arg3);                    \
-	register long _arg4 __asm__("r10") = (long)(arg4);                    \
-	register long _arg5 __asm__("r8")  = (long)(arg5);                    \
-	                                                                      \
-	__asm__ volatile (                                                    \
-		"syscall\n"                                                   \
-		: "=a"(_ret)                                                  \
-		: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
-		  "0"(_num)                                                   \
-		: "rcx", "r11", "memory", "cc"                                \
-	);                                                                    \
-	_ret;                                                                 \
+#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5)		\
+({								\
+	long _ret = (num);					\
+	register long _arg4 __asm__("r10") = (long)(arg4);	\
+	register long _arg5 __asm__("r8")  = (long)(arg5);	\
+	__asm__ volatile (					\
+		"syscall\n"					\
+		: "+a"(_ret)	/* %rax */			\
+		: "D"(arg1),	/* %rdi */			\
+		  "S"(arg2),	/* %rsi */			\
+		  "d"(arg3),	/* %rdx */			\
+		  "r"(_arg4),	/* %r10 */			\
+		  "r"(_arg5)	/* %r8  */			\
+		: "rcx", "r11", "memory", "cc"			\
+	);							\
+	_ret;							\
 })
 
-#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6)                  \
-({                                                                            \
-	long _ret;                                                            \
-	register long _num  __asm__("rax") = (num);                           \
-	register long _arg1 __asm__("rdi") = (long)(arg1);                    \
-	register long _arg2 __asm__("rsi") = (long)(arg2);                    \
-	register long _arg3 __asm__("rdx") = (long)(arg3);                    \
-	register long _arg4 __asm__("r10") = (long)(arg4);                    \
-	register long _arg5 __asm__("r8")  = (long)(arg5);                    \
-	register long _arg6 __asm__("r9")  = (long)(arg6);                    \
-	                                                                      \
-	__asm__ volatile (                                                    \
-		"syscall\n"                                                   \
-		: "=a"(_ret)                                                  \
-		: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
-		  "r"(_arg6), "0"(_num)                                       \
-		: "rcx", "r11", "memory", "cc"                                \
-	);                                                                    \
-	_ret;                                                                 \
+#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6)	\
+({								\
+	long _ret = (num);					\
+	register long _arg4 __asm__("r10") = (long)(arg4);	\
+	register long _arg5 __asm__("r8")  = (long)(arg5);	\
+	register long _arg6 __asm__("r9")  = (long)(arg6);	\
+	__asm__ volatile (					\
+		"syscall\n"					\
+		: "+a"(_ret)	/* %rax */			\
+		: "D"(arg1),	/* %rdi */			\
+		  "S"(arg2),	/* %rsi */			\
+		  "d"(arg3),	/* %rdx */			\
+		  "r"(_arg4),	/* %r10 */			\
+		  "r"(_arg5),	/* %r8  */			\
+		  "r"(_arg6)	/* %r9  */			\
+		: "rcx", "r11", "memory", "cc"			\
+	);							\
+	_ret;							\
 })
 
 /* startup code */
-- 
Ammar Faizi


  parent reply	other threads:[~2022-03-24  7:31 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-24  7:30 [PATCH v1 00/11] Add dynamic memory allocator support for nolibc Ammar Faizi
2022-03-24  7:30 ` [PATCH v1 01/11] tools/nolibc: x86-64: Update System V ABI document link Ammar Faizi
2022-03-24  7:30 ` [PATCH v1 02/11] tools/nolibc: Remove .global _start from the entry point code Ammar Faizi
2022-03-24  7:30 ` [PATCH v1 03/11] tools/nolibc: Replace `asm` with `__asm__` Ammar Faizi
2022-03-24  7:41   ` Willy Tarreau
2022-03-24  9:03     ` Ammar Faizi
2022-03-24  7:30 ` Ammar Faizi [this message]
2022-03-24  7:57   ` [PATCH v1 04/11] tools/nolibc: x86-64: Use appropriate register constraints if exist Willy Tarreau
2022-03-24  8:33     ` Alviro Iskandar Setiawan
2022-03-24  9:00       ` Ammar Faizi
2022-03-24 15:42       ` Willy Tarreau
2022-03-24  7:30 ` [PATCH v1 05/11] tools/nolibc: i386: " Ammar Faizi
2022-03-24  7:30 ` [PATCH v1 06/11] tools/nolibc: i386: Implement syscall with 6 arguments Ammar Faizi
2022-03-24  7:30 ` [PATCH v1 07/11] tools/nolibc/sys: Implement `mmap()` and `munmap()` Ammar Faizi
2022-03-24  7:30 ` [PATCH v1 08/11] tools/nolibc/types: Implement `offsetof()` and `container_of()` macro Ammar Faizi
2022-03-24  7:30 ` [PATCH v1 09/11] tools/nolibc/stdlib: Implement `malloc()`, `calloc()`, `realloc()` and `free()` Ammar Faizi
2022-03-24  7:30 ` [PATCH v1 10/11] tools/nolibc/string: Implement `strnlen()` Ammar Faizi
2022-03-24  7:30 ` [PATCH v1 11/11] tools/include/string: Implement `strdup()` and `strndup()` Ammar Faizi

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