s390: pass struct pt_regs instead of registers to syscalls

Instead of fetching all registers from struct pt_regs and passing
them to the syscall wrappers, let the system call wrappers only
fetch the values really required.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

3 files changed, 75 insertions, 51 deletions

diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index fa67b66bf144..023a15dc25a3 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -40,9 +40,7 @@
 #include <asm/fpu/internal.h>
 #include <asm/irqflags.h>
 
-typedef long (*sys_call_ptr_t)(unsigned long, unsigned long,
-			       unsigned long, unsigned long,
-			       unsigned long, unsigned long);
+typedef long (*sys_call_ptr_t)(struct pt_regs *regs);
 
 static inline void set_cpu_flag(int flag)
 {
diff --git a/arch/s390/include/asm/syscall_wrapper.h b/arch/s390/include/asm/syscall_wrapper.h
index 5364bfc866e0..ad2c996e7e93 100644
--- a/arch/s390/include/asm/syscall_wrapper.h
+++ b/arch/s390/include/asm/syscall_wrapper.h
@@ -7,6 +7,33 @@
 #ifndef _ASM_S390_SYSCALL_WRAPPER_H
 #define _ASM_S390_SYSCALL_WRAPPER_H
 
+#define __SC_TYPE(t, a) t
+
+#define SYSCALL_PT_ARG6(regs, m, t1, t2, t3, t4, t5, t6)\
+	SYSCALL_PT_ARG5(regs, m, t1, t2, t3, t4, t5),	\
+		m(t6, (regs->gprs[7]))
+
+#define SYSCALL_PT_ARG5(regs, m, t1, t2, t3, t4, t5)	\
+	SYSCALL_PT_ARG4(regs, m, t1, t2, t3, t4),	\
+		m(t5, (regs->gprs[6]))
+
+#define SYSCALL_PT_ARG4(regs, m, t1, t2, t3, t4)	\
+	SYSCALL_PT_ARG3(regs, m, t1, t2, t3),		\
+		m(t4, (regs->gprs[5]))
+
+#define SYSCALL_PT_ARG3(regs, m, t1, t2, t3)		\
+	SYSCALL_PT_ARG2(regs, m, t1, t2),		\
+		m(t3, (regs->gprs[4]))
+
+#define SYSCALL_PT_ARG2(regs, m, t1, t2)		\
+	SYSCALL_PT_ARG1(regs, m, t1),			\
+		m(t2, (regs->gprs[3]))
+
+#define SYSCALL_PT_ARG1(regs, m, t1)			\
+		m(t1, (regs->orig_gpr2))
+
+#define SYSCALL_PT_ARGS(x, ...) SYSCALL_PT_ARG##x(__VA_ARGS__)
+
 #ifdef CONFIG_COMPAT
 #define __SC_COMPAT_TYPE(t, a) \
 	__typeof(__builtin_choose_expr(sizeof(t) > 4, 0L, (t)0)) a
@@ -29,14 +56,15 @@
 	(t)__ReS;							\
 })
 
-#define __S390_SYS_STUBx(x, name, ...)					\
-	long __s390_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__));		\
-	ALLOW_ERROR_INJECTION(__s390_sys##name, ERRNO);			\
-	long __s390_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__))		\
-	{								\
-		long ret = __s390x_sys##name(__MAP(x,__SC_COMPAT_CAST,__VA_ARGS__));\
-		__MAP(x,__SC_TEST,__VA_ARGS__);				\
-		return ret;						\
+#define __S390_SYS_STUBx(x, name, ...)						\
+	long __s390_sys##name(struct pt_regs *regs);				\
+	ALLOW_ERROR_INJECTION(__s390_sys##name, ERRNO);				\
+	long __s390_sys##name(struct pt_regs *regs)				\
+	{									\
+		long ret = __do_sys##name(SYSCALL_PT_ARGS(x, regs,		\
+			__SC_COMPAT_CAST, __MAP(x, __SC_TYPE, __VA_ARGS__)));	\
+		__MAP(x,__SC_TEST,__VA_ARGS__);					\
+		return ret;							\
 	}
 
 /*
@@ -65,23 +93,24 @@
 	SYSCALL_ALIAS(__s390x_sys_##name, sys_ni_posix_timers);		\
 	SYSCALL_ALIAS(__s390_sys_##name, sys_ni_posix_timers)
 
-#define COMPAT_SYSCALL_DEFINEx(x, name, ...)					\
-	__diag_push();								\
-	__diag_ignore(GCC, 8, "-Wattribute-alias",				\
-		      "Type aliasing is used to sanitize syscall arguments");\
-	long __s390_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));		\
-	long __s390_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))		\
-		__attribute__((alias(__stringify(__se_compat_sys##name))));	\
-	ALLOW_ERROR_INJECTION(__s390_compat_sys##name, ERRNO);			\
-	static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\
-	long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__));		\
-	long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__))		\
-	{									\
-		long ret = __do_compat_sys##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__));\
-		__MAP(x,__SC_TEST,__VA_ARGS__);					\
-		return ret;							\
-	}									\
-	__diag_pop();								\
+#define COMPAT_SYSCALL_DEFINEx(x, name, ...)						\
+	__diag_push();									\
+	__diag_ignore(GCC, 8, "-Wattribute-alias",					\
+		      "Type aliasing is used to sanitize syscall arguments");		\
+	long __s390_compat_sys##name(struct pt_regs *regs);				\
+	long __s390_compat_sys##name(struct pt_regs *regs)				\
+		__attribute__((alias(__stringify(__se_compat_sys##name))));		\
+	ALLOW_ERROR_INJECTION(__s390_compat_sys##name, ERRNO);				\
+	static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));	\
+	long __se_compat_sys##name(struct pt_regs *regs);				\
+	long __se_compat_sys##name(struct pt_regs *regs)				\
+	{										\
+		long ret = __do_compat_sys##name(SYSCALL_PT_ARGS(x, regs, __SC_DELOUSE,	\
+						 __MAP(x, __SC_TYPE, __VA_ARGS__)));	\
+		__MAP(x,__SC_TEST,__VA_ARGS__);						\
+		return ret;								\
+	}										\
+	__diag_pop();									\
 	static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
 
 /*
@@ -113,23 +142,24 @@
 
 #endif /* CONFIG_COMPAT */
 
-#define __SYSCALL_DEFINEx(x, name, ...)						\
-	__diag_push();								\
-	__diag_ignore(GCC, 8, "-Wattribute-alias",				\
-		      "Type aliasing is used to sanitize syscall arguments");\
-	long __s390x_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))			\
-		__attribute__((alias(__stringify(__se_sys##name))));		\
-	ALLOW_ERROR_INJECTION(__s390x_sys##name, ERRNO);			\
-	long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__));			\
-	static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));	\
-	__S390_SYS_STUBx(x, name, __VA_ARGS__)					\
-	long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__))			\
-	{									\
-		long ret = __do_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__));	\
-		__MAP(x,__SC_TEST,__VA_ARGS__);					\
-		return ret;							\
-	}									\
-	__diag_pop();								\
+#define __SYSCALL_DEFINEx(x, name, ...)							\
+	__diag_push();									\
+	__diag_ignore(GCC, 8, "-Wattribute-alias",					\
+		      "Type aliasing is used to sanitize syscall arguments");		\
+	long __s390x_sys##name(struct pt_regs *regs)					\
+		__attribute__((alias(__stringify(__se_sys##name))));			\
+	ALLOW_ERROR_INJECTION(__s390x_sys##name, ERRNO);				\
+	static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));		\
+	long __se_sys##name(struct pt_regs *regs);					\
+	__S390_SYS_STUBx(x, name, __VA_ARGS__)						\
+	long __se_sys##name(struct pt_regs *regs)					\
+	{										\
+		long ret = __do_sys##name(SYSCALL_PT_ARGS(x, regs,			\
+				    __SC_CAST, __MAP(x, __SC_TYPE, __VA_ARGS__)));	\
+		__MAP(x,__SC_TEST,__VA_ARGS__);						\
+		return ret;								\
+	}										\
+	__diag_pop();									\
 	static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
 
 #endif /* _ASM_X86_SYSCALL_WRAPPER_H */
diff --git a/arch/s390/kernel/syscall.c b/arch/s390/kernel/syscall.c
index 25c0fb19b0a5..bc8e650e377d 100644
--- a/arch/s390/kernel/syscall.c
+++ b/arch/s390/kernel/syscall.c
@@ -132,12 +132,8 @@ void do_syscall(struct pt_regs *regs)
 	 */
 	if (!test_pt_regs_flag(regs, PIF_SYSCALL_RET_SET)) {
 		regs->gprs[2] = -ENOSYS;
-		if (likely(nr < NR_syscalls)) {
-			regs->gprs[2] = current->thread.sys_call_table[nr](
-					regs->orig_gpr2, regs->gprs[3],
-					regs->gprs[4], regs->gprs[5],
-					regs->gprs[6], regs->gprs[7]);
-		}
+		if (likely(nr < NR_syscalls))
+			regs->gprs[2] = current->thread.sys_call_table[nr](regs);
 	} else {
 		clear_pt_regs_flag(regs, PIF_SYSCALL_RET_SET);
 	}