1 files changed, 87 insertions, 39 deletions

diff --git a/arch/mips/include/asm/syscall.h b/arch/mips/include/asm/syscall.h
index 7c713025b23f..d19e67e2aa6a 100644
--- a/arch/mips/include/asm/syscall.h
+++ b/arch/mips/include/asm/syscall.h
@@ -26,45 +26,90 @@
 #define __NR_syscall 4000
 #endif
 
+static inline bool mips_syscall_is_indirect(struct task_struct *task,
+					    struct pt_regs *regs)
+{
+	/* O32 ABI syscall() - Either 64-bit with O32 or 32-bit */
+	return (IS_ENABLED(CONFIG_32BIT) ||
+		test_tsk_thread_flag(task, TIF_32BIT_REGS)) &&
+		(regs->regs[2] == __NR_syscall);
+}
+
 static inline long syscall_get_nr(struct task_struct *task,
 				  struct pt_regs *regs)
 {
-	return current_thread_info()->syscall;
+	return task_thread_info(task)->syscall;
 }
 
-static inline unsigned long mips_get_syscall_arg(unsigned long *arg,
-	struct task_struct *task, struct pt_regs *regs, unsigned int n)
+static inline void syscall_set_nr(struct task_struct *task,
+				  struct pt_regs *regs,
+				  int nr)
 {
-	unsigned long usp __maybe_unused = regs->regs[29];
+	/*
+	 * New syscall number has to be assigned to regs[2] because
+	 * it is loaded from there unconditionally after return from
+	 * syscall_trace_enter() invocation.
+	 *
+	 * Consequently, if the syscall was indirect and nr != __NR_syscall,
+	 * then after this assignment the syscall will cease to be indirect.
+	 */
+	task_thread_info(task)->syscall = regs->regs[2] = nr;
+}
 
+static inline void mips_syscall_update_nr(struct task_struct *task,
+					  struct pt_regs *regs)
+{
+	/*
+	 * v0 is the system call number, except for O32 ABI syscall(), where it
+	 * ends up in a0.
+	 */
+	if (mips_syscall_is_indirect(task, regs))
+		task_thread_info(task)->syscall = regs->regs[4];
+	else
+		task_thread_info(task)->syscall = regs->regs[2];
+}
+
+static inline void mips_get_syscall_arg(unsigned long *arg,
+	struct task_struct *task, struct pt_regs *regs, unsigned int n)
+{
+#ifdef CONFIG_32BIT
 	switch (n) {
 	case 0: case 1: case 2: case 3:
 		*arg = regs->regs[4 + n];
-
-		return 0;
-
-#ifdef CONFIG_32BIT
+		return;
 	case 4: case 5: case 6: case 7:
-		return get_user(*arg, (int *)usp + n);
+		*arg = regs->args[n];
+		return;
+	}
+#else
+	*arg = regs->regs[4 + n];
+	if ((IS_ENABLED(CONFIG_MIPS32_O32) &&
+	     test_tsk_thread_flag(task, TIF_32BIT_REGS)))
+		*arg = (unsigned int)*arg;
 #endif
+}
 
-#ifdef CONFIG_64BIT
+static inline void mips_set_syscall_arg(unsigned long *arg,
+	struct task_struct *task, struct pt_regs *regs, unsigned int n)
+{
+#ifdef CONFIG_32BIT
+	switch (n) {
+	case 0: case 1: case 2: case 3:
+		regs->regs[4 + n] = *arg;
+		return;
 	case 4: case 5: case 6: case 7:
-#ifdef CONFIG_MIPS32_O32
-		if (test_thread_flag(TIF_32BIT_REGS))
-			return get_user(*arg, (int *)usp + n);
-		else
-#endif
-			*arg = regs->regs[4 + n];
-
-		return 0;
-#endif
-
-	default:
-		BUG();
+		*arg = regs->args[n] = *arg;
+		return;
 	}
+#else
+	regs->regs[4 + n] = *arg;
+#endif
+}
 
-	unreachable();
+static inline long syscall_get_error(struct task_struct *task,
+				     struct pt_regs *regs)
+{
+	return regs->regs[7] ? -regs->regs[2] : 0;
 }
 
 static inline long syscall_get_return_value(struct task_struct *task,
@@ -94,39 +139,42 @@ static inline void syscall_set_return_value(struct task_struct *task,
 
 static inline void syscall_get_arguments(struct task_struct *task,
 					 struct pt_regs *regs,
-					 unsigned int i, unsigned int n,
 					 unsigned long *args)
 {
-	int ret;
-	/* O32 ABI syscall() - Either 64-bit with O32 or 32-bit */
-	if ((IS_ENABLED(CONFIG_32BIT) ||
-	    test_tsk_thread_flag(task, TIF_32BIT_REGS)) &&
-	    (regs->regs[2] == __NR_syscall))
+	unsigned int i = 0;
+	unsigned int n = 6;
+
+	/* O32 ABI syscall() */
+	if (mips_syscall_is_indirect(task, regs))
 		i++;
 
 	while (n--)
-		ret |= mips_get_syscall_arg(args++, task, regs, i++);
+		mips_get_syscall_arg(args++, task, regs, i++);
+}
 
-	/*
-	 * No way to communicate an error because this is a void function.
-	 */
-#if 0
-	return ret;
-#endif
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 unsigned long *args)
+{
+	unsigned int i = 0;
+	unsigned int n = 6;
+
+	while (n--)
+		mips_set_syscall_arg(args++, task, regs, i++);
 }
 
 extern const unsigned long sys_call_table[];
 extern const unsigned long sys32_call_table[];
 extern const unsigned long sysn32_call_table[];
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 	int arch = AUDIT_ARCH_MIPS;
 #ifdef CONFIG_64BIT
-	if (!test_thread_flag(TIF_32BIT_REGS)) {
+	if (!test_tsk_thread_flag(task, TIF_32BIT_REGS)) {
 		arch |= __AUDIT_ARCH_64BIT;
 		/* N32 sets only TIF_32BIT_ADDR */
-		if (test_thread_flag(TIF_32BIT_ADDR))
+		if (test_tsk_thread_flag(task, TIF_32BIT_ADDR))
 			arch |= __AUDIT_ARCH_CONVENTION_MIPS64_N32;
 	}
 #endif