Merge tag 'mips-fixes_6.14_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux

Pull MIPS fixes from Thomas Bogendoerfer:
 "Fix for o32 ptrace/get_syscall_info"

* tag 'mips-fixes_6.14_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
  MIPS: fix mips_get_syscall_arg() for o32
  MIPS: Export syscall stack arguments properly for remote use

Author: torvalds

arch/mips/include/asm/ptrace.h

@@ -27,8 +27,8 @@
  */
 struct pt_regs {
 #ifdef CONFIG_32BIT
-	/* Pad bytes for argument save space on the stack. */
-	unsigned long pad0[8];
+	/* Saved syscall stack arguments; entries 0-3 unused. */
+	unsigned long args[8];
 #endif
 
 	/* Saved main processor registers. */

arch/mips/include/asm/syscall.h

@@ -57,37 +57,21 @@ static inline void mips_syscall_update_nr(struct task_struct *task,
 static inline void mips_get_syscall_arg(unsigned long *arg,
 	struct task_struct *task, struct pt_regs *regs, unsigned int n)
 {
-	unsigned long usp __maybe_unused = regs->regs[29];
-
+#ifdef CONFIG_32BIT
 	switch (n) {
 	case 0: case 1: case 2: case 3:
 		*arg = regs->regs[4 + n];
-
-		return;
-
-#ifdef CONFIG_32BIT
-	case 4: case 5: case 6: case 7:
-		get_user(*arg, (int *)usp + n);
 		return;
-#endif
-
-#ifdef CONFIG_64BIT
 	case 4: case 5: case 6: case 7:
-#ifdef CONFIG_MIPS32_O32
-		if (test_tsk_thread_flag(task, TIF_32BIT_REGS))
-			get_user(*arg, (int *)usp + n);
-		else
-#endif
-			*arg = regs->regs[4 + n];
-
+		*arg = regs->args[n];
 		return;
-#endif
-
-	default:
-		BUG();
 	}
-
-	unreachable();
+#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
 }
 
 static inline long syscall_get_error(struct task_struct *task,

arch/mips/kernel/asm-offsets.c

@@ -27,6 +27,12 @@ void output_ptreg_defines(void);
 void output_ptreg_defines(void)
 {
 	COMMENT("MIPS pt_regs offsets.");
+#ifdef CONFIG_32BIT
+	OFFSET(PT_ARG4, pt_regs, args[4]);
+	OFFSET(PT_ARG5, pt_regs, args[5]);
+	OFFSET(PT_ARG6, pt_regs, args[6]);
+	OFFSET(PT_ARG7, pt_regs, args[7]);
+#endif
 	OFFSET(PT_R0, pt_regs, regs[0]);
 	OFFSET(PT_R1, pt_regs, regs[1]);
 	OFFSET(PT_R2, pt_regs, regs[2]);

arch/mips/kernel/scall32-o32.S

@@ -64,10 +64,10 @@ load_a6: user_lw(t7, 24(t0))		# argument #7 from usp
 load_a7: user_lw(t8, 28(t0))		# argument #8 from usp
 loads_done:
 
-	sw	t5, 16(sp)		# argument #5 to ksp
-	sw	t6, 20(sp)		# argument #6 to ksp
-	sw	t7, 24(sp)		# argument #7 to ksp
-	sw	t8, 28(sp)		# argument #8 to ksp
+	sw	t5, PT_ARG4(sp)		# argument #5 to ksp
+	sw	t6, PT_ARG5(sp)		# argument #6 to ksp
+	sw	t7, PT_ARG6(sp)		# argument #7 to ksp
+	sw	t8, PT_ARG7(sp)		# argument #8 to ksp
 	.set	pop
 
 	.section __ex_table,"a"