[PATCH] arm: syscall.h: fix up syscall_set/get_arguments

[Will Drewry]

syscall_{get,set}_arguments currently allow up to 7 arguments and make
the system call number a virtual argument.  This breaks the internal
asm/syscall.h ABI and makes the implementation incompatible with
existing implementations.

This change converts those functions to behave as they do on other
arches: 6 arguments and leave the syscall to syscall_get_nr and
syscall_rollback.

Signed-off-by: Will Drewry <wad@xxxxxxxxxxxx>
---
 arch/arm/include/asm/syscall.h |   33 +++------------------------------
 1 file changed, 3 insertions(+), 30 deletions(-)

diff --git a/arch/arm/include/asm/syscall.h b/arch/arm/include/asm/syscall.h
index c334a23..c30035a 100644
--- a/arch/arm/include/asm/syscall.h
+++ b/arch/arm/include/asm/syscall.h
@@ -43,29 +43,14 @@ static inline void syscall_set_return_value(struct
task_struct *task,
 	regs->ARM_r0 = (long) error ? error : val;
 }

-#define SYSCALL_MAX_ARGS 7
+#define SYSCALL_MAX_ARGS 6

 static inline void syscall_get_arguments(struct task_struct *task,
 					 struct pt_regs *regs,
 					 unsigned int i, unsigned int n,
 					 unsigned long *args)
 {
-	if (i + n > SYSCALL_MAX_ARGS) {
-		unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
-		unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
-		pr_warning("%s called with max args %d, handling only %d\n",
-			   __func__, i + n, SYSCALL_MAX_ARGS);
-		memset(args_bad, 0, n_bad * sizeof(args[0]));
-		n = SYSCALL_MAX_ARGS - i;
-	}
-
-	if (i == 0) {
-		args[0] = regs->ARM_ORIG_r0;
-		args++;
-		i++;
-		n--;
-	}
-
+	BUG_ON(i + n > SYSCALL_MAX_ARGS);
 	memcpy(args, &regs->ARM_r0 + i, n * sizeof(args[0]));
 }

@@ -74,19 +59,7 @@ static inline void syscall_set_arguments(struct
task_struct *task,
 					 unsigned int i, unsigned int n,
 					 const unsigned long *args)
 {
-	if (i + n > SYSCALL_MAX_ARGS) {
-		pr_warning("%s called with max args %d, handling only %d\n",
-			   __func__, i + n, SYSCALL_MAX_ARGS);
-		n = SYSCALL_MAX_ARGS - i;
-	}
-
-	if (i == 0) {
-		regs->ARM_ORIG_r0 = args[0];
-		args++;
-		i++;
-		n--;
-	}
-
+	BUG_ON(i + n > SYSCALL_MAX_ARGS);
 	memcpy(&regs->ARM_r0 + i, args, n * sizeof(args[0]));
 }

-- 
1.7.9.5
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