x86: pass in pt_regs pointer for syscalls that need it

Some syscalls need to access the pt_regs structure, either to copy
user register state or to modifiy it.  This patch adds stubs to load
the address of the pt_regs struct into the %eax register, and changes
the syscalls to regparm(1) to receive the pt_regs pointer as the
first argument.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 14 insertions, 21 deletions

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index b50604bb1e41..5a9dcfb01f71 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -603,24 +603,18 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 	return prev_p;
 }
 
-asmlinkage int sys_fork(struct pt_regs regs)
+ptregscall int sys_fork(struct pt_regs *regs)
 {
-	return do_fork(SIGCHLD, regs.sp, &regs, 0, NULL, NULL);
+	return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);
 }
 
-asmlinkage int sys_clone(struct pt_regs regs)
+ptregscall int sys_clone(struct pt_regs *regs, unsigned long clone_flags,
+			 unsigned long newsp, int __user *parent_tidptr,
+			 unsigned long unused, int __user *child_tidptr)
 {
-	unsigned long clone_flags;
-	unsigned long newsp;
-	int __user *parent_tidptr, *child_tidptr;
-
-	clone_flags = regs.bx;
-	newsp = regs.cx;
-	parent_tidptr = (int __user *)regs.dx;
-	child_tidptr = (int __user *)regs.di;
 	if (!newsp)
-		newsp = regs.sp;
-	return do_fork(clone_flags, newsp, &regs, 0, parent_tidptr, child_tidptr);
+		newsp = regs->sp;
+	return do_fork(clone_flags, newsp, regs, 0, parent_tidptr, child_tidptr);
 }
 
 /*
@@ -633,27 +627,26 @@ asmlinkage int sys_clone(struct pt_regs regs)
  * do not have enough call-clobbered registers to hold all
  * the information you need.
  */
-asmlinkage int sys_vfork(struct pt_regs regs)
+ptregscall int sys_vfork(struct pt_regs *regs)
 {
-	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.sp, &regs, 0, NULL, NULL);
+	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs, 0, NULL, NULL);
 }
 
 /*
  * sys_execve() executes a new program.
  */
-asmlinkage int sys_execve(struct pt_regs regs)
+ptregscall int sys_execve(struct pt_regs *regs, char __user *u_filename,
+			  char __user * __user *argv,
+			  char __user * __user *envp)
 {
 	int error;
 	char *filename;
 
-	filename = getname((char __user *) regs.bx);
+	filename = getname(u_filename);
 	error = PTR_ERR(filename);
 	if (IS_ERR(filename))
 		goto out;
-	error = do_execve(filename,
-			(char __user * __user *) regs.cx,
-			(char __user * __user *) regs.dx,
-			&regs);
+	error = do_execve(filename, argv, envp, regs);
 	if (error == 0) {
 		/* Make sure we don't return using sysenter.. */
 		set_thread_flag(TIF_IRET);