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>

2 files changed, 22 insertions, 10 deletions

diff --git a/arch/x86/include/asm/linkage.h b/arch/x86/include/asm/linkage.h
index 5d98d0b68ffc..2fd5926fb97d 100644
--- a/arch/x86/include/asm/linkage.h
+++ b/arch/x86/include/asm/linkage.h
@@ -18,6 +18,13 @@
 #define asmregparm __attribute__((regparm(3)))
 
 /*
+ * For syscalls that need a pointer to the pt_regs struct (ie. fork).
+ * The regs pointer is passed in %eax as the first argument.  The
+ * remaining function arguments remain on the stack.
+ */
+#define ptregscall __attribute__((regparm(1)))
+
+/*
  * Make sure the compiler doesn't do anything stupid with the
  * arguments on the stack - they are owned by the *caller*, not
  * the callee. This just fools gcc into not spilling into them,
diff --git a/arch/x86/include/asm/syscalls.h b/arch/x86/include/asm/syscalls.h
index c0b0bda754ee..617295255a17 100644
--- a/arch/x86/include/asm/syscalls.h
+++ b/arch/x86/include/asm/syscalls.h
@@ -29,21 +29,26 @@ asmlinkage int sys_get_thread_area(struct user_desc __user *);
 /* X86_32 only */
 #ifdef CONFIG_X86_32
 /* kernel/process_32.c */
-asmlinkage int sys_fork(struct pt_regs);
-asmlinkage int sys_clone(struct pt_regs);
-asmlinkage int sys_vfork(struct pt_regs);
-asmlinkage int sys_execve(struct pt_regs);
+ptregscall int sys_fork(struct pt_regs *);
+ptregscall int sys_clone(struct pt_regs *, unsigned long,
+			 unsigned long, int __user *,
+			 unsigned long, int __user *);
+ptregscall int sys_vfork(struct pt_regs *);
+ptregscall int sys_execve(struct pt_regs *, char __user *,
+			  char __user * __user *,
+			  char __user * __user *);
 
 /* kernel/signal_32.c */
 asmlinkage int sys_sigsuspend(int, int, old_sigset_t);
 asmlinkage int sys_sigaction(int, const struct old_sigaction __user *,
 			     struct old_sigaction __user *);
-asmlinkage int sys_sigaltstack(unsigned long);
-asmlinkage unsigned long sys_sigreturn(unsigned long);
-asmlinkage int sys_rt_sigreturn(unsigned long);
+ptregscall int sys_sigaltstack(struct pt_regs *, const stack_t __user *,
+			       stack_t __user *);
+ptregscall unsigned long sys_sigreturn(struct pt_regs *);
+ptregscall int sys_rt_sigreturn(struct pt_regs *);
 
 /* kernel/ioport.c */
-asmlinkage long sys_iopl(unsigned long);
+ptregscall long sys_iopl(struct pt_regs *, unsigned int);
 
 /* kernel/sys_i386_32.c */
 asmlinkage long sys_mmap2(unsigned long, unsigned long, unsigned long,
@@ -59,8 +64,8 @@ struct oldold_utsname;
 asmlinkage int sys_olduname(struct oldold_utsname __user *);
 
 /* kernel/vm86_32.c */
-asmlinkage int sys_vm86old(struct pt_regs);
-asmlinkage int sys_vm86(struct pt_regs);
+ptregscall int sys_vm86old(struct pt_regs *, struct vm86_struct __user *);
+ptregscall int sys_vm86(struct pt_regs *, unsigned long, unsigned long);
 
 #else /* CONFIG_X86_32 */