x86: get rid of pt_regs argument of iopl(2)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/x86/ia32/ia32entry.S

@@ -467,7 +467,6 @@ GLOBAL(\label)
 	PTREGSCALL stub32_execve, compat_sys_execve, %rcx
 	PTREGSCALL stub32_fork, sys_fork, %rdi
 	PTREGSCALL stub32_vfork, sys_vfork, %rdi
-	PTREGSCALL stub32_iopl, sys_iopl, %rsi
 
 	ALIGN
 GLOBAL(stub32_clone)

arch/x86/include/asm/syscalls.h

@@ -18,7 +18,7 @@
 /* Common in X86_32 and X86_64 */
 /* kernel/ioport.c */
 asmlinkage long sys_ioperm(unsigned long, unsigned long, int);
-long sys_iopl(unsigned int, struct pt_regs *);
+asmlinkage long sys_iopl(unsigned int);
 
 /* kernel/ldt.c */
 asmlinkage int sys_modify_ldt(int, void __user *, unsigned long);

arch/x86/kernel/entry_32.S

@@ -738,7 +738,6 @@ ENTRY(ptregs_##name) ; \
 	CFI_ENDPROC; \
 ENDPROC(ptregs_##name)
 
-PTREGSCALL1(iopl)
 PTREGSCALL0(sigreturn)
 PTREGSCALL0(rt_sigreturn)
 PTREGSCALL2(vm86)

arch/x86/kernel/entry_64.S

@@ -828,23 +828,6 @@ int_restore_rest:
 	CFI_ENDPROC
 END(system_call)
 
-/*
- * Certain special system calls that need to save a complete full stack frame.
- */
-	.macro PTREGSCALL label,func,arg
-ENTRY(\label)
-	PARTIAL_FRAME 1 8		/* offset 8: return address */
-	subq $REST_SKIP, %rsp
-	CFI_ADJUST_CFA_OFFSET REST_SKIP
-	call save_rest
-	DEFAULT_FRAME 0 8		/* offset 8: return address */
-	leaq 8(%rsp), \arg	/* pt_regs pointer */
-	call \func
-	jmp ptregscall_common
-	CFI_ENDPROC
-END(\label)
-	.endm
-
 	.macro FORK_LIKE func
 ENTRY(stub_\func)
 	CFI_STARTPROC
@@ -861,10 +844,22 @@ ENTRY(stub_\func)
 END(stub_\func)
 	.endm
 
+	.macro FIXED_FRAME label,func
+ENTRY(\label)
+	CFI_STARTPROC
+	PARTIAL_FRAME 0 8		/* offset 8: return address */
+	FIXUP_TOP_OF_STACK %r11, 8-ARGOFFSET
+	call \func
+	RESTORE_TOP_OF_STACK %r11, 8-ARGOFFSET
+	ret
+	CFI_ENDPROC
+END(\label)
+	.endm
+
 	FORK_LIKE  clone
 	FORK_LIKE  fork
 	FORK_LIKE  vfork
-	PTREGSCALL stub_iopl, sys_iopl, %rsi
+	FIXED_FRAME stub_iopl, sys_iopl
 
 ENTRY(ptregscall_common)
 	DEFAULT_FRAME 1 8	/* offset 8: return address */

arch/x86/kernel/ioport.c

@@ -93,8 +93,9 @@ asmlinkage long sys_ioperm(unsigned long from, unsigned long num, int turn_on)
  * on system-call entry - see also fork() and the signal handling
  * code.
  */
-long sys_iopl(unsigned int level, struct pt_regs *regs)
+SYSCALL_DEFINE1(iopl, unsigned int, level)
 {
+	struct pt_regs *regs = current_pt_regs();
 	unsigned int old = (regs->flags >> 12) & 3;
 	struct thread_struct *t = &current->thread;
 

arch/x86/syscalls/syscall_32.tbl

@@ -116,7 +116,7 @@
 107	i386	lstat			sys_newlstat			compat_sys_newlstat
 108	i386	fstat			sys_newfstat			compat_sys_newfstat
 109	i386	olduname		sys_uname
-110	i386	iopl			ptregs_iopl			stub32_iopl
+110	i386	iopl			sys_iopl
 111	i386	vhangup			sys_vhangup
 112	i386	idle
 113	i386	vm86old			ptregs_vm86old			sys32_vm86_warning

arch/x86/um/sys_call_table_32.c

@@ -24,7 +24,6 @@
 
 #define old_mmap sys_old_mmap
 
-#define ptregs_iopl sys_iopl
 #define ptregs_vm86old sys_vm86old
 #define ptregs_vm86 sys_vm86