s390: fold execve_tail() into start_thread(), convert to generic sys_execve()

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

arch/s390/include/asm/processor.h

@@ -32,6 +32,7 @@ static inline void get_cpu_id(struct cpuid *ptr)
 extern void s390_adjust_jiffies(void);
 extern const struct seq_operations cpuinfo_op;
 extern int sysctl_ieee_emulation_warnings;
+extern void execve_tail(void);
 
 /*
  * User space process size: 2GB for 31 bit, 4TB or 8PT for 64 bit.
@@ -114,6 +115,7 @@ struct stack_frame {
 	regs->psw.mask	= psw_user_bits | PSW_MASK_EA | PSW_MASK_BA;	\
 	regs->psw.addr	= new_psw | PSW_ADDR_AMODE;			\
 	regs->gprs[15]	= new_stackp;					\
+	execve_tail();							\
 } while (0)
 
 #define start_thread31(regs, new_psw, new_stackp) do {			\
@@ -123,6 +125,7 @@ struct stack_frame {
 	__tlb_flush_mm(current->mm);					\
 	crst_table_downgrade(current->mm, 1UL << 31);			\
 	update_mm(current->mm, current);				\
+	execve_tail();							\
 } while (0)
 
 /* Forward declaration, a strange C thing */

arch/s390/include/asm/unistd.h

@@ -415,6 +415,7 @@
 #   define __ARCH_WANT_COMPAT_SYS_TIME
 #   define __ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND
 # endif
+#define __ARCH_WANT_SYS_EXECVE
 
 /*
  * "Conditional" syscalls

arch/s390/kernel/compat_linux.c

@@ -420,32 +420,6 @@ sys32_rt_sigqueueinfo(int pid, int sig, compat_siginfo_t __user *uinfo)
 	return ret;
 }
 
-/*
- * sys32_execve() executes a new program after the asm stub has set
- * things up for us.  This should basically do what I want it to.
- */
-asmlinkage long sys32_execve(const char __user *name, compat_uptr_t __user *argv,
-			     compat_uptr_t __user *envp)
-{
-	struct pt_regs *regs = task_pt_regs(current);
-	char *filename;
-	long rc;
-
-	filename = getname(name);
-	rc = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		return rc;
-	rc = compat_do_execve(filename, argv, envp, regs);
-	if (rc)
-		goto out;
-	current->thread.fp_regs.fpc=0;
-	asm volatile("sfpc %0,0" : : "d" (0));
-	rc = regs->gprs[2];
-out:
-	putname(filename);
-	return rc;
-}
-
 asmlinkage long sys32_pread64(unsigned int fd, char __user *ubuf,
 				size_t count, u32 poshi, u32 poslo)
 {

arch/s390/kernel/compat_linux.h

@@ -193,8 +193,6 @@ long sys32_rt_sigprocmask(int how, compat_sigset_t __user *set,
 			  compat_sigset_t __user *oset, size_t sigsetsize);
 long sys32_rt_sigpending(compat_sigset_t __user *set, size_t sigsetsize);
 long sys32_rt_sigqueueinfo(int pid, int sig, compat_siginfo_t __user *uinfo);
-long sys32_execve(const char __user *name, compat_uptr_t __user *argv,
-		  compat_uptr_t __user *envp);
 long sys32_init_module(void __user *umod, unsigned long len,
 		       const char __user *uargs);
 long sys32_delete_module(const char __user *name_user, unsigned int flags);

arch/s390/kernel/compat_wrapper.S

@@ -1576,7 +1576,7 @@ ENTRY(sys32_execve_wrapper)
 	llgtr	%r2,%r2			# char *
 	llgtr	%r3,%r3			# compat_uptr_t *
 	llgtr	%r4,%r4			# compat_uptr_t *
-	jg	sys32_execve		# branch to system call
+	jg	compat_sys_execve	# branch to system call
 
 ENTRY(sys_fanotify_init_wrapper)
 	llgfr	%r2,%r2			# unsigned int

arch/s390/kernel/entry.S

@@ -368,8 +368,6 @@ ENTRY(kernel_execve)
 	l	%r12,__LC_THREAD_INFO
 	xc	__SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
 	ssm	__LC_SVC_NEW_PSW	# reenable interrupts
-	l	%r1,BASED(.Lexecve_tail)
-	basr	%r14,%r1		# call execve_tail
 	j	sysc_return
 
 /*
@@ -932,7 +930,6 @@ cleanup_idle_wait:
 .Ldo_notify_resume:	.long	do_notify_resume
 .Ldo_per_trap:		.long	do_per_trap
 .Ldo_execve:		.long	do_execve
-.Lexecve_tail:		.long	execve_tail
 .Ljump_table:		.long	pgm_check_table
 .Lschedule:		.long	schedule
 #ifdef CONFIG_PREEMPT

arch/s390/kernel/entry.h

@@ -58,9 +58,6 @@ long sys_fork(void);
 long sys_clone(unsigned long newsp, unsigned long clone_flags,
 	       int __user *parent_tidptr, int __user *child_tidptr);
 long sys_vfork(void);
-void execve_tail(void);
-long sys_execve(const char __user *name, const char __user *const __user *argv,
-		const char __user *const __user *envp);
 long sys_sigsuspend(int history0, int history1, old_sigset_t mask);
 long sys_sigaction(int sig, const struct old_sigaction __user *act,
 		   struct old_sigaction __user *oact);

arch/s390/kernel/entry64.S

@@ -386,7 +386,6 @@ ENTRY(kernel_execve)
 	lg	%r12,__LC_THREAD_INFO
 	xc	__SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
 	ssm	__LC_SVC_NEW_PSW	# reenable interrupts
-	brasl	%r14,execve_tail
 	j	sysc_return
 
 /*

arch/s390/kernel/process.c

@@ -249,31 +249,6 @@ asmlinkage void execve_tail(void)
 		asm volatile("sfpc %0,%0" : : "d" (0));
 }
 
-/*
- * sys_execve() executes a new program.
- */
-SYSCALL_DEFINE3(execve, const char __user *, name,
-		const char __user *const __user *, argv,
-		const char __user *const __user *, envp)
-{
-	struct pt_regs *regs = task_pt_regs(current);
-	char *filename;
-	long rc;
-
-	filename = getname(name);
-	rc = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		return rc;
-	rc = do_execve(filename, argv, envp, regs);
-	if (rc)
-		goto out;
-	execve_tail();
-	rc = regs->gprs[2];
-out:
-	putname(filename);
-	return rc;
-}
-
 /*
  * fill in the FPU structure for a core dump.
  */