S390: Always use svc 0

On s390x syscalls are triggered by svc instruction. One can
pass the syscall number encoded in the instruction "svc 123"
or by storing it in r1:
lghi r1,123
svc 0

If the syscall number is encoded in the instruction, this can
cause broken syscall restarts.  Therefore this patch is now just
passing the syscall number in r1.

See also kernel-commit:
"s390/signal: switch to using vdso for sigreturn and syscall restart"
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/arch/s390/[%e2%80%a6]call.c?h=v6.0-rc1&id=df29a7440c4b5c65765c8f60396b3b13063e24e9

As information, the "svc 0" feature was introduced in kernel 2.5.62:
commit b5aad611393ef2e132e3648fa4c6e56a9cfa8708

13 files changed, 46 insertions, 66 deletions

diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/clone.S b/sysdeps/unix/sysv/linux/s390/s390-32/clone.S
index 8b7d8dd39b..dc2d663387 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/clone.S
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/clone.S
@@ -30,9 +30,10 @@
 
 	.text
 ENTRY(__clone)
-	st	%r6,24(%r15)		/* store %r6 to save area */
+	stm     %r6,%r7,24(%r15)	/* Save registers.  */
+	cfi_offset (%r7, -68)
 	cfi_offset (%r6, -72)
-	ltr     %r1,%r2			/* check fn and move to %r1 */
+	ltr     %r7,%r2			/* check fn and move to %r7 */
 	jz      error			/* no NULL function pointers */
 	lhi     %r0,-8			/* Align the child_stack to a ...  */
 	nr      %r3,%r0			/* double word boundary and ...  */
@@ -43,10 +44,11 @@ ENTRY(__clone)
 	lr	%r4,%r6			/* move parent_tid to %r4 */
 	l	%r5,100(%r15)		/* load child_tid from stack */
 	l	%r6,96(%r15)		/* load tls from stack */
-	svc	SYS_ify(clone)
+	lhi	%r1,SYS_ify(clone)
+	svc	0
 	ltr	%r2,%r2			/* check return code */
 	jz	thread_start
-	l	%r6,24(%r15)		/* restore %r6 */
+	lm	%r6,%r7,24(%r15)	/* Load registers.  */
 	jm	SYSCALL_ERROR_LABEL
 	br	%r14
 error:
@@ -58,11 +60,11 @@ thread_start:
 	cfi_startproc
 	/* Mark r14 as undefined in order to stop unwinding here!  */
 	cfi_undefined (r14)
-	/* fn is in gpr 1, arg in gpr 0 */
+	/* fn is in gpr 7, arg in gpr 0 */
 	lr      %r2,%r0         /* set first parameter to void *arg */
 	ahi     %r15,-96        /* make room on the stack for the save area */
 	xc	0(4,%r15),0(%r15)
-	basr    %r14,%r1        /* jump to fn */
+	basr    %r14,%r7        /* jump to fn */
 	DO_CALL (exit, 1)
 	cfi_endproc
 
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/getcontext.S b/sysdeps/unix/sysv/linux/s390/s390-32/getcontext.S
index 842ea28a4c..8825caa972 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/getcontext.S
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/getcontext.S
@@ -32,16 +32,18 @@
   other than the PRESERVED state.  */
 
 ENTRY(__getcontext)
-	lr      %r1,%r2
+	lr	%r0,%r2
 
 	/* rt_sigprocmask (SIG_BLOCK, NULL, &sc->sc_mask, sigsetsize).  */
+	la	%r4,SC_MASK(%r2)
 	la      %r2,SIG_BLOCK
 	slr	%r3,%r3
-	la	%r4,SC_MASK(%r1)
 	lhi	%r5,_NSIG8
-	svc	SYS_ify(rt_sigprocmask)
+	lhi	%r1,SYS_ify(rt_sigprocmask)
+	svc	0
 
 	/* Store fpu context.  */
+	lr	%r1,%r0
 	stfpc   SC_FPC(%r1)
 	std     %f0,SC_FPRS(%r1)
 	std     %f1,SC_FPRS+8(%r1)
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/setcontext.S b/sysdeps/unix/sysv/linux/s390/s390-32/setcontext.S
index 83fc2b436f..14251bc39c 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/setcontext.S
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/setcontext.S
@@ -30,16 +30,18 @@
   other than the PRESERVED state.  */
 
 ENTRY(__setcontext)
-	lr	%r1,%r2
+	lr	%r0,%r2
 
 	/* rt_sigprocmask (SIG_SETMASK, &sc->sc_mask, NULL, sigsetsize).  */
+	la	%r3,SC_MASK(%r2)
 	la      %r2,SIG_SETMASK
-	la	%r3,SC_MASK(%r1)
 	slr	%r4,%r4
 	lhi	%r5,_NSIG8
-	svc	SYS_ify(rt_sigprocmask)
+	lhi	%r1,SYS_ify(rt_sigprocmask)
+	svc	0
 
 	/* Load fpu context.  */
+	lr	%r1,%r0
 	lfpc	SC_FPC(%r1)
 	ld	%f0,SC_FPRS(%r1)
 	ld      %f1,SC_FPRS+8(%r1)
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/swapcontext.S b/sysdeps/unix/sysv/linux/s390/s390-32/swapcontext.S
index def4e8b163..b75bf7596b 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/swapcontext.S
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/swapcontext.S
@@ -73,7 +73,8 @@ ENTRY(__swapcontext)
 	la	%r3,SC_MASK(%r5)
 	la	%r4,SC_MASK(%r1)
 	lhi	%r5,_NSIG8
-	svc	SYS_ify(rt_sigprocmask)
+	lhi	%r1,SYS_ify(rt_sigprocmask)
+	svc	0
 
 	/* Load fpu context.  */
 	lr	%r5,%r0
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h b/sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h
index 967949f231..e41106b377 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h
@@ -155,12 +155,8 @@
     lr %r0,%r7;								      \
     l %r7,96(%r15);							      \
   .endif;								      \
-  .if SYS_ify (syscall) < 256;						      \
-    svc SYS_ify (syscall);						      \
-  .else;								      \
     lhi %r1,SYS_ify (syscall);						      \
     svc 0;								      \
-  .endif;								      \
   .if args > 5;								      \
     lr %r7,%r0;								      \
   .endif
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/vfork.S b/sysdeps/unix/sysv/linux/s390/s390-32/vfork.S
index bdf8cb9411..76a5570517 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/vfork.S
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/vfork.S
@@ -28,7 +28,8 @@
 
 ENTRY (__libc_vfork)
 	/* Do vfork system call.  */
-	svc	SYS_ify (vfork)
+	lhi	%r1,SYS_ify (vfork)
+	svc	0
 
 	/* Check for error.  */
 	lhi	%r4,-4095
diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/clone.S b/sysdeps/unix/sysv/linux/s390/s390-64/clone.S
index 0941a38279..8d33bc28ca 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-64/clone.S
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/clone.S
@@ -31,9 +31,10 @@
 
 	.text
 ENTRY(__clone)
-	stg	%r6,48(%r15)		/* store %r6 to save area */
+	stmg	%r6,%r7,48(%r15)	/* Save registers.  */
+	cfi_offset (%r7,-104)
 	cfi_offset (%r6,-112)
-	ltgr    %r1,%r2			/* check fn and move to %r1 */
+	ltgr    %r7,%r2			/* check fn and move to %r7 */
 	jz      error			/* no NULL function pointers */
 	lghi	%r0,-16			/* Align the child_stack to a ...  */
 	ngr	%r3,%r0			/* double word boundary and ...  */
@@ -44,10 +45,11 @@ ENTRY(__clone)
 	lgr	%r4,%r6			/* move parent_tid to %r4 */
 	lg	%r5,168(%r15)		/* load child_tid from stack */
 	lg	%r6,160(%r15)		/* load tls from stack */
-	svc	SYS_ify(clone)
+	lghi	%r1,SYS_ify (clone)
+	svc	0
 	ltgr	%r2,%r2			/* check return code */
 	jz	thread_start
-	lg	%r6,48(%r15)		/* restore %r6 */
+	lmg	%r6,%r7,48(%r15)	/* Restore registers.  */
 	jgm	SYSCALL_ERROR_LABEL
 	br	%r14
 error:
@@ -59,11 +61,11 @@ thread_start:
 	cfi_startproc
 	/* Mark r14 as undefined in order to stop unwinding here!  */
 	cfi_undefined (r14)
-	/* fn is in gpr 1, arg in gpr 0 */
+	/* fn is in gpr 7, arg in gpr 0 */
 	lgr	%r2,%r0		/* set first parameter to void *arg */
 	aghi	%r15,-160	/* make room on the stack for the save area */
 	xc	0(8,%r15),0(%r15)
-	basr	%r14,%r1	/* jump to fn */
+	basr	%r14,%r7	/* jump to fn */
 	DO_CALL	(exit, 1)
 	cfi_endproc
 
diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/getcontext.S b/sysdeps/unix/sysv/linux/s390/s390-64/getcontext.S
index a0c70dc789..65a34fd3a2 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-64/getcontext.S
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/getcontext.S
@@ -32,16 +32,18 @@
   other than the PRESERVED state.  */
 
 ENTRY(__getcontext)
-	lgr     %r1,%r2
+	lgr	%r0,%r2
 
 	/* rt_sigprocmask (SIG_BLOCK, NULL, &sc->sc_mask, sigsetsize).  */
+	la	%r4,SC_MASK(%r2)
 	la      %r2,SIG_BLOCK
 	slgr	%r3,%r3
-	la	%r4,SC_MASK(%r1)
 	lghi	%r5,_NSIG8
-	svc	SYS_ify(rt_sigprocmask)
+	lghi	%r1,SYS_ify(rt_sigprocmask)
+	svc	0
 
 	/* Store fpu context.  */
+	lgr	%r1,%r0
 	stfpc   SC_FPC(%r1)
 	std     %f0,SC_FPRS(%r1)
 	std     %f1,SC_FPRS+8(%r1)
diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/setcontext.S b/sysdeps/unix/sysv/linux/s390/s390-64/setcontext.S
index b5626b686e..3e32370236 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-64/setcontext.S
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/setcontext.S
@@ -30,16 +30,18 @@
   other than the PRESERVED state.  */
 
 ENTRY(__setcontext)
-	lgr	%r1,%r2
+	lgr	%r0,%r2
 
 	/* sigprocmask (SIG_SETMASK, &sc->sc_mask, NULL).  */
+	la	%r3,SC_MASK(%r2)
 	la      %r2,SIG_SETMASK
-	la	%r3,SC_MASK(%r1)
 	slgr	%r4,%r4
 	lghi	%r5,_NSIG8
-	svc	SYS_ify(rt_sigprocmask)
+	lghi	%r1,SYS_ify(rt_sigprocmask)
+	svc	0
 
 	/* Load fpu context.  */
+	lgr	%r1,%r0
 	lfpc	SC_FPC(%r1)
 	ld	%f0,SC_FPRS(%r1)
 	ld      %f1,SC_FPRS+8(%r1)
diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/swapcontext.S b/sysdeps/unix/sysv/linux/s390/s390-64/swapcontext.S
index 29ee1fb47e..7b56b6cc19 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-64/swapcontext.S
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/swapcontext.S
@@ -73,7 +73,8 @@ ENTRY(__swapcontext)
 	la	%r3,SC_MASK(%r5)
 	la	%r4,SC_MASK(%r1)
 	lghi	%r5,_NSIG8
-	svc	SYS_ify(rt_sigprocmask)
+	lghi	%r1,SYS_ify(rt_sigprocmask)
+	svc	0
 
 	/* Load fpu context.  */
 	lgr	%r5,%r0
diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h b/sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h
index 1779af0a0f..150e33981a 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h
@@ -153,12 +153,8 @@
     lgr %r0,%r7;							      \
     lg %r7,160(%r15);							      \
   .endif;								      \
-  .if SYS_ify (syscall) < 256;						      \
-    svc SYS_ify (syscall);						      \
-  .else;								      \
     lghi %r1,SYS_ify (syscall);						      \
     svc 0;								      \
-  .endif;								      \
   .if args > 5;								      \
     lgr %r7,%r0;							      \
   .endif
diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/vfork.S b/sysdeps/unix/sysv/linux/s390/s390-64/vfork.S
index ddc1044fd3..52625fb92e 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-64/vfork.S
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/vfork.S
@@ -28,7 +28,8 @@
 
 ENTRY (__libc_vfork)
 	/* Do vfork system call.  */
-	svc	SYS_ify (vfork)
+	lghi	%r1,SYS_ify (vfork)
+	svc	0
 
 	/* Check for error.  */
 	lghi	%r4,-4095
diff --git a/sysdeps/unix/sysv/linux/s390/sysdep.h b/sysdeps/unix/sysv/linux/s390/sysdep.h
index 2d0a26779c..930d7efe03 100644
--- a/sysdeps/unix/sysv/linux/s390/sysdep.h
+++ b/sysdeps/unix/sysv/linux/s390/sysdep.h
@@ -21,32 +21,6 @@
 #undef SYS_ify
 #define SYS_ify(syscall_name)	__NR_##syscall_name
 
-#undef INTERNAL_SYSCALL_DIRECT
-#define INTERNAL_SYSCALL_DIRECT(name, nr, args...)			      \
-  ({									      \
-    DECLARGS_##nr(args)							      \
-    register long int _ret __asm__("2");				      \
-    __asm__ __volatile__ (						      \
-			  "svc    %b1\n\t"				      \
-			  : "=d" (_ret)					      \
-			  : "i" (__NR_##name) ASMFMT_##nr		      \
-			  : "memory" );					      \
-    _ret; })
-
-#undef INTERNAL_SYSCALL_SVC0
-#define INTERNAL_SYSCALL_SVC0(name, nr, args...)			      \
-  ({									      \
-    DECLARGS_##nr(args)							      \
-    register unsigned long int _nr __asm__("1") =			      \
-      (unsigned long int)(__NR_##name);					      \
-    register long int _ret __asm__("2");				      \
-    __asm__ __volatile__ (						      \
-			  "svc    0\n\t"				      \
-			  : "=d" (_ret)					      \
-			  : "d" (_nr) ASMFMT_##nr			      \
-			  : "memory" );					      \
-    _ret; })
-
 #undef INTERNAL_SYSCALL_NCS
 #define INTERNAL_SYSCALL_NCS(no, nr, args...)				      \
   ({									      \
@@ -61,10 +35,8 @@
     _ret; })
 
 #undef INTERNAL_SYSCALL
-#define INTERNAL_SYSCALL(name, nr, args...)				      \
-  (((__NR_##name) < 256)						      \
-   ? INTERNAL_SYSCALL_DIRECT(name, nr, args)				      \
-   : INTERNAL_SYSCALL_SVC0(name, nr, args))
+#define INTERNAL_SYSCALL(name, nr, args...)				\
+  INTERNAL_SYSCALL_NCS(__NR_##name, nr, args)
 
 #define DECLARGS_0()
 #define DECLARGS_1(arg1) \