S390: Remove not needed stack frame in syscall function.

As an svc invocation does not clobber any user space registers
despite of the return value r2 and it does not need a special
stack frame. This patch gets rid of the extra frame.
We just have to save and restore r6 and r7 as those are
preserved across function calls.

diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/syscall.S b/sysdeps/unix/sysv/linux/s390/s390-32/syscall.S
index 69561d0b7627a133f2d2c81b7737be40c64cf530..06280992abfe19329d1c5ddac3ca7a2e65a4dea8 100644 (file)
--- a/sysdeps/unix/sysv/linux/s390/s390-32/syscall.S
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/syscall.S
@@ -22,37 +22,19 @@
    more information about the value -4095 used below.*/
 
 ENTRY (syscall)
-       /* Save registers and setup stack.  */
-       stm     %r6,%r15,24(%r15)  /* save registers */
-       cfi_offset (%r15, -36)
-       cfi_offset (%r14, -40)
-       cfi_offset (%r13, -44)
-       cfi_offset (%r12, -48)
-       cfi_offset (%r11, -52)
-       cfi_offset (%r10, -56)
-       cfi_offset (%r9, -60)
-       cfi_offset (%r8, -64)
+       stm    %r6,%r7,24(%r15)    /* save registers */
        cfi_offset (%r7, -68)
        cfi_offset (%r6, -72)
-       lr      %r1,%r15
-       l       %r0,4(0,%r15)      /* load eos */
-       ahi     %r15,-96           /* buy stack space */
-       cfi_adjust_cfa_offset (96)
-       st      %r1,0(0,%r15)      /* store back chain */
-       st      %r0,4(0,%r15)      /* store eos */
 
        lr     %r1,%r2             /* move syscall number */
        lr     %r2,%r3             /* first parameter  */
        lr     %r3,%r4             /* second parameter */
        lr     %r4,%r5             /* third parameter  */
        lr     %r5,%r6             /* fourth parameter */
-       l      %r6,192(%r15)       /* fifth parameter  */
-       l      %r7,196(%r15)       /* sixth parameter  */
-
+       lm     %r6,%r7,96(%r15)    /* fifth / sixth parameter  */
        svc    0
-       l      %r15,0(%r15)        /* load back chain.  */
-       cfi_adjust_cfa_offset (-96)
-       lm     %r6,%r15,24(%r15)   /* load registers.  */
+
+       lm     %r6,%r7,24(%r15)    /* load registers.  */
 
        lhi    %r0,-4095
        clr    %r2,%r0             /* check R2 for error */

diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/syscall.S b/sysdeps/unix/sysv/linux/s390/s390-64/syscall.S
index bbe4d79848d70ebb238700345441ef6200cb0207..bcffab6f4ea406efaf3cf27c10d9533d4fe5c63b 100644 (file)
--- a/sysdeps/unix/sysv/linux/s390/s390-64/syscall.S
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/syscall.S
@@ -22,37 +22,19 @@
    more information about the value -4095 used below.*/
 
 ENTRY (syscall)
-       /* Save registers and setup stack.  */
-       stmg    %r6,%r15,48(%r15)  /* Save registers.  */
-       cfi_offset (%r15,-40)
-       cfi_offset (%r14,-48)
-       cfi_offset (%r13,-56)
-       cfi_offset (%r12,-64)
-       cfi_offset (%r11,-72)
-       cfi_offset (%r10,-80)
-       cfi_offset (%r9,-88)
-       cfi_offset (%r8,-96)
+       stmg   %r6,%r7,48(%r15)    /* Save registers.  */
        cfi_offset (%r7,-104)
        cfi_offset (%r6,-112)
-       lgr     %r1,%r15
-       lg      %r0,8(%r15)        /* Load eos.  */
-       aghi    %r15,-160          /* Buy stack space.  */
-       cfi_adjust_cfa_offset (160)
-       stg     %r1,0(%r15)        /* Store back chain.  */
-       stg     %r0,8(%r15)        /* Store eos.  */
 
        lgr    %r1,%r2             /* Move syscall number.  */
        lgr    %r2,%r3             /* First parameter.  */
        lgr    %r3,%r4             /* Second parameter.  */
        lgr    %r4,%r5             /* Third parameter.  */
        lgr    %r5,%r6             /* Fourth parameter.  */
-       lg     %r6,320(%r15)       /* Fifth parameter.  */
-       lg     %r7,328(%r15)       /* Sixth parameter.  */
-
+       lmg    %r6,%r7,160(%r15)   /* Fifth / Sixth parameter.  */
        svc    0
-       lg     %r15,0(%r15)        /* Load back chain.  */
-       cfi_adjust_cfa_offset (-160)
-       lmg    %r6,%r15,48(%r15)   /* Load registers.  */
+
+       lmg    %r6,%r7,48(%r15)    /* Load registers.  */
 
        lghi   %r0,-4095
        clgr   %r2,%r0             /* Check R2 for error.  */