Don't presume that the kernel will preserve non-call-saved registers;

save and restore a0 across the system call.

diff --git a/sysdeps/unix/sysv/linux/alpha/brk.S b/sysdeps/unix/sysv/linux/alpha/brk.S
index f44686b..74fef64 100644 (file)
--- a/sysdeps/unix/sysv/linux/alpha/brk.S
+++ b/sysdeps/unix/sysv/linux/alpha/brk.S
@@ -37,8 +37,9 @@ __curbrk: .skip 8
 #endif
 
        .text
-LEAF(__brk, 0)
+LEAF(__brk, 8)
        ldgp    gp, 0(t12)
+       subq    sp, 8, sp
 #ifdef PROF
        .set noat
        lda     AT, _mcount
@@ -47,9 +48,14 @@ LEAF(__brk, 0)
 #endif
        .prologue 1
 
+       /* Save the requested brk across the system call.  */
+       stq     a0, 0(sp)
+
        ldiq    v0, __NR_brk
        call_pal PAL_callsys
 
+       ldq     a0, 0(sp)
+
        /* Be prepared for an OSF-style brk.  */
        bne     a3, $err1
        beq     v0, $ok
@@ -62,11 +68,13 @@ LEAF(__brk, 0)
        /* Update __curbrk and return cleanly.  */
        mov     zero, v0
 $ok:   stq     a0, __curbrk
+       addq    sp, 8, sp
        ret
 
        /* What a horrible way to die.  */
 $err0: ldi     v0, ENOMEM
-$err1: jmp     zero, __syscall_error
+$err1: addq    sp, 8, sp
+       jmp     zero, __syscall_error
 
        END(__brk)