S390: Do not clobber R0 in 32-bit _dl_runtime_resolve

Preparation for the usage of R0 by __fentry__.

ChangeLog:

	* sysdeps/s390/s390-32/dl-trampoline.h (_dl_runtime_resolve):
	Do not clobber R0.

diff --git a/ChangeLog b/ChangeLog
index 751186d..8dd0059 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2018-08-10  Ilya Leoshkevich  <iii@linux.ibm.com>
 
+       * sysdeps/s390/s390-32/dl-trampoline.h (_dl_runtime_resolve):
+       Do not clobber R0.
+
+2018-08-10  Ilya Leoshkevich  <iii@linux.ibm.com>
+
        * sysdeps/s390/s390-64/dl-trampoline.h (_dl_runtime_profile):
        Use symbolic offsets for stack variables.
 

diff --git a/sysdeps/s390/s390-32/dl-trampoline.h b/sysdeps/s390/s390-32/dl-trampoline.h
index fa83b79..da50d9e 100644 (file)
--- a/sysdeps/s390/s390-32/dl-trampoline.h
+++ b/sysdeps/s390/s390-32/dl-trampoline.h
@@ -26,8 +26,9 @@
  *   v24, v26, v28, v30, v25, v27, v29, v31 : vector parameter registers
  *   24(r15), 28(r15) : PLT arguments PLT1, PLT2
  *   96(r15) : additional stack parameters
- * The normal clobber rules for function calls apply:
- *   r0 - r5 : call clobbered
+ * The slightly tightened normal clobber rules for function calls apply:
+ *   r0 : call saved (for __fentry__)
+ *   r1 - r5 : call clobbered
  *   r6 - r13 :        call saved
  *   r14 : return address (call clobbered)
  *   r15 : stack pointer (call saved)
@@ -50,6 +51,7 @@
 #define V29_OFF -144
 #define V30_OFF -128
 #define V31_OFF -112
+#define R0_OFF -76
 #define PLT1_OFF -72
 #define PLT2_OFF -68
 #define R2_OFF -64
@@ -65,6 +67,8 @@
        cfi_startproc
        .align 16
 _dl_runtime_resolve:
+       st     %r0,CFA_OFF+R0_OFF(%r15)
+       cfi_offset (r0, R0_OFF)
        stm    %r2,%r5,CFA_OFF+R2_OFF(%r15) # save registers
        cfi_offset (r2, R2_OFF)
        cfi_offset (r3, R3_OFF)
@@ -119,6 +123,7 @@ _dl_runtime_resolve:
        ld     %f0,CFA_OFF+F0_OFF(%r15)
        ld     %f2,CFA_OFF+F2_OFF(%r15)
        lm     %r2,%r5,CFA_OFF+R2_OFF(%r15)
+       l      %r0,CFA_OFF+R0_OFF(%r15)
        br     %r1
 1:     .long  _dl_fixup - 0b
        cfi_endproc
@@ -131,6 +136,7 @@ _dl_runtime_resolve:
 #undef V29_OFF
 #undef V30_OFF
 #undef V31_OFF
+#undef R0_OFF
 #undef PLT1_OFF
 #undef PLT2_OFF
 #undef R2_OFF