S390: Do not clobber R0 in 64-bit _dl_runtime_resolve

Preparation for the usage of R0 by __fentry__.

ChangeLog:

	* sysdeps/s390/s390-64/dl-trampoline.h (_dl_runtime_resolve):
	Do not clobber R0.

diff --git a/ChangeLog b/ChangeLog
index 5452201eb6b730c74ab5fb1b0351e7dd4a4eaf9d..fb04742ba7fbe2e5336c254c6d2ce0e6401c1388 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2018-08-10  Ilya Leoshkevich  <iii@linux.ibm.com>
+
+       * sysdeps/s390/s390-64/dl-trampoline.h (_dl_runtime_resolve):
+       Do not clobber R0.
+
 2018-08-10  Ilya Leoshkevich  <iii@linux.ibm.com>
 
        * sysdeps/s390/s390-32/dl-trampoline.h (_dl_runtime_profile):

diff --git a/sysdeps/s390/s390-64/dl-trampoline.h b/sysdeps/s390/s390-64/dl-trampoline.h
index e05974322c568613bb9caf00546012055cdf10ed..a9d56a6925f4cd50c0ab37bd5d85d7d77779a65a 100644 (file)
--- a/sysdeps/s390/s390-64/dl-trampoline.h
+++ b/sysdeps/s390/s390-64/dl-trampoline.h
@@ -23,8 +23,9 @@
  *   v24, v26, v28, v30, v25, v27, v29, v31 : vector parameter registers
  *   48(r15), 56(r15) : PLT arguments PLT1, PLT2
  *   160(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)
@@ -47,6 +48,7 @@
 #define V29_OFF -208
 #define V30_OFF -192
 #define V31_OFF -176
+#define R0_OFF -120
 #define PLT1_OFF -112
 #define PLT2_OFF -104
 #define R2_OFF -96
@@ -64,6 +66,8 @@
        cfi_startproc
        .align 16
 _dl_runtime_resolve:
+       stg    %r0,CFA_OFF+R0_OFF(%r15)
+       cfi_offset (r0, R0_OFF)
        stmg   %r2,%r5,CFA_OFF+R2_OFF(%r15) # save registers
        cfi_offset (r2, R2_OFF)
        cfi_offset (r3, R3_OFF)
@@ -120,6 +124,7 @@ _dl_runtime_resolve:
        ld     %f4,CFA_OFF+F4_OFF(%r15)
        ld     %f6,CFA_OFF+F6_OFF(%r15)
        lmg    %r2,%r5,CFA_OFF+R2_OFF(%r15)
+       lg     %r0,CFA_OFF+R0_OFF(%r15)
        br     %r1
        cfi_endproc
        .size _dl_runtime_resolve, .-_dl_runtime_resolve
@@ -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