hppa: Fix r19 save and restore.

We must save and restore r19 in both PIC and non-PIC
situations since the kernel paths that clobber r19
are independent of that PIC-ness of userspace.
In addition we choose r4 as the temporary register over
r3 which is being used by recent gcc's as the frame
pointer.

diff --git a/ports/ChangeLog.hppa b/ports/ChangeLog.hppa
index 6d5d5a3..b30a61c 100644 (file)
--- a/ports/ChangeLog.hppa
+++ b/ports/ChangeLog.hppa
@@ -1,5 +1,14 @@
 2012-10-29  Carlos O'Donell  <carlos@systemhalted.org>
 
+       * sysdeps/unix/sysv/linux/hppa/sysdep.h: Document register clobbering.
+       [PIC](TREG, SAVE_PIC, LOAD_PIC, TREG_ASM, SAVE_ASM_PIC, LOAD_ASM_PIC
+       CLOB_TREG, PIC_REG_DEF, PIC_REG_USE): Move...
+       (TREG, SAVE_PIC, LOAD_PIC, TREG_ASM, SAVE_ASM_PIC, LOAD_ASM_PIC
+       CLOB_TREG, PIC_REG_DEF, PIC_REG_USE): ... to here.
+       [!PIC](TREG, SAVE_PIC, LOAD_PIC, TREG_ASM, SAVE_ASM_PIC, LOAD_ASM_PIC
+       CLOB_TREG, PIC_REG_DEF, PIC_REG_USE): Remove.
+       (TREG): Use r4.
+
        * sysdeps/unix/sysv/linux/hppa/sysdep.h: Don't include sys/syscall.h.
        Document nop removal.
        (PSEUDO): Remove nop.

diff --git a/ports/sysdeps/unix/sysv/linux/hppa/sysdep.h b/ports/sysdeps/unix/sysv/linux/hppa/sysdep.h
index 5c0db64..daf2eaf 100644 (file)
--- a/ports/sysdeps/unix/sysv/linux/hppa/sysdep.h
+++ b/ports/sysdeps/unix/sysv/linux/hppa/sysdep.h
@@ -32,32 +32,28 @@
 #undef SYS_ify
 #define SYS_ify(syscall_name)  (__NR_##syscall_name)
 
+/* The vfork, fork, and clone syscalls clobber r19
+ * and r21. We list r21 as either clobbered or as an
+ * input to a 6-argument syscall. We must save and
+ * restore r19 in both PIC and non-PIC cases.
+ */
 /* WARNING: TREG must be a callee saves register so
    that it doesn't have to be restored after a call
    to another function */
-#ifdef PIC
-# define TREG %r3
-# define SAVE_PIC(SREG) copy %r19, SREG ASM_LINE_SEP
-# define LOAD_PIC(LREG) copy LREG, %r19 ASM_LINE_SEP
+#define TREG 4
+#define SAVE_PIC(SREG) \
+       copy %r19, SREG ASM_LINE_SEP    \
+       .cfi_register 19, SREG
+#define LOAD_PIC(LREG) \
+       copy LREG , %r19 ASM_LINE_SEP   \
+       .cfi_restore 19
 /* Inline assembly defines */
-# define TREG_ASM "%r4" /* Cant clobber r3, it holds framemarker */
-# define SAVE_ASM_PIC  "       copy %%r19, %" TREG_ASM "\n"
-# define LOAD_ASM_PIC  "       copy %" TREG_ASM ", %%r19\n"
-# define CLOB_TREG     TREG_ASM ,
-# define PIC_REG_DEF   register unsigned long __r19 asm("r19");
-# define PIC_REG_USE   , "r" (__r19)
-#else
-# define TREG %r3
-# define SAVE_PIC(SREG) nop ASM_LINE_SEP
-# define LOAD_PIC(LREG) nop ASM_LINE_SEP
-/* Inline assembly defines */
-# define TREG_ASM
-# define SAVE_ASM_PIC  "nop \n"
-# define LOAD_ASM_PIC  "nop \n"
-# define CLOB_TREG
-# define PIC_REG_DEF
-# define PIC_REG_USE
-#endif
+#define TREG_ASM "%r4" /* Cant clobber r3, it holds framemarker */
+#define SAVE_ASM_PIC   "       copy %%r19, %" TREG_ASM "\n"
+#define LOAD_ASM_PIC   "       copy %" TREG_ASM ", %%r19\n"
+#define CLOB_TREG      TREG_ASM ,
+#define PIC_REG_DEF    register unsigned long __r19 asm("r19");
+#define PIC_REG_USE    , "r" (__r19)
 
 #ifdef __ASSEMBLER__