Rename variable AT (which is the register's name) to SCPREG.

Fix some SCP references in register loads to use SCPREG instead.
Load SCPREG->sc_pc into $24 and jump to it, restoring $at in the delay slot.
This still leaves $24 clobbered.

diff --git a/sysdeps/mach/hurd/mips/sigreturn.c b/sysdeps/mach/hurd/mips/sigreturn.c
index 4df311253e356836b7d34ed4425ed2f922842a87..147243f5b9bc5b35fcaa89655392e89e6c02fae2 100644 (file)
--- a/sysdeps/mach/hurd/mips/sigreturn.c
+++ b/sysdeps/mach/hurd/mips/sigreturn.c
@@ -16,6 +16,8 @@ License along with the GNU C Library; see the file COPYING.LIB.  If
 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
 Cambridge, MA 02139, USA.  */
 
+register int sp asm ("$29"), fp asm ("$30");
+
 #include <hurd.h>
 #include <hurd/signal.h>
 #include <hurd/threadvar.h>
@@ -49,42 +51,53 @@ __sigreturn (const struct sigcontext *scp)
 
   /* Restore registers.  */
 #define restore_gpr(n) \
-       asm volatile ("lw $" #n ",%0" : : "m"(at->sc_gpr[(n)]))
+  asm volatile ("lw $" #n ",%0" : : "m" (scpreg->sc_gpr[n]))
 
   asm volatile (".set noreorder; .set noat;");
   {
-    register const struct sigcontext *at asm ("$1") = scp;
+    register const struct sigcontext *const scpreg asm ("$1") = scp;
+
+    /* Load the general-purpose registers from the sigcontext.  */
+    restore_gpr (2);
+    restore_gpr (3);
+    restore_gpr (4);
+    restore_gpr (5);
+    restore_gpr (6);
+    restore_gpr (7);
+    restore_gpr (8);
+    restore_gpr (9);
+    restore_gpr (10);
+    restore_gpr (11);
+    restore_gpr (12);
+    restore_gpr (13);
+    restore_gpr (14);
+    restore_gpr (15);
+    restore_gpr (16);
+    restore_gpr (17);
+    restore_gpr (18);
+    restore_gpr (19);
+    restore_gpr (20);
+    restore_gpr (21);
+    restore_gpr (22);
+    restore_gpr (23);
+    restore_gpr (24);
+    restore_gpr (25);
+    /* Registers 26-27 are kernel-only.  */
+    restore_gpr (28);
+
+    /* Now the special-purpose registers.  */
+    sp = scpreg->sc_sp;                /* Stack pointer.  */
+    fp = scpreg->sc_fp;                /* Frame pointer.  */
+    restore_gpr (31);          /* Return address.  */
 
-    restore_gpr(2);
-    restore_gpr(3);
-    restore_gpr(4);
-    restore_gpr(5);
-    restore_gpr(6);
-    restore_gpr(7);
-    restore_gpr(8);
-    restore_gpr(9);
-    restore_gpr(10);
-    restore_gpr(11);
-    restore_gpr(12);
-    restore_gpr(13);
-    restore_gpr(14);
-    restore_gpr(15);
-    restore_gpr(16);
-    restore_gpr(17);
-    restore_gpr(18);
-    restore_gpr(19);
-    restore_gpr(20);
-    restore_gpr(21);
-    restore_gpr(22);
-    restore_gpr(23);
-    restore_gpr(24);
-    restore_gpr(25);
-    restore_gpr(28);
-    asm volatile ("lw $29,%0" : : "m"(scp->sc_sp));
-    asm volatile ("lw $30,%0" : : "m"(scp->sc_fp));
-    asm volatile ("lw $31,%0" : : "m"(scp->sc_pc));
-    asm volatile ("j $31");
-    restore_gpr(1);
+    /* Now jump to the saved PC.  */
+    asm volatile ("lw $24, %0\n" /* Load saved PC into temporary $t8.  */
+                 "j $24\n"     /* Jump to the saved PC value.  */
+                 "lw $1, %1\n" /* Restore $at in delay slot.  */
+                 : :
+                 "m" (scpreg->sc_pc),
+                 "m" (scpreg->sc_r1) /* $at */
+                 : "$24");     /* XXX clobbers $24 (aka $t8)!! */
     asm volatile (".set reorder; .set at;");
   }