ARM: add STRACE_KNOWS_ONLY_EABI define which can be used to omit OABI support

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>

diff --git a/syscall.c b/syscall.c
index 1ccee6e79be200a69c808aef56b33cf3c6efa76e..af9c2a0b29508b69445f054e50b6d30001e95d22 100644 (file)
--- a/syscall.c
+++ b/syscall.c
@@ -1339,6 +1339,7 @@ get_scno(struct tcb *tcp)
                        break;
                case sizeof(arm_regs):
                        /* We are in 32-bit mode */
+                       /* Note: we don't support OABI, unlike 32-bit ARM build */
                        scno = arm_regs.ARM_r7;
                        update_personality(tcp, 0);
                        break;
@@ -1352,30 +1353,34 @@ get_scno(struct tcb *tcp)
        }
        /* Note: we support only 32-bit CPUs, not 26-bit */
 
-       if (arm_regs.ARM_cpsr & 0x20) {
+# ifndef STRACE_KNOWS_ONLY_EABI
+# warning STRACE_KNOWS_ONLY_EABI not set, will PTRACE_PEEKTEXT on every syscall (slower tracing)
+       if (arm_regs.ARM_cpsr & 0x20)
                /* Thumb mode */
-               scno = arm_regs.ARM_r7;
-       } else {
-               /* ARM mode */
-               errno = 0;
-               scno = ptrace(PTRACE_PEEKTEXT, tcp->pid, (void *)(arm_regs.ARM_pc - 4), NULL);
-               if (errno)
+               goto scno_in_r7;
+       /* ARM mode */
+       /* Check EABI/OABI by examining SVC insn's low 24 bits */
+       errno = 0;
+       scno = ptrace(PTRACE_PEEKTEXT, tcp->pid, (void *)(arm_regs.ARM_pc - 4), NULL);
+       if (errno)
+               return -1;
+       /* EABI syscall convention? */
+       if (scno != 0xef000000) {
+               /* No, it's OABI */
+               if ((scno & 0x0ff00000) != 0x0f900000) {
+                       fprintf(stderr, "pid %d unknown syscall trap 0x%08lx\n",
+                               tcp->pid, scno);
                        return -1;
-
-               /* EABI syscall convention? */
-               if (scno == 0xef000000) {
-                       scno = arm_regs.ARM_r7; /* yes */
-               } else {
-                       if ((scno & 0x0ff00000) != 0x0f900000) {
-                               fprintf(stderr, "pid %d unknown syscall trap 0x%08lx\n",
-                                       tcp->pid, scno);
-                               return -1;
-                       }
-                       /* Fixup the syscall number */
-                       scno &= 0x000fffff;
                }
+               /* Fixup the syscall number */
+               scno &= 0x000fffff;
+       } else {
+ scno_in_r7:
+               scno = arm_regs.ARM_r7;
        }
-
+# else
+       scno = arm_regs.ARM_r7;
+# endif
        scno = shuffle_scno(scno);
 #elif defined(M68K)
        if (upeek(tcp->pid, 4*PT_ORIG_D0, &scno) < 0)