Shave another uninteresting stack frame off aborts.
With this, stack frame 0 is the abort, not tgkill.
arm:
#00 pc 0001a41c /system/lib/libc.so (abort+63)
arm64:
#00 pc 000000000001d75c /system/lib64/libc.so (abort+120)
Also "include what you use" for <sys/syscall.h>.
Bug: N/A
Test: ran `crasher abort` and `crasher64 abort`
Change-Id: I6517ac67b39b4133e890d52efc115071c812958b
diff --git a/libc/bionic/abort.cpp b/libc/bionic/abort.cpp
index 3ba83d1..f401cab 100644
--- a/libc/bionic/abort.cpp
+++ b/libc/bionic/abort.cpp
@@ -32,6 +32,26 @@
#include <sys/syscall.h>
#include <unistd.h>
+// We call tgkill(2) directly instead of raise (or even the libc tgkill wrapper), to reduce the
+// number of uninteresting stack frames at the top of a crash.
+static inline __always_inline void inline_tgkill(pid_t pid, pid_t tid, int sig) {
+#if defined(__arm__)
+ register int r0 __asm__("r0") = pid;
+ register int r1 __asm__("r1") = tid;
+ register int r2 __asm__("r2") = sig;
+ register int r7 __asm__("r7") = __NR_tgkill;
+ __asm__("swi #0" : "=r"(r0) : "r"(r0), "r"(r1), "r"(r2), "r"(r7) : "memory");
+#elif defined(__aarch64__)
+ register long x0 __asm__("x0") = pid;
+ register long x1 __asm__("x1") = tid;
+ register long x2 __asm__("x2") = sig;
+ register long x8 __asm__("x8") = __NR_tgkill;
+ __asm__("svc #0" : "=r"(x0) : "r"(x0), "r"(x1), "r"(x2), "r"(x8) : "memory");
+#else
+ syscall(__NR_tgkill, pid, tid, sig);
+#endif
+}
+
void abort() {
// Protect ourselves against stale cached PID/TID values by fetching them via syscall.
// http://b/37769298
@@ -45,8 +65,7 @@
sigdelset(&mask, SIGABRT);
sigprocmask(SIG_SETMASK, &mask, NULL);
- // Use tgkill directly instead of raise, to avoid inserting spurious stack frames.
- tgkill(pid, tid, SIGABRT);
+ inline_tgkill(pid, tid, SIGABRT);
// If SIGABRT ignored, or caught and the handler returns,
// remove the SIGABRT signal handler and raise SIGABRT again.
@@ -57,7 +76,7 @@
sigaction(SIGABRT, &sa, &sa);
sigprocmask(SIG_SETMASK, &mask, NULL);
- tgkill(pid, tid, SIGABRT);
+ inline_tgkill(pid, tid, SIGABRT);
// If we get this far, just exit.
_exit(127);