Add setjmp support for aarch64-linux-musl

The MUSL libc setjmp/longjmp handling differs from the GNU libc
setjmp/longjmp handling. It may not be possible to properly support
sigsetjmp/siglongjmp on MUSL libc.

include/tdep-aarch64/jmpbuf.h

@@ -35,7 +35,11 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
 #define	_JB_STK_SHIFT	0
 #else
 #define JB_SP           13
-#define JB_RP           14
+# if defined(__GLIBC__)
+#  define JB_RP           14
+# else /* assume MUSL */
+#  define JB_RP           11
+# endif
 #define JB_MASK_SAVED   15
 #define JB_MASK         16
 #endif

src/aarch64/longjmp.S

@@ -25,9 +25,9 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
 	.global _UI_longjmp_cont
 	.type _UI_longjmp_cont, @function
 _UI_longjmp_cont:
-#if defined(__linux__) || defined(__QNX__)
+#if defined(__GLIBC__) || defined(__QNX__)
 	ret
-#elif defined(__FreeBSD__)
+#elif defined(__FreeBSD__) || defined(__linux__)
 	.cfi_startproc
 	/*
 	 * x0 - return address

src/setjmp/siglongjmp.c

@@ -90,17 +90,24 @@ siglongjmp (sigjmp_buf env, int val)
       /* default to resuming without restoring signal-mask */
       cont = &_UI_longjmp_cont;
 
+#if defined(__aarch64__) && defined(__linux__) && !defined(__GLIBC__)
+      if (unw_set_reg (&c, UNW_REG_EH + 0, wp[22]) < 0
+          || unw_set_reg (&c, UNW_REG_EH + 1, val) < 0
+          || unw_set_reg (&c, UNW_REG_EH + 19, wp[24]) < 0
+          || unw_set_reg (&c, UNW_REG_IP, (unw_word_t) (uintptr_t) cont))
+        abort ();
+#else /* !defined(__linux__) || defined(__GLIBC__) */
       /* Order of evaluation is important here: if unw_resume()
          restores signal mask, we must set it up appropriately, even
          if wp[JB_MASK_SAVED] is FALSE.  */
-#ifdef __FreeBSD__
+# ifdef __FreeBSD__
       if ((wp[JB_MASK_SAVED] & 0x1) == 0x1)
-#else
+# else
       if (!resume_restores_sigmask (&c, wp) && wp[JB_MASK_SAVED])
-#endif
+# endif
         {
           /* sigmask was saved */
-#if defined(__linux__) || defined(__sun)
+# if defined(__linux__) || defined(__sun)
           if (UNW_NUM_EH_REGS < 4 || _NSIG > 16 * sizeof (unw_word_t))
             /* signal mask doesn't fit into EH arguments and we can't
                put it on the stack without overwriting something
@@ -111,12 +118,12 @@ siglongjmp (sigjmp_buf env, int val)
                 || (_NSIG > 8 * sizeof (unw_word_t)
                     && unw_set_reg (&c, UNW_REG_EH + 3, wp[JB_MASK + 1]) < 0))
               abort ();
-#elif defined(__FreeBSD__)
+# elif defined(__FreeBSD__)
           if (unw_set_reg (&c, UNW_REG_EH + 2, (unw_word_t)&wp[JB_MASK]) < 0)
               abort();
-#else
-#error Port me
-#endif
+# else
+#  error Port me
+# endif
           cont = &_UI_siglongjmp_cont;
         }
 
@@ -124,6 +131,7 @@ siglongjmp (sigjmp_buf env, int val)
           || unw_set_reg (&c, UNW_REG_EH + 1, val) < 0
           || unw_set_reg (&c, UNW_REG_IP, (unw_word_t) (uintptr_t) cont))
         abort ();
+#endif /* defined(__linux__) && !defined(__GLIBC__) */
 
       unw_resume (&c);
 

tests/test-setjmp.c

@@ -209,6 +209,7 @@ main (int argc, char **argv UNUSED)
     }
 
   /* sigsetjmp(jbuf, 0) MUST NOT preserve signal mask: */
+  memset (sigjbuf, 0, sizeof(*sigjbuf));
   sigprocmask (SIG_SETMASK, (sigset_t *) &sigset1, NULL);
   if (sigsetjmp (sigjbuf, 0))
     {