You are correct, we need another entry for libgcc_s_resume, and we need
to load that after the barrier, otherwise we won't call libgcc_s_resume.
Something like this:
diff --git a/ports/sysdeps/unix/sysv/linux/arm/nptl/unwind-forcedunwind.c b/ports/sysdeps/unix/sysv/linux/arm/nptl/unwind-forcedunwind.c
index 58ca9ac..1e03b13 100644
--- a/ports/sysdeps/unix/sysv/linux/arm/nptl/unwind-forcedunwind.c
+++ b/ports/sysdeps/unix/sysv/linux/arm/nptl/unwind-forcedunwind.c
@@ -104,7 +104,12 @@ asm (
" mov r6, r0\n"
" cmp r3, #0\n"
" beq 4f\n"
-"5: mov r0, r6\n"
+ atomic_asm_full_barrier()
+"5: ldr r4, 6f\n"
+" ldr r5, 7f\n"
+"8: add r4, pc, r4\n"
+" ldr r3, [r4, r5]\n"
+" mov r0, r6\n"
" ldmfd sp!, {r4, r5, r6, lr}\n"
" " CFI_ADJUST_CFA_OFFSET (-16) "\n"
" " CFI_RESTORE (r4) "\n"
@@ -123,7 +128,13 @@ asm (
#else
"1: .word _GLOBAL_OFFSET_TABLE_ - 3b - 8\n"
#endif
-"2: .word libgcc_s_resume(GOTOFF)\n"
+"2: .word libgcc_s_handle(GOTOFF)\n"
+#ifdef __thumb2__
+"6: .word _GLOBAL_OFFSET_TABLE_ - 8b - 4\n"
+#else
+"6: .word _GLOBAL_OFFSET_TABLE_ - 8b - 8\n"
+#endif
+"7: .word libgcc_s_resume(GOTOFF)\n"
" .size _Unwind_Resume, .-_Unwind_Resume\n"
);
@@ -76,7 +92,7 @@ asm (
" " CFI_RESTORE (lr) "\n"
" bx r3\n"
" " CFI_RESTORE_STATE "\n"
-"4: bl init\n"
+"4: bl pthread_cancel_init\n"
" ldr r3, [r4, r5]\n"
" b 5b\n"
" " CFI_ENDPROC "\n"