kernel, libc: signals fixes

. kernel: signal handler args for ARM
	. kernel: sanity check return address (LSB indicates thumb mode)
	. libc: properly retrieve signal mask for ARM

together fix test37 on ARM.

Change-Id: I4e00f754c50104ed85c7fdf8ec5ad54568f20a81

kernel/system/do_sigsend.c

@@ -86,6 +86,12 @@ int do_sigsend(struct proc * caller, message * m_ptr)
    * handler
    */
   rp->p_reg.lr = (reg_t) fr.sf_retadr;
+  if(rp->p_reg.lr & 1) { printf("sigsend: LSB LR makes no sense.\n"); }
+
+  /* pass signal handler parameters in registers */
+  rp->p_reg.retreg = (reg_t) fr.sf_signo;
+  rp->p_reg.r1 = (reg_t) fr.sf_code;
+  rp->p_reg.r2 = (reg_t) fr.sf_scp;
 #endif
 
   /* Copy the sigframe structure to the user's stack. */

lib/libc/arch/arm/gen/setjmp.S

@@ -87,7 +87,11 @@ ENTRY(__longjmp14)
 	stmfd	sp!, {r0-r2, r14}
 	mov	r2, #0x00000000
 	add	r1, r0, #(_JB_SIGMASK * 4)
+#ifdef __minix
+	mov	r0, #2				/* SIG_SETMASK */
+#else
 	mov	r0, #3				/* SIG_SETMASK */
+#endif
 	bl	PIC_SYM(_C_LABEL(__sigprocmask14), PLT)
 	ldmfd	sp!, {r0-r2, r14}