!signal: adapt to new signal trampoline parameters.

`oldmask` storing is handled by kernel.
Needed for correct sigsuspend implementation.

WARN: breaking ABI change, signal trampoline parameters have changed.

JIRA: RTOS-1059

Author: nalajcie

arch/aarch64/signal.S

@@ -20,11 +20,10 @@
 .globl _signal_trampoline
 .type _signal_trampoline, %function
 _signal_trampoline:
-	ldr x0, [sp] /* signal number */
+	ldr x0, [sp], 8 /* signal number */
 	bl _signal_handler
 
-	/* Old signal mask in x0 */
-	ldp xzr, x1, [sp], #0x10 /* signal number (discarded), cpu_context_t *  */
+	ldp x0, x1, [sp], #0x10 /* oldmask, cpu_context_t *  */
 	ldp x2, x3, [sp], #0x10 /* pc, sp */
 	ldr x4, [sp], #0x10 /* psr, skip padding at the end */
 	bl sigreturn

arch/arm/signal.S

@@ -20,13 +20,14 @@
 .globl _signal_trampoline
 .type _signal_trampoline, %function
 _signal_trampoline:
-	/* Signal number, cpu_context * */
+	/* Signal number, oldmask - keep stack aligned to 8 */
 	pop {r0,r4}
 	blx _signal_handler
 
-	/* Old signal mask in r0 */
-	mov r1, r4
-	pop {r2,r3} /* pc, sp */
-	/* psr on stack */
+	mov r0, r4        /* move oldmask to r0 */
+	pop {r1,r2,r3,r4} /* cpu_context_t *, pc, psp, psr */
+
+	/* put psr back on stack, keep aligned to 8 (r5 as padding value) */
+	push {r4,r5}
 	bl sigreturn
 .size _signal_trampoline, .-_signal_trampoline

arch/ia32/signal.S

@@ -24,8 +24,7 @@ _signal_trampoline:
 	call _signal_handler
 
 	addl $4, %esp
-	/* Put old mask on stack */
-	push %eax
+	/* oldmask is now on top of the stack */
 	/* cpu context *, eip, esp on stack */
 	call sigreturn
 .size _signal_trampoline, .-_signal_trampoline

arch/riscv64/signal.S

@@ -24,10 +24,10 @@ _signal_trampoline:
 	lw a0, (sp)
 	call _signal_handler
 
-	/* Old signal mask in a0 */
-	ld a1, 8(sp)  /* cpu context * */
-	ld a2, 16(sp) /* sepc */
-	ld a3, 24(sp) /* sp */
-	addi sp, sp, 32
+	lw a0, 8(sp)  /* old signal mask */
+	ld a1, 16(sp) /* cpu context * */
+	ld a2, 24(sp) /* sepc */
+	ld a3, 32(sp) /* sp */
+	addi sp, sp, 40
 	call sigreturn
 .size _signal_trampoline, .-_signal_trampoline

arch/sparcv8leon/signal.S

@@ -29,9 +29,11 @@ _signal_trampoline:
 	call _signal_handler
 	ld [%i0], %o0 /* signal number */
 
-	/* oldmask in %o0 */
-	ld  [%i0 + 0x04], %o1 /* cpu_context * */
-	ldd [%i0 + 0x08], %o2 /* pc, npc */
+	ld [%i0 + 0x04], %o0 /* old signal mask */
+	ld [%i0 + 0x08], %o1 /* cpu_context * */
+	ld [%i0 + 0x0c], %o2 /* pc */
+	ld [%i0 + 0x10], %o3 /* npc */
+	ld [%i0 + 0x14], %o4 /* sp */
 	call sigreturn
-	ldd [%i0 + 0x10], %o4 /* sp, psr */
+	ld [%i0 + 0x18], %o5 /* psr */
 .size _signal_trampoline, .-_signal_trampoline

signal/signal.c

@@ -123,14 +123,13 @@ static int _signal_ismutable(int sig)
 }
 
 
-unsigned int _signal_handler(int phxsig)
+void _signal_handler(int phxsig)
 {
 	int sig;
-	unsigned int oldmask;
 
 	if ((phxsig < 0) || (phxsig >= NSIG)) {
 		/* Don't know what to do, ignore it */
-		return signalMask(0U, 0U);
+		return;
 	}
 
 	/* Received Phoenix signal, need to convert it to POSIX signal */
@@ -142,9 +141,7 @@ unsigned int _signal_handler(int phxsig)
 	/* Invoke handler */
 	(signal_common.sightab[sig])(sig);
 
-	/* Mask restored by sigreturn */
-
-	return oldmask;
+	/* oldmask kept on stack and restored by sigreturn */
 }