Commit bf02454a authored by Vineet Gupta's avatar Vineet Gupta
Browse files

ARC: smp-boot: Decouple Non masters waiting API from jump to entry point 



For run-on-reset SMP configs, non master cores call a routine which
waits until Master gives it a "go" signal (currently using a shared
mem flag). The same routine then jumps off the well known entry point of
all non Master cores i.e. @first_lines_of_secondary

This patch moves out the last part into one single place in early boot
code.

This is better in terms of absraction (the wait API only waits) and
returns, leaving out the "jump off to" part.

In actual implementation this requires some restructuring of the early
boot code as well as Master now jumps to BSS setup explicitly,
vs. falling thru into it before.

Technically this patch doesn't cause any functional change, it just
moves the ugly #ifdef'ry from assembly code to "C"

Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent 517e7610

arch/arc/kernel/head.S

+7 −7
Original line number Original line Diff line number Diff line
@@ -71,14 +71,14 @@ ENTRY(stext) 
	GET_CPU_ID  r5

	GET_CPU_ID  r5

	cmp	r5, 0

	cmp	r5, 0

	mov.nz	r0, r5

	mov.nz	r0, r5

#ifdef CONFIG_ARC_SMP_HALT_ON_RESET

	bz	.Lmaster_proceed

	; Non-Master can proceed as system would be booted sufficiently



	jnz	first_lines_of_secondary

#else

	; Non-Masters wait for Master to boot enough and bring them up

	; Non-Masters wait for Master to boot enough and bring them up

	jnz	arc_platform_smp_wait_to_boot

	; when they resume, tail-call to entry point

#endif

	mov	blink, @first_lines_of_secondary

	; Master falls thru

	j	arc_platform_smp_wait_to_boot



.Lmaster_proceed:

#endif

#endif





	; Clear BSS before updating any globals

	; Clear BSS before updating any globals

arch/arc/kernel/smp.c

+4 −2
Original line number Original line Diff line number Diff line
@@ -98,14 +98,16 @@ static void arc_default_smp_cpu_kick(int cpu, unsigned long pc) 




void arc_platform_smp_wait_to_boot(int cpu)

void arc_platform_smp_wait_to_boot(int cpu)

{

{

	/* for halt-on-reset, we've waited already */

	if (IS_ENABLED(CONFIG_ARC_SMP_HALT_ON_RESET))

		return;



	while (wake_flag != cpu)

	while (wake_flag != cpu)

		;

		;





	wake_flag = 0;

	wake_flag = 0;

	__asm__ __volatile__("j @first_lines_of_secondary	\n");

}

}







const char *arc_platform_smp_cpuinfo(void)

const char *arc_platform_smp_cpuinfo(void)

{

{

	return plat_smp_ops.info ? : "";

	return plat_smp_ops.info ? : "";

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