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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: Vineet Gupta <vgupta@synopsys.com>
This commit is contained in:
Vineet Gupta 2017-01-12 14:30:29 -08:00
parent 517e7610d2
commit bf02454a74
2 changed files with 11 additions and 9 deletions
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14
arch/arc/kernel/head.S
View File

@ -71,14 +71,14 @@ ENTRY(stext)
GET_CPU_ID r5
cmp r5, 0
mov.nz r0, r5
#ifdef CONFIG_ARC_SMP_HALT_ON_RESET
; Non-Master can proceed as system would be booted sufficiently
jnz first_lines_of_secondary
#else
bz .Lmaster_proceed
; Non-Masters wait for Master to boot enough and bring them up
jnz arc_platform_smp_wait_to_boot
#endif
; Master falls thru
; when they resume, tail-call to entry point
mov blink, @first_lines_of_secondary
j arc_platform_smp_wait_to_boot
.Lmaster_proceed:
#endif
; Clear BSS before updating any globals

6
arch/arc/kernel/smp.c
View File

@ -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)
{
/* for halt-on-reset, we've waited already */
if (IS_ENABLED(CONFIG_ARC_SMP_HALT_ON_RESET))
return;
while (wake_flag != cpu)
;
wake_flag = 0;
__asm__ __volatile__("j @first_lines_of_secondary \n");
}
const char *arc_platform_smp_cpuinfo(void)
{
return plat_smp_ops.info ? : "";