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>

diff --git a/arch/arc/kernel/head.S b/arch/arc/kernel/head.S
index 689dd867fdff53eeafa0d01d980ecf425f66a759..8b90d25a15cca8ebd334402848d98aa22f07b8bf 100644 (file)
--- a/arch/arc/kernel/head.S
+++ b/arch/arc/kernel/head.S
@@ -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

diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index 88674d972c9d056f33f87205aa77049c11006129..44a0d21ed3424dfa68ae9eadb15c56d17ca28f1b 100644 (file)
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -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 ? : "";