From bf02454a741b58682a82c314a9a46bed930ed2f7 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Thu, 12 Jan 2017 14:30:29 -0800 Subject: [PATCH] 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 --- arch/arc/kernel/head.S | 14 +++++++------- arch/arc/kernel/smp.c | 6 ++++-- 2 files changed, 11 insertions(+), 9 deletions(-) diff --git a/arch/arc/kernel/head.S b/arch/arc/kernel/head.S index 689dd867fdff..8b90d25a15cc 100644 --- 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 88674d972c9d..44a0d21ed342 100644 --- 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 ? : ""; -- 2.30.2