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| author | Vineet Gupta <vgupta@synopsys.com> | 2016-06-21 14:24:33 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-06-17 06:41:57 +0200 |
| commit | 2552e2c11575c72114a2f8902a7488c810c41691 (patch) | |
| tree | d29459310c83fef87ca65bf7fd6b4a18af9b1976 | |
| parent | 8cb6045ec40d90d8074dd072c2ec9d0fc7b91956 (diff) | |
| download | linux-stable-2552e2c11575c72114a2f8902a7488c810c41691.tar.gz linux-stable-2552e2c11575c72114a2f8902a7488c810c41691.tar.bz2 linux-stable-2552e2c11575c72114a2f8902a7488c810c41691.zip | |
ARCv2: smp-boot: wake_flag polling by non-Masters needs to be uncached
[ Upstream commit 78f824d4312a8944f5340c6b161bba3bf2c81096 ]
This is needed on HS38 cores, for setting up IO-Coherency aperture properly
The polling could perturb the caches and coherecy fabric which could be
wrong in the small window when Master is setting up IOC aperture etc
in arc_cache_init()
We do it only for ARCv2 based builds to not affect EZChip ARCompact
based platform.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/arc/kernel/smp.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c index 44a0d21ed342..2afbafadb6ab 100644 --- a/arch/arc/kernel/smp.c +++ b/arch/arc/kernel/smp.c @@ -90,10 +90,23 @@ void __init smp_cpus_done(unsigned int max_cpus) */ static volatile int wake_flag; +#ifdef CONFIG_ISA_ARCOMPACT + +#define __boot_read(f) f +#define __boot_write(f, v) f = v + +#else + +#define __boot_read(f) arc_read_uncached_32(&f) +#define __boot_write(f, v) arc_write_uncached_32(&f, v) + +#endif + static void arc_default_smp_cpu_kick(int cpu, unsigned long pc) { BUG_ON(cpu == 0); - wake_flag = cpu; + + __boot_write(wake_flag, cpu); } void arc_platform_smp_wait_to_boot(int cpu) @@ -102,10 +115,10 @@ void arc_platform_smp_wait_to_boot(int cpu) if (IS_ENABLED(CONFIG_ARC_SMP_HALT_ON_RESET)) return; - while (wake_flag != cpu) + while (__boot_read(wake_flag) != cpu) ; - wake_flag = 0; + __boot_write(wake_flag, 0); } const char *arc_platform_smp_cpuinfo(void) |