4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Vineet Gupta <[email protected]> [ 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 <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/arc/kernel/smp.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) --- a/arch/arc/kernel/smp.c +++ b/arch/arc/kernel/smp.c @@ -90,10 +90,23 @@ void __init smp_cpus_done(unsigned int m */ 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 c 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)
