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authorHuacai Chen <chenhc@lemote.com>2016-01-21 21:09:49 +0800
committerRalf Baechle <ralf@linux-mips.org>2016-01-22 01:59:57 +0100
commit5754843225f78ac7cbe142a6899890a9733a5a5d (patch)
tree032eeea9de09cab6232b0034381378d144127084 /arch/mips/loongson64
parent5188129b8c9f58ba089bfd3809a163a8c087c797 (diff)
downloadlinux-5754843225f78ac7cbe142a6899890a9733a5a5d.tar.bz2
MIPS: Loongson-3: Fix SMP_ASK_C0COUNT IPI handler
When Core-0 handle SMP_ASK_C0COUNT IPI, we should make other cores to see the result as soon as possible (especially when Store-Fill-Buffer is enabled). Otherwise, C0_Count syncronization makes no sense. BTW, array is more suitable than per-cpu variable for syncronization, and there is a corner case should be avoid: C0_Count of Core-0 can be really 0. Signed-off-by: Huacai Chen <chenhc@lemote.com> Cc: Aurelien Jarno <aurelien@aurel32.net> Cc: Steven J. Hill <Steven.Hill@imgtec.com> Cc: Fuxin Zhang <zhangfx@lemote.com> Cc: Zhangjin Wu <wuzhangjin@gmail.com> Cc: Huacai Chen <chenhc@lemote.com> Cc: linux-mips@linux-mips.org Cc: <stable@vger.kernel.org> Patchwork: https://patchwork.linux-mips.org/patch/12160/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/loongson64')
-rw-r--r--arch/mips/loongson64/loongson-3/smp.c20
1 files changed, 13 insertions, 7 deletions
diff --git a/arch/mips/loongson64/loongson-3/smp.c b/arch/mips/loongson64/loongson-3/smp.c
index 1a4738a8f2d3..509832a9836c 100644
--- a/arch/mips/loongson64/loongson-3/smp.c
+++ b/arch/mips/loongson64/loongson-3/smp.c
@@ -30,13 +30,13 @@
#include "smp.h"
DEFINE_PER_CPU(int, cpu_state);
-DEFINE_PER_CPU(uint32_t, core0_c0count);
static void *ipi_set0_regs[16];
static void *ipi_clear0_regs[16];
static void *ipi_status0_regs[16];
static void *ipi_en0_regs[16];
static void *ipi_mailbox_buf[16];
+static uint32_t core0_c0count[NR_CPUS];
/* read a 32bit value from ipi register */
#define loongson3_ipi_read32(addr) readl(addr)
@@ -275,12 +275,14 @@ void loongson3_ipi_interrupt(struct pt_regs *regs)
if (action & SMP_ASK_C0COUNT) {
BUG_ON(cpu != 0);
c0count = read_c0_count();
- for (i = 1; i < num_possible_cpus(); i++)
- per_cpu(core0_c0count, i) = c0count;
+ c0count = c0count ? c0count : 1;
+ for (i = 1; i < nr_cpu_ids; i++)
+ core0_c0count[i] = c0count;
+ __wbflush(); /* Let others see the result ASAP */
}
}
-#define MAX_LOOPS 1111
+#define MAX_LOOPS 800
/*
* SMP init and finish on secondary CPUs
*/
@@ -305,16 +307,20 @@ static void loongson3_init_secondary(void)
cpu_logical_map(cpu) / loongson_sysconf.cores_per_package;
i = 0;
- __this_cpu_write(core0_c0count, 0);
+ core0_c0count[cpu] = 0;
loongson3_send_ipi_single(0, SMP_ASK_C0COUNT);
- while (!__this_cpu_read(core0_c0count)) {
+ while (!core0_c0count[cpu]) {
i++;
cpu_relax();
}
if (i > MAX_LOOPS)
i = MAX_LOOPS;
- initcount = __this_cpu_read(core0_c0count) + i;
+ if (cpu_data[cpu].package)
+ initcount = core0_c0count[cpu] + i;
+ else /* Local access is faster for loops */
+ initcount = core0_c0count[cpu] + i/2;
+
write_c0_count(initcount);
}