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| author | Huacai Chen <chenhc@lemote.com> | 2016-01-21 21:09:49 +0800 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2016-01-22 01:59:57 +0100 |
| commit | 5754843225f78ac7cbe142a6899890a9733a5a5d (patch) | |
| tree | 032eeea9de09cab6232b0034381378d144127084 /arch/mips | |
| parent | 5188129b8c9f58ba089bfd3809a163a8c087c797 (diff) | |
| download | lwn-5754843225f78ac7cbe142a6899890a9733a5a5d.tar.gz lwn-5754843225f78ac7cbe142a6899890a9733a5a5d.zip | |
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')
| -rw-r--r-- | arch/mips/loongson64/loongson-3/smp.c | 20 |
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); } |