From 9d07bc841c9779b4d7902e417f4e509996ce805d Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Wed, 16 Mar 2011 14:54:35 +1100 Subject: [PATCH] powerpc: Properly handshake CPUs going out of boot spin loop We need to wait a bit for them to have done their CPU setup or we might end up with translation and EE on with different LPCR values between threads Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/smp.h | 1 + arch/powerpc/kernel/head_64.S | 18 +++++++++++++----- arch/powerpc/kernel/prom.c | 27 ++++++++++----------------- arch/powerpc/kernel/setup_32.c | 1 + arch/powerpc/kernel/setup_64.c | 13 ++++++++++++- 5 files changed, 37 insertions(+), 23 deletions(-) diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h index a902a0d3ae0d..bb4c033a8fb0 100644 --- a/arch/powerpc/include/asm/smp.h +++ b/arch/powerpc/include/asm/smp.h @@ -29,6 +29,7 @@ #include extern int boot_cpuid; +extern int boot_cpu_count; extern void cpu_die(void); diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S index 95944278380c..0700e1135c91 100644 --- a/arch/powerpc/kernel/head_64.S +++ b/arch/powerpc/kernel/head_64.S @@ -242,23 +242,31 @@ generic_secondary_common_init: ld r23,0(r23) ld r23,CPU_SPEC_RESTORE(r23) cmpdi 0,r23,0 - beq 4f + beq 3f ld r23,0(r23) mtctr r23 bctrl -3: HMT_LOW +3: LOAD_REG_ADDR(r3, boot_cpu_count) /* Decrement boot_cpu_count */ + lwarx r4,0,r3 + subi r4,r4,1 + stwcx. r4,0,r3 + bne 3b + isync + +4: HMT_LOW lbz r23,PACAPROCSTART(r13) /* Test if this processor should */ /* start. */ #ifndef CONFIG_SMP - b 3b /* Never go on non-SMP */ + b 4b /* Never go on non-SMP */ #else cmpwi 0,r23,0 - beq 3b /* Loop until told to go */ + beq 4b /* Loop until told to go */ sync /* order paca.run and cur_cpu_spec */ + isync /* In case code patching happened */ -4: /* Create a temp kernel stack for use before relocation is on. */ + /* Create a temp kernel stack for use before relocation is on. */ ld r1,PACAEMERGSP(r13) subi r1,r1,STACK_FRAME_OVERHEAD diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c index e74fa12afc82..c391dc4c8bad 100644 --- a/arch/powerpc/kernel/prom.c +++ b/arch/powerpc/kernel/prom.c @@ -268,13 +268,12 @@ static int __init early_init_dt_scan_cpus(unsigned long node, const char *uname, int depth, void *data) { - static int logical_cpuid = 0; char *type = of_get_flat_dt_prop(node, "device_type", NULL); const u32 *prop; const u32 *intserv; int i, nthreads; unsigned long len; - int found = 0; + int found = -1; /* We are scanning "cpu" nodes only */ if (type == NULL || strcmp(type, "cpu") != 0) @@ -299,11 +298,8 @@ static int __init early_init_dt_scan_cpus(unsigned long node, * booted proc. */ if (initial_boot_params && initial_boot_params->version >= 2) { - if (intserv[i] == - initial_boot_params->boot_cpuid_phys) { - found = 1; - break; - } + if (intserv[i] == initial_boot_params->boot_cpuid_phys) + found = boot_cpu_count; } else { /* * Check if it's the boot-cpu, set it's hw index now, @@ -311,23 +307,20 @@ static int __init early_init_dt_scan_cpus(unsigned long node, * off secondary threads. */ if (of_get_flat_dt_prop(node, - "linux,boot-cpu", NULL) != NULL) { - found = 1; - break; - } + "linux,boot-cpu", NULL) != NULL) + found = boot_cpu_count; } - #ifdef CONFIG_SMP /* logical cpu id is always 0 on UP kernels */ - logical_cpuid++; + boot_cpu_count++; #endif } - if (found) { - DBG("boot cpu: logical %d physical %d\n", logical_cpuid, + if (found >= 0) { + DBG("boot cpu: logical %d physical %d\n", found, intserv[i]); - boot_cpuid = logical_cpuid; - set_hard_smp_processor_id(boot_cpuid, intserv[i]); + boot_cpuid = found; + set_hard_smp_processor_id(found, intserv[i]); /* * PAPR defines "logical" PVR values for cpus that diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c index 1d2fbc905303..620d792b52e4 100644 --- a/arch/powerpc/kernel/setup_32.c +++ b/arch/powerpc/kernel/setup_32.c @@ -48,6 +48,7 @@ extern void bootx_init(unsigned long r4, unsigned long phys); int boot_cpuid = -1; EXPORT_SYMBOL_GPL(boot_cpuid); +int __initdata boot_cpu_count; int boot_cpuid_phys; int smp_hw_index[NR_CPUS]; diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index 5a0401fcaebd..91a5cc5f0d02 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -72,6 +72,7 @@ #endif int boot_cpuid = 0; +int __initdata boot_cpu_count; u64 ppc64_pft_size; /* Pick defaults since we might want to patch instructions @@ -233,6 +234,7 @@ void early_setup_secondary(void) void smp_release_cpus(void) { unsigned long *ptr; + int i; DBG(" -> smp_release_cpus()\n"); @@ -245,7 +247,16 @@ void smp_release_cpus(void) ptr = (unsigned long *)((unsigned long)&__secondary_hold_spinloop - PHYSICAL_START); *ptr = __pa(generic_secondary_smp_init); - mb(); + + /* And wait a bit for them to catch up */ + for (i = 0; i < 100000; i++) { + mb(); + HMT_low(); + if (boot_cpu_count == 0) + break; + udelay(1); + } + DBG("boot_cpu_count = %d\n", boot_cpu_count); DBG(" <- smp_release_cpus()\n"); } -- 2.34.1