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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2011-03-16 14:54:35 +1100
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2011-04-20 11:03:24 +1000
commit9d07bc841c9779b4d7902e417f4e509996ce805d (patch)
tree7a381096d3da7497aac58c4ec18c74299ee47fb4 /arch
parentad0693ee722b93b63a89c845e99513f242e43aa6 (diff)
downloadlinaro-lsk-9d07bc841c9779b4d7902e417f4e509996ce805d.tar.gz
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 <benh@kernel.crashing.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/include/asm/smp.h1
-rw-r--r--arch/powerpc/kernel/head_64.S18
-rw-r--r--arch/powerpc/kernel/prom.c27
-rw-r--r--arch/powerpc/kernel/setup_32.c1
-rw-r--r--arch/powerpc/kernel/setup_64.c13
5 files changed, 37 insertions, 23 deletions
diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h
index a902a0d3ae0..bb4c033a8fb 100644
--- a/arch/powerpc/include/asm/smp.h
+++ b/arch/powerpc/include/asm/smp.h
@@ -29,6 +29,7 @@
#include <asm/percpu.h>
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 95944278380..0700e1135c9 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 e74fa12afc8..c391dc4c8ba 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 1d2fbc90530..620d792b52e 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 5a0401fcaeb..91a5cc5f0d0 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");
}