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: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent ad0693ee
......@@ -29,6 +29,7 @@
#include <asm/percpu.h>
extern int boot_cpuid;
extern int boot_cpu_count;
extern void cpu_die(void);
......
......@@ -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
......
......@@ -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
......
......@@ -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];
......
......@@ -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");
}
......
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