Guarantee that the boot CPU has index 0. This simplifies the
implementation of tests that require multiple CPUs.
Also fix a small bug in the allocation of the cpus array.
Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
Fixes: f77c0515 ("s390x: Add initial smp code")
Fixes: 52076a63 ("s390x: Consolidate sclp read info")
Reviewed-by: Nico Boehr <nrb@xxxxxxxxxxxxx>
Reviewed-by: Steffen Eiden <seiden@xxxxxxxxxxxxx>
---
lib/s390x/smp.c | 27 +++++++++++++++++++--------
1 file changed, 19 insertions(+), 8 deletions(-)
diff --git a/lib/s390x/smp.c b/lib/s390x/smp.c
index b753eab5..eae742d2 100644
--- a/lib/s390x/smp.c
+++ b/lib/s390x/smp.c
@@ -25,7 +25,6 @@
#include "sclp.h"
static struct cpu *cpus;
-static struct cpu *cpu0;
static struct spinlock lock;
extern void smp_cpu_setup_state(void);
@@ -69,7 +68,7 @@ static int smp_cpu_stop_nolock(uint16_t addr, bool store)
uint8_t order = store ? SIGP_STOP_AND_STORE_STATUS : SIGP_STOP;
cpu = smp_cpu_from_addr(addr);
- if (!cpu || cpu == cpu0)
+ if (!cpu || addr == cpus[0].addr)
return -1;
if (sigp_retry(addr, order, 0, NULL))
@@ -193,7 +192,7 @@ int smp_cpu_setup(uint16_t addr, struct psw psw)
sigp_retry(cpu->addr, SIGP_SET_PREFIX, (unsigned long )lc, NULL);
/* Copy all exception psws. */
- memcpy(lc, cpu0->lowcore, 512);
+ memcpy(lc, cpus[0].lowcore, 512);
/* Setup stack */
cpu->stack = (uint64_t *)alloc_pages(2);
@@ -251,15 +250,27 @@ void smp_setup(void)
if (num > 1)
printf("SMP: Initializing, found %d cpus\n", num);
- cpus = calloc(num, sizeof(cpus));
+ cpus = calloc(num, sizeof(*cpus));
for (i = 0; i < num; i++) {
cpus[i].addr = entry[i].address;
cpus[i].active = false;
+ /*
+ * Fill in the boot CPU. If the boot CPU is not at index 0,
+ * swap it with the one at index 0. This guarantees that the
+ * boot CPU will always have index 0. If the boot CPU was
+ * already at index 0, a few extra useless assignments are
+ * performed, but everything will work ok.
+ * Notice that there is no guarantee that the list of CPUs
+ * returned by the Read SCP Info command is in any
+ * particular order, or that its order will stay consistent
+ * across multiple invocations.
+ */
if (entry[i].address == cpu0_addr) {
- cpu0 = &cpus[i];
- cpu0->stack = stackptr;
- cpu0->lowcore = (void *)0;
- cpu0->active = true;
+ cpus[i].addr = cpus[0].addr;
+ cpus[0].addr = cpu0_addr;
+ cpus[0].stack = stackptr;
+ cpus[0].lowcore = (void *)0;
+ cpus[0].active = true;
}
}
spin_unlock(&lock);
--
2.34.1
