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authorLinus Torvalds <torvalds@linux-foundation.org>2021-04-03 10:49:38 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-04-03 10:49:38 -0700
commit9c2ef23e4dae122d2b18e834d90f8bd4dda48fe6 (patch)
tree7810e410e8b43e98a86d5ab485d0574f66b2aca3
parentfa16199500c8863da145870f01d61617d967b6c3 (diff)
parent53f1d31708f6240e4615b0927df31f182e389e2f (diff)
Merge tag 'powerpc-5.12-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman: "Fix a bug on pseries where spurious wakeups from H_PROD would prevent partition migration from succeeding. Fix oopses seen in pcpu_alloc(), caused by parallel faults of the percpu mapping causing us to corrupt the protection key used for the mapping, and cause a fatal key fault. Thanks to Aneesh Kumar K.V, Murilo Opsfelder Araujo, and Nathan Lynch" * tag 'powerpc-5.12-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/mm/book3s64: Use the correct storage key value when calling H_PROTECT powerpc/pseries/mobility: handle premature return from H_JOIN powerpc/pseries/mobility: use struct for shared state
-rw-r--r--arch/powerpc/platforms/pseries/lpar.c3
-rw-r--r--arch/powerpc/platforms/pseries/mobility.c48
2 files changed, 46 insertions, 5 deletions
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index 764170fdb0f7..3805519a6469 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -887,7 +887,8 @@ static long pSeries_lpar_hpte_updatepp(unsigned long slot,
want_v = hpte_encode_avpn(vpn, psize, ssize);
- flags = (newpp & 7) | H_AVPN;
+ flags = (newpp & (HPTE_R_PP | HPTE_R_N | HPTE_R_KEY_LO)) | H_AVPN;
+ flags |= (newpp & HPTE_R_KEY_HI) >> 48;
if (mmu_has_feature(MMU_FTR_KERNEL_RO))
/* Move pp0 into bit 8 (IBM 55) */
flags |= (newpp & HPTE_R_PP0) >> 55;
diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index ea4d6a660e0d..e83e0891272d 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -452,12 +452,28 @@ static int do_suspend(void)
return ret;
}
+/**
+ * struct pseries_suspend_info - State shared between CPUs for join/suspend.
+ * @counter: Threads are to increment this upon resuming from suspend
+ * or if an error is received from H_JOIN. The thread which performs
+ * the first increment (i.e. sets it to 1) is responsible for
+ * waking the other threads.
+ * @done: False if join/suspend is in progress. True if the operation is
+ * complete (successful or not).
+ */
+struct pseries_suspend_info {
+ atomic_t counter;
+ bool done;
+};
+
static int do_join(void *arg)
{
- atomic_t *counter = arg;
+ struct pseries_suspend_info *info = arg;
+ atomic_t *counter = &info->counter;
long hvrc;
int ret;
+retry:
/* Must ensure MSR.EE off for H_JOIN. */
hard_irq_disable();
hvrc = plpar_hcall_norets(H_JOIN);
@@ -473,8 +489,20 @@ static int do_join(void *arg)
case H_SUCCESS:
/*
* The suspend is complete and this cpu has received a
- * prod.
+ * prod, or we've received a stray prod from unrelated
+ * code (e.g. paravirt spinlocks) and we need to join
+ * again.
+ *
+ * This barrier orders the return from H_JOIN above vs
+ * the load of info->done. It pairs with the barrier
+ * in the wakeup/prod path below.
*/
+ smp_mb();
+ if (READ_ONCE(info->done) == false) {
+ pr_info_ratelimited("premature return from H_JOIN on CPU %i, retrying",
+ smp_processor_id());
+ goto retry;
+ }
ret = 0;
break;
case H_BAD_MODE:
@@ -488,6 +516,13 @@ static int do_join(void *arg)
if (atomic_inc_return(counter) == 1) {
pr_info("CPU %u waking all threads\n", smp_processor_id());
+ WRITE_ONCE(info->done, true);
+ /*
+ * This barrier orders the store to info->done vs subsequent
+ * H_PRODs to wake the other CPUs. It pairs with the barrier
+ * in the H_SUCCESS case above.
+ */
+ smp_mb();
prod_others();
}
/*
@@ -535,11 +570,16 @@ static int pseries_suspend(u64 handle)
int ret;
while (true) {
- atomic_t counter = ATOMIC_INIT(0);
+ struct pseries_suspend_info info;
unsigned long vasi_state;
int vasi_err;
- ret = stop_machine(do_join, &counter, cpu_online_mask);
+ info = (struct pseries_suspend_info) {
+ .counter = ATOMIC_INIT(0),
+ .done = false,
+ };
+
+ ret = stop_machine(do_join, &info, cpu_online_mask);
if (ret == 0)
break;
/*

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