From 1c343f7b0e177e8ca7f4d4a5dd1fa790f85abbcc Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Mon, 13 Jun 2016 13:14:56 +0200 Subject: KVM: s390/mm: Fix CMMA reset during reboot commit 1e133ab296f ("s390/mm: split arch/s390/mm/pgtable.c") factored out the page table handling code from __gmap_zap and __s390_reset_cmma into ptep_zap_unused and added a simple flag that tells which one of the function (reset or not) is to be made. This also changed the behaviour, as it also zaps unused page table entries on reset. Turns out that this is wrong as s390_reset_cmma uses the page walker, which DOES NOT take the ptl lock. The most simple fix is to not do the zapping part on reset (which uses the walker) Signed-off-by: Christian Borntraeger Fixes: 1e133ab296f ("s390/mm: split arch/s390/mm/pgtable.c") Cc: stable@vger.kernel.org # 4.6+ Signed-off-by: Martin Schwidefsky --- arch/s390/mm/pgtable.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/s390') diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index 4324b87f9398..9f0ce0e6eeb4 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -437,7 +437,7 @@ void ptep_zap_unused(struct mm_struct *mm, unsigned long addr, pgste = pgste_get_lock(ptep); pgstev = pgste_val(pgste); pte = *ptep; - if (pte_swap(pte) && + if (!reset && pte_swap(pte) && ((pgstev & _PGSTE_GPS_USAGE_MASK) == _PGSTE_GPS_USAGE_UNUSED || (pgstev & _PGSTE_GPS_ZERO))) { ptep_zap_swap_entry(mm, pte_to_swp_entry(pte)); -- cgit v1.2.3 From 9254e70c4ef1fee2e5c43feded4433d19cbb6177 Mon Sep 17 00:00:00 2001 From: Hendrik Brueckner Date: Thu, 9 Jun 2016 12:28:13 +0200 Subject: s390/cpum_cf: use perf software context for hardware counters On s390, there are two different hardware PMUs for counting and sampling. Previously, both PMUs have shared the perf_hw_context which is not correct and, recently, results in this warning: ------------[ cut here ]------------ WARNING: CPU: 5 PID: 1 at kernel/events/core.c:8485 perf_pmu_register+0x420/0x428 Modules linked in: CPU: 5 PID: 1 Comm: swapper/0 Not tainted 4.7.0-rc1+ #2 task: 00000009c5240000 ti: 00000009c5234000 task.ti: 00000009c5234000 Krnl PSW : 0704c00180000000 0000000000220c50 (perf_pmu_register+0x420/0x428) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3 Krnl GPRS: ffffffffffffffff 0000000000b15ac6 0000000000000000 00000009cb440000 000000000022087a 0000000000000000 0000000000b78fa0 0000000000000000 0000000000a9aa90 0000000000000084 0000000000000005 000000000088a97a 0000000000000004 0000000000749dd0 000000000022087a 00000009c5237cc0 Krnl Code: 0000000000220c44: a7f4ff54 brc 15,220aec 0000000000220c48: 92011000 mvi 0(%r1),1 #0000000000220c4c: a7f40001 brc 15,220c4e >0000000000220c50: a7f4ff12 brc 15,220a74 0000000000220c54: 0707 bcr 0,%r7 0000000000220c56: 0707 bcr 0,%r7 0000000000220c58: ebdff0800024 stmg %r13,%r15,128(%r15) 0000000000220c5e: a7f13fe0 tmll %r15,16352 Call Trace: ([<000000000022087a>] perf_pmu_register+0x4a/0x428) ([<0000000000b2c25c>] init_cpum_sampling_pmu+0x14c/0x1f8) ([<0000000000100248>] do_one_initcall+0x48/0x140) ([<0000000000b25d26>] kernel_init_freeable+0x1e6/0x2a0) ([<000000000072bda4>] kernel_init+0x24/0x138) ([<000000000073495e>] kernel_thread_starter+0x6/0xc) ([<0000000000734958>] kernel_thread_starter+0x0/0xc) Last Breaking-Event-Address: [<0000000000220c4c>] perf_pmu_register+0x41c/0x428 ---[ end trace 0c6ef9f5b771ad97 ]--- Using the perf_sw_context is an option because the cpum_cf PMU does not use interrupts. To make this more clear, initialize the capabilities in the PMU structure. Signed-off-by: Hendrik Brueckner Suggested-by: Peter Zijlstra Acked-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/perf_cpum_cf.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) (limited to 'arch/s390') diff --git a/arch/s390/kernel/perf_cpum_cf.c b/arch/s390/kernel/perf_cpum_cf.c index 59215c518f37..7ec63b1d920d 100644 --- a/arch/s390/kernel/perf_cpum_cf.c +++ b/arch/s390/kernel/perf_cpum_cf.c @@ -649,6 +649,8 @@ static int cpumf_pmu_commit_txn(struct pmu *pmu) /* Performance monitoring unit for s390x */ static struct pmu cpumf_pmu = { + .task_ctx_nr = perf_sw_context, + .capabilities = PERF_PMU_CAP_NO_INTERRUPT, .pmu_enable = cpumf_pmu_enable, .pmu_disable = cpumf_pmu_disable, .event_init = cpumf_pmu_event_init, @@ -708,12 +710,6 @@ static int __init cpumf_pmu_init(void) goto out; } - /* The CPU measurement counter facility does not have overflow - * interrupts to do sampling. Sampling must be provided by - * external means, for example, by timers. - */ - cpumf_pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT; - cpumf_pmu.attr_groups = cpumf_cf_event_group(); rc = perf_pmu_register(&cpumf_pmu, "cpum_cf", PERF_TYPE_RAW); if (rc) { -- cgit v1.2.3