--- /dev/null
+From 73ce9aec65b17433e18163d07eb5cb6bf114bd6c Mon Sep 17 00:00:00 2001
+From: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
+Date: Wed, 22 Nov 2017 10:45:39 +0530
+Subject: powerpc/perf: Fix IMC_MAX_PMU macro
+
+From: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
+
+commit 73ce9aec65b17433e18163d07eb5cb6bf114bd6c upstream.
+
+IMC_MAX_PMU is used for static storage (per_nest_pmu_arr) which holds
+nest pmu information. Current value for the macro is 32 based on
+the initial number of nest pmu units supported by the nest microcode.
+But going forward, microcode could support more nest units. Instead
+of static storage, patch to fix the code to dynamically allocate an
+array based on the number of nest imc units found in the device tree.
+
+Fixes:8f95faaac56c1 ('powerpc/powernv: Detect and create IMC device')
+Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
+Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
+Cc: Andrew Donnellan <ajd@linux.ibm.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ arch/powerpc/include/asm/imc-pmu.h | 6 +-----
+ arch/powerpc/perf/imc-pmu.c | 15 ++++++++++++---
+ arch/powerpc/platforms/powernv/opal-imc.c | 16 ++++++++++++++++
+ 3 files changed, 29 insertions(+), 8 deletions(-)
+
+--- a/arch/powerpc/include/asm/imc-pmu.h
++++ b/arch/powerpc/include/asm/imc-pmu.h
+@@ -21,11 +21,6 @@
+ #include <asm/opal.h>
+
+ /*
+- * For static allocation of some of the structures.
+- */
+-#define IMC_MAX_PMUS 32
+-
+-/*
+ * Compatibility macros for IMC devices
+ */
+ #define IMC_DTB_COMPAT "ibm,opal-in-memory-counters"
+@@ -125,4 +120,5 @@ enum {
+ extern int init_imc_pmu(struct device_node *parent,
+ struct imc_pmu *pmu_ptr, int pmu_id);
+ extern void thread_imc_disable(void);
++extern int get_max_nest_dev(void);
+ #endif /* __ASM_POWERPC_IMC_PMU_H */
+--- a/arch/powerpc/perf/imc-pmu.c
++++ b/arch/powerpc/perf/imc-pmu.c
+@@ -26,7 +26,7 @@
+ */
+ static DEFINE_MUTEX(nest_init_lock);
+ static DEFINE_PER_CPU(struct imc_pmu_ref *, local_nest_imc_refc);
+-static struct imc_pmu *per_nest_pmu_arr[IMC_MAX_PMUS];
++static struct imc_pmu **per_nest_pmu_arr;
+ static cpumask_t nest_imc_cpumask;
+ struct imc_pmu_ref *nest_imc_refc;
+ static int nest_pmus;
+@@ -286,13 +286,14 @@ static struct imc_pmu_ref *get_nest_pmu_
+ static void nest_change_cpu_context(int old_cpu, int new_cpu)
+ {
+ struct imc_pmu **pn = per_nest_pmu_arr;
+- int i;
+
+ if (old_cpu < 0 || new_cpu < 0)
+ return;
+
+- for (i = 0; *pn && i < IMC_MAX_PMUS; i++, pn++)
++ while (*pn) {
+ perf_pmu_migrate_context(&(*pn)->pmu, old_cpu, new_cpu);
++ pn++;
++ }
+ }
+
+ static int ppc_nest_imc_cpu_offline(unsigned int cpu)
+@@ -1212,6 +1213,7 @@ static void imc_common_cpuhp_mem_free(st
+ kfree(pmu_ptr->attr_groups[IMC_EVENT_ATTR]->attrs);
+ kfree(pmu_ptr->attr_groups[IMC_EVENT_ATTR]);
+ kfree(pmu_ptr);
++ kfree(per_nest_pmu_arr);
+ return;
+ }
+
+@@ -1236,6 +1238,13 @@ static int imc_mem_init(struct imc_pmu *
+ return -ENOMEM;
+
+ /* Needed for hotplug/migration */
++ if (!per_nest_pmu_arr) {
++ per_nest_pmu_arr = kcalloc(get_max_nest_dev() + 1,
++ sizeof(struct imc_pmu *),
++ GFP_KERNEL);
++ if (!per_nest_pmu_arr)
++ return -ENOMEM;
++ }
+ per_nest_pmu_arr[pmu_index] = pmu_ptr;
+ break;
+ case IMC_DOMAIN_CORE:
+--- a/arch/powerpc/platforms/powernv/opal-imc.c
++++ b/arch/powerpc/platforms/powernv/opal-imc.c
+@@ -159,6 +159,22 @@ static void disable_core_pmu_counters(vo
+ put_online_cpus();
+ }
+
++int get_max_nest_dev(void)
++{
++ struct device_node *node;
++ u32 pmu_units = 0, type;
++
++ for_each_compatible_node(node, NULL, IMC_DTB_UNIT_COMPAT) {
++ if (of_property_read_u32(node, "type", &type))
++ continue;
++
++ if (type == IMC_TYPE_CHIP)
++ pmu_units++;
++ }
++
++ return pmu_units;
++}
++
+ static int opal_imc_counters_probe(struct platform_device *pdev)
+ {
+ struct device_node *imc_dev = pdev->dev.of_node;
--- /dev/null
+From 110df8bd3e418b3476cae80babe8add48a8ea523 Mon Sep 17 00:00:00 2001
+From: Anju T Sudhakar <anju@linux.vnet.ibm.com>
+Date: Thu, 7 Dec 2017 22:53:27 +0530
+Subject: powerpc/perf: Fix kfree memory allocated for nest pmus
+
+From: Anju T Sudhakar <anju@linux.vnet.ibm.com>
+
+commit 110df8bd3e418b3476cae80babe8add48a8ea523 upstream.
+
+imc_common_cpuhp_mem_free() is the common function for all
+IMC (In-memory Collection counters) domains to unregister cpuhotplug
+callback and free memory. Since kfree of memory allocated for
+nest-imc (per_nest_pmu_arr) is in the common code, all
+domains (core/nest/thread) can do the kfree in the failure case.
+
+This could potentially create a call trace as shown below, where
+core(/thread/nest) imc pmu initialization fails and in the failure
+path imc_common_cpuhp_mem_free() free the memory(per_nest_pmu_arr),
+which is allocated by successfully registered nest units.
+
+The call trace is generated in a scenario where core-imc
+initialization is made to fail and a cpuhotplug is performed in a p9
+system. During cpuhotplug ppc_nest_imc_cpu_offline() tries to access
+per_nest_pmu_arr, which is already freed by core-imc.
+
+ NIP [c000000000cb6a94] mutex_lock+0x34/0x90
+ LR [c000000000cb6a88] mutex_lock+0x28/0x90
+ Call Trace:
+ mutex_lock+0x28/0x90 (unreliable)
+ perf_pmu_migrate_context+0x90/0x3a0
+ ppc_nest_imc_cpu_offline+0x190/0x1f0
+ cpuhp_invoke_callback+0x160/0x820
+ cpuhp_thread_fun+0x1bc/0x270
+ smpboot_thread_fn+0x250/0x290
+ kthread+0x1a8/0x1b0
+ ret_from_kernel_thread+0x5c/0x74
+
+To address this scenario do the kfree(per_nest_pmu_arr) only in case
+of nest-imc initialization failure, and when there is no other nest
+units registered.
+
+Fixes: 73ce9aec65b1 ("powerpc/perf: Fix IMC_MAX_PMU macro")
+Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
+Reviewed-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
+Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
+Cc: Andrew Donnellan <ajd@linux.ibm.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ arch/powerpc/perf/imc-pmu.c | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+--- a/arch/powerpc/perf/imc-pmu.c
++++ b/arch/powerpc/perf/imc-pmu.c
+@@ -1189,6 +1189,7 @@ static void imc_common_cpuhp_mem_free(st
+ if (nest_pmus == 1) {
+ cpuhp_remove_state(CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE);
+ kfree(nest_imc_refc);
++ kfree(per_nest_pmu_arr);
+ }
+
+ if (nest_pmus > 0)
+@@ -1213,7 +1214,6 @@ static void imc_common_cpuhp_mem_free(st
+ kfree(pmu_ptr->attr_groups[IMC_EVENT_ATTR]->attrs);
+ kfree(pmu_ptr->attr_groups[IMC_EVENT_ATTR]);
+ kfree(pmu_ptr);
+- kfree(per_nest_pmu_arr);
+ return;
+ }
+
+@@ -1327,6 +1327,8 @@ int init_imc_pmu(struct device_node *par
+ ret = nest_pmu_cpumask_init();
+ if (ret) {
+ mutex_unlock(&nest_init_lock);
++ kfree(nest_imc_refc);
++ kfree(per_nest_pmu_arr);
+ goto err_free;
+ }
+ }
projects / thirdparty / kernel / stable-queue.git / commitdiff
