From d91680e687f47984ffd3200c8e5d587903e7bd11 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Thu, 11 Oct 2018 11:29:14 +0100 Subject: [PATCH 1/2] arm64: Fix /proc/iomem for reserved but not memory regions We describe ranges of 'reserved' memory to userspace via /proc/iomem. Commit 50d7ba36b916 ("arm64: export memblock_reserve()d regions via /proc/iomem") updated the logic to export regions that were reserved because their contents should be preserved. This allowed kexec-tools to tell the difference between 'reserved' memory that must be preserved and not overwritten, (e.g. the ACPI tables), and 'nomap' memory that must not be touched without knowing the memory-attributes (e.g. RAS CPER regions). The above commit wrongly assumed that memblock_reserve() would not be used to reserve regions that aren't memory. It turns out this is exactly what early_init_dt_reserve_memory_arch() will do if it finds a DT reserved-memory that was also carved out of the memory node, which results in a WARN_ON_ONCE() and the region being reserved instead of ignored. The ramoops description on hikey and dragonboard-410c both do this, so we can't simply write this configuration off as "buggy firmware". Avoid this issue by rewriting reserve_memblock_reserved_regions() so that only the portions of reserved regions which overlap with mapped memory are actually reserved. Fixes: 50d7ba36b916 ("arm64: export memblock_reserve()d regions via /proc/iomem") Reported-by: John Stultz Reported-by: Paolo Pisati CC: Akashi Takahiro CC: Ard Biesheuvel Reviewed-by: James Morse Signed-off-by: Will Deacon --- arch/arm64/kernel/setup.c | 56 +++++++++++++++++++-------------------- 1 file changed, 27 insertions(+), 29 deletions(-) diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index 5b4fac434c841..b3354ff94e798 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -64,6 +64,9 @@ #include #include +static int num_standard_resources; +static struct resource *standard_resources; + phys_addr_t __fdt_pointer __initdata; /* @@ -206,14 +209,19 @@ static void __init request_standard_resources(void) { struct memblock_region *region; struct resource *res; + unsigned long i = 0; kernel_code.start = __pa_symbol(_text); kernel_code.end = __pa_symbol(__init_begin - 1); kernel_data.start = __pa_symbol(_sdata); kernel_data.end = __pa_symbol(_end - 1); + num_standard_resources = memblock.memory.cnt; + standard_resources = alloc_bootmem_low(num_standard_resources * + sizeof(*standard_resources)); + for_each_memblock(memory, region) { - res = alloc_bootmem_low(sizeof(*res)); + res = &standard_resources[i++]; if (memblock_is_nomap(region)) { res->name = "reserved"; res->flags = IORESOURCE_MEM; @@ -243,36 +251,26 @@ static void __init request_standard_resources(void) static int __init reserve_memblock_reserved_regions(void) { - phys_addr_t start, end, roundup_end = 0; - struct resource *mem, *res; - u64 i; - - for_each_reserved_mem_region(i, &start, &end) { - if (end <= roundup_end) - continue; /* done already */ - - start = __pfn_to_phys(PFN_DOWN(start)); - end = __pfn_to_phys(PFN_UP(end)) - 1; - roundup_end = end; - - res = kzalloc(sizeof(*res), GFP_ATOMIC); - if (WARN_ON(!res)) - return -ENOMEM; - res->start = start; - res->end = end; - res->name = "reserved"; - res->flags = IORESOURCE_MEM; - - mem = request_resource_conflict(&iomem_resource, res); - /* - * We expected memblock_reserve() regions to conflict with - * memory created by request_standard_resources(). - */ - if (WARN_ON_ONCE(!mem)) + u64 i, j; + + for (i = 0; i < num_standard_resources; ++i) { + struct resource *mem = &standard_resources[i]; + phys_addr_t r_start, r_end, mem_size = resource_size(mem); + + if (!memblock_is_region_reserved(mem->start, mem_size)) continue; - kfree(res); - reserve_region_with_split(mem, start, end, "reserved"); + for_each_reserved_mem_region(j, &r_start, &r_end) { + resource_size_t start, end; + + start = max(PFN_PHYS(PFN_DOWN(r_start)), mem->start); + end = min(PFN_PHYS(PFN_UP(r_end)) - 1, mem->end); + + if (start > mem->end || end < mem->start) + continue; + + reserve_region_with_split(mem, start, end, "reserved"); + } } return 0; From ca2b497253ad01c80061a1f3ee9eb91b5d54a849 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 5 Oct 2018 13:24:36 +0100 Subject: [PATCH 2/2] arm64: perf: Reject stand-alone CHAIN events for PMUv3 It doesn't make sense for a perf event to be configured as a CHAIN event in isolation, so extend the arm_pmu structure with a ->filter_match() function to allow the backend PMU implementation to reject CHAIN events early. Cc: Reviewed-by: Suzuki K Poulose Signed-off-by: Will Deacon --- arch/arm64/kernel/perf_event.c | 7 +++++++ drivers/perf/arm_pmu.c | 8 +++++++- include/linux/perf/arm_pmu.h | 1 + 3 files changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c index 8e38d5267f222..e213f8e867f65 100644 --- a/arch/arm64/kernel/perf_event.c +++ b/arch/arm64/kernel/perf_event.c @@ -966,6 +966,12 @@ static int armv8pmu_set_event_filter(struct hw_perf_event *event, return 0; } +static int armv8pmu_filter_match(struct perf_event *event) +{ + unsigned long evtype = event->hw.config_base & ARMV8_PMU_EVTYPE_EVENT; + return evtype != ARMV8_PMUV3_PERFCTR_CHAIN; +} + static void armv8pmu_reset(void *info) { struct arm_pmu *cpu_pmu = (struct arm_pmu *)info; @@ -1114,6 +1120,7 @@ static int armv8_pmu_init(struct arm_pmu *cpu_pmu) cpu_pmu->stop = armv8pmu_stop, cpu_pmu->reset = armv8pmu_reset, cpu_pmu->set_event_filter = armv8pmu_set_event_filter; + cpu_pmu->filter_match = armv8pmu_filter_match; return 0; } diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c index 7f01f6f60b870..d0b7dd8fb184b 100644 --- a/drivers/perf/arm_pmu.c +++ b/drivers/perf/arm_pmu.c @@ -485,7 +485,13 @@ static int armpmu_filter_match(struct perf_event *event) { struct arm_pmu *armpmu = to_arm_pmu(event->pmu); unsigned int cpu = smp_processor_id(); - return cpumask_test_cpu(cpu, &armpmu->supported_cpus); + int ret; + + ret = cpumask_test_cpu(cpu, &armpmu->supported_cpus); + if (ret && armpmu->filter_match) + return armpmu->filter_match(event); + + return ret; } static ssize_t armpmu_cpumask_show(struct device *dev, diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h index 10f92e1d8e7bb..bf309ff6f2444 100644 --- a/include/linux/perf/arm_pmu.h +++ b/include/linux/perf/arm_pmu.h @@ -99,6 +99,7 @@ struct arm_pmu { void (*stop)(struct arm_pmu *); void (*reset)(void *); int (*map_event)(struct perf_event *event); + int (*filter_match)(struct perf_event *event); int num_events; bool secure_access; /* 32-bit ARM only */ #define ARMV8_PMUV3_MAX_COMMON_EVENTS 0x40