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author | Cody P Schafer <cody@linux.vnet.ibm.com> | 2014-03-14 05:00:42 (GMT) |
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committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2014-03-23 22:48:32 (GMT) |
commit | 0e93a6edd9de7000d36788b1b8985efa610b698d (patch) | |
tree | e64f4c00f61a706dc23a48995b3ce3258b0c0d88 /arch | |
parent | 220a0c609ad173f0130d7ecffbc70e5a9f8d2061 (diff) | |
download | linux-0e93a6edd9de7000d36788b1b8985efa610b698d.tar.xz |
powerpc/perf: Add support for the hv 24x7 interface
This provides a basic interface between hv_24x7 and perf. Similar to
the one provided for gpci, it lacks transaction support and does not
list any events.
Example usage via perf tool:
perf stat -e 'hv_24x7/domain=2,offset=8,starting_index=0,lpar=0xffffffff/' -r 0 -C 0 -x ' ' sleep 0.1
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/powerpc/perf/hv-24x7.c | 510 |
1 files changed, 510 insertions, 0 deletions
diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c new file mode 100644 index 0000000..297c9105 --- /dev/null +++ b/arch/powerpc/perf/hv-24x7.c @@ -0,0 +1,510 @@ +/* + * Hypervisor supplied "24x7" performance counter support + * + * Author: Cody P Schafer <cody@linux.vnet.ibm.com> + * Copyright 2014 IBM Corporation. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#define pr_fmt(fmt) "hv-24x7: " fmt + +#include <linux/perf_event.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <asm/firmware.h> +#include <asm/hvcall.h> +#include <asm/io.h> + +#include "hv-24x7.h" +#include "hv-24x7-catalog.h" +#include "hv-common.h" + +/* + * TODO: Merging events: + * - Think of the hcall as an interface to a 4d array of counters: + * - x = domains + * - y = indexes in the domain (core, chip, vcpu, node, etc) + * - z = offset into the counter space + * - w = lpars (guest vms, "logical partitions") + * - A single request is: x,y,y_last,z,z_last,w,w_last + * - this means we can retrieve a rectangle of counters in y,z for a single x. + * + * - Things to consider (ignoring w): + * - input cost_per_request = 16 + * - output cost_per_result(ys,zs) = 8 + 8 * ys + ys * zs + * - limited number of requests per hcall (must fit into 4K bytes) + * - 4k = 16 [buffer header] - 16 [request size] * request_count + * - 255 requests per hcall + * - sometimes it will be more efficient to read extra data and discard + */ + +/* + * Example usage: + * perf stat -e 'hv_24x7/domain=2,offset=8,starting_index=0,lpar=0xffffffff/' + */ + +/* u3 0-6, one of HV_24X7_PERF_DOMAIN */ +EVENT_DEFINE_RANGE_FORMAT(domain, config, 0, 3); +/* u16 */ +EVENT_DEFINE_RANGE_FORMAT(starting_index, config, 16, 31); +/* u32, see "data_offset" */ +EVENT_DEFINE_RANGE_FORMAT(offset, config, 32, 63); +/* u16 */ +EVENT_DEFINE_RANGE_FORMAT(lpar, config1, 0, 15); + +EVENT_DEFINE_RANGE(reserved1, config, 4, 15); +EVENT_DEFINE_RANGE(reserved2, config1, 16, 63); +EVENT_DEFINE_RANGE(reserved3, config2, 0, 63); + +static struct attribute *format_attrs[] = { + &format_attr_domain.attr, + &format_attr_offset.attr, + &format_attr_starting_index.attr, + &format_attr_lpar.attr, + NULL, +}; + +static struct attribute_group format_group = { + .name = "format", + .attrs = format_attrs, +}; + +static struct kmem_cache *hv_page_cache; + +/* + * read_offset_data - copy data from one buffer to another while treating the + * source buffer as a small view on the total avaliable + * source data. + * + * @dest: buffer to copy into + * @dest_len: length of @dest in bytes + * @requested_offset: the offset within the source data we want. Must be > 0 + * @src: buffer to copy data from + * @src_len: length of @src in bytes + * @source_offset: the offset in the sorce data that (src,src_len) refers to. + * Must be > 0 + * + * returns the number of bytes copied. + * + * The following ascii art shows the various buffer possitioning we need to + * handle, assigns some arbitrary varibles to points on the buffer, and then + * shows how we fiddle with those values to get things we care about (copy + * start in src and copy len) + * + * s = @src buffer + * d = @dest buffer + * '.' areas in d are written to. + * + * u + * x w v z + * d |.........| + * s |----------------------| + * + * u + * x w z v + * d |........------| + * s |------------------| + * + * x w u,z,v + * d |........| + * s |------------------| + * + * x,w u,v,z + * d |..................| + * s |------------------| + * + * x u + * w v z + * d |........| + * s |------------------| + * + * x z w v + * d |------| + * s |------| + * + * x = source_offset + * w = requested_offset + * z = source_offset + src_len + * v = requested_offset + dest_len + * + * w_offset_in_s = w - x = requested_offset - source_offset + * z_offset_in_s = z - x = src_len + * v_offset_in_s = v - x = request_offset + dest_len - src_len + */ +static ssize_t read_offset_data(void *dest, size_t dest_len, + loff_t requested_offset, void *src, + size_t src_len, loff_t source_offset) +{ + size_t w_offset_in_s = requested_offset - source_offset; + size_t z_offset_in_s = src_len; + size_t v_offset_in_s = requested_offset + dest_len - src_len; + size_t u_offset_in_s = min(z_offset_in_s, v_offset_in_s); + size_t copy_len = u_offset_in_s - w_offset_in_s; + + if (requested_offset < 0 || source_offset < 0) + return -EINVAL; + + if (z_offset_in_s <= w_offset_in_s) + return 0; + + memcpy(dest, src + w_offset_in_s, copy_len); + return copy_len; +} + +static unsigned long h_get_24x7_catalog_page(char page[static 4096], + u32 version, u32 index) +{ + WARN_ON(!IS_ALIGNED((unsigned long)page, 4096)); + return plpar_hcall_norets(H_GET_24X7_CATALOG_PAGE, + virt_to_phys(page), + version, + index); +} + +static ssize_t catalog_read(struct file *filp, struct kobject *kobj, + struct bin_attribute *bin_attr, char *buf, + loff_t offset, size_t count) +{ + unsigned long hret; + ssize_t ret = 0; + size_t catalog_len = 0, catalog_page_len = 0, page_count = 0; + loff_t page_offset = 0; + uint32_t catalog_version_num = 0; + void *page = kmem_cache_alloc(hv_page_cache, GFP_USER); + struct hv_24x7_catalog_page_0 *page_0 = page; + if (!page) + return -ENOMEM; + + hret = h_get_24x7_catalog_page(page, 0, 0); + if (hret) { + ret = -EIO; + goto e_free; + } + + catalog_version_num = be32_to_cpu(page_0->version); + catalog_page_len = be32_to_cpu(page_0->length); + catalog_len = catalog_page_len * 4096; + + page_offset = offset / 4096; + page_count = count / 4096; + + if (page_offset >= catalog_page_len) + goto e_free; + + if (page_offset != 0) { + hret = h_get_24x7_catalog_page(page, catalog_version_num, + page_offset); + if (hret) { + ret = -EIO; + goto e_free; + } + } + + ret = read_offset_data(buf, count, offset, + page, 4096, page_offset * 4096); +e_free: + if (hret) + pr_err("h_get_24x7_catalog_page(ver=%d, page=%lld) failed: rc=%ld\n", + catalog_version_num, page_offset, hret); + kfree(page); + + pr_devel("catalog_read: offset=%lld(%lld) count=%zu(%zu) catalog_len=%zu(%zu) => %zd\n", + offset, page_offset, count, page_count, catalog_len, + catalog_page_len, ret); + + return ret; +} + +#define PAGE_0_ATTR(_name, _fmt, _expr) \ +static ssize_t _name##_show(struct device *dev, \ + struct device_attribute *dev_attr, \ + char *buf) \ +{ \ + unsigned long hret; \ + ssize_t ret = 0; \ + void *page = kmem_cache_alloc(hv_page_cache, GFP_USER); \ + struct hv_24x7_catalog_page_0 *page_0 = page; \ + if (!page) \ + return -ENOMEM; \ + hret = h_get_24x7_catalog_page(page, 0, 0); \ + if (hret) { \ + ret = -EIO; \ + goto e_free; \ + } \ + ret = sprintf(buf, _fmt, _expr); \ +e_free: \ + kfree(page); \ + return ret; \ +} \ +static DEVICE_ATTR_RO(_name) + +PAGE_0_ATTR(catalog_version, "%lld\n", + (unsigned long long)be32_to_cpu(page_0->version)); +PAGE_0_ATTR(catalog_len, "%lld\n", + (unsigned long long)be32_to_cpu(page_0->length) * 4096); +static BIN_ATTR_RO(catalog, 0/* real length varies */); + +static struct bin_attribute *if_bin_attrs[] = { + &bin_attr_catalog, + NULL, +}; + +static struct attribute *if_attrs[] = { + &dev_attr_catalog_len.attr, + &dev_attr_catalog_version.attr, + NULL, +}; + +static struct attribute_group if_group = { + .name = "interface", + .bin_attrs = if_bin_attrs, + .attrs = if_attrs, +}; + +static const struct attribute_group *attr_groups[] = { + &format_group, + &if_group, + NULL, +}; + +static bool is_physical_domain(int domain) +{ + return domain == HV_24X7_PERF_DOMAIN_PHYSICAL_CHIP || + domain == HV_24X7_PERF_DOMAIN_PHYSICAL_CORE; +} + +static unsigned long single_24x7_request(u8 domain, u32 offset, u16 ix, + u16 lpar, u64 *res, + bool success_expected) +{ + unsigned long ret; + + /* + * request_buffer and result_buffer are not required to be 4k aligned, + * but are not allowed to cross any 4k boundary. Aligning them to 4k is + * the simplest way to ensure that. + */ + struct reqb { + struct hv_24x7_request_buffer buf; + struct hv_24x7_request req; + } __packed __aligned(4096) request_buffer = { + .buf = { + .interface_version = HV_24X7_IF_VERSION_CURRENT, + .num_requests = 1, + }, + .req = { + .performance_domain = domain, + .data_size = cpu_to_be16(8), + .data_offset = cpu_to_be32(offset), + .starting_lpar_ix = cpu_to_be16(lpar), + .max_num_lpars = cpu_to_be16(1), + .starting_ix = cpu_to_be16(ix), + .max_ix = cpu_to_be16(1), + } + }; + + struct resb { + struct hv_24x7_data_result_buffer buf; + struct hv_24x7_result res; + struct hv_24x7_result_element elem; + __be64 result; + } __packed __aligned(4096) result_buffer = {}; + + ret = plpar_hcall_norets(H_GET_24X7_DATA, + virt_to_phys(&request_buffer), sizeof(request_buffer), + virt_to_phys(&result_buffer), sizeof(result_buffer)); + + if (ret) { + if (success_expected) + pr_err_ratelimited("hcall failed: %d %#x %#x %d => 0x%lx (%ld) detail=0x%x failing ix=%x\n", + domain, offset, ix, lpar, + ret, ret, + result_buffer.buf.detailed_rc, + result_buffer.buf.failing_request_ix); + return ret; + } + + *res = be64_to_cpu(result_buffer.result); + return ret; +} + +static unsigned long event_24x7_request(struct perf_event *event, u64 *res, + bool success_expected) +{ + return single_24x7_request(event_get_domain(event), + event_get_offset(event), + event_get_starting_index(event), + event_get_lpar(event), + res, + success_expected); +} + +static int h_24x7_event_init(struct perf_event *event) +{ + struct hv_perf_caps caps; + unsigned domain; + unsigned long hret; + u64 ct; + + /* Not our event */ + if (event->attr.type != event->pmu->type) + return -ENOENT; + + /* Unused areas must be 0 */ + if (event_get_reserved1(event) || + event_get_reserved2(event) || + event_get_reserved3(event)) { + pr_devel("reserved set when forbidden 0x%llx(0x%llx) 0x%llx(0x%llx) 0x%llx(0x%llx)\n", + event->attr.config, + event_get_reserved1(event), + event->attr.config1, + event_get_reserved2(event), + event->attr.config2, + event_get_reserved3(event)); + return -EINVAL; + } + + /* unsupported modes and filters */ + if (event->attr.exclude_user || + event->attr.exclude_kernel || + event->attr.exclude_hv || + event->attr.exclude_idle || + event->attr.exclude_host || + event->attr.exclude_guest || + is_sampling_event(event)) /* no sampling */ + return -EINVAL; + + /* no branch sampling */ + if (has_branch_stack(event)) + return -EOPNOTSUPP; + + /* offset must be 8 byte aligned */ + if (event_get_offset(event) % 8) { + pr_devel("bad alignment\n"); + return -EINVAL; + } + + /* Domains above 6 are invalid */ + domain = event_get_domain(event); + if (domain > 6) { + pr_devel("invalid domain %d\n", domain); + return -EINVAL; + } + + hret = hv_perf_caps_get(&caps); + if (hret) { + pr_devel("could not get capabilities: rc=%ld\n", hret); + return -EIO; + } + + /* PHYSICAL domains & other lpars require extra capabilities */ + if (!caps.collect_privileged && (is_physical_domain(domain) || + (event_get_lpar(event) != event_get_lpar_max()))) { + pr_devel("hv permisions disallow: is_physical_domain:%d, lpar=0x%llx\n", + is_physical_domain(domain), + event_get_lpar(event)); + return -EACCES; + } + + /* see if the event complains */ + if (event_24x7_request(event, &ct, false)) { + pr_devel("test hcall failed\n"); + return -EIO; + } + + return 0; +} + +static u64 h_24x7_get_value(struct perf_event *event) +{ + unsigned long ret; + u64 ct; + ret = event_24x7_request(event, &ct, true); + if (ret) + /* We checked this in event init, shouldn't fail here... */ + return 0; + + return ct; +} + +static void h_24x7_event_update(struct perf_event *event) +{ + s64 prev; + u64 now; + now = h_24x7_get_value(event); + prev = local64_xchg(&event->hw.prev_count, now); + local64_add(now - prev, &event->count); +} + +static void h_24x7_event_start(struct perf_event *event, int flags) +{ + if (flags & PERF_EF_RELOAD) + local64_set(&event->hw.prev_count, h_24x7_get_value(event)); +} + +static void h_24x7_event_stop(struct perf_event *event, int flags) +{ + h_24x7_event_update(event); +} + +static int h_24x7_event_add(struct perf_event *event, int flags) +{ + if (flags & PERF_EF_START) + h_24x7_event_start(event, flags); + + return 0; +} + +static int h_24x7_event_idx(struct perf_event *event) +{ + return 0; +} + +static struct pmu h_24x7_pmu = { + .task_ctx_nr = perf_invalid_context, + + .name = "hv_24x7", + .attr_groups = attr_groups, + .event_init = h_24x7_event_init, + .add = h_24x7_event_add, + .del = h_24x7_event_stop, + .start = h_24x7_event_start, + .stop = h_24x7_event_stop, + .read = h_24x7_event_update, + .event_idx = h_24x7_event_idx, +}; + +static int hv_24x7_init(void) +{ + int r; + unsigned long hret; + struct hv_perf_caps caps; + + if (!firmware_has_feature(FW_FEATURE_LPAR)) { + pr_info("not a virtualized system, not enabling\n"); + return -ENODEV; + } + + hret = hv_perf_caps_get(&caps); + if (hret) { + pr_info("could not obtain capabilities, error 0x%80lx, not enabling\n", + hret); + return -ENODEV; + } + + hv_page_cache = kmem_cache_create("hv-page-4096", 4096, 4096, 0, NULL); + if (!hv_page_cache) + return -ENOMEM; + + r = perf_pmu_register(&h_24x7_pmu, h_24x7_pmu.name, -1); + if (r) + return r; + + return 0; +} + +device_initcall(hv_24x7_init); |