From e4f226b1580b36550727c324b404207f8d2f3b71 Mon Sep 17 00:00:00 2001 From: Sukadev Bhattiprolu Date: Tue, 9 Feb 2016 02:47:45 -0500 Subject: [PATCH] powerpc/perf/hv-gpci: Increase request buffer size The GPCI hcall allows for a 4K buffer but we limit the buffer to 1K. The problem with a 1K buffer is if a request results in returning more values than can be accomodated in the 1K buffer the request will fail. The buffer we are using is currently allocated on the stack and hence limited in size. Instead use a per-CPU 4K buffer like we do with 24x7 counters (hv-24x7.c). While here, rename the macro GPCI_MAX_DATA_BYTES to HGPCI_MAX_DATA_BYTES for consistency with 24x7 counters. Signed-off-by: Sukadev Bhattiprolu Signed-off-by: Michael Ellerman --- arch/powerpc/perf/hv-gpci.c | 43 +++++++++++++++++++++---------------- 1 file changed, 25 insertions(+), 18 deletions(-) diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c index 856fe6e03c2a..7aa37236bb70 100644 --- a/arch/powerpc/perf/hv-gpci.c +++ b/arch/powerpc/perf/hv-gpci.c @@ -127,8 +127,16 @@ static const struct attribute_group *attr_groups[] = { NULL, }; -#define GPCI_MAX_DATA_BYTES \ - (1024 - sizeof(struct hv_get_perf_counter_info_params)) +#define HGPCI_REQ_BUFFER_SIZE 4096 +#define HGPCI_MAX_DATA_BYTES \ + (HGPCI_REQ_BUFFER_SIZE - sizeof(struct hv_get_perf_counter_info_params)) + +DEFINE_PER_CPU(char, hv_gpci_reqb[HGPCI_REQ_BUFFER_SIZE]) __aligned(sizeof(uint64_t)); + +struct hv_gpci_request_buffer { + struct hv_get_perf_counter_info_params params; + uint8_t bytes[HGPCI_MAX_DATA_BYTES]; +} __packed; static unsigned long single_gpci_request(u32 req, u32 starting_index, u16 secondary_index, u8 version_in, u32 offset, u8 length, @@ -137,24 +145,21 @@ static unsigned long single_gpci_request(u32 req, u32 starting_index, unsigned long ret; size_t i; u64 count; + struct hv_gpci_request_buffer *arg; + + arg = (void *)get_cpu_var(hv_gpci_reqb); + memset(arg, 0, HGPCI_REQ_BUFFER_SIZE); - struct { - struct hv_get_perf_counter_info_params params; - uint8_t bytes[GPCI_MAX_DATA_BYTES]; - } __packed __aligned(sizeof(uint64_t)) arg = { - .params = { - .counter_request = cpu_to_be32(req), - .starting_index = cpu_to_be32(starting_index), - .secondary_index = cpu_to_be16(secondary_index), - .counter_info_version_in = version_in, - } - }; + arg->params.counter_request = cpu_to_be32(req); + arg->params.starting_index = cpu_to_be32(starting_index); + arg->params.secondary_index = cpu_to_be16(secondary_index); + arg->params.counter_info_version_in = version_in; ret = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO, - virt_to_phys(&arg), sizeof(arg)); + virt_to_phys(arg), HGPCI_REQ_BUFFER_SIZE); if (ret) { pr_devel("hcall failed: 0x%lx\n", ret); - return ret; + goto out; } /* @@ -163,9 +168,11 @@ static unsigned long single_gpci_request(u32 req, u32 starting_index, */ count = 0; for (i = offset; i < offset + length; i++) - count |= arg.bytes[i] << (i - offset); + count |= arg->bytes[i] << (i - offset); *value = count; +out: + put_cpu_var(hv_gpci_reqb); return ret; } @@ -245,10 +252,10 @@ static int h_gpci_event_init(struct perf_event *event) } /* last byte within the buffer? */ - if ((event_get_offset(event) + length) > GPCI_MAX_DATA_BYTES) { + if ((event_get_offset(event) + length) > HGPCI_MAX_DATA_BYTES) { pr_devel("request outside of buffer: %zu > %zu\n", (size_t)event_get_offset(event) + length, - GPCI_MAX_DATA_BYTES); + HGPCI_MAX_DATA_BYTES); return -EINVAL; } -- 2.20.1