From 010a18a1b12ec6d5219b7e602aa6abe12344dd1a Mon Sep 17 00:00:00 2001 From: Markus Metzger Date: Mon, 17 Nov 2014 11:18:05 +0100 Subject: [PATCH] btrace, linux: use data_size and data_offset In struct perf_event_mmap_page there are new fields data_size and data_offset that give the location of the perf_event data buffer relative to the mmap page. Use them if they are present. gdb/ * nat/linux-btrace.c (linux_enable_bts): Check for PERF_ATTR_SIZE_VER5. Check for data_offset and data_size fields. Use them. --- gdb/ChangeLog | 6 ++++++ gdb/nat/linux-btrace.c | 21 ++++++++++++++++----- 2 files changed, 22 insertions(+), 5 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 4c96e8a459d..a4cce4d43e0 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2015-07-02 Markus Metzger + + * nat/linux-btrace.c (linux_enable_bts): Check for + PERF_ATTR_SIZE_VER5. + Check for data_offset and data_size fields. Use them. + 2015-07-02 Markus Metzger * NEWS: Announce new commands "record btrace pt" and "record pt". diff --git a/gdb/nat/linux-btrace.c b/gdb/nat/linux-btrace.c index ddd79a32974..3b630f53801 100644 --- a/gdb/nat/linux-btrace.c +++ b/gdb/nat/linux-btrace.c @@ -642,7 +642,7 @@ linux_enable_bts (ptid_t ptid, const struct btrace_config_bts *conf) struct perf_event_mmap_page *header; struct btrace_target_info *tinfo; struct btrace_tinfo_bts *bts; - unsigned long long size, pages; + unsigned long long size, pages, data_offset, data_size; int pid, pg; tinfo = xzalloc (sizeof (*tinfo)); @@ -704,16 +704,27 @@ linux_enable_bts (ptid_t ptid, const struct btrace_config_bts *conf) break; } - if (header == MAP_FAILED) + if (pages == 0) goto err_file; + data_offset = PAGE_SIZE; + data_size = size; + +#if defined (PERF_ATTR_SIZE_VER5) + if (offsetof (struct perf_event_mmap_page, data_size) <= header->size) + { + data_offset = header->data_offset; + data_size = header->data_size; + } +#endif /* defined (PERF_ATTR_SIZE_VER5) */ + bts->header = header; - bts->bts.mem = ((const uint8_t *) header) + PAGE_SIZE; - bts->bts.size = size; + bts->bts.mem = ((const uint8_t *) header) + data_offset; + bts->bts.size = data_size; bts->bts.data_head = &header->data_head; bts->bts.last_head = 0; - tinfo->conf.bts.size = size; + tinfo->conf.bts.size = data_size; return tinfo; err_file: -- 2.30.2