diff options
Diffstat (limited to 'gdb/nat')
| -rw-r--r-- | gdb/nat/linux-btrace.c | 39 |
1 files changed, 30 insertions, 9 deletions
diff --git a/gdb/nat/linux-btrace.c b/gdb/nat/linux-btrace.c index e827e92..62c0acf 100644 --- a/gdb/nat/linux-btrace.c +++ b/gdb/nat/linux-btrace.c @@ -398,11 +398,12 @@ linux_supports_btrace (struct target_ops *ops, enum btrace_format format) /* Enable branch tracing in BTS format. */ static struct btrace_target_info * -linux_enable_bts (ptid_t ptid, const struct btrace_config *conf) +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; int pid, pg; tinfo = xzalloc (sizeof (*tinfo)); @@ -433,14 +434,33 @@ linux_enable_bts (ptid_t ptid, const struct btrace_config *conf) if (bts->file < 0) goto err; - /* We try to allocate as much buffer as we can get. - We could allow the user to specify the size of the buffer, but then - we'd leave this search for the maximum buffer size to him. */ - for (pg = 4; pg >= 0; --pg) + /* Convert the requested size in bytes to pages (rounding up). */ + pages = (((unsigned long long) conf->size) + PAGE_SIZE - 1) / PAGE_SIZE; + /* We need at least one page. */ + if (pages == 0) + pages = 1; + + /* The buffer size can be requested in powers of two pages. Adjust PAGES + to the next power of two. */ + for (pg = 0; pages != (1u << pg); ++pg) + if ((pages & (1u << pg)) != 0) + pages += (1u << pg); + + /* We try to allocate the requested size. + If that fails, try to get as much as we can. */ + for (; pages > 0; pages >>= 1) { + size_t length; + + size = pages * PAGE_SIZE; + length = size + PAGE_SIZE; + + /* Check for overflows. */ + if ((unsigned long long) length < size) + continue; + /* The number of pages we request needs to be a power of two. */ - header = mmap (NULL, ((1 << pg) + 1) * PAGE_SIZE, PROT_READ, MAP_SHARED, - bts->file, 0); + header = mmap (NULL, length, PROT_READ, MAP_SHARED, bts->file, 0); if (header != MAP_FAILED) break; } @@ -450,10 +470,11 @@ linux_enable_bts (ptid_t ptid, const struct btrace_config *conf) bts->header = header; bts->bts.mem = ((const uint8_t *) header) + PAGE_SIZE; - bts->bts.size = (1 << pg) * PAGE_SIZE; + bts->bts.size = size; bts->bts.data_head = &header->data_head; bts->bts.last_head = 0; + tinfo->conf.bts.size = size; return tinfo; err_file: @@ -479,7 +500,7 @@ linux_enable_btrace (ptid_t ptid, const struct btrace_config *conf) break; case BTRACE_FORMAT_BTS: - tinfo = linux_enable_bts (ptid, conf); + tinfo = linux_enable_bts (ptid, &conf->bts); break; } |