* [PATCH v3 1/1] get page size using sysconf (_SC_PAGESIZE) instead of PAGE_SIZE
2022-04-28 11:50 [PATCH v3 0/1] get page size using sysconf (_SC_PAGESIZE) instead of PAGE_SIZE Zied Guermazi
@ 2022-04-28 11:50 ` Zied Guermazi
2022-04-28 16:14 ` Pedro Alves
0 siblings, 1 reply; 4+ messages in thread
From: Zied Guermazi @ 2022-04-28 11:50 UTC (permalink / raw)
To: gdb-patches; +Cc: Zied Guermazi
PAGE_SIZE is not defined in all build configurations, e.g cross compiling
for aarch64 GNU/Linux machine. This patch gets the value at runtime using
posix call sysconf (_SC_PAGESIZE)
---
gdb/nat/linux-btrace.c | 43 ++++++++++++++++++++++++++++--------------
1 file changed, 29 insertions(+), 14 deletions(-)
diff --git a/gdb/nat/linux-btrace.c b/gdb/nat/linux-btrace.c
index b0d6dcd7cf1..82794e616dd 100644
--- a/gdb/nat/linux-btrace.c
+++ b/gdb/nat/linux-btrace.c
@@ -445,6 +445,17 @@ diagnose_perf_event_open_fail ()
error (_("Failed to start recording: %s"), safe_strerror (errno));
}
+/* Returns System page size. */
+
+static long
+system_page_size ()
+{
+ long page_size = sysconf (_SC_PAGESIZE);
+ if (page_size == -1)
+ perror_with_name (_("Failed to get system page size: %s"));
+ return page_size;
+}
+
/* Enable branch tracing in BTS format. */
static struct btrace_target_info *
@@ -486,9 +497,10 @@ linux_enable_bts (ptid_t ptid, const struct btrace_config_bts *conf)
if (fd.get () < 0)
diagnose_perf_event_open_fail ();
+ long page_size = system_page_size ();
/* Convert the requested size in bytes to pages (rounding up). */
- pages = ((size_t) conf->size / PAGE_SIZE
- + ((conf->size % PAGE_SIZE) == 0 ? 0 : 1));
+ pages = ((size_t) conf->size / page_size
+ + ((conf->size % page_size) == 0 ? 0 : 1));
/* We need at least one page. */
if (pages == 0)
pages = 1;
@@ -507,17 +519,17 @@ linux_enable_bts (ptid_t ptid, const struct btrace_config_bts *conf)
size_t length;
__u64 data_size;
- data_size = (__u64) pages * PAGE_SIZE;
+ data_size = (__u64) pages * (__u64) page_size;
/* Don't ask for more than we can represent in the configuration. */
if ((__u64) UINT_MAX < data_size)
continue;
size = (size_t) data_size;
- length = size + PAGE_SIZE;
+ length = size + (size_t) page_size;
/* Check for overflows. */
- if ((__u64) length != data_size + PAGE_SIZE)
+ if ((__u64) length != data_size + (__u64) page_size)
continue;
errno = 0;
@@ -532,7 +544,7 @@ linux_enable_bts (ptid_t ptid, const struct btrace_config_bts *conf)
struct perf_event_mmap_page *header = (struct perf_event_mmap_page *)
data.get ();
- data_offset = PAGE_SIZE;
+ data_offset = (__u64) page_size;
#if defined (PERF_ATTR_SIZE_VER5)
if (offsetof (struct perf_event_mmap_page, data_size) <= header->size)
@@ -630,8 +642,9 @@ linux_enable_pt (ptid_t ptid, const struct btrace_config_pt *conf)
diagnose_perf_event_open_fail ();
/* Allocate the configuration page. */
- scoped_mmap data (nullptr, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,
- fd.get (), 0);
+ long page_size = system_page_size ();
+ scoped_mmap data (nullptr, (size_t) page_size, PROT_READ | PROT_WRITE,
+ MAP_SHARED, fd.get (), 0);
if (data.get () == MAP_FAILED)
error (_("Failed to map trace user page: %s."), safe_strerror (errno));
@@ -641,8 +654,8 @@ linux_enable_pt (ptid_t ptid, const struct btrace_config_pt *conf)
header->aux_offset = header->data_offset + header->data_size;
/* Convert the requested size in bytes to pages (rounding up). */
- pages = ((size_t) conf->size / PAGE_SIZE
- + ((conf->size % PAGE_SIZE) == 0 ? 0 : 1));
+ pages = ((size_t) conf->size / page_size
+ + ((conf->size % page_size) == 0 ? 0 : 1));
/* We need at least one page. */
if (pages == 0)
pages = 1;
@@ -661,7 +674,7 @@ linux_enable_pt (ptid_t ptid, const struct btrace_config_pt *conf)
size_t length;
__u64 data_size;
- data_size = (__u64) pages * PAGE_SIZE;
+ data_size = (__u64) pages * (__u64) page_size;
/* Don't ask for more than we can represent in the configuration. */
if ((__u64) UINT_MAX < data_size)
@@ -732,7 +745,8 @@ linux_enable_btrace (ptid_t ptid, const struct btrace_config *conf)
static enum btrace_error
linux_disable_bts (struct btrace_tinfo_bts *tinfo)
{
- munmap((void *) tinfo->header, tinfo->bts.size + PAGE_SIZE);
+ long page_size = system_page_size ();
+ munmap ((void *) tinfo->header, (size_t) (tinfo->bts.size + page_size));
close (tinfo->file);
return BTRACE_ERR_NONE;
@@ -743,8 +757,9 @@ linux_disable_bts (struct btrace_tinfo_bts *tinfo)
static enum btrace_error
linux_disable_pt (struct btrace_tinfo_pt *tinfo)
{
- munmap((void *) tinfo->pt.mem, tinfo->pt.size);
- munmap((void *) tinfo->header, PAGE_SIZE);
+ long page_size = system_page_size ();
+ munmap ((void *) tinfo->pt.mem, tinfo->pt.size);
+ munmap ((void *) tinfo->header, (size_t) page_size);
close (tinfo->file);
return BTRACE_ERR_NONE;
--
2.25.1
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