[tip: perf/core] perf dso: Add dso__data_write_cache_addr()

From: tip-bot2 for Adrian Hunter
Date: Tue Nov 12 2019 - 06:20:33 EST

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The following commit has been merged into the perf/core branch of tip:

Commit-ID: b86a9d918a389162803d833d4dc491fde9b62fa2
Gitweb: https://git.kernel.org/tip/b86a9d918a389162803d833d4dc491fde9b62fa2
Author: Adrian Hunter <adrian.hunter@xxxxxxxxx>
AuthorDate: Fri, 25 Oct 2019 15:59:57 +03:00
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitterDate: Wed, 06 Nov 2019 15:43:06 -03:00

perf dso: Add dso__data_write_cache_addr()

Add functions to write into the dso file data cache, but not change the
file itself.

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Leo Yan <leo.yan@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: x86@xxxxxxxxxx
Link: http://lore.kernel.org/lkml/20191025130000.13032-4-adrian.hunter@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/dso.c | 73 +++++++++++++++++++++++++++++++++---------
tools/perf/util/dso.h | 7 ++++-
2 files changed, 65 insertions(+), 15 deletions(-)

diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 460330d..0f1b772 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -827,14 +827,16 @@ out:
return cache;
}

-static ssize_t
-dso_cache__memcpy(struct dso_cache *cache, u64 offset,
- u8 *data, u64 size)
+static ssize_t dso_cache__memcpy(struct dso_cache *cache, u64 offset, u8 *data,
+ u64 size, bool out)
{
u64 cache_offset = offset - cache->offset;
u64 cache_size = min(cache->size - cache_offset, size);

- memcpy(data, cache->data + cache_offset, cache_size);
+ if (out)
+ memcpy(data, cache->data + cache_offset, cache_size);
+ else
+ memcpy(cache->data + cache_offset, data, cache_size);
return cache_size;
}

@@ -910,8 +912,8 @@ static struct dso_cache *dso_cache__find(struct dso *dso,
return cache ? cache : dso_cache__populate(dso, machine, offset, ret);
}

-static ssize_t dso_cache_read(struct dso *dso, struct machine *machine,
- u64 offset, u8 *data, ssize_t size)
+static ssize_t dso_cache_io(struct dso *dso, struct machine *machine,
+ u64 offset, u8 *data, ssize_t size, bool out)
{
struct dso_cache *cache;
ssize_t ret = 0;
@@ -920,16 +922,16 @@ static ssize_t dso_cache_read(struct dso *dso, struct machine *machine,
if (!cache)
return ret;

- return dso_cache__memcpy(cache, offset, data, size);
+ return dso_cache__memcpy(cache, offset, data, size, out);
}

/*
* Reads and caches dso data DSO__DATA_CACHE_SIZE size chunks
* in the rb_tree. Any read to already cached data is served
- * by cached data.
+ * by cached data. Writes update the cache only, not the backing file.
*/
-static ssize_t cached_read(struct dso *dso, struct machine *machine,
- u64 offset, u8 *data, ssize_t size)
+static ssize_t cached_io(struct dso *dso, struct machine *machine,
+ u64 offset, u8 *data, ssize_t size, bool out)
{
ssize_t r = 0;
u8 *p = data;
@@ -937,7 +939,7 @@ static ssize_t cached_read(struct dso *dso, struct machine *machine,
do {
ssize_t ret;

- ret = dso_cache_read(dso, machine, offset, p, size);
+ ret = dso_cache_io(dso, machine, offset, p, size, out);
if (ret < 0)
return ret;

@@ -1021,8 +1023,9 @@ off_t dso__data_size(struct dso *dso, struct machine *machine)
return dso->data.file_size;
}

-static ssize_t data_read_offset(struct dso *dso, struct machine *machine,
- u64 offset, u8 *data, ssize_t size)
+static ssize_t data_read_write_offset(struct dso *dso, struct machine *machine,
+ u64 offset, u8 *data, ssize_t size,
+ bool out)
{
if (dso__data_file_size(dso, machine))
return -1;
@@ -1034,7 +1037,7 @@ static ssize_t data_read_offset(struct dso *dso, struct machine *machine,
if (offset + size < offset)
return -1;

- return cached_read(dso, machine, offset, data, size);
+ return cached_io(dso, machine, offset, data, size, out);
}

/**
@@ -1054,7 +1057,7 @@ ssize_t dso__data_read_offset(struct dso *dso, struct machine *machine,
if (dso->data.status == DSO_DATA_STATUS_ERROR)
return -1;

- return data_read_offset(dso, machine, offset, data, size);
+ return data_read_write_offset(dso, machine, offset, data, size, true);
}

/**
@@ -1075,6 +1078,46 @@ ssize_t dso__data_read_addr(struct dso *dso, struct map *map,
return dso__data_read_offset(dso, machine, offset, data, size);
}

+/**
+ * dso__data_write_cache_offs - Write data to dso data cache at file offset
+ * @dso: dso object
+ * @machine: machine object
+ * @offset: file offset
+ * @data: buffer to write
+ * @size: size of the @data buffer
+ *
+ * Write into the dso file data cache, but do not change the file itself.
+ */
+ssize_t dso__data_write_cache_offs(struct dso *dso, struct machine *machine,
+ u64 offset, const u8 *data_in, ssize_t size)
+{
+ u8 *data = (u8 *)data_in; /* cast away const to use same fns for r/w */
+
+ if (dso->data.status == DSO_DATA_STATUS_ERROR)
+ return -1;
+
+ return data_read_write_offset(dso, machine, offset, data, size, false);
+}
+
+/**
+ * dso__data_write_cache_addr - Write data to dso data cache at dso address
+ * @dso: dso object
+ * @machine: machine object
+ * @add: virtual memory address
+ * @data: buffer to write
+ * @size: size of the @data buffer
+ *
+ * External interface to write into the dso file data cache, but do not change
+ * the file itself.
+ */
+ssize_t dso__data_write_cache_addr(struct dso *dso, struct map *map,
+ struct machine *machine, u64 addr,
+ const u8 *data, ssize_t size)
+{
+ u64 offset = map->map_ip(map, addr);
+ return dso__data_write_cache_offs(dso, machine, offset, data, size);
+}
+
struct map *dso__new_map(const char *name)
{
struct map *map = NULL;
diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index e4dddb7..2f1fcbc 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -285,6 +285,8 @@ void dso__set_module_info(struct dso *dso, struct kmod_path *m,
* dso__data_size
* dso__data_read_offset
* dso__data_read_addr
+ * dso__data_write_cache_offs
+ * dso__data_write_cache_addr
*
* Please refer to the dso.c object code for each function and
* arguments documentation. Following text tries to explain the
@@ -332,6 +334,11 @@ ssize_t dso__data_read_addr(struct dso *dso, struct map *map,
struct machine *machine, u64 addr,
u8 *data, ssize_t size);
bool dso__data_status_seen(struct dso *dso, enum dso_data_status_seen by);
+ssize_t dso__data_write_cache_offs(struct dso *dso, struct machine *machine,
+ u64 offset, const u8 *data, ssize_t size);
+ssize_t dso__data_write_cache_addr(struct dso *dso, struct map *map,
+ struct machine *machine, u64 addr,
+ const u8 *data, ssize_t size);

struct map *dso__new_map(const char *name);
struct dso *machine__findnew_kernel(struct machine *machine, const char *name,

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