On 8/8/25 1:14 AM, Manos Pitsidianakis wrote:
On Fri, 08 Aug 2025 05:06, Pierrick Bouvier <pierrick.bouv...@linaro.org> wrote:
We define a scoreboard that will hold our data per cpu. As well, we
define a buffer per cpu that will be used to read registers and memories
in a thread-safe way.
For now, we just instrument all instructions with an empty callback.
Signed-off-by: Pierrick Bouvier <pierrick.bouv...@linaro.org>
---
contrib/plugins/uftrace.c | 74 +++++++++++++++++++++++++++++++++++++
contrib/plugins/meson.build | 3 +-
2 files changed, 76 insertions(+), 1 deletion(-)
create mode 100644 contrib/plugins/uftrace.c
diff --git a/contrib/plugins/uftrace.c b/contrib/plugins/uftrace.c
new file mode 100644
index 00000000000..d60c1077496
--- /dev/null
+++ b/contrib/plugins/uftrace.c
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2025, Pierrick Bouvier <pierrick.bouv...@linaro.org>
+ *
+ * Generates a trace compatible with uftrace (similar to uftrace record).
+ * https://github.com/namhyung/uftrace
+ *
+ * See docs/about/emulation.rst|Uftrace for details and examples.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include <qemu-plugin.h>
+#include <glib.h>
+
+QEMU_PLUGIN_EXPORT int qemu_plugin_version = QEMU_PLUGIN_VERSION;
+
+typedef struct Cpu {
+ GByteArray *buf;
+} Cpu;
+
+static struct qemu_plugin_scoreboard *score;
+
+static void track_callstack(unsigned int cpu_index, void *udata)
+{
+}
+
+static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb)
+{
+ size_t n_insns = qemu_plugin_tb_n_insns(tb);
+
+ for (int i = 0; i < n_insns; i++) {
s/int i/size_t i/
+ struct qemu_plugin_insn *insn = qemu_plugin_tb_get_insn(tb, i);
This can return NULL,
+
+ uintptr_t pc = qemu_plugin_insn_vaddr(insn);
And this would lead to a NULL dereference (it performs insn->vaddr
access)
+ qemu_plugin_register_vcpu_insn_exec_cb(insn, track_callstack,
+ QEMU_PLUGIN_CB_R_REGS,
+ (void *) pc);
Hm indentation got broken here, should be
+ qemu_plugin_register_vcpu_insn_exec_cb(insn, track_callstack,
+ QEMU_PLUGIN_CB_R_REGS,
+ (void *)pc);
+
+ }
+}
+
+static void vcpu_init(qemu_plugin_id_t id, unsigned int vcpu_index)
+{
+ Cpu *cpu = qemu_plugin_scoreboard_find(score, vcpu_index);
+ cpu->buf = g_byte_array_new();
+}
+
+static void vcpu_end(unsigned int vcpu_index)
+{
+ Cpu *cpu = qemu_plugin_scoreboard_find(score, vcpu_index);
+ g_byte_array_free(cpu->buf, true);
+ memset(cpu, 0, sizeof(Cpu));
Nitpick, cpu->buf = NULL; is easier to understand (suggestion)
Looking at this twice, it does not scale with other commits, which will
free other members. That's why there was a memset in the first place.
Sorry, I rebuilt intermediate commits by reverting various parts, so it
may result in suck quirks.
+}
+
+static void at_exit(qemu_plugin_id_t id, void *data)
+{
+ for (size_t i = 0; i < qemu_plugin_num_vcpus(); ++i) {
+ vcpu_end(i);
+ }
+
+ qemu_plugin_scoreboard_free(score);
+}
+
+QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugin_id_t id,
+ const qemu_info_t *info,
+ int argc, char **argv)
+{
+ score = qemu_plugin_scoreboard_new(sizeof(Cpu));
+ qemu_plugin_register_vcpu_init_cb(id, vcpu_init);
+ qemu_plugin_register_atexit_cb(id, at_exit, NULL);
+ qemu_plugin_register_vcpu_tb_trans_cb(id, vcpu_tb_trans);
+
+ return 0;
+}
diff --git a/contrib/plugins/meson.build b/contrib/plugins/meson.build
index 1876bc78438..7eb3629c95d 100644
--- a/contrib/plugins/meson.build
+++ b/contrib/plugins/meson.build
@@ -1,5 +1,6 @@
contrib_plugins = ['bbv', 'cache', 'cflow', 'drcov', 'execlog', 'hotblocks',
- 'hotpages', 'howvec', 'hwprofile', 'ips', 'stoptrigger']
+ 'hotpages', 'howvec', 'hwprofile', 'ips', 'stoptrigger',
+ 'uftrace']
if host_os != 'windows'
# lockstep uses socket.h
contrib_plugins += 'lockstep'
--
2.47.2
If no other comments rise for this patch, you can add my r-b after
fixing the NULL check:
Reviewed-by: Manos Pitsidianakis <manos.pitsidiana...@linaro.org>
