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authorLinus Torvalds <torvalds@linux-foundation.org>2020-02-06 07:12:11 +0000
committerLinus Torvalds <torvalds@linux-foundation.org>2020-02-06 07:12:11 +0000
commite310396bb8d7db977a0e10ef7b5040e98b89c34c (patch)
tree461357ada35c637292884f0af1dc9fc41c0203ff /fs/proc
parentc1ef57a3a3f5e69e98baf89055b423da62791c13 (diff)
parenta00574036c261421721fa770ccd21a1012e1fbbd (diff)
downloadlwn-e310396bb8d7db977a0e10ef7b5040e98b89c34c.tar.gz
lwn-e310396bb8d7db977a0e10ef7b5040e98b89c34c.zip
Merge tag 'trace-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt: - Added new "bootconfig". This looks for a file appended to initrd to add boot config options, and has been discussed thoroughly at Linux Plumbers. Very useful for adding kprobes at bootup. Only enabled if "bootconfig" is on the real kernel command line. - Created dynamic event creation. Merges common code between creating synthetic events and kprobe events. - Rename perf "ring_buffer" structure to "perf_buffer" - Rename ftrace "ring_buffer" structure to "trace_buffer" Had to rename existing "trace_buffer" to "array_buffer" - Allow trace_printk() to work withing (some) tracing code. - Sort of tracing configs to be a little better organized - Fixed bug where ftrace_graph hash was not being protected properly - Various other small fixes and clean ups * tag 'trace-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (88 commits) bootconfig: Show the number of nodes on boot message tools/bootconfig: Show the number of bootconfig nodes bootconfig: Add more parse error messages bootconfig: Use bootconfig instead of boot config ftrace: Protect ftrace_graph_hash with ftrace_sync ftrace: Add comment to why rcu_dereference_sched() is open coded tracing: Annotate ftrace_graph_notrace_hash pointer with __rcu tracing: Annotate ftrace_graph_hash pointer with __rcu bootconfig: Only load bootconfig if "bootconfig" is on the kernel cmdline tracing: Use seq_buf for building dynevent_cmd string tracing: Remove useless code in dynevent_arg_pair_add() tracing: Remove check_arg() callbacks from dynevent args tracing: Consolidate some synth_event_trace code tracing: Fix now invalid var_ref_vals assumption in trace action tracing: Change trace_boot to use synth_event interface tracing: Move tracing selftests to bottom of menu tracing: Move mmio tracer config up with the other tracers tracing: Move tracing test module configs together tracing: Move all function tracing configs together tracing: Documentation for in-kernel synthetic event API ...
Diffstat (limited to 'fs/proc')
-rw-r--r--fs/proc/Makefile1
-rw-r--r--fs/proc/bootconfig.c89
2 files changed, 90 insertions, 0 deletions
diff --git a/fs/proc/Makefile b/fs/proc/Makefile
index ead487e80510..bd08616ed8ba 100644
--- a/fs/proc/Makefile
+++ b/fs/proc/Makefile
@@ -33,3 +33,4 @@ proc-$(CONFIG_PROC_KCORE) += kcore.o
proc-$(CONFIG_PROC_VMCORE) += vmcore.o
proc-$(CONFIG_PRINTK) += kmsg.o
proc-$(CONFIG_PROC_PAGE_MONITOR) += page.o
+proc-$(CONFIG_BOOT_CONFIG) += bootconfig.o
diff --git a/fs/proc/bootconfig.c b/fs/proc/bootconfig.c
new file mode 100644
index 000000000000..9955d75c0585
--- /dev/null
+++ b/fs/proc/bootconfig.c
@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * /proc/bootconfig - Extra boot configuration
+ */
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/printk.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/bootconfig.h>
+#include <linux/slab.h>
+
+static char *saved_boot_config;
+
+static int boot_config_proc_show(struct seq_file *m, void *v)
+{
+ if (saved_boot_config)
+ seq_puts(m, saved_boot_config);
+ return 0;
+}
+
+/* Rest size of buffer */
+#define rest(dst, end) ((end) > (dst) ? (end) - (dst) : 0)
+
+/* Return the needed total length if @size is 0 */
+static int __init copy_xbc_key_value_list(char *dst, size_t size)
+{
+ struct xbc_node *leaf, *vnode;
+ const char *val;
+ char *key, *end = dst + size;
+ int ret = 0;
+
+ key = kzalloc(XBC_KEYLEN_MAX, GFP_KERNEL);
+
+ xbc_for_each_key_value(leaf, val) {
+ ret = xbc_node_compose_key(leaf, key, XBC_KEYLEN_MAX);
+ if (ret < 0)
+ break;
+ ret = snprintf(dst, rest(dst, end), "%s = ", key);
+ if (ret < 0)
+ break;
+ dst += ret;
+ vnode = xbc_node_get_child(leaf);
+ if (vnode && xbc_node_is_array(vnode)) {
+ xbc_array_for_each_value(vnode, val) {
+ ret = snprintf(dst, rest(dst, end), "\"%s\"%s",
+ val, vnode->next ? ", " : "\n");
+ if (ret < 0)
+ goto out;
+ dst += ret;
+ }
+ } else {
+ ret = snprintf(dst, rest(dst, end), "\"%s\"\n", val);
+ if (ret < 0)
+ break;
+ dst += ret;
+ }
+ }
+out:
+ kfree(key);
+
+ return ret < 0 ? ret : dst - (end - size);
+}
+
+static int __init proc_boot_config_init(void)
+{
+ int len;
+
+ len = copy_xbc_key_value_list(NULL, 0);
+ if (len < 0)
+ return len;
+
+ if (len > 0) {
+ saved_boot_config = kzalloc(len + 1, GFP_KERNEL);
+ if (!saved_boot_config)
+ return -ENOMEM;
+
+ len = copy_xbc_key_value_list(saved_boot_config, len + 1);
+ if (len < 0) {
+ kfree(saved_boot_config);
+ return len;
+ }
+ }
+
+ proc_create_single("bootconfig", 0, NULL, boot_config_proc_show);
+
+ return 0;
+}
+fs_initcall(proc_boot_config_init);