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| author | Thomas Gleixner <tglx@linutronix.de> | 2022-09-15 13:11:30 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-10-17 16:41:16 +0200 |
| commit | f5c1bb2afe93396d41c5cbdcb909b08a75b8dde4 (patch) | |
| tree | ea7d2c0ffd9a4c54bb865b0b3fdccbfb21f4189a /arch/x86/kernel | |
| parent | x86/retbleed: Add SKL call thunk (diff) | |
| download | linux-f5c1bb2afe93396d41c5cbdcb909b08a75b8dde4.tar.xz linux-f5c1bb2afe93396d41c5cbdcb909b08a75b8dde4.zip | |
x86/calldepth: Add ret/call counting for debug
Add a debuigfs mechanism to validate the accounting, e.g. vs. call/ret
balance and to gather statistics about the stuffing to call ratio.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111148.204285506@infradead.org
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/callthunks.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/arch/x86/kernel/callthunks.c b/arch/x86/kernel/callthunks.c index 01f6f6b5a93c..dfe7ffff88b9 100644 --- a/arch/x86/kernel/callthunks.c +++ b/arch/x86/kernel/callthunks.c @@ -2,6 +2,7 @@ #define pr_fmt(fmt) "callthunks: " fmt +#include <linux/debugfs.h> #include <linux/kallsyms.h> #include <linux/memory.h> #include <linux/moduleloader.h> @@ -35,6 +36,15 @@ static int __init debug_thunks(char *str) } __setup("debug-callthunks", debug_thunks); +#ifdef CONFIG_CALL_THUNKS_DEBUG +DEFINE_PER_CPU(u64, __x86_call_count); +DEFINE_PER_CPU(u64, __x86_ret_count); +DEFINE_PER_CPU(u64, __x86_stuffs_count); +DEFINE_PER_CPU(u64, __x86_ctxsw_count); +EXPORT_SYMBOL_GPL(__x86_ctxsw_count); +EXPORT_SYMBOL_GPL(__x86_call_count); +#endif + extern s32 __call_sites[], __call_sites_end[]; struct thunk_desc { @@ -283,3 +293,46 @@ void noinline callthunks_patch_module_calls(struct callthunk_sites *cs, mutex_unlock(&text_mutex); } #endif /* CONFIG_MODULES */ + +#if defined(CONFIG_CALL_THUNKS_DEBUG) && defined(CONFIG_DEBUG_FS) +static int callthunks_debug_show(struct seq_file *m, void *p) +{ + unsigned long cpu = (unsigned long)m->private; + + seq_printf(m, "C: %16llu R: %16llu S: %16llu X: %16llu\n,", + per_cpu(__x86_call_count, cpu), + per_cpu(__x86_ret_count, cpu), + per_cpu(__x86_stuffs_count, cpu), + per_cpu(__x86_ctxsw_count, cpu)); + return 0; +} + +static int callthunks_debug_open(struct inode *inode, struct file *file) +{ + return single_open(file, callthunks_debug_show, inode->i_private); +} + +static const struct file_operations dfs_ops = { + .open = callthunks_debug_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static int __init callthunks_debugfs_init(void) +{ + struct dentry *dir; + unsigned long cpu; + + dir = debugfs_create_dir("callthunks", NULL); + for_each_possible_cpu(cpu) { + void *arg = (void *)cpu; + char name [10]; + + sprintf(name, "cpu%lu", cpu); + debugfs_create_file(name, 0644, dir, arg, &dfs_ops); + } + return 0; +} +__initcall(callthunks_debugfs_init); +#endif |