static_call: Add call depth tracking support

When indirect calls are switched to direct calls then it has to be ensured
that the call target is not the function, but the call thunk when call
depth tracking is enabled. But static calls are available before call
thunks have been set up.

Ensure a second run through the static call patching code after call thunks
have been created. When call thunks are not enabled this has no side
effects.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111148.306100465@infradead.org
This commit is contained in:
Peter Zijlstra 2022-09-15 13:11:31 +02:00
parent f5c1bb2afe
commit 7825451fa4
5 changed files with 44 additions and 5 deletions

View File

@ -91,11 +91,16 @@ struct callthunk_sites {
extern void callthunks_patch_builtin_calls(void);
extern void callthunks_patch_module_calls(struct callthunk_sites *sites,
struct module *mod);
extern void *callthunks_translate_call_dest(void *dest);
#else
static __always_inline void callthunks_patch_builtin_calls(void) {}
static __always_inline void
callthunks_patch_module_calls(struct callthunk_sites *sites,
struct module *mod) {}
static __always_inline void *callthunks_translate_call_dest(void *dest)
{
return dest;
}
#endif
#ifdef CONFIG_SMP

View File

@ -6,6 +6,7 @@
#include <linux/kallsyms.h>
#include <linux/memory.h>
#include <linux/moduleloader.h>
#include <linux/static_call.h>
#include <asm/alternative.h>
#include <asm/asm-offsets.h>
@ -271,10 +272,27 @@ void __init callthunks_patch_builtin_calls(void)
pr_info("Setting up call depth tracking\n");
mutex_lock(&text_mutex);
callthunks_setup(&cs, &builtin_coretext);
static_call_force_reinit();
thunks_initialized = true;
mutex_unlock(&text_mutex);
}
void *callthunks_translate_call_dest(void *dest)
{
void *target;
lockdep_assert_held(&text_mutex);
if (!thunks_initialized || skip_addr(dest))
return dest;
if (!is_coretext(NULL, dest))
return dest;
target = patch_dest(dest, false);
return target ? : dest;
}
#ifdef CONFIG_MODULES
void noinline callthunks_patch_module_calls(struct callthunk_sites *cs,
struct module *mod)

View File

@ -34,6 +34,7 @@ static void __ref __static_call_transform(void *insn, enum insn_type type,
switch (type) {
case CALL:
func = callthunks_translate_call_dest(func);
code = text_gen_insn(CALL_INSN_OPCODE, insn, func);
if (func == &__static_call_return0) {
emulate = code;

View File

@ -162,6 +162,8 @@ extern void arch_static_call_transform(void *site, void *tramp, void *func, bool
extern int __init static_call_init(void);
extern void static_call_force_reinit(void);
struct static_call_mod {
struct static_call_mod *next;
struct module *mod; /* for vmlinux, mod == NULL */

View File

@ -15,7 +15,18 @@ extern struct static_call_site __start_static_call_sites[],
extern struct static_call_tramp_key __start_static_call_tramp_key[],
__stop_static_call_tramp_key[];
static bool static_call_initialized;
static int static_call_initialized;
/*
* Must be called before early_initcall() to be effective.
*/
void static_call_force_reinit(void)
{
if (WARN_ON_ONCE(!static_call_initialized))
return;
static_call_initialized++;
}
/* mutex to protect key modules/sites */
static DEFINE_MUTEX(static_call_mutex);
@ -475,7 +486,8 @@ int __init static_call_init(void)
{
int ret;
if (static_call_initialized)
/* See static_call_force_reinit(). */
if (static_call_initialized == 1)
return 0;
cpus_read_lock();
@ -490,11 +502,12 @@ int __init static_call_init(void)
BUG();
}
static_call_initialized = true;
#ifdef CONFIG_MODULES
register_module_notifier(&static_call_module_nb);
if (!static_call_initialized)
register_module_notifier(&static_call_module_nb);
#endif
static_call_initialized = 1;
return 0;
}
early_initcall(static_call_init);