mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 09:19:51 +00:00
kgdbts: Switch to do_sys_openat2() for breakpoint testing
Currently kgdbts can get stuck waiting for do_sys_open() to be called in some of the current tests. This is because C compilers often automatically inline this function, which is a very thin wrapper around do_sys_openat2(), into some of its callers. gcc-10 does this on (at least) both x86 and arm64. We can fix the test suite by placing the breakpoints on do_sys_openat2() instead since that isn't (currently) inlined. However do_sys_openat2() is a static function so we cannot simply use an addressof. Since we are testing debug machinery it is acceptable to use kallsyms to lookup a suitable address because this is more or less what kdb does in the same circumstances. Re-implement lookup_addr() to be based on kallsyms rather than function pointers. Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://lore.kernel.org/r/20210325094807.3546702-1-daniel.thompson@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
dbdc671d5c
commit
1114ab22e4
1 changed files with 28 additions and 18 deletions
|
@ -92,6 +92,7 @@
|
|||
#include <linux/kthread.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/sched/task.h>
|
||||
#include <linux/kallsyms.h>
|
||||
|
||||
#include <asm/sections.h>
|
||||
|
||||
|
@ -200,21 +201,30 @@ static noinline void kgdbts_break_test(void)
|
|||
v2printk("kgdbts: breakpoint complete\n");
|
||||
}
|
||||
|
||||
/* Lookup symbol info in the kernel */
|
||||
/*
|
||||
* This is a cached wrapper for kallsyms_lookup_name().
|
||||
*
|
||||
* The cache is a big win for several tests. For example it more the doubles
|
||||
* the cycles per second during the sys_open test. This is not theoretic,
|
||||
* the performance improvement shows up at human scale, especially when
|
||||
* testing using emulators.
|
||||
*
|
||||
* Obviously neither re-entrant nor thread-safe but that is OK since it
|
||||
* can only be called from the debug trap (and therefore all other CPUs
|
||||
* are halted).
|
||||
*/
|
||||
static unsigned long lookup_addr(char *arg)
|
||||
{
|
||||
unsigned long addr = 0;
|
||||
static char cached_arg[KSYM_NAME_LEN];
|
||||
static unsigned long cached_addr;
|
||||
|
||||
if (!strcmp(arg, "kgdbts_break_test"))
|
||||
addr = (unsigned long)kgdbts_break_test;
|
||||
else if (!strcmp(arg, "sys_open"))
|
||||
addr = (unsigned long)do_sys_open;
|
||||
else if (!strcmp(arg, "kernel_clone"))
|
||||
addr = (unsigned long)kernel_clone;
|
||||
else if (!strcmp(arg, "hw_break_val"))
|
||||
addr = (unsigned long)&hw_break_val;
|
||||
addr = (unsigned long) dereference_function_descriptor((void *)addr);
|
||||
return addr;
|
||||
if (strcmp(arg, cached_arg)) {
|
||||
strscpy(cached_arg, arg, KSYM_NAME_LEN);
|
||||
cached_addr = kallsyms_lookup_name(arg);
|
||||
}
|
||||
|
||||
return (unsigned long)dereference_function_descriptor(
|
||||
(void *)cached_addr);
|
||||
}
|
||||
|
||||
static void break_helper(char *bp_type, char *arg, unsigned long vaddr)
|
||||
|
@ -310,7 +320,7 @@ static int check_and_rewind_pc(char *put_str, char *arg)
|
|||
|
||||
if (arch_needs_sstep_emulation && sstep_addr &&
|
||||
ip + offset == sstep_addr &&
|
||||
((!strcmp(arg, "sys_open") || !strcmp(arg, "kernel_clone")))) {
|
||||
((!strcmp(arg, "do_sys_openat2") || !strcmp(arg, "kernel_clone")))) {
|
||||
/* This is special case for emulated single step */
|
||||
v2printk("Emul: rewind hit single step bp\n");
|
||||
restart_from_top_after_write = 1;
|
||||
|
@ -619,14 +629,14 @@ static struct test_struct do_kernel_clone_test[] = {
|
|||
*/
|
||||
static struct test_struct sys_open_test[] = {
|
||||
{ "?", "S0*" }, /* Clear break points */
|
||||
{ "sys_open", "OK", sw_break, }, /* set sw breakpoint */
|
||||
{ "do_sys_openat2", "OK", sw_break, }, /* set sw breakpoint */
|
||||
{ "c", "T0*", NULL, get_thread_id_continue }, /* Continue */
|
||||
{ "sys_open", "OK", sw_rem_break }, /*remove breakpoint */
|
||||
{ "g", "sys_open", NULL, check_and_rewind_pc }, /* check location */
|
||||
{ "do_sys_openat2", "OK", sw_rem_break }, /*remove breakpoint */
|
||||
{ "g", "do_sys_openat2", NULL, check_and_rewind_pc }, /* check location */
|
||||
{ "write", "OK", write_regs, emul_reset }, /* Write registers */
|
||||
{ "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */
|
||||
{ "g", "sys_open", NULL, check_single_step },
|
||||
{ "sys_open", "OK", sw_break, }, /* set sw breakpoint */
|
||||
{ "g", "do_sys_openat2", NULL, check_single_step },
|
||||
{ "do_sys_openat2", "OK", sw_break, }, /* set sw breakpoint */
|
||||
{ "7", "T0*", skip_back_repeat_test }, /* Loop based on repeat_test */
|
||||
{ "D", "OK", NULL, final_ack_set }, /* detach and unregister I/O */
|
||||
{ "", "", get_cont_catch, put_cont_catch },
|
||||
|
|
Loading…
Reference in a new issue