linux/samples/ftrace/ftrace-direct-modify.c
Linus Torvalds 611c9d8830 LoongArch changes for v6.4
1, Better backtraces for humanization;
 2, Relay BCE exceptions to userland as SIGSEGV;
 3, Provide kernel fpu functions;
 4, Optimize memory ops (memset/memcpy/memmove);
 5, Optimize checksum and crc32(c) calculation;
 6, Add ARCH_HAS_FORTIFY_SOURCE selection;
 7, Add function error injection support;
 8, Add ftrace with direct call support;
 9, Add basic perf tools support.
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Merge tag 'loongarch-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson

Pull LoongArch updates from Huacai Chen:

 - Better backtraces for humanization

 - Relay BCE exceptions to userland as SIGSEGV

 - Provide kernel fpu functions

 - Optimize memory ops (memset/memcpy/memmove)

 - Optimize checksum and crc32(c) calculation

 - Add ARCH_HAS_FORTIFY_SOURCE selection

 - Add function error injection support

 - Add ftrace with direct call support

 - Add basic perf tools support

* tag 'loongarch-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson: (24 commits)
  tools/perf: Add basic support for LoongArch
  LoongArch: ftrace: Add direct call trampoline samples support
  LoongArch: ftrace: Add direct call support
  LoongArch: ftrace: Implement ftrace_find_callable_addr() to simplify code
  LoongArch: ftrace: Fix build error if DYNAMIC_FTRACE_WITH_REGS is not set
  LoongArch: ftrace: Abstract DYNAMIC_FTRACE_WITH_ARGS accesses
  LoongArch: Add support for function error injection
  LoongArch: Add ARCH_HAS_FORTIFY_SOURCE selection
  LoongArch: crypto: Add crc32 and crc32c hw acceleration
  LoongArch: Add checksum optimization for 64-bit system
  LoongArch: Optimize memory ops (memset/memcpy/memmove)
  LoongArch: Provide kernel fpu functions
  LoongArch: Relay BCE exceptions to userland as SIGSEGV with si_code=SEGV_BNDERR
  LoongArch: Tweak the BADV and CPUCFG.PRID lines in show_regs()
  LoongArch: Humanize the ESTAT line when showing registers
  LoongArch: Humanize the ECFG line when showing registers
  LoongArch: Humanize the EUEN line when showing registers
  LoongArch: Humanize the PRMD line when showing registers
  LoongArch: Humanize the CRMD line when showing registers
  LoongArch: Fix format of CSR lines during show_regs()
  ...
2023-05-04 12:40:16 -07:00

188 lines
4.0 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/ftrace.h>
#include <asm/asm-offsets.h>
extern void my_direct_func1(void);
extern void my_direct_func2(void);
void my_direct_func1(void)
{
trace_printk("my direct func1\n");
}
void my_direct_func2(void)
{
trace_printk("my direct func2\n");
}
extern void my_tramp1(void *);
extern void my_tramp2(void *);
static unsigned long my_ip = (unsigned long)schedule;
#ifdef CONFIG_X86_64
#include <asm/ibt.h>
#include <asm/nospec-branch.h>
asm (
" .pushsection .text, \"ax\", @progbits\n"
" .type my_tramp1, @function\n"
" .globl my_tramp1\n"
" my_tramp1:"
ASM_ENDBR
" pushq %rbp\n"
" movq %rsp, %rbp\n"
CALL_DEPTH_ACCOUNT
" call my_direct_func1\n"
" leave\n"
" .size my_tramp1, .-my_tramp1\n"
ASM_RET
" .type my_tramp2, @function\n"
" .globl my_tramp2\n"
" my_tramp2:"
ASM_ENDBR
" pushq %rbp\n"
" movq %rsp, %rbp\n"
CALL_DEPTH_ACCOUNT
" call my_direct_func2\n"
" leave\n"
ASM_RET
" .size my_tramp2, .-my_tramp2\n"
" .popsection\n"
);
#endif /* CONFIG_X86_64 */
#ifdef CONFIG_S390
asm (
" .pushsection .text, \"ax\", @progbits\n"
" .type my_tramp1, @function\n"
" .globl my_tramp1\n"
" my_tramp1:"
" lgr %r1,%r15\n"
" stmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
" stg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
" aghi %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
" stg %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
" brasl %r14,my_direct_func1\n"
" aghi %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
" lmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
" lg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
" lgr %r1,%r0\n"
" br %r1\n"
" .size my_tramp1, .-my_tramp1\n"
" .type my_tramp2, @function\n"
" .globl my_tramp2\n"
" my_tramp2:"
" lgr %r1,%r15\n"
" stmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
" stg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
" aghi %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
" stg %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
" brasl %r14,my_direct_func2\n"
" aghi %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
" lmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
" lg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
" lgr %r1,%r0\n"
" br %r1\n"
" .size my_tramp2, .-my_tramp2\n"
" .popsection\n"
);
#endif /* CONFIG_S390 */
#ifdef CONFIG_LOONGARCH
asm (
" .pushsection .text, \"ax\", @progbits\n"
" .type my_tramp1, @function\n"
" .globl my_tramp1\n"
" my_tramp1:\n"
" addi.d $sp, $sp, -16\n"
" st.d $t0, $sp, 0\n"
" st.d $ra, $sp, 8\n"
" bl my_direct_func1\n"
" ld.d $t0, $sp, 0\n"
" ld.d $ra, $sp, 8\n"
" addi.d $sp, $sp, 16\n"
" jr $t0\n"
" .size my_tramp1, .-my_tramp1\n"
" .type my_tramp2, @function\n"
" .globl my_tramp2\n"
" my_tramp2:\n"
" addi.d $sp, $sp, -16\n"
" st.d $t0, $sp, 0\n"
" st.d $ra, $sp, 8\n"
" bl my_direct_func2\n"
" ld.d $t0, $sp, 0\n"
" ld.d $ra, $sp, 8\n"
" addi.d $sp, $sp, 16\n"
" jr $t0\n"
" .size my_tramp2, .-my_tramp2\n"
" .popsection\n"
);
#endif /* CONFIG_LOONGARCH */
static struct ftrace_ops direct;
static unsigned long my_tramp = (unsigned long)my_tramp1;
static unsigned long tramps[2] = {
(unsigned long)my_tramp1,
(unsigned long)my_tramp2,
};
static int simple_thread(void *arg)
{
static int t;
int ret = 0;
while (!kthread_should_stop()) {
set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(2 * HZ);
if (ret)
continue;
t ^= 1;
ret = modify_ftrace_direct(&direct, tramps[t]);
if (!ret)
my_tramp = tramps[t];
WARN_ON_ONCE(ret);
}
return 0;
}
static struct task_struct *simple_tsk;
static int __init ftrace_direct_init(void)
{
int ret;
ftrace_set_filter_ip(&direct, (unsigned long) my_ip, 0, 0);
ret = register_ftrace_direct(&direct, my_tramp);
if (!ret)
simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn");
return ret;
}
static void __exit ftrace_direct_exit(void)
{
kthread_stop(simple_tsk);
unregister_ftrace_direct(&direct, my_tramp, true);
}
module_init(ftrace_direct_init);
module_exit(ftrace_direct_exit);
MODULE_AUTHOR("Steven Rostedt");
MODULE_DESCRIPTION("Example use case of using modify_ftrace_direct()");
MODULE_LICENSE("GPL");