summaryrefslogtreecommitdiff
path: root/samples/ftrace/ftrace-direct-multi-modify.c
diff options
context:
space:
mode:
Diffstat (limited to 'samples/ftrace/ftrace-direct-multi-modify.c')
-rw-r--r--samples/ftrace/ftrace-direct-multi-modify.c383
1 files changed, 383 insertions, 0 deletions
diff --git a/samples/ftrace/ftrace-direct-multi-modify.c b/samples/ftrace/ftrace-direct-multi-modify.c
new file mode 100644
index 000000000000..8f7986d698d8
--- /dev/null
+++ b/samples/ftrace/ftrace-direct-multi-modify.c
@@ -0,0 +1,383 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/ftrace.h>
+#if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32)
+#include <asm/asm-offsets.h>
+#endif
+
+extern void my_direct_func1(unsigned long ip);
+extern void my_direct_func2(unsigned long ip);
+
+void my_direct_func1(unsigned long ip)
+{
+ trace_printk("my direct func1 ip %lx\n", ip);
+}
+
+void my_direct_func2(unsigned long ip)
+{
+ trace_printk("my direct func2 ip %lx\n", ip);
+}
+
+extern void my_tramp1(void *);
+extern void my_tramp2(void *);
+
+#ifdef CONFIG_RISCV
+#include <asm/asm.h>
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp1, @function\n"
+" .globl my_tramp1\n"
+" my_tramp1:\n"
+" addi sp,sp,-3*"SZREG"\n"
+" "REG_S" a0,0*"SZREG"(sp)\n"
+" "REG_S" t0,1*"SZREG"(sp)\n"
+" "REG_S" ra,2*"SZREG"(sp)\n"
+" mv a0,t0\n"
+" call my_direct_func1\n"
+" "REG_L" a0,0*"SZREG"(sp)\n"
+" "REG_L" t0,1*"SZREG"(sp)\n"
+" "REG_L" ra,2*"SZREG"(sp)\n"
+" addi sp,sp,3*"SZREG"\n"
+" jr t0\n"
+" .size my_tramp1, .-my_tramp1\n"
+
+" .type my_tramp2, @function\n"
+" .globl my_tramp2\n"
+" my_tramp2:\n"
+" addi sp,sp,-3*"SZREG"\n"
+" "REG_S" a0,0*"SZREG"(sp)\n"
+" "REG_S" t0,1*"SZREG"(sp)\n"
+" "REG_S" ra,2*"SZREG"(sp)\n"
+" mv a0,t0\n"
+" call my_direct_func2\n"
+" "REG_L" a0,0*"SZREG"(sp)\n"
+" "REG_L" t0,1*"SZREG"(sp)\n"
+" "REG_L" ra,2*"SZREG"(sp)\n"
+" addi sp,sp,3*"SZREG"\n"
+" jr t0\n"
+" .size my_tramp2, .-my_tramp2\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_RISCV */
+
+#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
+" pushq %rdi\n"
+" movq 8(%rbp), %rdi\n"
+" call my_direct_func1\n"
+" popq %rdi\n"
+" leave\n"
+ ASM_RET
+" .size my_tramp1, .-my_tramp1\n"
+
+" .type my_tramp2, @function\n"
+" .globl my_tramp2\n"
+" my_tramp2:"
+ ASM_ENDBR
+" pushq %rbp\n"
+" movq %rsp, %rbp\n"
+ CALL_DEPTH_ACCOUNT
+" pushq %rdi\n"
+" movq 8(%rbp), %rdi\n"
+" call my_direct_func2\n"
+" popq %rdi\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"
+" lgr %r2,%r0\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"
+"\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"
+" lgr %r2,%r0\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_ARM64
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp1, @function\n"
+" .globl my_tramp1\n"
+" my_tramp1:"
+" hint 34\n" // bti c
+" sub sp, sp, #32\n"
+" stp x9, x30, [sp]\n"
+" str x0, [sp, #16]\n"
+" mov x0, x30\n"
+" bl my_direct_func1\n"
+" ldp x30, x9, [sp]\n"
+" ldr x0, [sp, #16]\n"
+" add sp, sp, #32\n"
+" ret x9\n"
+" .size my_tramp1, .-my_tramp1\n"
+
+" .type my_tramp2, @function\n"
+" .globl my_tramp2\n"
+" my_tramp2:"
+" hint 34\n" // bti c
+" sub sp, sp, #32\n"
+" stp x9, x30, [sp]\n"
+" str x0, [sp, #16]\n"
+" mov x0, x30\n"
+" bl my_direct_func2\n"
+" ldp x30, x9, [sp]\n"
+" ldr x0, [sp, #16]\n"
+" add sp, sp, #32\n"
+" ret x9\n"
+" .size my_tramp2, .-my_tramp2\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_ARM64 */
+
+#ifdef CONFIG_LOONGARCH
+#include <asm/asm.h>
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp1, @function\n"
+" .globl my_tramp1\n"
+" my_tramp1:\n"
+" addi.d $sp, $sp, -32\n"
+" st.d $a0, $sp, 0\n"
+" st.d $t0, $sp, 8\n"
+" st.d $ra, $sp, 16\n"
+" move $a0, $t0\n"
+" bl my_direct_func1\n"
+" ld.d $a0, $sp, 0\n"
+" ld.d $t0, $sp, 8\n"
+" ld.d $ra, $sp, 16\n"
+" addi.d $sp, $sp, 32\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, -32\n"
+" st.d $a0, $sp, 0\n"
+" st.d $t0, $sp, 8\n"
+" st.d $ra, $sp, 16\n"
+" move $a0, $t0\n"
+" bl my_direct_func2\n"
+" ld.d $a0, $sp, 0\n"
+" ld.d $t0, $sp, 8\n"
+" ld.d $ra, $sp, 16\n"
+" addi.d $sp, $sp, 32\n"
+" jr $t0\n"
+" .size my_tramp2, .-my_tramp2\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_LOONGARCH */
+
+#ifdef CONFIG_PPC
+#include <asm/ppc_asm.h>
+
+#ifdef CONFIG_PPC64
+#define STACK_FRAME_SIZE 48
+#else
+#define STACK_FRAME_SIZE 24
+#endif
+
+#if defined(CONFIG_PPC64_ELF_ABI_V2) && !defined(CONFIG_PPC_KERNEL_PCREL)
+#define PPC64_TOC_SAVE_AND_UPDATE \
+" std 2, 24(1)\n" \
+" bcl 20, 31, 1f\n" \
+" 1: mflr 12\n" \
+" ld 2, (99f - 1b)(12)\n"
+#define PPC64_TOC_RESTORE \
+" ld 2, 24(1)\n"
+#define PPC64_TOC \
+" 99: .quad .TOC.@tocbase\n"
+#else
+#define PPC64_TOC_SAVE_AND_UPDATE ""
+#define PPC64_TOC_RESTORE ""
+#define PPC64_TOC ""
+#endif
+
+#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
+#define PPC_FTRACE_RESTORE_LR \
+ PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" \
+" mtlr 0\n"
+#define PPC_FTRACE_RET \
+" blr\n"
+#define PPC_FTRACE_RECOVER_IP \
+" lwz 8, 4(3)\n" \
+" li 9, 6\n" \
+" slw 8, 8, 9\n" \
+" sraw 8, 8, 9\n" \
+" add 3, 3, 8\n" \
+" addi 3, 3, 4\n"
+#else
+#define PPC_FTRACE_RESTORE_LR \
+ PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n" \
+" mtctr 0\n"
+#define PPC_FTRACE_RET \
+" mtlr 0\n" \
+" bctr\n"
+#define PPC_FTRACE_RECOVER_IP ""
+#endif
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp1, @function\n"
+" .globl my_tramp1\n"
+" my_tramp1:\n"
+ PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n"
+ PPC_STLU" 1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
+" mflr 0\n"
+ PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n"
+ PPC_STLU" 1, -"__stringify(STACK_FRAME_SIZE)"(1)\n"
+ PPC64_TOC_SAVE_AND_UPDATE
+ PPC_STL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
+" mr 3, 0\n"
+ PPC_FTRACE_RECOVER_IP
+" bl my_direct_func1\n"
+ PPC_LL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
+ PPC64_TOC_RESTORE
+" addi 1, 1, "__stringify(STACK_FRAME_SIZE)"\n"
+ PPC_FTRACE_RESTORE_LR
+" addi 1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n"
+ PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n"
+ PPC_FTRACE_RET
+" .size my_tramp1, .-my_tramp1\n"
+
+" .type my_tramp2, @function\n"
+" .globl my_tramp2\n"
+" my_tramp2:\n"
+ PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n"
+ PPC_STLU" 1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
+" mflr 0\n"
+ PPC_STL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n"
+ PPC_STLU" 1, -"__stringify(STACK_FRAME_SIZE)"(1)\n"
+ PPC64_TOC_SAVE_AND_UPDATE
+ PPC_STL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
+" mr 3, 0\n"
+ PPC_FTRACE_RECOVER_IP
+" bl my_direct_func2\n"
+ PPC_LL" 3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
+ PPC64_TOC_RESTORE
+" addi 1, 1, "__stringify(STACK_FRAME_SIZE)"\n"
+ PPC_FTRACE_RESTORE_LR
+" addi 1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n"
+ PPC_LL" 0, "__stringify(PPC_LR_STKOFF)"(1)\n"
+ PPC_FTRACE_RET
+ PPC64_TOC
+ " .size my_tramp2, .-my_tramp2\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_PPC */
+
+static unsigned long my_tramp = (unsigned long)my_tramp1;
+static unsigned long tramps[2] = {
+ (unsigned long)my_tramp1,
+ (unsigned long)my_tramp2,
+};
+
+static struct ftrace_ops direct;
+
+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_multi_init(void)
+{
+ int ret;
+
+ ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0);
+ ftrace_set_filter_ip(&direct, (unsigned long) schedule, 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_multi_exit(void)
+{
+ kthread_stop(simple_tsk);
+ unregister_ftrace_direct(&direct, my_tramp, true);
+}
+
+module_init(ftrace_direct_multi_init);
+module_exit(ftrace_direct_multi_exit);
+
+MODULE_AUTHOR("Jiri Olsa");
+MODULE_DESCRIPTION("Example use case of using modify_ftrace_direct()");
+MODULE_LICENSE("GPL");
generated by cgit (git 2.34.1) at 2025-12-25 19:45:48 +0000