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authorNiklas Cassel <cassel@kernel.org>2026-09-16 15:00:32 +0200
committerNiklas Cassel <cassel@kernel.org>2026-09-16 16:18:00 +0200
commit8d836581f9b1f57ceaa2b47654754ef1260b410b (patch)
tree1dbd4d0dfb99c2e238356cbe947e5b0be3e3a571 /samples/ftrace
downloadlinux-stable-8d836581f9b1f57ceaa2b47654754ef1260b410b.tar.gz
linux-stable-8d836581f9b1f57ceaa2b47654754ef1260b410b.zip
ata: libata-scsi: fix ata_dsm_trim_pages() kernel-docgrafted
make htmldocs fails with: Documentation/driver-api/libata:604: ./drivers/ata/libata-scsi.c:2301: ERROR: Unexpected indentation. [docutils] The Return: section of ata_dsm_trim_pages() ends its first sentence with a colon and continues with an indented bullet list. reStructuredText requires a blank line before an indented block, so docutils chokes on the list. Simply adding the missing blank line does not work either: Return: is a kernel-doc "special section", which is terminated by the first blank line, so the bullet list would end up in the Description section, detached from the sentence introducing it. Spell the two bounds out as prose instead, so that the Return: section stays self-contained. Documentation-only change. Fixes: e64e6b5dc867 ("ata: libata-scsi: scale DSM TRIM payload by MAX PAGES PER DSM COMMAND") Reported-by: Thomas Huth <thuth@redhat.com> Closes: https://lore.kernel.org/linux-ide/b0a0b8e8-cc4f-4c7b-8bc5-fee0712d405a@redhat.com/ Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Thomas Huth <thuth@redhat.com> Link: https://lore.kernel.org/r/20260916130031.29990-2-cassel@kernel.org Signed-off-by: Niklas Cassel <cassel@kernel.org>
Diffstat (limited to 'samples/ftrace')
-rw-r--r--samples/ftrace/Makefile11
-rw-r--r--samples/ftrace/ftrace-direct-modify.c345
-rw-r--r--samples/ftrace/ftrace-direct-multi-modify.c389
-rw-r--r--samples/ftrace/ftrace-direct-multi.c241
-rw-r--r--samples/ftrace/ftrace-direct-too.c256
-rw-r--r--samples/ftrace/ftrace-direct.c223
-rw-r--r--samples/ftrace/ftrace-ops.c252
-rw-r--r--samples/ftrace/sample-trace-array.c143
-rw-r--r--samples/ftrace/sample-trace-array.h84
9 files changed, 1944 insertions, 0 deletions
diff --git a/samples/ftrace/Makefile b/samples/ftrace/Makefile
new file mode 100644
index 000000000..589baf2ec
--- /dev/null
+++ b/samples/ftrace/Makefile
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-$(CONFIG_SAMPLE_FTRACE_DIRECT) += ftrace-direct.o
+obj-$(CONFIG_SAMPLE_FTRACE_DIRECT) += ftrace-direct-too.o
+obj-$(CONFIG_SAMPLE_FTRACE_DIRECT) += ftrace-direct-modify.o
+obj-$(CONFIG_SAMPLE_FTRACE_DIRECT_MULTI) += ftrace-direct-multi.o
+obj-$(CONFIG_SAMPLE_FTRACE_DIRECT_MULTI) += ftrace-direct-multi-modify.o
+obj-$(CONFIG_SAMPLE_FTRACE_OPS) += ftrace-ops.o
+
+CFLAGS_sample-trace-array.o := -I$(src)
+obj-$(CONFIG_SAMPLE_TRACE_ARRAY) += sample-trace-array.o
diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c
new file mode 100644
index 000000000..164d9dd6f
--- /dev/null
+++ b/samples/ftrace/ftrace-direct-modify.c
@@ -0,0 +1,345 @@
+// 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(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_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,-2*"SZREG"\n"
+" "REG_S" t0,0*"SZREG"(sp)\n"
+" "REG_S" ra,1*"SZREG"(sp)\n"
+" call my_direct_func1\n"
+" "REG_L" t0,0*"SZREG"(sp)\n"
+" "REG_L" ra,1*"SZREG"(sp)\n"
+" addi sp,sp,2*"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,-2*"SZREG"\n"
+" "REG_S" t0,0*"SZREG"(sp)\n"
+" "REG_S" ra,1*"SZREG"(sp)\n"
+" call my_direct_func2\n"
+" "REG_L" t0,0*"SZREG"(sp)\n"
+" "REG_L" ra,1*"SZREG"(sp)\n"
+" addi sp,sp,2*"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
+" call my_direct_func1\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
+" 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_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, #16\n"
+" stp x9, x30, [sp]\n"
+" bl my_direct_func1\n"
+" ldp x30, x9, [sp]\n"
+" add sp, sp, #16\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, #16\n"
+" stp x9, x30, [sp]\n"
+" bl my_direct_func2\n"
+" ldp x30, x9, [sp]\n"
+" add sp, sp, #16\n"
+" ret x9\n"
+" .size my_tramp2, .-my_tramp2\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_ARM64 */
+
+#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 $ra, $sp, 0\n"
+" ld.d $t0, $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 $ra, $sp, 0\n"
+" ld.d $t0, $sp, 8\n"
+" addi.d $sp, $sp, 16\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"
+#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"
+#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
+" bl my_direct_func1\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
+" bl my_direct_func2\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 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)
+ return ret;
+ simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn");
+ if (IS_ERR(simple_tsk)) {
+ unregister_ftrace_direct(&direct, my_tramp, true);
+ return PTR_ERR(simple_tsk);
+ }
+
+ return 0;
+}
+
+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");
diff --git a/samples/ftrace/ftrace-direct-multi-modify.c b/samples/ftrace/ftrace-direct-multi-modify.c
new file mode 100644
index 000000000..b03766c62
--- /dev/null
+++ b/samples/ftrace/ftrace-direct-multi-modify.c
@@ -0,0 +1,389 @@
+// 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 $ra, $sp, 8\n"
+" ld.d $t0, $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 $ra, $sp, 8\n"
+" ld.d $t0, $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)
+ return ret;
+ simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn");
+ if (IS_ERR(simple_tsk)) {
+ unregister_ftrace_direct(&direct, my_tramp, true);
+ return PTR_ERR(simple_tsk);
+ }
+
+ return 0;
+}
+
+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");
diff --git a/samples/ftrace/ftrace-direct-multi.c b/samples/ftrace/ftrace-direct-multi.c
new file mode 100644
index 000000000..3fe6ddaf0
--- /dev/null
+++ b/samples/ftrace/ftrace-direct-multi.c
@@ -0,0 +1,241 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/module.h>
+
+#include <linux/mm.h> /* for handle_mm_fault() */
+#include <linux/ftrace.h>
+#include <linux/sched/stat.h>
+#if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32)
+#include <asm/asm-offsets.h>
+#endif
+
+extern void my_direct_func(unsigned long ip);
+
+void my_direct_func(unsigned long ip)
+{
+ trace_printk("ip %lx\n", ip);
+}
+
+extern void my_tramp(void *);
+
+#ifdef CONFIG_RISCV
+#include <asm/asm.h>
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:\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_func\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_tramp, .-my_tramp\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_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:"
+ ASM_ENDBR
+" pushq %rbp\n"
+" movq %rsp, %rbp\n"
+ CALL_DEPTH_ACCOUNT
+" pushq %rdi\n"
+" movq 8(%rbp), %rdi\n"
+" call my_direct_func\n"
+" popq %rdi\n"
+" leave\n"
+ ASM_RET
+" .size my_tramp, .-my_tramp\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_X86_64 */
+
+#ifdef CONFIG_S390
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:"
+" 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_func\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_tramp, .-my_tramp\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_S390 */
+
+#ifdef CONFIG_ARM64
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:"
+" 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_func\n"
+" ldp x30, x9, [sp]\n"
+" ldr x0, [sp, #16]\n"
+" add sp, sp, #32\n"
+" ret x9\n"
+" .size my_tramp, .-my_tramp\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_ARM64 */
+
+#ifdef CONFIG_LOONGARCH
+
+#include <asm/asm.h>
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:\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_func\n"
+" ld.d $a0, $sp, 0\n"
+" ld.d $ra, $sp, 8\n"
+" ld.d $t0, $sp, 16\n"
+" addi.d $sp, $sp, 32\n"
+" jr $t0\n"
+" .size my_tramp, .-my_tramp\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_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:\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_func\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_tramp, .-my_tramp\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_PPC */
+
+static struct ftrace_ops direct;
+
+static int __init ftrace_direct_multi_init(void)
+{
+ ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0);
+ ftrace_set_filter_ip(&direct, (unsigned long) schedule, 0, 0);
+
+ return register_ftrace_direct(&direct, (unsigned long) my_tramp);
+}
+
+static void __exit ftrace_direct_multi_exit(void)
+{
+ unregister_ftrace_direct(&direct, (unsigned long) 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 register_ftrace_direct_multi()");
+MODULE_LICENSE("GPL");
diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c
new file mode 100644
index 000000000..bf2411aa6
--- /dev/null
+++ b/samples/ftrace/ftrace-direct-too.c
@@ -0,0 +1,256 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/module.h>
+
+#include <linux/mm.h> /* for handle_mm_fault() */
+#include <linux/ftrace.h>
+#if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32)
+#include <asm/asm-offsets.h>
+#endif
+
+extern void my_direct_func(struct vm_area_struct *vma, unsigned long address,
+ unsigned int flags, struct pt_regs *regs);
+
+void my_direct_func(struct vm_area_struct *vma, unsigned long address,
+ unsigned int flags, struct pt_regs *regs)
+{
+ trace_printk("handle mm fault vma=%p address=%lx flags=%x regs=%p\n",
+ vma, address, flags, regs);
+}
+
+extern void my_tramp(void *);
+
+#ifdef CONFIG_RISCV
+#include <asm/asm.h>
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:\n"
+" addi sp,sp,-5*"SZREG"\n"
+" "REG_S" a0,0*"SZREG"(sp)\n"
+" "REG_S" a1,1*"SZREG"(sp)\n"
+" "REG_S" a2,2*"SZREG"(sp)\n"
+" "REG_S" t0,3*"SZREG"(sp)\n"
+" "REG_S" ra,4*"SZREG"(sp)\n"
+" call my_direct_func\n"
+" "REG_L" a0,0*"SZREG"(sp)\n"
+" "REG_L" a1,1*"SZREG"(sp)\n"
+" "REG_L" a2,2*"SZREG"(sp)\n"
+" "REG_L" t0,3*"SZREG"(sp)\n"
+" "REG_L" ra,4*"SZREG"(sp)\n"
+" addi sp,sp,5*"SZREG"\n"
+" jr t0\n"
+" .size my_tramp, .-my_tramp\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_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:"
+ ASM_ENDBR
+" pushq %rbp\n"
+" movq %rsp, %rbp\n"
+ CALL_DEPTH_ACCOUNT
+" pushq %rdi\n"
+" pushq %rsi\n"
+" pushq %rdx\n"
+" pushq %rcx\n"
+" call my_direct_func\n"
+" popq %rcx\n"
+" popq %rdx\n"
+" popq %rsi\n"
+" popq %rdi\n"
+" leave\n"
+ ASM_RET
+" .size my_tramp, .-my_tramp\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_X86_64 */
+
+#ifdef CONFIG_S390
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:"
+" 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_func\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_tramp, .-my_tramp\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_S390 */
+
+#ifdef CONFIG_ARM64
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:"
+" hint 34\n" // bti c
+" sub sp, sp, #48\n"
+" stp x9, x30, [sp]\n"
+" stp x0, x1, [sp, #16]\n"
+" stp x2, x3, [sp, #32]\n"
+" bl my_direct_func\n"
+" ldp x30, x9, [sp]\n"
+" ldp x0, x1, [sp, #16]\n"
+" ldp x2, x3, [sp, #32]\n"
+" add sp, sp, #48\n"
+" ret x9\n"
+" .size my_tramp, .-my_tramp\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_ARM64 */
+
+#ifdef CONFIG_LOONGARCH
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:\n"
+" addi.d $sp, $sp, -48\n"
+" st.d $a0, $sp, 0\n"
+" st.d $a1, $sp, 8\n"
+" st.d $a2, $sp, 16\n"
+" st.d $t0, $sp, 24\n"
+" st.d $ra, $sp, 32\n"
+" bl my_direct_func\n"
+" ld.d $a0, $sp, 0\n"
+" ld.d $a1, $sp, 8\n"
+" ld.d $a2, $sp, 16\n"
+" ld.d $ra, $sp, 24\n"
+" ld.d $t0, $sp, 32\n"
+" addi.d $sp, $sp, 48\n"
+" jr $t0\n"
+" .size my_tramp, .-my_tramp\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_LOONGARCH */
+
+#ifdef CONFIG_PPC
+#include <asm/ppc_asm.h>
+
+#ifdef CONFIG_PPC64
+#define STACK_FRAME_SIZE 64
+#define STACK_FRAME_ARG1 32
+#define STACK_FRAME_ARG2 40
+#define STACK_FRAME_ARG3 48
+#define STACK_FRAME_ARG4 56
+#else
+#define STACK_FRAME_SIZE 32
+#define STACK_FRAME_ARG1 16
+#define STACK_FRAME_ARG2 20
+#define STACK_FRAME_ARG3 24
+#define STACK_FRAME_ARG4 28
+#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"
+#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"
+#endif
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:\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_ARG1)"(1)\n"
+ PPC_STL" 4, "__stringify(STACK_FRAME_ARG2)"(1)\n"
+ PPC_STL" 5, "__stringify(STACK_FRAME_ARG3)"(1)\n"
+ PPC_STL" 6, "__stringify(STACK_FRAME_ARG4)"(1)\n"
+" bl my_direct_func\n"
+ PPC_LL" 6, "__stringify(STACK_FRAME_ARG4)"(1)\n"
+ PPC_LL" 5, "__stringify(STACK_FRAME_ARG3)"(1)\n"
+ PPC_LL" 4, "__stringify(STACK_FRAME_ARG2)"(1)\n"
+ PPC_LL" 3, "__stringify(STACK_FRAME_ARG1)"(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_tramp, .-my_tramp\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_PPC */
+
+static struct ftrace_ops direct;
+
+static int __init ftrace_direct_init(void)
+{
+ ftrace_set_filter_ip(&direct, (unsigned long) handle_mm_fault, 0, 0);
+
+ return register_ftrace_direct(&direct, (unsigned long) my_tramp);
+}
+
+static void __exit ftrace_direct_exit(void)
+{
+ unregister_ftrace_direct(&direct, (unsigned long)my_tramp, true);
+}
+
+module_init(ftrace_direct_init);
+module_exit(ftrace_direct_exit);
+
+MODULE_AUTHOR("Steven Rostedt");
+MODULE_DESCRIPTION("Another example use case of using register_ftrace_direct()");
+MODULE_LICENSE("GPL");
diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c
new file mode 100644
index 000000000..5368c8c39
--- /dev/null
+++ b/samples/ftrace/ftrace-direct.c
@@ -0,0 +1,223 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/module.h>
+
+#include <linux/sched.h> /* for wake_up_process() */
+#include <linux/ftrace.h>
+#if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32)
+#include <asm/asm-offsets.h>
+#endif
+
+extern void my_direct_func(struct task_struct *p);
+
+void my_direct_func(struct task_struct *p)
+{
+ trace_printk("waking up %s-%d\n", p->comm, p->pid);
+}
+
+extern void my_tramp(void *);
+
+#ifdef CONFIG_RISCV
+#include <asm/asm.h>
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:\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"
+" call my_direct_func\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_tramp, .-my_tramp\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_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:"
+ ASM_ENDBR
+" pushq %rbp\n"
+" movq %rsp, %rbp\n"
+ CALL_DEPTH_ACCOUNT
+" pushq %rdi\n"
+" call my_direct_func\n"
+" popq %rdi\n"
+" leave\n"
+ ASM_RET
+" .size my_tramp, .-my_tramp\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_X86_64 */
+
+#ifdef CONFIG_S390
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:"
+" 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_func\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_tramp, .-my_tramp\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_S390 */
+
+#ifdef CONFIG_ARM64
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:"
+" hint 34\n" // bti c
+" sub sp, sp, #32\n"
+" stp x9, x30, [sp]\n"
+" str x0, [sp, #16]\n"
+" bl my_direct_func\n"
+" ldp x30, x9, [sp]\n"
+" ldr x0, [sp, #16]\n"
+" add sp, sp, #32\n"
+" ret x9\n"
+" .size my_tramp, .-my_tramp\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_ARM64 */
+
+#ifdef CONFIG_LOONGARCH
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:\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"
+" bl my_direct_func\n"
+" ld.d $a0, $sp, 0\n"
+" ld.d $ra, $sp, 8\n"
+" ld.d $t0, $sp, 16\n"
+" addi.d $sp, $sp, 32\n"
+" jr $t0\n"
+" .size my_tramp, .-my_tramp\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"
+#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"
+#endif
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:\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"
+" bl my_direct_func\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_tramp, .-my_tramp\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_PPC */
+
+static struct ftrace_ops direct;
+
+static int __init ftrace_direct_init(void)
+{
+ ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0);
+
+ return register_ftrace_direct(&direct, (unsigned long) my_tramp);
+}
+
+static void __exit ftrace_direct_exit(void)
+{
+ unregister_ftrace_direct(&direct, (unsigned long)my_tramp, true);
+}
+
+module_init(ftrace_direct_init);
+module_exit(ftrace_direct_exit);
+
+MODULE_AUTHOR("Steven Rostedt");
+MODULE_DESCRIPTION("Example use case of using register_ftrace_direct()");
+MODULE_LICENSE("GPL");
diff --git a/samples/ftrace/ftrace-ops.c b/samples/ftrace/ftrace-ops.c
new file mode 100644
index 000000000..8cae38d8b
--- /dev/null
+++ b/samples/ftrace/ftrace-ops.c
@@ -0,0 +1,252 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/ftrace.h>
+#include <linux/ktime.h>
+#include <linux/module.h>
+
+#include <asm/barrier.h>
+
+/*
+ * Arbitrary large value chosen to be sufficiently large to minimize noise but
+ * sufficiently small to complete quickly.
+ */
+static unsigned int nr_function_calls = 100000;
+module_param(nr_function_calls, uint, 0);
+MODULE_PARM_DESC(nr_function_calls, "How many times to call the relevant tracee");
+
+/*
+ * The number of ops associated with a call site affects whether a tracer can
+ * be called directly or whether it's necessary to go via the list func, which
+ * can be significantly more expensive.
+ */
+static unsigned int nr_ops_relevant = 1;
+module_param(nr_ops_relevant, uint, 0);
+MODULE_PARM_DESC(nr_ops_relevant, "How many ftrace_ops to associate with the relevant tracee");
+
+/*
+ * On architectures where all call sites share the same trampoline, having
+ * tracers enabled for distinct functions can force the use of the list func
+ * and incur overhead for all call sites.
+ */
+static unsigned int nr_ops_irrelevant;
+module_param(nr_ops_irrelevant, uint, 0);
+MODULE_PARM_DESC(nr_ops_irrelevant, "How many ftrace_ops to associate with the irrelevant tracee");
+
+/*
+ * On architectures with DYNAMIC_FTRACE_WITH_REGS, saving the full pt_regs can
+ * be more expensive than only saving the minimal necessary regs.
+ */
+static bool save_regs;
+module_param(save_regs, bool, 0);
+MODULE_PARM_DESC(save_regs, "Register ops with FTRACE_OPS_FL_SAVE_REGS (save all registers in the trampoline)");
+
+static bool assist_recursion;
+module_param(assist_recursion, bool, 0);
+MODULE_PARM_DESC(assist_reursion, "Register ops with FTRACE_OPS_FL_RECURSION");
+
+static bool assist_rcu;
+module_param(assist_rcu, bool, 0);
+MODULE_PARM_DESC(assist_reursion, "Register ops with FTRACE_OPS_FL_RCU");
+
+/*
+ * By default, a trivial tracer is used which immediately returns to mimimize
+ * overhead. Sometimes a consistency check using a more expensive tracer is
+ * desireable.
+ */
+static bool check_count;
+module_param(check_count, bool, 0);
+MODULE_PARM_DESC(check_count, "Check that tracers are called the expected number of times\n");
+
+/*
+ * Usually it's not interesting to leave the ops registered after the test
+ * runs, but sometimes it can be useful to leave them registered so that they
+ * can be inspected through the tracefs 'enabled_functions' file.
+ */
+static bool persist;
+module_param(persist, bool, 0);
+MODULE_PARM_DESC(persist, "Successfully load module and leave ftrace ops registered after test completes\n");
+
+/*
+ * Marked as noinline to ensure that an out-of-line traceable copy is
+ * generated by the compiler.
+ *
+ * The barrier() ensures the compiler won't elide calls by determining there
+ * are no side-effects.
+ */
+static noinline void tracee_relevant(void)
+{
+ barrier();
+}
+
+/*
+ * Marked as noinline to ensure that an out-of-line traceable copy is
+ * generated by the compiler.
+ *
+ * The barrier() ensures the compiler won't elide calls by determining there
+ * are no side-effects.
+ */
+static noinline void tracee_irrelevant(void)
+{
+ barrier();
+}
+
+struct sample_ops {
+ struct ftrace_ops ops;
+ unsigned int count;
+};
+
+static void ops_func_nop(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *op,
+ struct ftrace_regs *fregs)
+{
+ /* do nothing */
+}
+
+static void ops_func_count(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *op,
+ struct ftrace_regs *fregs)
+{
+ struct sample_ops *self;
+
+ self = container_of(op, struct sample_ops, ops);
+ self->count++;
+}
+
+static struct sample_ops *ops_relevant;
+static struct sample_ops *ops_irrelevant;
+
+static struct sample_ops *ops_alloc_init(void *tracee, ftrace_func_t func,
+ unsigned long flags, int nr)
+{
+ struct sample_ops *ops;
+
+ ops = kcalloc(nr, sizeof(*ops), GFP_KERNEL);
+ if (WARN_ON_ONCE(!ops))
+ return NULL;
+
+ for (unsigned int i = 0; i < nr; i++) {
+ ops[i].ops.func = func;
+ ops[i].ops.flags = flags;
+ WARN_ON_ONCE(ftrace_set_filter_ip(&ops[i].ops, (unsigned long)tracee, 0, 0));
+ WARN_ON_ONCE(register_ftrace_function(&ops[i].ops));
+ }
+
+ return ops;
+}
+
+static void ops_destroy(struct sample_ops *ops, int nr)
+{
+ if (!ops)
+ return;
+
+ for (unsigned int i = 0; i < nr; i++) {
+ WARN_ON_ONCE(unregister_ftrace_function(&ops[i].ops));
+ ftrace_free_filter(&ops[i].ops);
+ }
+
+ kfree(ops);
+}
+
+static void ops_check(struct sample_ops *ops, int nr,
+ unsigned int expected_count)
+{
+ if (!ops || !check_count)
+ return;
+
+ for (unsigned int i = 0; i < nr; i++) {
+ if (ops->count == expected_count)
+ continue;
+ pr_warn("Counter called %u times (expected %u)\n",
+ ops->count, expected_count);
+ }
+}
+
+static ftrace_func_t tracer_relevant = ops_func_nop;
+static ftrace_func_t tracer_irrelevant = ops_func_nop;
+
+static int __init ftrace_ops_sample_init(void)
+{
+ unsigned long flags = 0;
+ ktime_t start, end;
+ u64 period;
+
+ if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && save_regs) {
+ pr_info("this kernel does not support saving registers\n");
+ save_regs = false;
+ } else if (save_regs) {
+ flags |= FTRACE_OPS_FL_SAVE_REGS;
+ }
+
+ if (assist_recursion)
+ flags |= FTRACE_OPS_FL_RECURSION;
+
+ if (assist_rcu)
+ flags |= FTRACE_OPS_FL_RCU;
+
+ if (check_count) {
+ tracer_relevant = ops_func_count;
+ tracer_irrelevant = ops_func_count;
+ }
+
+ pr_info("registering:\n"
+ " relevant ops: %u\n"
+ " tracee: %ps\n"
+ " tracer: %ps\n"
+ " irrelevant ops: %u\n"
+ " tracee: %ps\n"
+ " tracer: %ps\n"
+ " saving registers: %s\n"
+ " assist recursion: %s\n"
+ " assist RCU: %s\n",
+ nr_ops_relevant, tracee_relevant, tracer_relevant,
+ nr_ops_irrelevant, tracee_irrelevant, tracer_irrelevant,
+ save_regs ? "YES" : "NO",
+ assist_recursion ? "YES" : "NO",
+ assist_rcu ? "YES" : "NO");
+
+ ops_relevant = ops_alloc_init(tracee_relevant, tracer_relevant,
+ flags, nr_ops_relevant);
+ ops_irrelevant = ops_alloc_init(tracee_irrelevant, tracer_irrelevant,
+ flags, nr_ops_irrelevant);
+
+ start = ktime_get();
+ for (unsigned int i = 0; i < nr_function_calls; i++)
+ tracee_relevant();
+ end = ktime_get();
+
+ ops_check(ops_relevant, nr_ops_relevant, nr_function_calls);
+ ops_check(ops_irrelevant, nr_ops_irrelevant, 0);
+
+ period = ktime_to_ns(ktime_sub(end, start));
+
+ pr_info("Attempted %u calls to %ps in %lluns (%lluns / call)\n",
+ nr_function_calls, tracee_relevant,
+ period, nr_function_calls ? div_u64(period, nr_function_calls) : -1LL);
+
+ if (persist)
+ return 0;
+
+ ops_destroy(ops_relevant, nr_ops_relevant);
+ ops_destroy(ops_irrelevant, nr_ops_irrelevant);
+
+ /*
+ * The benchmark completed successfully, but there's no reason to keep
+ * the module around. Return an error so the user doesn't have to
+ * manually unload the module.
+ */
+ return -EINVAL;
+}
+module_init(ftrace_ops_sample_init);
+
+static void __exit ftrace_ops_sample_exit(void)
+{
+ ops_destroy(ops_relevant, nr_ops_relevant);
+ ops_destroy(ops_irrelevant, nr_ops_irrelevant);
+}
+module_exit(ftrace_ops_sample_exit);
+
+MODULE_AUTHOR("Mark Rutland");
+MODULE_DESCRIPTION("Example of using custom ftrace_ops");
+MODULE_LICENSE("GPL");
diff --git a/samples/ftrace/sample-trace-array.c b/samples/ftrace/sample-trace-array.c
new file mode 100644
index 000000000..414761610
--- /dev/null
+++ b/samples/ftrace/sample-trace-array.c
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/trace.h>
+#include <linux/trace_events.h>
+#include <linux/timer.h>
+#include <linux/err.h>
+#include <linux/jiffies.h>
+#include <linux/workqueue.h>
+
+/*
+ * Any file that uses trace points, must include the header.
+ * But only one file, must include the header by defining
+ * CREATE_TRACE_POINTS first. This will make the C code that
+ * creates the handles for the trace points.
+ */
+#define CREATE_TRACE_POINTS
+#include "sample-trace-array.h"
+
+struct trace_array *tr;
+static void mytimer_handler(struct timer_list *unused);
+static struct task_struct *simple_tsk;
+
+static void trace_work_fn(struct work_struct *work)
+{
+ /*
+ * Disable tracing for event "sample_event".
+ */
+ trace_array_set_clr_event(tr, "sample-subsystem", "sample_event",
+ false);
+}
+static DECLARE_WORK(trace_work, trace_work_fn);
+
+/*
+ * mytimer: Timer setup to disable tracing for event "sample_event". This
+ * timer is only for the purposes of the sample module to demonstrate access of
+ * Ftrace instances from within kernel.
+ */
+static DEFINE_TIMER(mytimer, mytimer_handler);
+
+static void mytimer_handler(struct timer_list *unused)
+{
+ schedule_work(&trace_work);
+}
+
+static void simple_thread_func(int count)
+{
+ set_current_state(TASK_INTERRUPTIBLE);
+ schedule_timeout(HZ);
+
+ /*
+ * Printing count value using trace_array_printk() - trace_printk()
+ * equivalent for the instance buffers.
+ */
+ trace_array_printk(tr, _THIS_IP_, "trace_array_printk: count=%d\n",
+ count);
+ /*
+ * Tracepoint for event "sample_event". This will print the
+ * current value of count and current jiffies.
+ */
+ trace_sample_event(count, jiffies);
+}
+
+static int simple_thread(void *arg)
+{
+ int count = 0;
+ unsigned long delay = msecs_to_jiffies(5000);
+
+ /*
+ * Enable tracing for "sample_event".
+ */
+ trace_array_set_clr_event(tr, "sample-subsystem", "sample_event", true);
+
+ /*
+ * Adding timer - mytimer. This timer will disable tracing after
+ * delay seconds.
+ *
+ */
+ add_timer(&mytimer);
+ mod_timer(&mytimer, jiffies+delay);
+
+ while (!kthread_should_stop())
+ simple_thread_func(count++);
+
+ timer_delete(&mytimer);
+ cancel_work_sync(&trace_work);
+
+ /*
+ * trace_array_put() decrements the reference counter associated with
+ * the trace array - "tr". We are done using the trace array, hence
+ * decrement the reference counter so that it can be destroyed using
+ * trace_array_destroy().
+ */
+ trace_array_put(tr);
+
+ return 0;
+}
+
+static int __init sample_trace_array_init(void)
+{
+ /*
+ * Return a pointer to the trace array with name "sample-instance" if it
+ * exists, else create a new trace array.
+ *
+ * NOTE: This function increments the reference counter
+ * associated with the trace array - "tr".
+ */
+ tr = trace_array_get_by_name("sample-instance", "sched,timer,kprobes");
+
+ if (!tr)
+ return -1;
+ /*
+ * If context specific per-cpu buffers havent already been allocated.
+ */
+ trace_array_init_printk(tr);
+
+ simple_tsk = kthread_run(simple_thread, NULL, "sample-instance");
+ if (IS_ERR(simple_tsk)) {
+ trace_array_put(tr);
+ trace_array_destroy(tr);
+ return -1;
+ }
+
+ return 0;
+}
+
+static void __exit sample_trace_array_exit(void)
+{
+ kthread_stop(simple_tsk);
+
+ /*
+ * We are unloading our module and no longer require the trace array.
+ * Remove/destroy "tr" using trace_array_destroy()
+ */
+ trace_array_destroy(tr);
+}
+
+module_init(sample_trace_array_init);
+module_exit(sample_trace_array_exit);
+
+MODULE_AUTHOR("Divya Indi");
+MODULE_DESCRIPTION("Sample module for kernel access to Ftrace instances");
+MODULE_LICENSE("GPL");
diff --git a/samples/ftrace/sample-trace-array.h b/samples/ftrace/sample-trace-array.h
new file mode 100644
index 000000000..6f8962428
--- /dev/null
+++ b/samples/ftrace/sample-trace-array.h
@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * If TRACE_SYSTEM is defined, that will be the directory created
+ * in the ftrace directory under /sys/kernel/tracing/events/<system>
+ *
+ * The define_trace.h below will also look for a file name of
+ * TRACE_SYSTEM.h where TRACE_SYSTEM is what is defined here.
+ * In this case, it would look for sample-trace.h
+ *
+ * If the header name will be different than the system name
+ * (as in this case), then you can override the header name that
+ * define_trace.h will look up by defining TRACE_INCLUDE_FILE
+ *
+ * This file is called sample-trace-array.h but we want the system
+ * to be called "sample-subsystem". Therefore we must define the name of this
+ * file:
+ *
+ * #define TRACE_INCLUDE_FILE sample-trace-array
+ *
+ * As we do in the bottom of this file.
+ *
+ * Notice that TRACE_SYSTEM should be defined outside of #if
+ * protection, just like TRACE_INCLUDE_FILE.
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM sample-subsystem
+
+/*
+ * TRACE_SYSTEM is expected to be a C valid variable (alpha-numeric
+ * and underscore), although it may start with numbers. If for some
+ * reason it is not, you need to add the following lines:
+ */
+#undef TRACE_SYSTEM_VAR
+#define TRACE_SYSTEM_VAR sample_subsystem
+
+/*
+ * But the above is only needed if TRACE_SYSTEM is not alpha-numeric
+ * and underscored. By default, TRACE_SYSTEM_VAR will be equal to
+ * TRACE_SYSTEM. As TRACE_SYSTEM_VAR must be alpha-numeric, if
+ * TRACE_SYSTEM is not, then TRACE_SYSTEM_VAR must be defined with
+ * only alpha-numeric and underscores.
+ *
+ * The TRACE_SYSTEM_VAR is only used internally and not visible to
+ * user space.
+ */
+
+/*
+ * Notice that this file is not protected like a normal header.
+ * We also must allow for rereading of this file. The
+ *
+ * || defined(TRACE_HEADER_MULTI_READ)
+ *
+ * serves this purpose.
+ */
+#if !defined(_SAMPLE_TRACE_ARRAY_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _SAMPLE_TRACE_ARRAY_H
+
+#include <linux/tracepoint.h>
+TRACE_EVENT(sample_event,
+
+ TP_PROTO(int count, unsigned long time),
+
+ TP_ARGS(count, time),
+
+ TP_STRUCT__entry(
+ __field(int, count)
+ __field(unsigned long, time)
+ ),
+
+ TP_fast_assign(
+ __entry->count = count;
+ __entry->time = time;
+ ),
+
+ TP_printk("count value=%d at jiffies=%lu", __entry->count,
+ __entry->time)
+ );
+#endif
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#define TRACE_INCLUDE_FILE sample-trace-array
+#include <trace/define_trace.h>