diff options
Diffstat (limited to 'samples/ftrace/ftrace-direct-too.c')
| -rw-r--r-- | samples/ftrace/ftrace-direct-too.c | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c new file mode 100644 index 0000000000..e39c3563ae --- /dev/null +++ b/samples/ftrace/ftrace-direct-too.c @@ -0,0 +1,147 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <linux/module.h> + +#include <linux/mm.h> /* for handle_mm_fault() */ +#include <linux/ftrace.h> +#ifndef CONFIG_ARM64 +#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_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 $t0, $sp, 24\n" +" ld.d $ra, $sp, 32\n" +" addi.d $sp, $sp, 48\n" +" jr $t0\n" +" .size my_tramp, .-my_tramp\n" +" .popsection\n" +); + +#endif /* CONFIG_LOONGARCH */ + +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"); |