diff options
Diffstat (limited to 'samples/ftrace/ftrace-direct-too.c')
| -rw-r--r-- | samples/ftrace/ftrace-direct-too.c | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c new file mode 100644 index 000000000000..3d0fa260332d --- /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 $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 */ + +#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"); |