samples/ftrace/ftrace-direct-too.c

Source file repositories/reference/linux-study-clean/samples/ftrace/ftrace-direct-too.c

File Facts

System
Linux kernel
Corpus path
samples/ftrace/ftrace-direct-too.c
Extension
.c
Size
6337 bytes
Lines
257
Domain
Support Tooling And Documentation
Bucket
samples
Inferred role
Support Tooling And Documentation: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

#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"

Annotation

Implementation Notes