arch/riscv/kernel/mcount-dyn.S

Source file repositories/reference/linux-study-clean/arch/riscv/kernel/mcount-dyn.S

File Facts

System
Linux kernel
Corpus path
arch/riscv/kernel/mcount-dyn.S
Extension
.S
Size
5148 bytes
Lines
211
Domain
Architecture Layer
Bucket
arch/riscv
Inferred role
Architecture Layer: arch/riscv
Status
atlas-only

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#include <linux/init.h>
#include <linux/linkage.h>
#include <linux/export.h>
#include <asm/asm.h>
#include <asm/csr.h>
#include <asm/unistd.h>
#include <asm/thread_info.h>
#include <asm/asm-offsets.h>
#include <asm/ftrace.h>

	.text

#define ABI_SIZE_ON_STACK	80
#define ABI_A0			0
#define ABI_A1			8
#define ABI_A2			16
#define ABI_A3			24
#define ABI_A4			32
#define ABI_A5			40
#define ABI_A6			48
#define ABI_A7			56
#define ABI_T0			64
#define ABI_RA			72

	.macro SAVE_ABI
	addi	sp, sp, -ABI_SIZE_ON_STACK

	REG_S	a0, ABI_A0(sp)
	REG_S	a1, ABI_A1(sp)
	REG_S	a2, ABI_A2(sp)
	REG_S	a3, ABI_A3(sp)
	REG_S	a4, ABI_A4(sp)
	REG_S	a5, ABI_A5(sp)
	REG_S	a6, ABI_A6(sp)
	REG_S	a7, ABI_A7(sp)
	REG_S	t0, ABI_T0(sp)
	REG_S	ra, ABI_RA(sp)
	.endm

	.macro RESTORE_ABI
	REG_L	a0, ABI_A0(sp)
	REG_L	a1, ABI_A1(sp)
	REG_L	a2, ABI_A2(sp)
	REG_L	a3, ABI_A3(sp)
	REG_L	a4, ABI_A4(sp)
	REG_L	a5, ABI_A5(sp)
	REG_L	a6, ABI_A6(sp)
	REG_L	a7, ABI_A7(sp)
	REG_L	t0, ABI_T0(sp)
	REG_L	ra, ABI_RA(sp)

	addi	sp, sp, ABI_SIZE_ON_STACK
	.endm

/**
* SAVE_ABI_REGS - save regs against the ftrace_regs struct
*
* After the stack is established,
*
* 0(sp) stores the PC of the traced function which can be accessed
* by &(fregs)->epc in tracing function.
*
* 8(sp) stores the function return address (i.e. parent IP) that
* can be accessed by &(fregs)->ra in tracing function.
*
* The other regs are saved at the respective location and accessed
* by the respective ftrace_regs member.
*
* Here is the layout of stack for your reference.
*

Annotation

Implementation Notes