arch/riscv/kernel/probes/uprobes.c

Source file repositories/reference/linux-study-clean/arch/riscv/kernel/probes/uprobes.c

File Facts

System
Linux kernel
Corpus path
arch/riscv/kernel/probes/uprobes.c
Extension
.c
Size
3780 bytes
Lines
183
Domain
Architecture Layer
Bucket
arch/riscv
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

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

// SPDX-License-Identifier: GPL-2.0-only

#include <linux/highmem.h>
#include <linux/ptrace.h>
#include <linux/uprobes.h>
#include <asm/insn.h>

#include "decode-insn.h"

#define UPROBE_TRAP_NR	UINT_MAX

bool is_swbp_insn(uprobe_opcode_t *insn)
{
#ifdef CONFIG_RISCV_ISA_C
	return (*insn & 0xffff) == UPROBE_SWBP_INSN;
#else
	return *insn == UPROBE_SWBP_INSN;
#endif
}

bool is_trap_insn(uprobe_opcode_t *insn)
{
	return riscv_insn_is_ebreak(*insn) || riscv_insn_is_c_ebreak(*insn);
}

unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
{
	return instruction_pointer(regs);
}

int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
			     unsigned long addr)
{
	probe_opcode_t opcode;

	opcode = *(probe_opcode_t *)(&auprobe->insn[0]);

	auprobe->insn_size = GET_INSN_LENGTH(opcode);

	switch (riscv_probe_decode_insn(&opcode, &auprobe->api)) {
	case INSN_REJECTED:
		return -EINVAL;

	case INSN_GOOD_NO_SLOT:
		auprobe->simulate = true;
		break;

	case INSN_GOOD:
		auprobe->simulate = false;
		break;

	default:
		return -EINVAL;
	}

	return 0;
}

int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
	struct uprobe_task *utask = current->utask;

	utask->autask.saved_cause = current->thread.bad_cause;
	current->thread.bad_cause = UPROBE_TRAP_NR;

	instruction_pointer_set(regs, utask->xol_vaddr);

	return 0;
}

int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
	struct uprobe_task *utask = current->utask;

	WARN_ON_ONCE(current->thread.bad_cause != UPROBE_TRAP_NR);
	current->thread.bad_cause = utask->autask.saved_cause;

	instruction_pointer_set(regs, utask->vaddr + auprobe->insn_size);

	return 0;
}

bool arch_uprobe_xol_was_trapped(struct task_struct *t)
{
	if (t->thread.bad_cause != UPROBE_TRAP_NR)
		return true;

	return false;
}

Annotation

Implementation Notes