arch/csky/abiv1/alignment.c

File Facts

System

Linux kernel

Corpus path

arch/csky/abiv1/alignment.c

Extension

.c

Size

5881 bytes

Lines

341

Domain

Architecture Layer

Bucket

arch/csky

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.

• CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.
• Touches user memory; correctness depends on fault-safe copying and privilege boundary handling.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/kernel.h
• linux/uaccess.h
• linux/ptrace.h

Detected Declarations

• function get_ptreg
• function put_ptreg
• function ldb_asm
• function stb_asm
• function ldh_c
• function sth_c
• function ldw_c
• function stw_c
• function csky_alignment
• function csky_alignment_init

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.

#include <linux/kernel.h>
#include <linux/uaccess.h>
#include <linux/ptrace.h>

static int align_kern_enable = 1;
static int align_usr_enable = 1;
static int align_kern_count = 0;
static int align_usr_count = 0;

static inline uint32_t get_ptreg(struct pt_regs *regs, uint32_t rx)
{
	return rx == 15 ? regs->lr : *((uint32_t *)&(regs->a0) - 2 + rx);
}

static inline void put_ptreg(struct pt_regs *regs, uint32_t rx, uint32_t val)
{
	if (rx == 15)
		regs->lr = val;
	else
		*((uint32_t *)&(regs->a0) - 2 + rx) = val;
}

/*
 * Get byte-value from addr and set it to *valp.
 *
 * Success: return 0
 * Failure: return 1
 */
static int ldb_asm(uint32_t addr, uint32_t *valp)
{
	uint32_t val;
	int err;

	asm volatile (
		"movi	%0, 0\n"
		"1:\n"
		"ldb	%1, (%2)\n"
		"br	3f\n"
		"2:\n"
		"movi	%0, 1\n"
		"br	3f\n"
		".section __ex_table,\"a\"\n"
		".align 2\n"
		".long	1b, 2b\n"
		".previous\n"
		"3:\n"
		: "=&r"(err), "=r"(val)
		: "r" (addr)
	);

	*valp = val;

	return err;
}

/*
 * Put byte-value to addr.
 *
 * Success: return 0
 * Failure: return 1
 */
static int stb_asm(uint32_t addr, uint32_t val)
{
	int err;

	asm volatile (
		"movi	%0, 0\n"
		"1:\n"
		"stb	%1, (%2)\n"
		"br	3f\n"
		"2:\n"
		"movi	%0, 1\n"
		"br	3f\n"
		".section __ex_table,\"a\"\n"
		".align 2\n"
		".long	1b, 2b\n"
		".previous\n"
		"3:\n"
		: "=&r"(err)
		: "r"(val), "r" (addr)
	);

	return err;
}

/*
 * Get half-word from [rx + imm]

Annotation

• Immediate include surface: `linux/kernel.h`, `linux/uaccess.h`, `linux/ptrace.h`.
• Detected declarations: `function get_ptreg`, `function put_ptreg`, `function ldb_asm`, `function stb_asm`, `function ldh_c`, `function sth_c`, `function ldw_c`, `function stw_c`, `function csky_alignment`, `function csky_alignment_init`.
• Atlas domain: Architecture Layer / arch/csky.
• Implementation status: source implementation candidate.
• This snippet crosses the user/kernel memory boundary; validate fault handling and access checks before translating the pattern.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.