lib/raid/xor/arm/xor.c

Source file repositories/reference/linux-study-clean/lib/raid/xor/arm/xor.c

File Facts

System
Linux kernel
Corpus path
lib/raid/xor/arm/xor.c
Extension
.c
Size
3702 bytes
Lines
137
Domain
Kernel Services
Bucket
lib
Inferred role
Kernel Services: implementation source
Status
source implementation candidate

Why This File Exists

Shared kernel service surface used by multiple subsystems, including helpers, cryptography, virtualization support, and async I/O infrastructure.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Copyright (C) 2001 Russell King
 */
#include "xor_impl.h"
#include "xor_arch.h"

#define __XOR(a1, a2) a1 ^= a2

#define GET_BLOCK_2(dst) \
	__asm__("ldmia	%0, {%1, %2}" \
		: "=r" (dst), "=r" (a1), "=r" (a2) \
		: "0" (dst))

#define GET_BLOCK_4(dst) \
	__asm__("ldmia	%0, {%1, %2, %3, %4}" \
		: "=r" (dst), "=r" (a1), "=r" (a2), "=r" (a3), "=r" (a4) \
		: "0" (dst))

#define XOR_BLOCK_2(src) \
	__asm__("ldmia	%0!, {%1, %2}" \
		: "=r" (src), "=r" (b1), "=r" (b2) \
		: "0" (src)); \
	__XOR(a1, b1); __XOR(a2, b2);

#define XOR_BLOCK_4(src) \
	__asm__("ldmia	%0!, {%1, %2, %3, %4}" \
		: "=r" (src), "=r" (b1), "=r" (b2), "=r" (b3), "=r" (b4) \
		: "0" (src)); \
	__XOR(a1, b1); __XOR(a2, b2); __XOR(a3, b3); __XOR(a4, b4)

#define PUT_BLOCK_2(dst) \
	__asm__ __volatile__("stmia	%0!, {%2, %3}" \
		: "=r" (dst) \
		: "0" (dst), "r" (a1), "r" (a2))

#define PUT_BLOCK_4(dst) \
	__asm__ __volatile__("stmia	%0!, {%2, %3, %4, %5}" \
		: "=r" (dst) \
		: "0" (dst), "r" (a1), "r" (a2), "r" (a3), "r" (a4))

static void
xor_arm4regs_2(unsigned long bytes, unsigned long * __restrict p1,
	       const unsigned long * __restrict p2)
{
	unsigned int lines = bytes / sizeof(unsigned long) / 4;
	register unsigned int a1 __asm__("r4");
	register unsigned int a2 __asm__("r5");
	register unsigned int a3 __asm__("r6");
	register unsigned int a4 __asm__("r10");
	register unsigned int b1 __asm__("r8");
	register unsigned int b2 __asm__("r9");
	register unsigned int b3 __asm__("ip");
	register unsigned int b4 __asm__("lr");

	do {
		GET_BLOCK_4(p1);
		XOR_BLOCK_4(p2);
		PUT_BLOCK_4(p1);
	} while (--lines);
}

static void
xor_arm4regs_3(unsigned long bytes, unsigned long * __restrict p1,
	       const unsigned long * __restrict p2,
	       const unsigned long * __restrict p3)
{
	unsigned int lines = bytes / sizeof(unsigned long) / 4;
	register unsigned int a1 __asm__("r4");
	register unsigned int a2 __asm__("r5");
	register unsigned int a3 __asm__("r6");
	register unsigned int a4 __asm__("r10");
	register unsigned int b1 __asm__("r8");
	register unsigned int b2 __asm__("r9");
	register unsigned int b3 __asm__("ip");
	register unsigned int b4 __asm__("lr");

	do {
		GET_BLOCK_4(p1);
		XOR_BLOCK_4(p2);
		XOR_BLOCK_4(p3);
		PUT_BLOCK_4(p1);
	} while (--lines);
}

static void
xor_arm4regs_4(unsigned long bytes, unsigned long * __restrict p1,
	       const unsigned long * __restrict p2,
	       const unsigned long * __restrict p3,
	       const unsigned long * __restrict p4)

Annotation

Implementation Notes