cregit-Linux how code gets into the kernel

Release 4.11 arch/arm/include/asm/word-at-a-time.h

#ifndef __ASM_ARM_WORD_AT_A_TIME_H

#define __ASM_ARM_WORD_AT_A_TIME_H

#ifndef __ARMEB__

/*
 * Little-endian word-at-a-time zero byte handling.
 * Heavily based on the x86 algorithm.
 */
#include <linux/kernel.h>


struct word_at_a_time {
	

const unsigned long one_bits, high_bits;
};


#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }


static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c) { unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits; *bits = mask; return mask; }

Contributors

PersonTokensPropCommitsCommitProp
Will Deacon52100.00%1100.00%
Total52100.00%1100.00%

#define prep_zero_mask(a, bits, c) (bits)
static inline unsigned long create_zero_mask(unsigned long bits) { bits = (bits - 1) & ~bits; return bits >> 7; }

Contributors

PersonTokensPropCommitsCommitProp
Will Deacon28100.00%1100.00%
Total28100.00%1100.00%


static inline unsigned long find_zero(unsigned long mask) { unsigned long ret; #if __LINUX_ARM_ARCH__ >= 5 /* We have clz available. */ ret = fls(mask) >> 3; #else /* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */ ret = (0x0ff0001 + mask) >> 23; /* Fix the 1 for 00 case */ ret &= mask; #endif return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Will Deacon54100.00%1100.00%
Total54100.00%1100.00%

#define zero_bytemask(mask) (mask) #else /* __ARMEB__ */ #include <asm-generic/word-at-a-time.h> #endif #ifdef CONFIG_DCACHE_WORD_ACCESS /* * Load an unaligned word from kernel space. * * In the (very unlikely) case of the word being a page-crosser * and the next page not being mapped, take the exception and * return zeroes in the non-existing part. */
static inline unsigned long load_unaligned_zeropad(const void *addr) { unsigned long ret, offset; /* Load word from unaligned pointer addr */ asm( "1: ldr %0, [%2]\n" "2:\n" " .pushsection .text.fixup,\"ax\"\n" " .align 2\n" "3: and %1, %2, #0x3\n" " bic %2, %2, #0x3\n" " ldr %0, [%2]\n" " lsl %1, %1, #0x3\n" #ifndef __ARMEB__ " lsr %0, %0, %1\n" #else " lsl %0, %0, %1\n" #endif " b 2b\n" " .popsection\n" " .pushsection __ex_table,\"a\"\n" " .align 3\n" " .long 1b, 3b\n" " .popsection" : "=&r" (ret), "=&r" (offset) : "r" (addr), "Qo" (*(unsigned long *)addr)); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Will Deacon3397.06%266.67%
Ard Biesheuvel12.94%133.33%
Total34100.00%3100.00%

#endif /* DCACHE_WORD_ACCESS */ #endif /* __ASM_ARM_WORD_AT_A_TIME_H */

Overall Contributors

PersonTokensPropCommitsCommitProp
Will Deacon23299.57%375.00%
Ard Biesheuvel10.43%125.00%
Total233100.00%4100.00%
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with cregit.