cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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bitmap.c (2735B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 *  linux/fs/ext4/bitmap.c
      4 *
      5 * Copyright (C) 1992, 1993, 1994, 1995
      6 * Remy Card (card@masi.ibp.fr)
      7 * Laboratoire MASI - Institut Blaise Pascal
      8 * Universite Pierre et Marie Curie (Paris VI)
      9 */
     10
     11#include <linux/buffer_head.h>
     12#include "ext4.h"
     13
     14unsigned int ext4_count_free(char *bitmap, unsigned int numchars)
     15{
     16	return numchars * BITS_PER_BYTE - memweight(bitmap, numchars);
     17}
     18
     19int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
     20				  struct ext4_group_desc *gdp,
     21				  struct buffer_head *bh, int sz)
     22{
     23	__u32 hi;
     24	__u32 provided, calculated;
     25	struct ext4_sb_info *sbi = EXT4_SB(sb);
     26
     27	if (!ext4_has_metadata_csum(sb))
     28		return 1;
     29
     30	provided = le16_to_cpu(gdp->bg_inode_bitmap_csum_lo);
     31	calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
     32	if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) {
     33		hi = le16_to_cpu(gdp->bg_inode_bitmap_csum_hi);
     34		provided |= (hi << 16);
     35	} else
     36		calculated &= 0xFFFF;
     37
     38	return provided == calculated;
     39}
     40
     41void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
     42				struct ext4_group_desc *gdp,
     43				struct buffer_head *bh, int sz)
     44{
     45	__u32 csum;
     46	struct ext4_sb_info *sbi = EXT4_SB(sb);
     47
     48	if (!ext4_has_metadata_csum(sb))
     49		return;
     50
     51	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
     52	gdp->bg_inode_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
     53	if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
     54		gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(csum >> 16);
     55}
     56
     57int ext4_block_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
     58				  struct ext4_group_desc *gdp,
     59				  struct buffer_head *bh)
     60{
     61	__u32 hi;
     62	__u32 provided, calculated;
     63	struct ext4_sb_info *sbi = EXT4_SB(sb);
     64	int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;
     65
     66	if (!ext4_has_metadata_csum(sb))
     67		return 1;
     68
     69	provided = le16_to_cpu(gdp->bg_block_bitmap_csum_lo);
     70	calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
     71	if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END) {
     72		hi = le16_to_cpu(gdp->bg_block_bitmap_csum_hi);
     73		provided |= (hi << 16);
     74	} else
     75		calculated &= 0xFFFF;
     76
     77	if (provided == calculated)
     78		return 1;
     79
     80	return 0;
     81}
     82
     83void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
     84				struct ext4_group_desc *gdp,
     85				struct buffer_head *bh)
     86{
     87	int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;
     88	__u32 csum;
     89	struct ext4_sb_info *sbi = EXT4_SB(sb);
     90
     91	if (!ext4_has_metadata_csum(sb))
     92		return;
     93
     94	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
     95	gdp->bg_block_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
     96	if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END)
     97		gdp->bg_block_bitmap_csum_hi = cpu_to_le16(csum >> 16);
     98}