Frediano Ziglio
2012-Aug-02 09:47 UTC
[syslinux] [PATCH 3/3] ALPHA: implement and use rdwr_bytes
This is part of some patches to support sectors > 512.
Currently I'm able to boot a Ubuntu kernel but seems that mboot is not
working for some reason.
This patch add a rdwr_bytes functions which remove the assumption in
some places that sector is 512. This function is quite helpful if you
are going to read/write a range of bytes to/from the stack without
creating stack overflows for free.
I think this is the safer patch of the three.
Signed-off-by: Frediano Ziglio <frediano.ziglio at citrix.com>
---
core/fs/diskio.c | 80 +++++++++++++++++++++++++++++++++++++++++++--
core/fs/ext2/ext2.c | 2 +-
core/fs/fat/fat.c | 2 +-
core/fs/iso9660/iso9660.c | 8 ++--
core/fs/ntfs/ntfs.c | 4 +-
core/include/disk.h | 2 +
6 files changed, 87 insertions(+), 11 deletions(-)
diff --git a/core/fs/diskio.c b/core/fs/diskio.c
index 6683816..7e58d6f 100644
--- a/core/fs/diskio.c
+++ b/core/fs/diskio.c
@@ -265,6 +265,80 @@ static int edd_rdwr_sectors(struct disk *disk, void *buf,
return done;
}
+#define rdwr_sectors0(buf, lba, count, is_write) \
+ disk->rdwr_sectors(disk, buf, lba, count, is_write)
+/*
+ * Read a range of bytes
+ */
+int rdwr_bytes(struct disk *disk, void *buf,
+ bytes_t lba, size_t count, bool is_write)
+{
+ int done, res;
+ unsigned mask, before, len;
+ unsigned shift = disk->sector_shift;
+
+ dprintf("called rdwr_bytes from %llu for %u bytes\n", (unsigned
long long) lba, (unsigned) count);
+
+ mask = disk->sector_size - 1;
+
+ /* aligned, fix count/lba */
+ if (((lba|count) & mask) == 0) {
+ return (rdwr_sectors0(buf, lba >> shift, count >> shift, is_write)
<< shift);
+ }
+
+ /* do the hard work */
+ done = 0;
+ if ((lba & mask) != 0) {
+ /* align start sector */
+ before = lba & mask;
+ len = disk->sector_size - before;
+ if (len > count) len = count;
+ res = rdwr_sectors0(core_xfer_buf, lba >> shift, 1, 0);
+ if (!res) return done;
+ if (is_write) {
+ memcpy(core_xfer_buf + before, buf, len);
+ res = rdwr_sectors0(core_xfer_buf, lba >> shift, 1, 1);
+ if (!res) return done;
+ } else {
+ memcpy(buf, core_xfer_buf + before, len);
+ }
+ buf += len;
+ lba += len;
+ count -= len;
+ done += len;
+ }
+
+ /* read/write full sectors */
+ len = count >> shift;
+ if (len) {
+ res = rdwr_sectors0(buf, lba >> shift, len, is_write) << shift;
+ done += res;
+ len <<= shift;
+ if (res < len) return done;
+ lba += len;
+ count -= len;
+ done += len;
+ buf += len;
+ }
+
+ /* last partial sector */
+ if (count) {
+ len = count;
+ res = rdwr_sectors0(core_xfer_buf, lba >> shift, 1, 0);
+ if (!res) return done;
+ if (is_write) {
+ memcpy(core_xfer_buf, buf, len);
+ res = rdwr_sectors0(core_xfer_buf, lba >> shift, 1, 1);
+ if (!res) return done;
+ } else {
+ memcpy(buf, core_xfer_buf, len);
+ }
+ done += len;
+ }
+
+ return done;
+}
+
struct edd_disk_params {
uint16_t len;
uint16_t flags;
@@ -292,9 +366,7 @@ static inline bool is_power_of_2(uint32_t x)
void getoneblk(struct disk *disk, char *buf, block_t block, int block_size)
{
- int sec_per_block = block_size / disk->sector_size;
-
- disk->rdwr_sectors(disk, buf, block * sec_per_block, sec_per_block, 0);
+ rdwr_bytes(disk, buf, (bytes_t)block * block_size, block_size, 0);
}
@@ -373,6 +445,8 @@ struct disk *disk_init(uint8_t devno, bool cdrom, sector_t
part_start,
is_power_of_2(edd_params.sector_size))
sector_size = edd_params.sector_size;
}
+ if (hard_max_transfer > (0x10000/sector_size))
+ hard_max_transfer = (0x10000/sector_size);
}
}
diff --git a/core/fs/ext2/ext2.c b/core/fs/ext2/ext2.c
index 716670c..bddde8d 100644
--- a/core/fs/ext2/ext2.c
+++ b/core/fs/ext2/ext2.c
@@ -274,7 +274,7 @@ static int ext2_fs_init(struct fs_info *fs)
struct cache *cs;
/* read the super block */
- disk->rdwr_sectors(disk, &sb, 2, 2, 0);
+ rdwr_bytes(disk, &sb, 2*512, 2*512, 0);
/* check if it is ext2, since we also support btrfs now */
if (sb.s_magic != EXT2_SUPER_MAGIC)
diff --git a/core/fs/fat/fat.c b/core/fs/fat/fat.c
index b08923c..3c7620e 100644
--- a/core/fs/fat/fat.c
+++ b/core/fs/fat/fat.c
@@ -731,7 +731,7 @@ static int vfat_fs_init(struct fs_info *fs)
fs->sector_size = 1 << fs->sector_shift;
fs->block_size = 1 << fs->block_shift;
- disk->rdwr_sectors(disk, &fat, 0, 1, 0);
+ rdwr_bytes(disk, &fat, 0, 512, 0);
/* XXX: Find better sanity checks... */
if (!fat.bxResSectors || !fat.bxFATs)
diff --git a/core/fs/iso9660/iso9660.c b/core/fs/iso9660/iso9660.c
index 3cd3ac4..60b3b55 100644
--- a/core/fs/iso9660/iso9660.c
+++ b/core/fs/iso9660/iso9660.c
@@ -251,7 +251,7 @@ static int iso_fs_init(struct fs_info *fs)
char pvd[2048]; /* Primary Volume Descriptor */
uint32_t pvd_lba;
struct disk *disk = fs->fs_dev->disk;
- int blktosec;
+ int blkshift;
sbi = malloc(sizeof(*sbi));
if (!sbi) {
@@ -268,14 +268,14 @@ static int iso_fs_init(struct fs_info *fs)
fs->block_shift = 11; /* A CD-ROM block is always 2K */
fs->sector_size = 1 << fs->sector_shift;
fs->block_size = 1 << fs->block_shift;
- blktosec = fs->block_shift - fs->sector_shift;
+ blkshift = fs->block_shift;
pvd_lba = iso_boot_info.pvd;
if (!pvd_lba)
pvd_lba = 16; /* Default if not otherwise defined */
- disk->rdwr_sectors(disk, pvd, (sector_t)pvd_lba << blktosec,
- 1 << blktosec, false);
+ rdwr_bytes(disk, pvd, (bytes_t)pvd_lba << blkshift,
+ 1 << blkshift, false);
memcpy(&sbi->root, pvd + ROOT_DIR_OFFSET, sizeof(sbi->root));
/* Initialize the cache */
diff --git a/core/fs/ntfs/ntfs.c b/core/fs/ntfs/ntfs.c
index 500d0fd..f6c8e24 100644
--- a/core/fs/ntfs/ntfs.c
+++ b/core/fs/ntfs/ntfs.c
@@ -1311,8 +1311,8 @@ static int ntfs_fs_init(struct fs_info *fs)
dprintf("in %s()\n", __func__);
- read_count = disk->rdwr_sectors(disk, &ntfs, 0, 1, 0);
- if (!read_count)
+ read_count = rdwr_bytes(disk, &ntfs, 0, 512, 0);
+ if (read_count != 512)
return -1;
if (!ntfs_check_sb_fields(&ntfs))
diff --git a/core/include/disk.h b/core/include/disk.h
index ac23e92..f0a3fa8 100644
--- a/core/include/disk.h
+++ b/core/include/disk.h
@@ -7,6 +7,7 @@
typedef uint64_t sector_t;
typedef uint64_t block_t;
+typedef uint64_t bytes_t;
/*
* struct disk: contains the information about a specific disk and also
@@ -29,6 +30,7 @@ struct disk {
extern void read_sectors(char *, sector_t, int);
extern void getoneblk(struct disk *, char *, block_t, int);
+extern int rdwr_bytes(struct disk *, void *, bytes_t, size_t, bool);
/* diskio.c */
struct disk *disk_init(uint8_t, bool, sector_t, uint16_t, uint16_t, uint32_t);
--
1.7.5.4
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Wisdom of the Ancients
