* VM_XIP Request for comments
@ 2005-10-25 22:42 Jared Hulbert
2005-10-27 17:39 ` Jared Hulbert
2005-10-27 19:09 ` Christoph Hellwig
0 siblings, 2 replies; 4+ messages in thread
From: Jared Hulbert @ 2005-10-25 22:42 UTC (permalink / raw)
To: linux-mm
What would it take to get this first patch in the kernel?
The reason for the first patch is in the second patch, which I will
try to get into the kernel list. With this mmap()'ed files can be
used directly from flash when possible and COW's it when necessary..
Index: include/linux/mm.h
===================================================================
--- include/linux/mm.h (revision 3)
+++ include/linux/mm.h (revision 7)
@@ -159,6 +159,7 @@
#define VM_DONTEXPAND 0x00040000 /* Cannot expand with mremap() */
#define VM_RESERVED 0x00080000 /* Don't unmap it from swap_out */
#define VM_ACCOUNT 0x00100000 /* Is a VM accounted object */
+#define VM_XIP 0x00200000 /* Execute In Place from ROM/flash */
#define VM_HUGETLB 0x00400000 /* Huge TLB Page VM */
#define VM_NONLINEAR 0x00800000 /* Is non-linear (remap_file_pages) */
#define VM_MAPPED_COPY 0x01000000 /* T if mapped copy of data (nommu mmap) */
Index: mm/memory.c
===================================================================
--- mm/memory.c (revision 3)
+++ mm/memory.c (revision 7)
@@ -945,7 +945,8 @@
continue;
}
- if (!vma || (vma->vm_flags & VM_IO)
+ if (!vma || ((vma->vm_flags & VM_IO)
+ && !(vma->vm_flags & VM_XIP))
|| !(flags & vma->vm_flags))
return i ? : -EFAULT;
@@ -1252,6 +1253,46 @@
int ret;
if (unlikely(!pfn_valid(pfn))) {
+ if ((vma->vm_flags & VM_XIP) && pte_present(pte) &&
+ pte_read(pte)) {
+ /*
+ * Handle COW of XIP memory.
+ * Note that the source memory actually isn't a ram
+ * page so no struct page is associated to the source
+ * pte.
+ */
+ char *dst;
+ int ret;
+
+ spin_unlock(&mm->page_table_lock);
+ new_page = alloc_page(GFP_HIGHUSER);
+ if (!new_page)
+ return VM_FAULT_OOM;
+
+ /* copy XIP data to memory */
+
+ dst = kmap_atomic(new_page, KM_USER0);
+ ret = copy_from_user(dst, (void*)address, PAGE_SIZE);
+ kunmap_atomic(dst, KM_USER0);
+
+ /* make sure pte didn't change while we dropped the
+ lock */
+ spin_lock(&mm->page_table_lock);
+ if (!ret && pte_same(*page_table, pte)) {
+ ++mm->_rss;
+ break_cow(vma, new_page, address, page_table);
+ lru_cache_add(new_page);
+ page_add_file_rmap(new_page);
+ spin_unlock(&mm->page_table_lock);
+ return VM_FAULT_MINOR; /* Minor fault */
+ }
+
+ /* pte changed: back off */
+ spin_unlock(&mm->page_table_lock);
+ page_cache_release(new_page);
+ return ret ? VM_FAULT_OOM : VM_FAULT_MINOR;
+ }
+
/*
* This should really halt the system so it can be debugged or
* at least the kernel stops what it's doing before it corrupts
Index: include/linux/cramfs_fs_sb.h
===================================================================
--- include/linux/cramfs_fs_sb.h (revision 3)
+++ include/linux/cramfs_fs_sb.h (revision 7)
@@ -10,6 +10,10 @@
unsigned long blocks;
unsigned long files;
unsigned long flags;
+#ifdef CONFIG_CRAMFS_LINEAR
+ unsigned long linear_phys_addr;
+ char * linear_virt_addr;
+#endif /* CONFIG_CRAMFS_LINEAR */
};
static inline struct cramfs_sb_info *CRAMFS_SB(struct super_block *sb)
Index: init/do_mounts.c
===================================================================
--- init/do_mounts.c (revision 3)
+++ init/do_mounts.c (revision 7)
@@ -328,6 +328,15 @@
return 0;
}
#endif
+#ifdef CONFIG_ROOT_CRAMFS_LINEAR
+static int __init mount_cramfs_linear_root(void)
+{
+ create_dev("/dev/root", ROOT_DEV, root_device_name);
+ if (do_mount_root("/dev/root","cramfs",root_mountflags,root_mount_data) == 0)
+ return 1;
+ return 0;
+}
+#endif
#if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
void __init change_floppy(char *fmt, ...)
@@ -361,6 +370,13 @@
void __init mount_root(void)
{
+#ifdef CONFIG_ROOT_CRAMFS_LINEAR
+ if (ROOT_DEV == MKDEV(0, 0)) {
+ if (mount_cramfs_linear_root())
+ return;
+ printk (KERN_ERR "VFS: Unable to mount linear cramfs root.\n");
+ }
+#endif
#ifdef CONFIG_ROOT_NFS
if (MAJOR(ROOT_DEV) == UNNAMED_MAJOR) {
if (mount_nfs_root())
Index: fs/cramfs/inode.c
===================================================================
--- fs/cramfs/inode.c (revision 3)
+++ fs/cramfs/inode.c (revision 7)
@@ -11,6 +11,39 @@
* The actual compression is based on zlib, see the other files.
*/
+/* Linear Addressing code
+ *
+ * Copyright (C) 2000 Shane Nay.
+ *
+ * Allows you to have a linearly addressed cramfs filesystem.
+ * Saves the need for buffer, and the munging of the buffer.
+ * Savings a bit over 32k with default PAGE_SIZE, BUFFER_SIZE
+ * etc. Usefull on embedded platform with ROM :-).
+ *
+ * Downsides- Currently linear addressed cramfs partitions
+ * don't co-exist with block cramfs partitions.
+ *
+ */
+
+/*
+ * 28-Dec-2000: XIP mode for linear cramfs
+ * Copyright (C) 2000 Robert Leslie <rob@mars.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
@@ -25,6 +58,7 @@
#include <asm/semaphore.h>
#include <asm/uaccess.h>
+#include <asm/tlbflush.h>
static struct super_operations cramfs_ops;
static struct inode_operations cramfs_dir_inode_operations;
@@ -71,6 +105,66 @@
return 0;
}
+ #ifdef CONFIG_CRAMFS_LINEAR_XIP
+ static int cramfs_mmap(struct file *file, struct vm_area_struct *vma)
+ {
+ unsigned long address, length;
+ struct inode *inode = file->f_dentry->d_inode;
+ struct super_block *sb = inode->i_sb;
+ struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
+
+ /* this is only used in the case of read-only maps for XIP */
+
+ if (vma->vm_flags & VM_WRITE)
+ return generic_file_mmap(file, vma);
+
+ if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
+ return -EINVAL;
+
+ address = PAGE_ALIGN(sbi->linear_phys_addr + OFFSET(inode));
+ address += vma->vm_pgoff << PAGE_SHIFT;
+
+ length = vma->vm_end - vma->vm_start;
+
+ if (length > inode->i_size)
+ length = inode->i_size;
+
+ length = PAGE_ALIGN(length);
+
+ /*
+ * Don't dump addresses that are not real memory to a core file.
+ */
+ vma->vm_flags |= (VM_IO | VM_XIP);
+ flush_tlb_page(vma, address);
+ if (remap_pfn_range(vma, vma->vm_start, address >> PAGE_SHIFT, length,
+ vma->vm_page_prot))
+ return -EAGAIN;
+
+ #ifdef DEBUG_CRAMFS_XIP
+ printk("cramfs_mmap: mapped %s at 0x%08lx, length %lu to vma 0x%08lx"
+ ", page_prot 0x%08lx\n",
+ file->f_dentry->d_name.name, address, length,
+ vma->vm_start, pgprot_val(vma->vm_page_prot));
+ #endif
+
+ return 0;
+ }
+
+ static struct file_operations cramfs_linear_xip_fops = {
+ read: generic_file_read,
+ mmap: cramfs_mmap,
+ };
+
+ #define CRAMFS_INODE_IS_XIP(x) ((x)->i_mode & S_ISVTX)
+
+ #endif
+
+ #ifdef CONFIG_CRAMFS_LINEAR
+ static struct backing_dev_info cramfs_backing_dev_info = {
+ .ra_pages = 0, /* No readahead */
+ };
+ #endif
+
static struct inode *get_cramfs_inode(struct super_block *sb,
struct cramfs_inode * cramfs_inode)
{
@@ -86,6 +180,9 @@
inode->i_blocks = (cramfs_inode->size - 1) / 512 + 1;
inode->i_blksize = PAGE_CACHE_SIZE;
inode->i_gid = cramfs_inode->gid;
+#ifdef CONFIG_CRAMFS_LINEAR
+ inode->i_mapping->backing_dev_info = &cramfs_backing_dev_info;
+#endif
/* Struct copy intentional */
inode->i_mtime = inode->i_atime = inode->i_ctime = zerotime;
inode->i_ino = CRAMINO(cramfs_inode);
@@ -94,7 +191,11 @@
contents. 1 yields the right result in GNU find, even
without -noleaf option. */
if (S_ISREG(inode->i_mode)) {
+#ifdef CONFIG_CRAMFS_LINEAR_XIP
+ inode->i_fop = CRAMFS_INODE_IS_XIP(inode) ?
&cramfs_linear_xip_fops : &generic_ro_fops;
+#else
inode->i_fop = &generic_ro_fops;
+#endif
inode->i_data.a_ops = &cramfs_aops;
} else if (S_ISDIR(inode->i_mode)) {
inode->i_op = &cramfs_dir_inode_operations;
@@ -113,7 +214,20 @@
return inode;
}
+#ifdef CONFIG_CRAMFS_LINEAR
/*
+ * Return a pointer to the block in the linearly addressed cramfs image.
+ */
+static void *cramfs_read(struct super_block *sb, unsigned int offset,
unsigned int len)
+{
+ struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
+
+ if (!len)
+ return NULL;
+ return (void*)(sbi->linear_virt_addr + offset);
+}
+#else /* Not linear addressing - aka regular block mode. */
+/*
* We have our own block cache: don't fill up the buffer cache
* with the rom-image, because the way the filesystem is set
* up the accesses should be fairly regular and cached in the
@@ -222,6 +336,7 @@
}
return read_buffers[buffer] + offset;
}
+#endif /* CONFIG_CRAMFS_LINEAR */
static void cramfs_put_super(struct super_block *sb)
{
@@ -237,7 +352,11 @@
static int cramfs_fill_super(struct super_block *sb, void *data, int silent)
{
+#ifndef CONFIG_CRAMFS_LINEAR
int i;
+#else
+ char *p;
+#endif
struct cramfs_super super;
unsigned long root_offset;
struct cramfs_sb_info *sbi;
@@ -251,11 +370,48 @@
sb->s_fs_info = sbi;
memset(sbi, 0, sizeof(struct cramfs_sb_info));
+#ifndef CONFIG_CRAMFS_LINEAR
/* Invalidate the read buffers on mount: think disk change.. */
down(&read_mutex);
for (i = 0; i < READ_BUFFERS; i++)
buffer_blocknr[i] = -1;
+#else /* CONFIG_CRAMFS_LINEAR */
+ /*
+ * The physical location of the cramfs image is specified as
+ * a mount parameter. This parameter is mandatory for obvious
+ * reasons. Some validation is made on the phys address but this
+ * is not exhaustive and we count on the fact that someone using
+ * this feature is supposed to know what he/she's doing.
+ */
+ if (!data || !(p = strstr((char *)data, "physaddr="))) {
+ printk(KERN_ERR "cramfs: unknown physical address for linear cramfs
image\n");
+ goto out;
+ }
+ sbi->linear_phys_addr = simple_strtoul(p + 9, NULL, 0);
+ if (sbi->linear_phys_addr & (PAGE_SIZE-1)) {
+ printk(KERN_ERR "cramfs: physical address 0x%lx for linear cramfs
isn't aligned to a page boundary\n",
+ sbi->linear_phys_addr);
+ goto out;
+ }
+ if (sbi->linear_phys_addr == 0) {
+ printk(KERN_ERR "cramfs: physical address for linear cramfs image
can't be 0\n");
+ goto out;
+ }
+ printk(KERN_INFO "cramfs: checking physical address 0x%lx for linear
cramfs image\n",
+ sbi->linear_phys_addr);
+
+ /* Map only one page for now. Will remap it when fs size is known. */
+ sbi->linear_virt_addr =
+ ioremap(sbi->linear_phys_addr, PAGE_SIZE);
+ if (!sbi->linear_virt_addr) {
+ printk(KERN_ERR "cramfs: ioremap of the linear cramfs image failed\n");
+ goto out;
+ }
+
+ down(&read_mutex);
+#endif /* CONFIG_CRAMFS_LINEAR */
+
/* Read the first block and get the superblock from it */
memcpy(&super, cramfs_read(sb, 0, sizeof(super)), sizeof(super));
up(&read_mutex);
@@ -316,8 +472,27 @@
iput(root);
goto out;
}
+
+#ifdef CONFIG_CRAMFS_LINEAR
+ /* Remap the whole filesystem now */
+ iounmap(sbi->linear_virt_addr);
+ printk(KERN_INFO "cramfs: linear cramfs image appears to be %lu KB in size\n",
+ sbi->size/1024);
+
+ sbi->linear_virt_addr =
+ ioremap_cached(sbi->linear_phys_addr, sbi->size);
+
+ if (!sbi->linear_virt_addr) {
+ printk(KERN_ERR "cramfs: ioremap of the linear cramfs image failed\n");
+ goto out;
+ }
+#endif /* CONFIG_CRAMFS_LINEAR */
return 0;
out:
+#ifdef CONFIG_CRAMFS_LINEAR
+ if (sbi->linear_virt_addr)
+ iounmap(sbi->linear_virt_addr);
+#endif /* CONFIG_CRAMFS_LINEAR */
kfree(sbi);
sb->s_fs_info = NULL;
return -EINVAL;
@@ -475,6 +650,20 @@
u32 blkptr_offset = OFFSET(inode) + page->index*4;
u32 start_offset, compr_len;
+#ifdef CONFIG_CRAMFS_LINEAR_XIP
+ if(CRAMFS_INODE_IS_XIP(inode)) {
+ blkptr_offset =
+ PAGE_ALIGN(OFFSET(inode)) +
+ page->index * PAGE_CACHE_SIZE;
+ down(&read_mutex);
+ memcpy(page_address(page),
+ cramfs_read(sb, blkptr_offset, PAGE_CACHE_SIZE),
+ PAGE_CACHE_SIZE);
+ up(&read_mutex);
+ bytes_filled = PAGE_CACHE_SIZE;
+ pgdata = kmap(page);
+ } else {
+#endif /* CONFIG_CRAMFS_LINEAR_XIP */
start_offset = OFFSET(inode) + maxblock*4;
down(&read_mutex);
if (page->index)
@@ -492,6 +681,9 @@
compr_len);
up(&read_mutex);
}
+#ifdef CONFIG_CRAMFS_LINEAR_XIP
+ }
+#endif /* CONFIG_CRAMFS_LINEAR_XIP */
} else
pgdata = kmap(page);
memset(pgdata + bytes_filled, 0, PAGE_CACHE_SIZE - bytes_filled);
@@ -532,7 +724,11 @@
static struct super_block *cramfs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
+#ifdef CONFIG_CRAMFS_LINEAR
+ return get_sb_nodev(fs_type, flags, data, cramfs_fill_super);
+#else
return get_sb_bdev(fs_type, flags, dev_name, data, cramfs_fill_super);
+#endif
}
static struct file_system_type cramfs_fs_type = {
@@ -540,7 +736,9 @@
.name = "cramfs",
.get_sb = cramfs_get_sb,
.kill_sb = kill_block_super,
+#ifndef CONFIG_CRAMFS_LINEAR
.fs_flags = FS_REQUIRES_DEV,
+#endif /* CONFIG_CRAMFS_LINEAR */
};
static int __init init_cramfs_fs(void)
Index: fs/Kconfig
===================================================================
--- fs/Kconfig (revision 3)
+++ fs/Kconfig (revision 7)
@@ -1137,6 +1137,51 @@
If unsure, say N.
+config CRAMFS_LINEAR
+ bool "Use linear addressing for CramFs"
+ depends on CRAMFS
+ help
+ This option tells the CramFs driver to load data directly from
+ a linear adressed memory range (usually non volatile memory
+ like flash) instead of going through the block device layer.
+ This saves some memory since no intermediate buffering is
+ necessary.
+
+ This is also a prerequisite for XIP of binaries stored on the
+ filesystem.
+
+ The location of the CramFs image in memory is board
+ dependent. Therefore, if you say Y, you must know the proper
+ physical address where to store the CramFs image and specify
+ it using the physaddr=0x******** mount option (for example:
+ "mount -t cramfs -o physaddr=0x100000 none /mnt").
+
+ If unsure, say N.
+
+config CRAMFS_LINEAR_XIP
+ bool "Support XIP on linear CramFs"
+ depends on CRAMFS_LINEAR
+ help
+ You must say Y to this option if you want to be able to run
+ applications directly from non-volatile memory. XIP
+ applications are marked by setting the sticky bit (ie, "chmod
+ +t <app name>"). A cramfs file system then needs to be
+ created using mkcramfs (with XIP cramfs support in
+ it). Applications marked for XIP execution will not be
+ compressed since they have to run directly from flash.
+
+config ROOT_CRAMFS_LINEAR
+ bool "Root file system on linear CramFs"
+ depends on CRAMFS_LINEAR
+ help
+ Say Y if you have enabled linear CramFs, and you want to be
+ able to use the linear CramFs image as a root file system. To
+ actually have the kernel mount this CramFs image as a root
+ file system, you must also pass the command line parameter
+ "root=/dev/null rootflags=physaddr=0x********" to the kernel
+ (replace 0x******** with the physical address location of the
+ linear CramFs image to boot with).
+
config VXFS_FS
tristate "FreeVxFS file system support (VERITAS VxFS(TM) compatible)"
help
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: VM_XIP Request for comments
2005-10-25 22:42 VM_XIP Request for comments Jared Hulbert
@ 2005-10-27 17:39 ` Jared Hulbert
2005-10-27 19:09 ` Christoph Hellwig
1 sibling, 0 replies; 4+ messages in thread
From: Jared Hulbert @ 2005-10-27 17:39 UTC (permalink / raw)
To: jaredeh, linux-mm
No response...
Is this off topic? Am I breaking a code of conduct I am not aware of?
Everyone too busy?
On 10/25/05, Jared Hulbert <jaredeh@gmail.com> wrote:
> What would it take to get this first patch in the kernel?
>
> The reason for the first patch is in the second patch, which I will
> try to get into the kernel list. With this mmap()'ed files can be
> used directly from flash when possible and COW's it when necessary..
>
>
> Index: include/linux/mm.h
> ===================================================================
> --- include/linux/mm.h (revision 3)
> +++ include/linux/mm.h (revision 7)
> @@ -159,6 +159,7 @@
> #define VM_DONTEXPAND 0x00040000 /* Cannot expand with mremap() */
> #define VM_RESERVED 0x00080000 /* Don't unmap it from swap_out */
> #define VM_ACCOUNT 0x00100000 /* Is a VM accounted object */
> +#define VM_XIP 0x00200000 /* Execute In Place from ROM/flash */
> #define VM_HUGETLB 0x00400000 /* Huge TLB Page VM */
> #define VM_NONLINEAR 0x00800000 /* Is non-linear (remap_file_pages) */
> #define VM_MAPPED_COPY 0x01000000 /* T if mapped copy of data (nommu mmap) */
> Index: mm/memory.c
> ===================================================================
> --- mm/memory.c (revision 3)
> +++ mm/memory.c (revision 7)
> @@ -945,7 +945,8 @@
> continue;
> }
>
> - if (!vma || (vma->vm_flags & VM_IO)
> + if (!vma || ((vma->vm_flags & VM_IO)
> + && !(vma->vm_flags & VM_XIP))
> || !(flags & vma->vm_flags))
> return i ? : -EFAULT;
>
> @@ -1252,6 +1253,46 @@
> int ret;
>
> if (unlikely(!pfn_valid(pfn))) {
> + if ((vma->vm_flags & VM_XIP) && pte_present(pte) &&
> + pte_read(pte)) {
> + /*
> + * Handle COW of XIP memory.
> + * Note that the source memory actually isn't a ram
> + * page so no struct page is associated to the source
> + * pte.
> + */
> + char *dst;
> + int ret;
> +
> + spin_unlock(&mm->page_table_lock);
> + new_page = alloc_page(GFP_HIGHUSER);
> + if (!new_page)
> + return VM_FAULT_OOM;
> +
> + /* copy XIP data to memory */
> +
> + dst = kmap_atomic(new_page, KM_USER0);
> + ret = copy_from_user(dst, (void*)address, PAGE_SIZE);
> + kunmap_atomic(dst, KM_USER0);
> +
> + /* make sure pte didn't change while we dropped the
> + lock */
> + spin_lock(&mm->page_table_lock);
> + if (!ret && pte_same(*page_table, pte)) {
> + ++mm->_rss;
> + break_cow(vma, new_page, address, page_table);
> + lru_cache_add(new_page);
> + page_add_file_rmap(new_page);
> + spin_unlock(&mm->page_table_lock);
> + return VM_FAULT_MINOR; /* Minor fault */
> + }
> +
> + /* pte changed: back off */
> + spin_unlock(&mm->page_table_lock);
> + page_cache_release(new_page);
> + return ret ? VM_FAULT_OOM : VM_FAULT_MINOR;
> + }
> +
> /*
> * This should really halt the system so it can be debugged or
> * at least the kernel stops what it's doing before it corrupts
>
> Index: include/linux/cramfs_fs_sb.h
> ===================================================================
> --- include/linux/cramfs_fs_sb.h (revision 3)
> +++ include/linux/cramfs_fs_sb.h (revision 7)
> @@ -10,6 +10,10 @@
> unsigned long blocks;
> unsigned long files;
> unsigned long flags;
> +#ifdef CONFIG_CRAMFS_LINEAR
> + unsigned long linear_phys_addr;
> + char * linear_virt_addr;
> +#endif /* CONFIG_CRAMFS_LINEAR */
> };
>
> static inline struct cramfs_sb_info *CRAMFS_SB(struct super_block *sb)
> Index: init/do_mounts.c
> ===================================================================
> --- init/do_mounts.c (revision 3)
> +++ init/do_mounts.c (revision 7)
> @@ -328,6 +328,15 @@
> return 0;
> }
> #endif
> +#ifdef CONFIG_ROOT_CRAMFS_LINEAR
> +static int __init mount_cramfs_linear_root(void)
> +{
> + create_dev("/dev/root", ROOT_DEV, root_device_name);
> + if (do_mount_root("/dev/root","cramfs",root_mountflags,root_mount_data) == 0)
> + return 1;
> + return 0;
> +}
> +#endif
>
> #if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
> void __init change_floppy(char *fmt, ...)
> @@ -361,6 +370,13 @@
>
> void __init mount_root(void)
> {
> +#ifdef CONFIG_ROOT_CRAMFS_LINEAR
> + if (ROOT_DEV == MKDEV(0, 0)) {
> + if (mount_cramfs_linear_root())
> + return;
> + printk (KERN_ERR "VFS: Unable to mount linear cramfs root.\n");
> + }
> +#endif
> #ifdef CONFIG_ROOT_NFS
> if (MAJOR(ROOT_DEV) == UNNAMED_MAJOR) {
> if (mount_nfs_root())
> Index: fs/cramfs/inode.c
> ===================================================================
> --- fs/cramfs/inode.c (revision 3)
> +++ fs/cramfs/inode.c (revision 7)
> @@ -11,6 +11,39 @@
> * The actual compression is based on zlib, see the other files.
> */
>
> +/* Linear Addressing code
> + *
> + * Copyright (C) 2000 Shane Nay.
> + *
> + * Allows you to have a linearly addressed cramfs filesystem.
> + * Saves the need for buffer, and the munging of the buffer.
> + * Savings a bit over 32k with default PAGE_SIZE, BUFFER_SIZE
> + * etc. Usefull on embedded platform with ROM :-).
> + *
> + * Downsides- Currently linear addressed cramfs partitions
> + * don't co-exist with block cramfs partitions.
> + *
> + */
> +
> +/*
> + * 28-Dec-2000: XIP mode for linear cramfs
> + * Copyright (C) 2000 Robert Leslie <rob@mars.org>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
> + */
> +
> #include <linux/module.h>
> #include <linux/fs.h>
> #include <linux/pagemap.h>
> @@ -25,6 +58,7 @@
> #include <asm/semaphore.h>
>
> #include <asm/uaccess.h>
> +#include <asm/tlbflush.h>
>
> static struct super_operations cramfs_ops;
> static struct inode_operations cramfs_dir_inode_operations;
> @@ -71,6 +105,66 @@
> return 0;
> }
>
> + #ifdef CONFIG_CRAMFS_LINEAR_XIP
> + static int cramfs_mmap(struct file *file, struct vm_area_struct *vma)
> + {
> + unsigned long address, length;
> + struct inode *inode = file->f_dentry->d_inode;
> + struct super_block *sb = inode->i_sb;
> + struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
> +
> + /* this is only used in the case of read-only maps for XIP */
> +
> + if (vma->vm_flags & VM_WRITE)
> + return generic_file_mmap(file, vma);
> +
> + if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
> + return -EINVAL;
> +
> + address = PAGE_ALIGN(sbi->linear_phys_addr + OFFSET(inode));
> + address += vma->vm_pgoff << PAGE_SHIFT;
> +
> + length = vma->vm_end - vma->vm_start;
> +
> + if (length > inode->i_size)
> + length = inode->i_size;
> +
> + length = PAGE_ALIGN(length);
> +
> + /*
> + * Don't dump addresses that are not real memory to a core file.
> + */
> + vma->vm_flags |= (VM_IO | VM_XIP);
> + flush_tlb_page(vma, address);
> + if (remap_pfn_range(vma, vma->vm_start, address >> PAGE_SHIFT, length,
> + vma->vm_page_prot))
> + return -EAGAIN;
> +
> + #ifdef DEBUG_CRAMFS_XIP
> + printk("cramfs_mmap: mapped %s at 0x%08lx, length %lu to vma 0x%08lx"
> + ", page_prot 0x%08lx\n",
> + file->f_dentry->d_name.name, address, length,
> + vma->vm_start, pgprot_val(vma->vm_page_prot));
> + #endif
> +
> + return 0;
> + }
> +
> + static struct file_operations cramfs_linear_xip_fops = {
> + read: generic_file_read,
> + mmap: cramfs_mmap,
> + };
> +
> + #define CRAMFS_INODE_IS_XIP(x) ((x)->i_mode & S_ISVTX)
> +
> + #endif
> +
> + #ifdef CONFIG_CRAMFS_LINEAR
> + static struct backing_dev_info cramfs_backing_dev_info = {
> + .ra_pages = 0, /* No readahead */
> + };
> + #endif
> +
> static struct inode *get_cramfs_inode(struct super_block *sb,
> struct cramfs_inode * cramfs_inode)
> {
> @@ -86,6 +180,9 @@
> inode->i_blocks = (cramfs_inode->size - 1) / 512 + 1;
> inode->i_blksize = PAGE_CACHE_SIZE;
> inode->i_gid = cramfs_inode->gid;
> +#ifdef CONFIG_CRAMFS_LINEAR
> + inode->i_mapping->backing_dev_info = &cramfs_backing_dev_info;
> +#endif
> /* Struct copy intentional */
> inode->i_mtime = inode->i_atime = inode->i_ctime = zerotime;
> inode->i_ino = CRAMINO(cramfs_inode);
> @@ -94,7 +191,11 @@
> contents. 1 yields the right result in GNU find, even
> without -noleaf option. */
> if (S_ISREG(inode->i_mode)) {
> +#ifdef CONFIG_CRAMFS_LINEAR_XIP
> + inode->i_fop = CRAMFS_INODE_IS_XIP(inode) ?
> &cramfs_linear_xip_fops : &generic_ro_fops;
> +#else
> inode->i_fop = &generic_ro_fops;
> +#endif
> inode->i_data.a_ops = &cramfs_aops;
> } else if (S_ISDIR(inode->i_mode)) {
> inode->i_op = &cramfs_dir_inode_operations;
> @@ -113,7 +214,20 @@
> return inode;
> }
>
> +#ifdef CONFIG_CRAMFS_LINEAR
> /*
> + * Return a pointer to the block in the linearly addressed cramfs image.
> + */
> +static void *cramfs_read(struct super_block *sb, unsigned int offset,
> unsigned int len)
> +{
> + struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
> +
> + if (!len)
> + return NULL;
> + return (void*)(sbi->linear_virt_addr + offset);
> +}
> +#else /* Not linear addressing - aka regular block mode. */
> +/*
> * We have our own block cache: don't fill up the buffer cache
> * with the rom-image, because the way the filesystem is set
> * up the accesses should be fairly regular and cached in the
> @@ -222,6 +336,7 @@
> }
> return read_buffers[buffer] + offset;
> }
> +#endif /* CONFIG_CRAMFS_LINEAR */
>
> static void cramfs_put_super(struct super_block *sb)
> {
> @@ -237,7 +352,11 @@
>
> static int cramfs_fill_super(struct super_block *sb, void *data, int silent)
> {
> +#ifndef CONFIG_CRAMFS_LINEAR
> int i;
> +#else
> + char *p;
> +#endif
> struct cramfs_super super;
> unsigned long root_offset;
> struct cramfs_sb_info *sbi;
> @@ -251,11 +370,48 @@
> sb->s_fs_info = sbi;
> memset(sbi, 0, sizeof(struct cramfs_sb_info));
>
> +#ifndef CONFIG_CRAMFS_LINEAR
> /* Invalidate the read buffers on mount: think disk change.. */
> down(&read_mutex);
> for (i = 0; i < READ_BUFFERS; i++)
> buffer_blocknr[i] = -1;
>
> +#else /* CONFIG_CRAMFS_LINEAR */
> + /*
> + * The physical location of the cramfs image is specified as
> + * a mount parameter. This parameter is mandatory for obvious
> + * reasons. Some validation is made on the phys address but this
> + * is not exhaustive and we count on the fact that someone using
> + * this feature is supposed to know what he/she's doing.
> + */
> + if (!data || !(p = strstr((char *)data, "physaddr="))) {
> + printk(KERN_ERR "cramfs: unknown physical address for linear cramfs
> image\n");
> + goto out;
> + }
> + sbi->linear_phys_addr = simple_strtoul(p + 9, NULL, 0);
> + if (sbi->linear_phys_addr & (PAGE_SIZE-1)) {
> + printk(KERN_ERR "cramfs: physical address 0x%lx for linear cramfs
> isn't aligned to a page boundary\n",
> + sbi->linear_phys_addr);
> + goto out;
> + }
> + if (sbi->linear_phys_addr == 0) {
> + printk(KERN_ERR "cramfs: physical address for linear cramfs image
> can't be 0\n");
> + goto out;
> + }
> + printk(KERN_INFO "cramfs: checking physical address 0x%lx for linear
> cramfs image\n",
> + sbi->linear_phys_addr);
> +
> + /* Map only one page for now. Will remap it when fs size is known. */
> + sbi->linear_virt_addr =
> + ioremap(sbi->linear_phys_addr, PAGE_SIZE);
> + if (!sbi->linear_virt_addr) {
> + printk(KERN_ERR "cramfs: ioremap of the linear cramfs image failed\n");
> + goto out;
> + }
> +
> + down(&read_mutex);
> +#endif /* CONFIG_CRAMFS_LINEAR */
> +
> /* Read the first block and get the superblock from it */
> memcpy(&super, cramfs_read(sb, 0, sizeof(super)), sizeof(super));
> up(&read_mutex);
> @@ -316,8 +472,27 @@
> iput(root);
> goto out;
> }
> +
> +#ifdef CONFIG_CRAMFS_LINEAR
> + /* Remap the whole filesystem now */
> + iounmap(sbi->linear_virt_addr);
> + printk(KERN_INFO "cramfs: linear cramfs image appears to be %lu KB in size\n",
> + sbi->size/1024);
> +
> + sbi->linear_virt_addr =
> + ioremap_cached(sbi->linear_phys_addr, sbi->size);
> +
> + if (!sbi->linear_virt_addr) {
> + printk(KERN_ERR "cramfs: ioremap of the linear cramfs image failed\n");
> + goto out;
> + }
> +#endif /* CONFIG_CRAMFS_LINEAR */
> return 0;
> out:
> +#ifdef CONFIG_CRAMFS_LINEAR
> + if (sbi->linear_virt_addr)
> + iounmap(sbi->linear_virt_addr);
> +#endif /* CONFIG_CRAMFS_LINEAR */
> kfree(sbi);
> sb->s_fs_info = NULL;
> return -EINVAL;
> @@ -475,6 +650,20 @@
> u32 blkptr_offset = OFFSET(inode) + page->index*4;
> u32 start_offset, compr_len;
>
> +#ifdef CONFIG_CRAMFS_LINEAR_XIP
> + if(CRAMFS_INODE_IS_XIP(inode)) {
> + blkptr_offset =
> + PAGE_ALIGN(OFFSET(inode)) +
> + page->index * PAGE_CACHE_SIZE;
> + down(&read_mutex);
> + memcpy(page_address(page),
> + cramfs_read(sb, blkptr_offset, PAGE_CACHE_SIZE),
> + PAGE_CACHE_SIZE);
> + up(&read_mutex);
> + bytes_filled = PAGE_CACHE_SIZE;
> + pgdata = kmap(page);
> + } else {
> +#endif /* CONFIG_CRAMFS_LINEAR_XIP */
> start_offset = OFFSET(inode) + maxblock*4;
> down(&read_mutex);
> if (page->index)
> @@ -492,6 +681,9 @@
> compr_len);
> up(&read_mutex);
> }
> +#ifdef CONFIG_CRAMFS_LINEAR_XIP
> + }
> +#endif /* CONFIG_CRAMFS_LINEAR_XIP */
> } else
> pgdata = kmap(page);
> memset(pgdata + bytes_filled, 0, PAGE_CACHE_SIZE - bytes_filled);
> @@ -532,7 +724,11 @@
> static struct super_block *cramfs_get_sb(struct file_system_type *fs_type,
> int flags, const char *dev_name, void *data)
> {
> +#ifdef CONFIG_CRAMFS_LINEAR
> + return get_sb_nodev(fs_type, flags, data, cramfs_fill_super);
> +#else
> return get_sb_bdev(fs_type, flags, dev_name, data, cramfs_fill_super);
> +#endif
> }
>
> static struct file_system_type cramfs_fs_type = {
> @@ -540,7 +736,9 @@
> .name = "cramfs",
> .get_sb = cramfs_get_sb,
> .kill_sb = kill_block_super,
> +#ifndef CONFIG_CRAMFS_LINEAR
> .fs_flags = FS_REQUIRES_DEV,
> +#endif /* CONFIG_CRAMFS_LINEAR */
> };
>
> static int __init init_cramfs_fs(void)
> Index: fs/Kconfig
> ===================================================================
> --- fs/Kconfig (revision 3)
> +++ fs/Kconfig (revision 7)
> @@ -1137,6 +1137,51 @@
>
> If unsure, say N.
>
> +config CRAMFS_LINEAR
> + bool "Use linear addressing for CramFs"
> + depends on CRAMFS
> + help
> + This option tells the CramFs driver to load data directly from
> + a linear adressed memory range (usually non volatile memory
> + like flash) instead of going through the block device layer.
> + This saves some memory since no intermediate buffering is
> + necessary.
> +
> + This is also a prerequisite for XIP of binaries stored on the
> + filesystem.
> +
> + The location of the CramFs image in memory is board
> + dependent. Therefore, if you say Y, you must know the proper
> + physical address where to store the CramFs image and specify
> + it using the physaddr=0x******** mount option (for example:
> + "mount -t cramfs -o physaddr=0x100000 none /mnt").
> +
> + If unsure, say N.
> +
> +config CRAMFS_LINEAR_XIP
> + bool "Support XIP on linear CramFs"
> + depends on CRAMFS_LINEAR
> + help
> + You must say Y to this option if you want to be able to run
> + applications directly from non-volatile memory. XIP
> + applications are marked by setting the sticky bit (ie, "chmod
> + +t <app name>"). A cramfs file system then needs to be
> + created using mkcramfs (with XIP cramfs support in
> + it). Applications marked for XIP execution will not be
> + compressed since they have to run directly from flash.
> +
> +config ROOT_CRAMFS_LINEAR
> + bool "Root file system on linear CramFs"
> + depends on CRAMFS_LINEAR
> + help
> + Say Y if you have enabled linear CramFs, and you want to be
> + able to use the linear CramFs image as a root file system. To
> + actually have the kernel mount this CramFs image as a root
> + file system, you must also pass the command line parameter
> + "root=/dev/null rootflags=physaddr=0x********" to the kernel
> + (replace 0x******** with the physical address location of the
> + linear CramFs image to boot with).
> +
> config VXFS_FS
> tristate "FreeVxFS file system support (VERITAS VxFS(TM) compatible)"
> help
>
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: VM_XIP Request for comments
2005-10-25 22:42 VM_XIP Request for comments Jared Hulbert
2005-10-27 17:39 ` Jared Hulbert
@ 2005-10-27 19:09 ` Christoph Hellwig
2005-10-28 7:59 ` Jared Hulbert
1 sibling, 1 reply; 4+ messages in thread
From: Christoph Hellwig @ 2005-10-27 19:09 UTC (permalink / raw)
To: Jared Hulbert; +Cc: linux-mm
On Tue, Oct 25, 2005 at 03:42:25PM -0700, Jared Hulbert wrote:
> What would it take to get this first patch in the kernel?
>
> The reason for the first patch is in the second patch, which I will
> try to get into the kernel list. With this mmap()'ed files can be
> used directly from flash when possible and COW's it when necessary..
Can't you use the XIP infrastructure we already have? Grep for
CONFIG_XIP and CONFIG_EXT2_FS_XIP
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: VM_XIP Request for comments
2005-10-27 19:09 ` Christoph Hellwig
@ 2005-10-28 7:59 ` Jared Hulbert
0 siblings, 0 replies; 4+ messages in thread
From: Jared Hulbert @ 2005-10-28 7:59 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: linux-mm
On 10/27/05, Christoph Hellwig <hch@infradead.org> wrote:
> On Tue, Oct 25, 2005 at 03:42:25PM -0700, Jared Hulbert wrote:
> > What would it take to get this first patch in the kernel?
> >
> > The reason for the first patch is in the second patch, which I will
> > try to get into the kernel list. With this mmap()'ed files can be
> > used directly from flash when possible and COW's it when necessary..
>
> Can't you use the XIP infrastructure we already have? Grep for
> CONFIG_XIP and CONFIG_EXT2_FS_XIP
I can't find CONFIG_XIP. But I assume you are talking about
filemap_xip.c and Documentation/filesystems/xip.txt.
Hmm.
I don't know. The code and discussions about it looked very big-iron
DSCC specific but now on second pass it was meant to more generic. If
I can learn this infrastructure then maybe this will work.
So I'm supposed to create a function in the target fs that gets
plugged into get_xip_page(). Then I call that function to create an
proper XIP'ed page in my mmap() and fread() calls. I could use the
first arg of get_xip_page() to pass in the start address of the cramfs
volume and the second the offset of the page in the file I want to
map.
Is that about right?
This is a lot more overhead than the current XIP Linear CRAMFS patches
but it would allow me choose a page-by-page compression/XIP scheme
rather than the file-by-file compression/XIP currently used in cramfs.
Hmm.
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^ permalink raw reply [flat|nested] 4+ messages in thread
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2005-10-25 22:42 VM_XIP Request for comments Jared Hulbert
2005-10-27 17:39 ` Jared Hulbert
2005-10-27 19:09 ` Christoph Hellwig
2005-10-28 7:59 ` Jared Hulbert
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