NOMMU: Provide shared-writable mmap support on ramfs

diff -uNrp linux-2.6.15-rc2-frv/fs/ramfs/file-mmu.c linux-2.6.15-rc2-frv-shmem/fs/ramfs/file-mmu.c
@@ -0,0 +1,57 @@
+/* file-mmu.c: ramfs MMU-based file operations
+ *
+ * Resizable simple ram filesystem for Linux.
+ *
+ * Copyright (C) 2000 Linus Torvalds.
+ *               2000 Transmeta Corp.
+ *
+ * Usage limits added by David Gibson, Linuxcare Australia.
+ * This file is released under the GPL.
+ */
+
+/*
+ * NOTE! This filesystem is probably most useful
+ * not as a real filesystem, but as an example of
+ * how virtual filesystems can be written.
+ *
+ * It doesn't get much simpler than this. Consider
+ * that this file implements the full semantics of
+ * a POSIX-compliant read-write filesystem.
+ *
+ * Note in particular how the filesystem does not
+ * need to implement any data structures of its own
+ * to keep track of the virtual data: using the VFS
+ * caches is sufficient.
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/smp_lock.h>
+#include <linux/backing-dev.h>
+#include <linux/ramfs.h>
+
+#include <asm/uaccess.h>
+#include "internal.h"
+
+struct address_space_operations ramfs_aops = {
+	.readpage	= simple_readpage,
+	.prepare_write	= simple_prepare_write,
+	.commit_write	= simple_commit_write
+};
+
+struct file_operations ramfs_file_operations = {
+	.read		= generic_file_read,
+	.write		= generic_file_write,
+	.mmap		= generic_file_mmap,
+	.fsync		= simple_sync_file,
+	.sendfile	= generic_file_sendfile,
+	.llseek		= generic_file_llseek,
+};
+
+struct inode_operations ramfs_file_inode_operations = {
+	.getattr	= simple_getattr,
+};

294 lines not on this page · raw message

diff -uNrp linux-2.6.15-rc2-frv/fs/ramfs/inode.c linux-2.6.15-rc2-frv-shmem/fs/ramfs/inode.c
@@ -34,13 +34,12 @@
 #include <linux/ramfs.h>
 
 #include <asm/uaccess.h>
+#include "internal.h"
 
 /* some random number */
 #define RAMFS_MAGIC	0x858458f6
 
 static struct super_operations ramfs_ops;
-static struct address_space_operations ramfs_aops;
-static struct inode_operations ramfs_file_inode_operations;
 static struct inode_operations ramfs_dir_inode_operations;
 
 static struct backing_dev_info ramfs_backing_dev_info = {

@@ -142,25 +141,6 @@ static int ramfs_symlink(struct inode * 
 	return error;
 }
 
-static struct address_space_operations ramfs_aops = {
-	.readpage	= simple_readpage,
-	.prepare_write	= simple_prepare_write,
-	.commit_write	= simple_commit_write
-};
-
-struct file_operations ramfs_file_operations = {
-	.read		= generic_file_read,
-	.write		= generic_file_write,
-	.mmap		= generic_file_mmap,
-	.fsync		= simple_sync_file,
-	.sendfile	= generic_file_sendfile,
-	.llseek		= generic_file_llseek,
-};
-
-static struct inode_operations ramfs_file_inode_operations = {
-	.getattr	= simple_getattr,
-};
-
 static struct inode_operations ramfs_dir_inode_operations = {
 	.create		= ramfs_create,
 	.lookup		= simple_lookup,

diff -uNrp linux-2.6.15-rc2-frv/fs/ramfs/internal.h linux-2.6.15-rc2-frv-shmem/fs/ramfs/internal.h
@@ -0,0 +1,15 @@
+/* internal.h: ramfs internal definitions
+ *
+ * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells ([email protected])
+ *
+ * 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.
+ */
+
+
+extern struct address_space_operations ramfs_aops;
+extern struct file_operations ramfs_file_operations;
+extern struct inode_operations ramfs_file_inode_operations;

diff -uNrp linux-2.6.15-rc2-frv/include/linux/ramfs.h linux-2.6.15-rc2-frv-shmem/include/linux/ramfs.h
@@ -5,6 +5,16 @@ struct inode *ramfs_get_inode(struct sup
 struct super_block *ramfs_get_sb(struct file_system_type *fs_type,
 	 int flags, const char *dev_name, void *data);
 
+#ifndef CONFIG_MMU
+extern unsigned long ramfs_nommu_get_unmapped_area(struct file *file,
+						   unsigned long addr,
+						   unsigned long len,
+						   unsigned long pgoff,
+						   unsigned long flags);
+
+extern int ramfs_nommu_mmap(struct file *file, struct vm_area_struct *vma);
+#endif
+
 extern struct file_operations ramfs_file_operations;
 extern struct vm_operations_struct generic_file_vm_ops;
 

diff -uNrp linux-2.6.15-rc2-frv/include/linux/mm.h linux-2.6.15-rc2-frv-shmem/include/linux/mm.h
@@ -656,9 +656,18 @@ int shmem_lock(struct file *file, int lo
 #define shmem_get_policy(a, b)	(NULL)
 #endif
 struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags);
+extern int shmem_mmap(struct file *file, struct vm_area_struct *vma);
 
 int shmem_zero_setup(struct vm_area_struct *);
 
+#ifndef CONFIG_MMU
+extern unsigned long shmem_get_unmapped_area(struct file *file,
+					     unsigned long addr,
+					     unsigned long len,
+					     unsigned long pgoff,
+					     unsigned long flags);
+#endif
+
 static inline int can_do_mlock(void)
 {
 	if (capable(CAP_IPC_LOCK))

diff -uNrp linux-2.6.15-rc2-frv/ipc/shm.c linux-2.6.15-rc2-frv-shmem/ipc/shm.c
@@ -157,14 +157,22 @@ static void shm_close (struct vm_area_st
 
 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
 {
-	file_accessed(file);
-	vma->vm_ops = &shm_vm_ops;
-	shm_inc(file->f_dentry->d_inode->i_ino);
-	return 0;
+	int ret;
+
+	ret = shmem_mmap(file, vma);
+	if (ret == 0) {
+		vma->vm_ops = &shm_vm_ops;
+		shm_inc(file->f_dentry->d_inode->i_ino);
+	}
+
+	return ret;
 }
 
 static struct file_operations shm_file_operations = {
-	.mmap	= shm_mmap
+	.mmap	= shm_mmap,
+#ifndef CONFIG_MMU
+	.get_unmapped_area = shmem_get_unmapped_area,
+#endif
 };
 
 static struct vm_operations_struct shm_vm_ops = {

diff -uNrp linux-2.6.15-rc2-frv/mm/nommu.c linux-2.6.15-rc2-frv-shmem/mm/nommu.c
@@ -1177,3 +1177,9 @@ int in_gate_area_no_task(unsigned long a
 {
 	return 0;
 }
+
+struct page * filemap_nopage(struct vm_area_struct * area, unsigned long address, int *type)
+{
+	BUG();
+	return NULL;
+}

diff -uNrp linux-2.6.15-rc2-frv/mm/shmem.c linux-2.6.15-rc2-frv-shmem/mm/shmem.c
@@ -1255,7 +1255,7 @@ out_nomem:
 	return retval;
 }
 
-static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
+int shmem_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	file_accessed(file);
 	vma->vm_ops = &shmem_vm_ops;

diff -uNrp linux-2.6.15-rc2-frv/mm/tiny-shmem.c linux-2.6.15-rc2-frv-shmem/mm/tiny-shmem.c
@@ -81,13 +81,19 @@ struct file *shmem_file_setup(char *name
 		goto close_file;
 
 	d_instantiate(dentry, inode);
-	inode->i_size = size;
 	inode->i_nlink = 0;	/* It is unlinked */
+
 	file->f_vfsmnt = mntget(shm_mnt);
 	file->f_dentry = dentry;
 	file->f_mapping = inode->i_mapping;
 	file->f_op = &ramfs_file_operations;
 	file->f_mode = FMODE_WRITE | FMODE_READ;
+
+	/* notify everyone as to the change of file size */
+	error = do_truncate(dentry, size, file);
+	if (error < 0)
+		goto close_file;
+
 	return file;
 
 close_file:

@@ -123,3 +129,24 @@ int shmem_unuse(swp_entry_t entry, struc
 {
 	return 0;
 }
+
+int shmem_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	file_accessed(file);
+#ifndef CONFIG_MMU
+	return ramfs_nommu_mmap(file, vma);
+#else
+	return 0;
+#endif
+}
+
+#ifndef CONFIG_MMU
+unsigned long shmem_get_unmapped_area(struct file *file,
+				      unsigned long addr,
+				      unsigned long len,
+				      unsigned long pgoff,
+				      unsigned long flags)
+{
+	return ramfs_nommu_get_unmapped_area(file, addr, len, pgoff, flags);
+}
+#endif

diff -uNrp linux-2.6.15-rc2-frv/arch/frv/kernel/futex.c linux-2.6.15-rc2-frv-shmem/arch/frv/kernel/futex.c
@@ -0,0 +1,242 @@
+/* futex.c: futex operations
+ *
+ * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells ([email protected])
+ *
+ * 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.
+ */
+
+#include <linux/futex.h>
+#include <asm/futex.h>
+#include <asm/errno.h>
+#include <asm/uaccess.h>
+
+/*
+ * the various futex operations; MMU fault checking is ignored under no-MMU
+ * conditions
+ */
+static inline int atomic_futex_op_xchg_set(int oparg, int __user *uaddr, int *_oldval)
+{
+	int oldval, ret;
+
+	asm("0:						\n"
+	    "	orcc		gr0,gr0,gr0,icc3	\n"	/* set ICC3.Z */
+	    "	ckeq		icc3,cc7		\n"
+	    "1:	ld.p		%M0,%1			\n"	/* LD.P/ORCR must be atomic */
+	    "	orcr		cc7,cc7,cc3		\n"	/* set CC3 to true */
+	    "2:	cst.p		%3,%M0		,cc3,#1	\n"
+	    "	corcc		gr29,gr29,gr0	,cc3,#1	\n"	/* clear ICC3.Z if store happens */
+	    "	beq		icc3,#0,0b		\n"
+	    "	setlos		0,%2			\n"
+	    "3:						\n"
+	    ".subsection 2				\n"
+	    "4:	setlos		%5,%2			\n"
+	    "	bra		3b			\n"
+	    ".previous					\n"
+	    ".section __ex_table,\"a\"			\n"
+	    "	.balign		8			\n"
+	    "	.long		1b,4b			\n"
+	    "	.long		2b,4b			\n"
+	    ".previous"
+	    : "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
+	    : "3"(oparg), "i"(-EFAULT)
+	    : "memory", "cc7", "cc3", "icc3"
+	    );
+
+	*_oldval = oldval;
+	return ret;
+}
+
+static inline int atomic_futex_op_xchg_add(int oparg, int __user *uaddr, int *_oldval)
+{
+	int oldval, ret;
+
+	asm("0:						\n"
+	    "	orcc		gr0,gr0,gr0,icc3	\n"	/* set ICC3.Z */
+	    "	ckeq		icc3,cc7		\n"
+	    "1:	ld.p		%M0,%1			\n"	/* LD.P/ORCR must be atomic */
+	    "	orcr		cc7,cc7,cc3		\n"	/* set CC3 to true */
+	    "	add		%1,%3,%3		\n"
+	    "2:	cst.p		%3,%M0		,cc3,#1	\n"
+	    "	corcc		gr29,gr29,gr0	,cc3,#1	\n"	/* clear ICC3.Z if store happens */
+	    "	beq		icc3,#0,0b		\n"
+	    "	setlos		0,%2			\n"
+	    "3:						\n"
+	    ".subsection 2				\n"
+	    "4:	setlos		%5,%2			\n"
+	    "	bra		3b			\n"
+	    ".previous					\n"
+	    ".section __ex_table,\"a\"			\n"
+	    "	.balign		8			\n"
+	    "	.long		1b,4b			\n"
+	    "	.long		2b,4b			\n"
+	    ".previous"
+	    : "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
+	    : "3"(oparg), "i"(-EFAULT)
+	    : "memory", "cc7", "cc3", "icc3"
+	    );
+
+	*_oldval = oldval;
+	return ret;
+}
+
+static inline int atomic_futex_op_xchg_or(int oparg, int __user *uaddr, int *_oldval)
+{
+	int oldval, ret;
+
+	asm("0:						\n"
+	    "	orcc		gr0,gr0,gr0,icc3	\n"	/* set ICC3.Z */
+	    "	ckeq		icc3,cc7		\n"
+	    "1:	ld.p		%M0,%1			\n"	/* LD.P/ORCR must be atomic */
+	    "	orcr		cc7,cc7,cc3		\n"	/* set CC3 to true */
+	    "	or		%1,%3,%3		\n"
+	    "2:	cst.p		%3,%M0		,cc3,#1	\n"
+	    "	corcc		gr29,gr29,gr0	,cc3,#1	\n"	/* clear ICC3.Z if store happens */
+	    "	beq		icc3,#0,0b		\n"
+	    "	setlos		0,%2			\n"
+	    "3:						\n"
+	    ".subsection 2				\n"
+	    "4:	setlos		%5,%2			\n"
+	    "	bra		3b			\n"
+	    ".previous					\n"
+	    ".section __ex_table,\"a\"			\n"
+	    "	.balign		8			\n"
+	    "	.long		1b,4b			\n"
+	    "	.long		2b,4b			\n"
+	    ".previous"
+	    : "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
+	    : "3"(oparg), "i"(-EFAULT)
+	    : "memory", "cc7", "cc3", "icc3"
+	    );
+
+	*_oldval = oldval;
+	return ret;
+}
+
+static inline int atomic_futex_op_xchg_and(int oparg, int __user *uaddr, int *_oldval)
+{
+	int oldval, ret;
+
+	asm("0:						\n"
+	    "	orcc		gr0,gr0,gr0,icc3	\n"	/* set ICC3.Z */
+	    "	ckeq		icc3,cc7		\n"
+	    "1:	ld.p		%M0,%1			\n"	/* LD.P/ORCR must be atomic */
+	    "	orcr		cc7,cc7,cc3		\n"	/* set CC3 to true */
+	    "	and		%1,%3,%3		\n"
+	    "2:	cst.p		%3,%M0		,cc3,#1	\n"
+	    "	corcc		gr29,gr29,gr0	,cc3,#1	\n"	/* clear ICC3.Z if store happens */
+	    "	beq		icc3,#0,0b		\n"
+	    "	setlos		0,%2			\n"
+	    "3:						\n"
+	    ".subsection 2				\n"
+	    "4:	setlos		%5,%2			\n"
+	    "	bra		3b			\n"
+	    ".previous					\n"
+	    ".section __ex_table,\"a\"			\n"
+	    "	.balign		8			\n"
+	    "	.long		1b,4b			\n"
+	    "	.long		2b,4b			\n"
+	    ".previous"
+	    : "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
+	    : "3"(oparg), "i"(-EFAULT)
+	    : "memory", "cc7", "cc3", "icc3"
+	    );
+
+	*_oldval = oldval;
+	return ret;
+}
+
+static inline int atomic_futex_op_xchg_xor(int oparg, int __user *uaddr, int *_oldval)
+{
+	int oldval, ret;
+
+	asm("0:						\n"
+	    "	orcc		gr0,gr0,gr0,icc3	\n"	/* set ICC3.Z */
+	    "	ckeq		icc3,cc7		\n"
+	    "1:	ld.p		%M0,%1			\n"	/* LD.P/ORCR must be atomic */
+	    "	orcr		cc7,cc7,cc3		\n"	/* set CC3 to true */
+	    "	xor		%1,%3,%3		\n"
+	    "2:	cst.p		%3,%M0		,cc3,#1	\n"
+	    "	corcc		gr29,gr29,gr0	,cc3,#1	\n"	/* clear ICC3.Z if store happens */
+	    "	beq		icc3,#0,0b		\n"
+	    "	setlos		0,%2			\n"
+	    "3:						\n"
+	    ".subsection 2				\n"
+	    "4:	setlos		%5,%2			\n"
+	    "	bra		3b			\n"
+	    ".previous					\n"
+	    ".section __ex_table,\"a\"			\n"
+	    "	.balign		8			\n"
+	    "	.long		1b,4b			\n"
+	    "	.long		2b,4b			\n"
+	    ".previous"
+	    : "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
+	    : "3"(oparg), "i"(-EFAULT)
+	    : "memory", "cc7", "cc3", "icc3"
+	    );
+
+	*_oldval = oldval;
+	return ret;
+}
+
+/*****************************************************************************/
+/*
+ * do the futex operations
+ */
+int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
+{
+	int op = (encoded_op >> 28) & 7;
+	int cmp = (encoded_op >> 24) & 15;
+	int oparg = (encoded_op << 8) >> 20;
+	int cmparg = (encoded_op << 20) >> 20;
+	int oldval = 0, ret;
+
+	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
+		oparg = 1 << oparg;
+
+	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
+		return -EFAULT;
+
+	inc_preempt_count();
+
+	switch (op) {
+	case FUTEX_OP_SET:
+		ret = atomic_futex_op_xchg_set(oparg, uaddr, &oldval);
+		break;
+	case FUTEX_OP_ADD:
+		ret = atomic_futex_op_xchg_add(oparg, uaddr, &oldval);
+		break;
+	case FUTEX_OP_OR:
+		ret = atomic_futex_op_xchg_or(oparg, uaddr, &oldval);
+		break;
+	case FUTEX_OP_ANDN:
+		ret = atomic_futex_op_xchg_and(~oparg, uaddr, &oldval);
+		break;
+	case FUTEX_OP_XOR:
+		ret = atomic_futex_op_xchg_xor(oparg, uaddr, &oldval);
+		break;
+	default:
+		ret = -ENOSYS;
+		break;
+	}
+
+	dec_preempt_count();
+
+	if (!ret) {
+		switch (cmp) {
+		case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
+		case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
+		case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
+		case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
+		case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
+		case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
+		default: ret = -ENOSYS; break;
+		}
+	}
+
+	return ret;
+
+} /* end futex_atomic_op_inuser() */

48 lines not on this page · raw message