diff options
Diffstat (limited to 'target/linux/xburst/patches-3.3/0009-dev-mem-Add-kernel-config-option-to-omit-this-device.patch')
| -rw-r--r-- | target/linux/xburst/patches-3.3/0009-dev-mem-Add-kernel-config-option-to-omit-this-device.patch | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/target/linux/xburst/patches-3.3/0009-dev-mem-Add-kernel-config-option-to-omit-this-device.patch b/target/linux/xburst/patches-3.3/0009-dev-mem-Add-kernel-config-option-to-omit-this-device.patch new file mode 100644 index 0000000..28388fb --- /dev/null +++ b/target/linux/xburst/patches-3.3/0009-dev-mem-Add-kernel-config-option-to-omit-this-device.patch @@ -0,0 +1,124 @@ +From 4003b9a2c05f4d0d37535c3dffbf4a7b47d5c36c Mon Sep 17 00:00:00 2001 +From: Maarten ter Huurne <maarten@treewalker.org> +Date: Wed, 8 Sep 2010 02:31:19 +0200 +Subject: [PATCH 09/21] /dev/mem: Add kernel config option to omit this + device. + +Omitting this device prevents software from accessing the hardware directly, which can cause trouble if the kernel accesses the same hardware. +It also saves some space on embedded systems. +--- + arch/x86/Kconfig.debug | 1 + + drivers/char/Kconfig | 10 ++++++++++ + drivers/char/mem.c | 17 +++++++++++++++++ + 3 files changed, 28 insertions(+), 0 deletions(-) + +--- a/arch/x86/Kconfig.debug ++++ b/arch/x86/Kconfig.debug +@@ -7,6 +7,7 @@ source "lib/Kconfig.debug" + + config STRICT_DEVMEM + bool "Filter access to /dev/mem" ++ depends on DEVMEM + ---help--- + If this option is disabled, you allow userspace (root) access to all + of memory, including kernel and userspace memory. Accidental +--- a/drivers/char/Kconfig ++++ b/drivers/char/Kconfig +@@ -6,6 +6,16 @@ menu "Character devices" + + source "drivers/tty/Kconfig" + ++config DEVMEM ++ bool "/dev/mem virtual device support" ++ default y ++ help ++ Say Y here if you want to support the /dev/mem device. ++ Some X server drivers access the video hardware using this device. ++ Accessing hardware directly from user space can be useful in some ++ cases, but it is not without risks. ++ When in doubt, say "N". ++ + config DEVKMEM + bool "/dev/kmem virtual device support" + default y +--- a/drivers/char/mem.c ++++ b/drivers/char/mem.c +@@ -87,6 +87,8 @@ void __weak unxlate_dev_mem_ptr(unsigned + { + } + ++#ifdef CONFIG_DEVMEM ++ + /* + * This funcion reads the *physical* memory. The f_pos points directly to the + * memory location. +@@ -210,6 +212,10 @@ static ssize_t write_mem(struct file *fi + return written; + } + ++#endif ++ ++#if defined(CONFIG_DEVMEM) || defined(CONFIG_DEVKMEM) ++ + int __weak phys_mem_access_prot_allowed(struct file *file, + unsigned long pfn, unsigned long size, pgprot_t *vma_prot) + { +@@ -331,6 +337,8 @@ static int mmap_mem(struct file *file, s + return 0; + } + ++#endif ++ + #ifdef CONFIG_DEVKMEM + static int mmap_kmem(struct file *file, struct vm_area_struct *vma) + { +@@ -694,6 +702,7 @@ static loff_t null_lseek(struct file *fi + return file->f_pos = 0; + } + ++#if defined(CONFIG_DEVMEM) || defined(CONFIG_DEVKMEM) || defined(CONFIG_DEVPORT) + /* + * The memory devices use the full 32/64 bits of the offset, and so we cannot + * check against negative addresses: they are ok. The return value is weird, +@@ -726,11 +735,15 @@ static loff_t memory_lseek(struct file * + mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); + return ret; + } ++#endif + ++#if defined(CONFIG_DEVMEM) || defined(CONFIG_DEVKMEM) || \ ++ defined(CONFIG_DEVPORT) || defined(CONFIG_CRASH_DUMP) + static int open_port(struct inode * inode, struct file * filp) + { + return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; + } ++#endif + + #define zero_lseek null_lseek + #define full_lseek null_lseek +@@ -740,6 +753,7 @@ static int open_port(struct inode * inod + #define open_kmem open_mem + #define open_oldmem open_mem + ++#ifdef CONFIG_DEVMEM + static const struct file_operations mem_fops = { + .llseek = memory_lseek, + .read = read_mem, +@@ -748,6 +762,7 @@ static const struct file_operations mem_ + .open = open_mem, + .get_unmapped_area = get_unmapped_area_mem, + }; ++#endif + + #ifdef CONFIG_DEVKMEM + static const struct file_operations kmem_fops = { +@@ -851,7 +866,9 @@ static const struct memdev { + const struct file_operations *fops; + struct backing_dev_info *dev_info; + } devlist[] = { ++#ifdef CONFIG_DEVMEM + [1] = { "mem", 0, &mem_fops, &directly_mappable_cdev_bdi }, ++#endif + #ifdef CONFIG_DEVKMEM + [2] = { "kmem", 0, &kmem_fops, &directly_mappable_cdev_bdi }, + #endif |