diff options
author | Ingo Molnar <mingo@elte.hu> | 2008-04-17 20:05:36 +0200 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2008-04-17 20:05:36 +0200 |
commit | c33fa9f5609e918824446ef9a75319d4a802f1f4 (patch) | |
tree | ab711865ba14d4e3d21c2e480e8b113fc73e08a2 /mm | |
parent | 4b119e21d0c66c22e8ca03df05d9de623d0eb50f (diff) | |
download | linux-c33fa9f5609e918824446ef9a75319d4a802f1f4.tar.bz2 |
uaccess: add probe_kernel_write()
add probe_kernel_read() and probe_kernel_write().
Uninlined and restricted to kernel range memory only, as suggested
by Linus.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/Makefile | 2 | ||||
-rw-r--r-- | mm/maccess.c | 49 |
2 files changed, 50 insertions, 1 deletions
diff --git a/mm/Makefile b/mm/Makefile index a5b0dd93427a..18c143b3c46c 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -8,7 +8,7 @@ mmu-$(CONFIG_MMU) := fremap.o highmem.o madvise.o memory.o mincore.o \ vmalloc.o obj-y := bootmem.o filemap.o mempool.o oom_kill.o fadvise.o \ - page_alloc.o page-writeback.o pdflush.o \ + maccess.o page_alloc.o page-writeback.o pdflush.o \ readahead.o swap.o truncate.o vmscan.o \ prio_tree.o util.o mmzone.o vmstat.o backing-dev.o \ page_isolation.o $(mmu-y) diff --git a/mm/maccess.c b/mm/maccess.c new file mode 100644 index 000000000000..24f81b971403 --- /dev/null +++ b/mm/maccess.c @@ -0,0 +1,49 @@ +/* + * Access kernel memory without faulting. + */ +#include <linux/uaccess.h> +#include <linux/module.h> +#include <linux/mm.h> + +/** + * probe_kernel_read(): safely attempt to read from a location + * @dst: pointer to the buffer that shall take the data + * @src: address to read from + * @size: size of the data chunk + * + * Safely read from address @src to the buffer at @dst. If a kernel fault + * happens, handle that and return -EFAULT. + */ +long probe_kernel_read(void *dst, void *src, size_t size) +{ + long ret; + + pagefault_disable(); + ret = __copy_from_user_inatomic(dst, + (__force const void __user *)src, size); + pagefault_enable(); + + return ret ? -EFAULT : 0; +} +EXPORT_SYMBOL_GPL(probe_kernel_read); + +/** + * probe_kernel_write(): safely attempt to write to a location + * @dst: address to write to + * @src: pointer to the data that shall be written + * @size: size of the data chunk + * + * Safely write to address @dst from the buffer at @src. If a kernel fault + * happens, handle that and return -EFAULT. + */ +long probe_kernel_write(void *dst, void *src, size_t size) +{ + long ret; + + pagefault_disable(); + ret = __copy_to_user_inatomic((__force void __user *)dst, src, size); + pagefault_enable(); + + return ret ? -EFAULT : 0; +} +EXPORT_SYMBOL_GPL(probe_kernel_write); |