From 53bb724f94f57b67213e08a4c155c8c5eb74c644 Mon Sep 17 00:00:00 2001 From: Brian Norris Date: Mon, 21 Sep 2015 13:26:59 -0700 Subject: mtd: provide proper 32/64-bit compat_ioctl() support for BLKPG After a bit of poking around wondering why my 32-bit user-space can't seem to send a proper ioctl(BLKPG) to an MTD on my 64-bit kernel (ARM64), I noticed that struct blkpg_ioctl_arg is actually pretty unsuitable for use in the ioctl() ABI, due to its use of raw pointers, and its lack of alignment/packing restrictions (32-bit arch'es tend to pack the 4 fields into 4 32-bit words, whereas 64-bit arch'es would add padding after the third int, and make this 6 32-bit words). Anyway, this means BLKPG deserves some special compat_ioctl handling. Do the conversion in a small shim for MTD. block/compat_ioctl.c already has compat support for the block subsystem, but it does so by a re-marshalling data to/from user-space (see compat_blkpg_ioctl()). Personally, I think this approach is cleaner. Tested only on MTD, with an ARM32 user space on an ARM64 kernel. Signed-off-by: Brian Norris --- include/linux/blkpg.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) create mode 100644 include/linux/blkpg.h (limited to 'include/linux') diff --git a/include/linux/blkpg.h b/include/linux/blkpg.h new file mode 100644 index 000000000000..bef124fde61e --- /dev/null +++ b/include/linux/blkpg.h @@ -0,0 +1,21 @@ +#ifndef _LINUX_BLKPG_H +#define _LINUX_BLKPG_H + +/* + * Partition table and disk geometry handling + */ + +#include +#include + +#ifdef CONFIG_COMPAT +/* For 32-bit/64-bit compatibility of struct blkpg_ioctl_arg */ +struct blkpg_compat_ioctl_arg { + compat_int_t op; + compat_int_t flags; + compat_int_t datalen; + compat_uptr_t data; +}; +#endif + +#endif /* _LINUX_BLKPG_H */ -- cgit v1.2.3