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| author | Brian Norris <computersforpeace@gmail.com> | 2015-09-21 23:26:59 +0300 |
|---|---|---|
| committer | Brian Norris <computersforpeace@gmail.com> | 2015-09-29 23:37:04 +0300 |
| commit | 53bb724f94f57b67213e08a4c155c8c5eb74c644 (patch) | |
| tree | 3acf74aec5e263a96c6f8a43161a8264d5ee0ed2 /include | |
| parent | 4404bd742db767a7f316b1207c46a04a38ca7198 (diff) | |
| download | linux-53bb724f94f57b67213e08a4c155c8c5eb74c644.tar.xz | |
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 <computersforpeace@gmail.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/blkpg.h | 21 | ||||
| -rw-r--r-- | include/uapi/linux/blkpg.h | 6 |
2 files changed, 24 insertions, 3 deletions
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 <linux/compat.h> +#include <uapi/linux/blkpg.h> + +#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 */ diff --git a/include/uapi/linux/blkpg.h b/include/uapi/linux/blkpg.h index a8519446c111..63739a035085 100644 --- a/include/uapi/linux/blkpg.h +++ b/include/uapi/linux/blkpg.h @@ -1,5 +1,5 @@ -#ifndef _LINUX_BLKPG_H -#define _LINUX_BLKPG_H +#ifndef _UAPI__LINUX_BLKPG_H +#define _UAPI__LINUX_BLKPG_H /* * Partition table and disk geometry handling @@ -56,4 +56,4 @@ struct blkpg_partition { char volname[BLKPG_VOLNAMELTH]; /* volume label */ }; -#endif /* _LINUX_BLKPG_H */ +#endif /* _UAPI__LINUX_BLKPG_H */ |