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Commit f240652b authored by Dave Hansen's avatar Dave Hansen Committed by Thomas Gleixner
Browse files

x86/mpx: Remove MPX APIs 



MPX is being removed from the kernel due to a lack of support in the
toolchain going forward (gcc).

The first step is to remove the userspace-visible ABIs so that applications
will stop using it.  The most visible one are the enable/disable prctl()s.
Remove them first.

This is the most minimal and least invasive change needed to ensure that
apps stop using MPX with new kernels.

Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190705175321.DB42F0AD@viggo.jf.intel.com
parent e28df79a

include/uapi/linux/prctl.h

+1 −1
Original line number Diff line number Diff line
@@ -181,7 +181,7 @@ struct prctl_mm_map { 
#define PR_GET_THP_DISABLE	42



/*

 * Tell the kernel to start/stop helping userspace manage bounds tables.

 * No longer implemented, but left here to ensure the numbers stay reserved:

 */

#define PR_MPX_ENABLE_MANAGEMENT  43

#define PR_MPX_DISABLE_MANAGEMENT 44

kernel/sys.c

+2 −14
Original line number Diff line number Diff line
@@ -103,12 +103,6 @@ 
#ifndef SET_TSC_CTL

# define SET_TSC_CTL(a)		(-EINVAL)

#endif

#ifndef MPX_ENABLE_MANAGEMENT

# define MPX_ENABLE_MANAGEMENT()	(-EINVAL)

#endif

#ifndef MPX_DISABLE_MANAGEMENT

# define MPX_DISABLE_MANAGEMENT()	(-EINVAL)

#endif

#ifndef GET_FP_MODE

# define GET_FP_MODE(a)		(-EINVAL)

#endif
@@ -2456,15 +2450,9 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, 
		up_write(&me->mm->mmap_sem);

		break;

	case PR_MPX_ENABLE_MANAGEMENT:

		if (arg2 || arg3 || arg4 || arg5)

			return -EINVAL;

		error = MPX_ENABLE_MANAGEMENT();

		break;

	case PR_MPX_DISABLE_MANAGEMENT:

		if (arg2 || arg3 || arg4 || arg5)

		/* No longer implemented: */

		return -EINVAL;

		error = MPX_DISABLE_MANAGEMENT();

		break;

	case PR_SET_FP_MODE:

		error = SET_FP_MODE(me, arg2);

		break;