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Commit 79fecc2b authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86/fpu: Split copy_user_to_xstate() into copy_kernel_to_xstate() & copy_user_to_xstate() 

Similar to:

  x86/fpu: Split copy_xstate_to_user() into copy_xstate_to_kernel() & copy_xstate_to_user()

No change in functionality.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-12-mingo@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 8c0817f4

arch/x86/include/asm/fpu/xstate.h

+2 −2
Original line number Diff line number Diff line
@@ -50,6 +50,6 @@ const void *get_xsave_field_ptr(int xstate_field); 
int using_compacted_format(void);

int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int offset, unsigned int size);

int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned int offset, unsigned int size);

int copy_user_to_xstate(const void *kbuf, const void __user *ubuf,

		     struct xregs_state *xsave);

int copy_kernel_to_xstate(const void *kbuf, const void __user *ubuf, struct xregs_state *xsave);

int copy_user_to_xstate(const void *kbuf, const void __user *ubuf, struct xregs_state *xsave);

#endif

arch/x86/kernel/fpu/regset.c

+7 −3
Original line number Diff line number Diff line
@@ -134,10 +134,14 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset, 


	fpu__activate_fpstate_write(fpu);



	if (boot_cpu_has(X86_FEATURE_XSAVES))

		ret = copy_user_to_xstate(kbuf, ubuf, xsave);

	if (boot_cpu_has(X86_FEATURE_XSAVES)) {

		if (kbuf)

			ret = copy_kernel_to_xstate(kbuf, ubuf, xsave);

		else

			ret = copy_user_to_xstate(kbuf, ubuf, xsave);

	} else {

		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, xsave, 0, -1);

	}



	/*

	 * In case of failure, mark all states as init:

arch/x86/kernel/fpu/xstate.c

+65 −1
Original line number Diff line number Diff line
@@ -1084,7 +1084,71 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i 
}



/*

 * Convert from a ptrace standard-format buffer to kernel XSAVES format

 * Convert from a ptrace standard-format kernel buffer to kernel XSAVES format

 * and copy to the target thread. This is called from xstateregs_set() and

 * there we check the CPU has XSAVES and a whole standard-sized buffer

 * exists.

 */

int copy_kernel_to_xstate(const void *kbuf, const void __user *ubuf,

		     struct xregs_state *xsave)

{

	unsigned int offset, size;

	int i;

	u64 xfeatures;

	u64 allowed_features;



	offset = offsetof(struct xregs_state, header);

	size = sizeof(xfeatures);



	if (kbuf) {

		memcpy(&xfeatures, kbuf + offset, size);

	} else {

		if (__copy_from_user(&xfeatures, ubuf + offset, size))

			return -EFAULT;

	}



	/*

	 * Reject if the user sets any disabled or supervisor features:

	 */

	allowed_features = xfeatures_mask & ~XFEATURE_MASK_SUPERVISOR;



	if (xfeatures & ~allowed_features)

		return -EINVAL;



	for (i = 0; i < XFEATURE_MAX; i++) {

		u64 mask = ((u64)1 << i);



		if (xfeatures & mask) {

			void *dst = __raw_xsave_addr(xsave, 1 << i);



			offset = xstate_offsets[i];

			size = xstate_sizes[i];



			if (kbuf) {

				memcpy(dst, kbuf + offset, size);

			} else {

				if (__copy_from_user(dst, ubuf + offset, size))

					return -EFAULT;

			}

		}

	}



	/*

	 * The state that came in from userspace was user-state only.

	 * Mask all the user states out of 'xfeatures':

	 */

	xsave->header.xfeatures &= XFEATURE_MASK_SUPERVISOR;



	/*

	 * Add back in the features that came in from userspace:

	 */

	xsave->header.xfeatures |= xfeatures;



	return 0;

}



/*

 * Convert from a ptrace standard-format user-space buffer to kernel XSAVES format

 * and copy to the target thread. This is called from xstateregs_set() and

 * there we check the CPU has XSAVES and a whole standard-sized buffer

 * exists.