Commit 56583c9a authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86/fpu: Clarify parameter names in the copy_xstate_to_*() methods 

Right now there's a confusing mixture of 'offset' and 'size' parameters:

 - __copy_xstate_to_*() input parameter 'end_pos' not not really an offset,
   but the full size of the copy to be performed.

 - input parameter 'count' to copy_xstate_to_*() shadows that of
   __copy_xstate_to_*()'s 'count' parameter name - but the roles
   are different: the first one is the total number of bytes to
   be copied, while the second one is a partial copy size.

To unconfuse all this, use a consistent set of parameter names:

 - 'size' is the partial copy size within a single xstate component
 - 'size_total' is the total copy requested
 - 'offset_start' is the requested starting offset.
 - 'offset' is the offset within an xstate component.

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/20170923130016.21448-9-mingo@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 8a5b7318

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

+2 −2
Original line number Original line Diff line number Diff line
@@ -48,8 +48,8 @@ void fpu__xstate_clear_all_cpu_caps(void); 
void *get_xsave_addr(struct xregs_state *xsave, int xstate);

void *get_xsave_addr(struct xregs_state *xsave, int xstate);

const void *get_xsave_field_ptr(int xstate_field);

const void *get_xsave_field_ptr(int xstate_field);

int using_compacted_format(void);

int using_compacted_format(void);

int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int pos, unsigned int count);

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 pos, unsigned int count);

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,

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

		     struct xregs_state *xsave);

		     struct xregs_state *xsave);

#endif
 
#endif

arch/x86/kernel/fpu/xstate.c

+22 −22
Original line number Original line Diff line number Diff line
@@ -927,15 +927,15 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, 
static inline int

static inline int

__copy_xstate_to_kernel(void *kbuf,

__copy_xstate_to_kernel(void *kbuf,

			const void *data,

			const void *data,

			unsigned int pos, unsigned int count, int end_pos)

			unsigned int offset, unsigned int size, int size_total)

{

{

	if (!count)

	if (!size)

		return 0;

		return 0;





	if (end_pos < 0 || pos < end_pos) {

	if (size_total < 0 || offset < size_total) {

		unsigned int copy = end_pos < 0 ? count : min(count, end_pos - pos);

		unsigned int copy = size_total < 0 ? size : min(size, size_total - offset);





		memcpy(kbuf + pos, data, copy);

		memcpy(kbuf + offset, data, copy);

	}

	}

	return 0;

	return 0;

}

}
@@ -947,7 +947,7 @@ __copy_xstate_to_kernel(void *kbuf, 
 * It supports partial copy but pos always starts from zero. This is called

 * It supports partial copy but pos always starts from zero. This is called

 * from xstateregs_get() and there we check the CPU has XSAVES.

 * from xstateregs_get() and there we check the CPU has XSAVES.

 */

 */

int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int pos, unsigned int count)

int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int offset_start, unsigned int size_total)

{

{

	unsigned int offset, size;

	unsigned int offset, size;

	int ret, i;

	int ret, i;
@@ -956,7 +956,7 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int po 
	/*

	/*

	 * Currently copy_regset_to_user() starts from pos 0:

	 * Currently copy_regset_to_user() starts from pos 0:

	 */

	 */

	if (unlikely(pos != 0))

	if (unlikely(offset_start != 0))

		return -EFAULT;

		return -EFAULT;





	/*

	/*
@@ -972,7 +972,7 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int po 
	offset = offsetof(struct xregs_state, header);

	offset = offsetof(struct xregs_state, header);

	size = sizeof(header);

	size = sizeof(header);





	ret = __copy_xstate_to_kernel(kbuf, &header, offset, size, count);

	ret = __copy_xstate_to_kernel(kbuf, &header, offset, size, size_total);

	if (ret)

	if (ret)

		return ret;

		return ret;
@@ -986,11 +986,11 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int po 
			offset = xstate_offsets[i];

			offset = xstate_offsets[i];

			size = xstate_sizes[i];

			size = xstate_sizes[i];





			ret = __copy_xstate_to_kernel(kbuf, src, offset, size, count);

			ret = __copy_xstate_to_kernel(kbuf, src, offset, size, size_total);

			if (ret)

			if (ret)

				return ret;

				return ret;





			if (offset + size >= count)

			if (offset + size >= size_total)

				break;

				break;

		}

		}
@@ -1002,7 +1002,7 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int po 
	offset = offsetof(struct fxregs_state, sw_reserved);

	offset = offsetof(struct fxregs_state, sw_reserved);

	size = sizeof(xstate_fx_sw_bytes);

	size = sizeof(xstate_fx_sw_bytes);





	ret = __copy_xstate_to_kernel(kbuf, xstate_fx_sw_bytes, offset, size, count);

	ret = __copy_xstate_to_kernel(kbuf, xstate_fx_sw_bytes, offset, size, size_total);

	if (ret)

	if (ret)

		return ret;

		return ret;
@@ -1010,15 +1010,15 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int po 
}

}





static inline int

static inline int

__copy_xstate_to_user(void __user *ubuf, const void *data, unsigned int pos, unsigned int count, int end_pos)

__copy_xstate_to_user(void __user *ubuf, const void *data, unsigned int offset, unsigned int size, int size_total)

{

{

	if (!count)

	if (!size)

		return 0;

		return 0;





	if (end_pos < 0 || pos < end_pos) {

	if (size_total < 0 || offset < size_total) {

		unsigned int copy = end_pos < 0 ? count : min(count, end_pos - pos);

		unsigned int copy = size_total < 0 ? size : min(size, size_total - offset);





		if (__copy_to_user(ubuf + pos, data, copy))

		if (__copy_to_user(ubuf + offset, data, copy))

			return -EFAULT;

			return -EFAULT;

	}

	}

	return 0;

	return 0;
@@ -1030,7 +1030,7 @@ __copy_xstate_to_user(void __user *ubuf, const void *data, unsigned int pos, uns 
 * zero. This is called from xstateregs_get() and there we check the CPU

 * zero. This is called from xstateregs_get() and there we check the CPU

 * has XSAVES.

 * has XSAVES.

 */

 */

int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned int pos, unsigned int count)

int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned int offset_start, unsigned int size_total)

{

{

	unsigned int offset, size;

	unsigned int offset, size;

	int ret, i;

	int ret, i;
@@ -1039,7 +1039,7 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i 
	/*

	/*

	 * Currently copy_regset_to_user() starts from pos 0:

	 * Currently copy_regset_to_user() starts from pos 0:

	 */

	 */

	if (unlikely(pos != 0))

	if (unlikely(offset_start != 0))

		return -EFAULT;

		return -EFAULT;





	/*

	/*
@@ -1055,7 +1055,7 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i 
	offset = offsetof(struct xregs_state, header);

	offset = offsetof(struct xregs_state, header);

	size = sizeof(header);

	size = sizeof(header);





	ret = __copy_xstate_to_user(ubuf, &header, offset, size, count);

	ret = __copy_xstate_to_user(ubuf, &header, offset, size, size_total);

	if (ret)

	if (ret)

		return ret;

		return ret;
@@ -1069,11 +1069,11 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i 
			offset = xstate_offsets[i];

			offset = xstate_offsets[i];

			size = xstate_sizes[i];

			size = xstate_sizes[i];





			ret = __copy_xstate_to_user(ubuf, src, offset, size, count);

			ret = __copy_xstate_to_user(ubuf, src, offset, size, size_total);

			if (ret)

			if (ret)

				return ret;

				return ret;





			if (offset + size >= count)

			if (offset + size >= size_total)

				break;

				break;

		}

		}
@@ -1085,7 +1085,7 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i 
	offset = offsetof(struct fxregs_state, sw_reserved);

	offset = offsetof(struct fxregs_state, sw_reserved);

	size = sizeof(xstate_fx_sw_bytes);

	size = sizeof(xstate_fx_sw_bytes);





	ret = __copy_xstate_to_user(ubuf, xstate_fx_sw_bytes, offset, size, count);

	ret = __copy_xstate_to_user(ubuf, xstate_fx_sw_bytes, offset, size, size_total);

	if (ret)

	if (ret)

		return ret;

		return ret;

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