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Commit adb402cd authored by Borislav Petkov's avatar Borislav Petkov Committed by Ingo Molnar
Browse files

x86/copy_user: Unify the code by removing the 64-bit asm _copy_*_user() variants 



We already have the same functionality in usercopy_32.c. Share it with
64-bit and get rid of some more asm glue which is not needed anymore.

Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161031151015.22087-1-bp@alien8.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 05b93c19

arch/x86/lib/copy_user_64.S

+0 −47
Original line number Diff line number Diff line
@@ -16,53 +16,6 @@ 
#include <asm/smap.h>

#include <asm/export.h>



/* Standard copy_to_user with segment limit checking */

ENTRY(_copy_to_user)

	mov PER_CPU_VAR(current_task), %rax

	movq %rdi,%rcx

	addq %rdx,%rcx

	jc bad_to_user

	cmpq TASK_addr_limit(%rax),%rcx

	ja bad_to_user

	ALTERNATIVE_2 "jmp copy_user_generic_unrolled",		\

		      "jmp copy_user_generic_string",		\

		      X86_FEATURE_REP_GOOD,			\

		      "jmp copy_user_enhanced_fast_string",	\

		      X86_FEATURE_ERMS

ENDPROC(_copy_to_user)

EXPORT_SYMBOL(_copy_to_user)



/* Standard copy_from_user with segment limit checking */

ENTRY(_copy_from_user)

	mov PER_CPU_VAR(current_task), %rax

	movq %rsi,%rcx

	addq %rdx,%rcx

	jc bad_from_user

	cmpq TASK_addr_limit(%rax),%rcx

	ja bad_from_user

	ALTERNATIVE_2 "jmp copy_user_generic_unrolled",		\

		      "jmp copy_user_generic_string",		\

		      X86_FEATURE_REP_GOOD,			\

		      "jmp copy_user_enhanced_fast_string",	\

		      X86_FEATURE_ERMS

ENDPROC(_copy_from_user)

EXPORT_SYMBOL(_copy_from_user)





	.section .fixup,"ax"

	/* must zero dest */

ENTRY(bad_from_user)

bad_from_user:

	movl %edx,%ecx

	xorl %eax,%eax

	rep

	stosb

bad_to_user:

	movl %edx,%eax

	ret

ENDPROC(bad_from_user)

	.previous



/*

 * copy_user_generic_unrolled - memory copy with exception handling.

 * This version is for CPUs like P4 that don't have efficient micro

arch/x86/lib/usercopy.c

+49 −0
Original line number Diff line number Diff line
@@ -34,3 +34,52 @@ copy_from_user_nmi(void *to, const void __user *from, unsigned long n) 
	return ret;

}

EXPORT_SYMBOL_GPL(copy_from_user_nmi);



/**

 * copy_to_user: - Copy a block of data into user space.

 * @to:   Destination address, in user space.

 * @from: Source address, in kernel space.

 * @n:    Number of bytes to copy.

 *

 * Context: User context only. This function may sleep if pagefaults are

 *          enabled.

 *

 * Copy data from kernel space to user space.

 *

 * Returns number of bytes that could not be copied.

 * On success, this will be zero.

 */

unsigned long _copy_to_user(void __user *to, const void *from, unsigned n)

{

	if (access_ok(VERIFY_WRITE, to, n))

		n = __copy_to_user(to, from, n);

	return n;

}

EXPORT_SYMBOL(_copy_to_user);



/**

 * copy_from_user: - Copy a block of data from user space.

 * @to:   Destination address, in kernel space.

 * @from: Source address, in user space.

 * @n:    Number of bytes to copy.

 *

 * Context: User context only. This function may sleep if pagefaults are

 *          enabled.

 *

 * Copy data from user space to kernel space.

 *

 * Returns number of bytes that could not be copied.

 * On success, this will be zero.

 *

 * If some data could not be copied, this function will pad the copied

 * data to the requested size using zero bytes.

 */

unsigned long _copy_from_user(void *to, const void __user *from, unsigned n)

{

	if (access_ok(VERIFY_READ, from, n))

		n = __copy_from_user(to, from, n);

	else

		memset(to, 0, n);

	return n;

}

EXPORT_SYMBOL(_copy_from_user);

arch/x86/lib/usercopy_32.c

+0 −49
Original line number Diff line number Diff line
@@ -640,52 +640,3 @@ unsigned long __copy_from_user_ll_nocache_nozero(void *to, const void __user *fr 
	return n;

}

EXPORT_SYMBOL(__copy_from_user_ll_nocache_nozero);
 


/**

 * copy_to_user: - Copy a block of data into user space.

 * @to:   Destination address, in user space.

 * @from: Source address, in kernel space.

 * @n:    Number of bytes to copy.

 *

 * Context: User context only. This function may sleep if pagefaults are

 *          enabled.

 *

 * Copy data from kernel space to user space.

 *

 * Returns number of bytes that could not be copied.

 * On success, this will be zero.

 */

unsigned long _copy_to_user(void __user *to, const void *from, unsigned n)

{

	if (access_ok(VERIFY_WRITE, to, n))

		n = __copy_to_user(to, from, n);

	return n;

}

EXPORT_SYMBOL(_copy_to_user);



/**

 * copy_from_user: - Copy a block of data from user space.

 * @to:   Destination address, in kernel space.

 * @from: Source address, in user space.

 * @n:    Number of bytes to copy.

 *

 * Context: User context only. This function may sleep if pagefaults are

 *          enabled.

 *

 * Copy data from user space to kernel space.

 *

 * Returns number of bytes that could not be copied.

 * On success, this will be zero.

 *

 * If some data could not be copied, this function will pad the copied

 * data to the requested size using zero bytes.

 */

unsigned long _copy_from_user(void *to, const void __user *from, unsigned n)

{

	if (access_ok(VERIFY_READ, from, n))

		n = __copy_from_user(to, from, n);

	else

		memset(to, 0, n);

	return n;

}

EXPORT_SYMBOL(_copy_from_user);