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

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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: Borislav 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: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Borislav Petkov 2016-10-31 16:10:15 +01:00 committed by Ingo Molnar
parent 05b93c19d5
commit adb402cd14
3 changed files with 49 additions and 96 deletions
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47
arch/x86/lib/copy_user_64.S
View File

@ -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

49
arch/x86/lib/usercopy.c
View File

@ -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);

49
arch/x86/lib/usercopy_32.c
View File

@ -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);