linux/arch/x86/lib/usercopy_64.c
Paul Gortmaker e683014c21 x86/lib: Audit and remove any unnecessary uses of module.h
Historically a lot of these existed because we did not have
a distinction between what was modular code and what was providing
support to modules via EXPORT_SYMBOL and friends.  That changed
when we forked out support for the latter into the export.h file.

This means we should be able to reduce the usage of module.h
in code that is obj-y Makefile or bool Kconfig.  The advantage
in doing so is that module.h itself sources about 15 other headers;
adding significantly to what we feed cpp, and it can obscure what
headers we are effectively using.

Since module.h was the source for init.h (for __init) and for
export.h (for EXPORT_SYMBOL) we consider each obj-y/bool instance
for the presence of either and replace as needed.  Build testing
revealed a couple implicit header usage issues that were fixed.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.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/20160714001901.31603-5-paul.gortmaker@windriver.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-14 15:06:58 +02:00

89 lines
2.1 KiB
C

/*
* User address space access functions.
*
* Copyright 1997 Andi Kleen <ak@muc.de>
* Copyright 1997 Linus Torvalds
* Copyright 2002 Andi Kleen <ak@suse.de>
*/
#include <linux/export.h>
#include <asm/uaccess.h>
/*
* Zero Userspace
*/
unsigned long __clear_user(void __user *addr, unsigned long size)
{
long __d0;
might_fault();
/* no memory constraint because it doesn't change any memory gcc knows
about */
stac();
asm volatile(
" testq %[size8],%[size8]\n"
" jz 4f\n"
"0: movq %[zero],(%[dst])\n"
" addq %[eight],%[dst]\n"
" decl %%ecx ; jnz 0b\n"
"4: movq %[size1],%%rcx\n"
" testl %%ecx,%%ecx\n"
" jz 2f\n"
"1: movb %b[zero],(%[dst])\n"
" incq %[dst]\n"
" decl %%ecx ; jnz 1b\n"
"2:\n"
".section .fixup,\"ax\"\n"
"3: lea 0(%[size1],%[size8],8),%[size8]\n"
" jmp 2b\n"
".previous\n"
_ASM_EXTABLE(0b,3b)
_ASM_EXTABLE(1b,2b)
: [size8] "=&c"(size), [dst] "=&D" (__d0)
: [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr),
[zero] "r" (0UL), [eight] "r" (8UL));
clac();
return size;
}
EXPORT_SYMBOL(__clear_user);
unsigned long clear_user(void __user *to, unsigned long n)
{
if (access_ok(VERIFY_WRITE, to, n))
return __clear_user(to, n);
return n;
}
EXPORT_SYMBOL(clear_user);
unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len)
{
if (access_ok(VERIFY_WRITE, to, len) && access_ok(VERIFY_READ, from, len)) {
return copy_user_generic((__force void *)to, (__force void *)from, len);
}
return len;
}
EXPORT_SYMBOL(copy_in_user);
/*
* Try to copy last bytes and clear the rest if needed.
* Since protection fault in copy_from/to_user is not a normal situation,
* it is not necessary to optimize tail handling.
*/
__visible unsigned long
copy_user_handle_tail(char *to, char *from, unsigned len)
{
for (; len; --len, to++) {
char c;
if (__get_user_nocheck(c, from++, sizeof(char)))
break;
if (__put_user_nocheck(c, to, sizeof(char)))
break;
}
clac();
/* If the destination is a kernel buffer, we always clear the end */
if (!__addr_ok(to))
memset(to, 0, len);
return len;
}