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um: Rework uaccess code

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Rework UML's uaccess code to reuse as much as possible
from asm-generic/uaccess.c.

Signed-off-by: Richard Weinberger <richard@nod.at>
This commit is contained in:
Richard Weinberger 2015-05-12 00:17:28 +02:00
parent 1d04c8d779
commit f8d65d27e6
7 changed files with 53 additions and 183 deletions
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2
arch/um/include/asm/thread_info.h
View File

@ -10,7 +10,7 @@
#include <asm/types.h>
#include <asm/page.h>
#include <asm/uaccess.h>
#include <asm/segment.h>
struct thread_info {
struct task_struct *task; /* main task structure */

174
arch/um/include/asm/uaccess.h
View File

@ -1,178 +1,52 @@
/*
* Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
* Copyright (C) 2015 Richard Weinberger (richard@nod.at)
* Licensed under the GPL
*/
#ifndef __UM_UACCESS_H
#define __UM_UACCESS_H
/* thread_info has a mm_segment_t in it, so put the definition up here */
typedef struct {
unsigned long seg;
} mm_segment_t;
#include <linux/thread_info.h>
#include <linux/errno.h>
#include <asm/processor.h>
#include <asm/thread_info.h>
#include <asm/elf.h>
#define VERIFY_READ 0
#define VERIFY_WRITE 1
/*
* The fs value determines whether argument validity checking should be
* performed or not. If get_fs() == USER_DS, checking is performed, with
* get_fs() == KERNEL_DS, checking is bypassed.
*
* For historical reasons, these macros are grossly misnamed.
*/
#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
#define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFF)
#define USER_DS MAKE_MM_SEG(TASK_SIZE)
#define get_ds() (KERNEL_DS)
#define get_fs() (current_thread_info()->addr_limit)
#define set_fs(x) (current_thread_info()->addr_limit = (x))
#define segment_eq(a, b) ((a).seg == (b).seg)
#define __under_task_size(addr, size) \
(((unsigned long) (addr) < TASK_SIZE) && \
(((unsigned long) (addr) + (size)) < TASK_SIZE))
#define __access_ok_vsyscall(type, addr, size) \
((type == VERIFY_READ) && \
((unsigned long) (addr) >= FIXADDR_USER_START) && \
#define __access_ok_vsyscall(addr, size) \
(((unsigned long) (addr) >= FIXADDR_USER_START) && \
((unsigned long) (addr) + (size) <= FIXADDR_USER_END) && \
((unsigned long) (addr) + (size) >= (unsigned long)(addr)))
#define __addr_range_nowrap(addr, size) \
((unsigned long) (addr) <= ((unsigned long) (addr) + (size)))
#define access_ok(type, addr, size) \
(__addr_range_nowrap(addr, size) && \
(__under_task_size(addr, size) || \
__access_ok_vsyscall(type, addr, size) || \
segment_eq(get_fs(), KERNEL_DS)))
extern int copy_from_user(void *to, const void __user *from, int n);
extern int copy_to_user(void __user *to, const void *from, int n);
/*
* strncpy_from_user: - Copy a NUL terminated string from userspace.
* @dst: Destination address, in kernel space. This buffer must be at
* least @count bytes long.
* @src: Source address, in user space.
* @count: Maximum number of bytes to copy, including the trailing NUL.
*
* Copies a NUL-terminated string from userspace to kernel space.
*
* On success, returns the length of the string (not including the trailing
* NUL).
*
* If access to userspace fails, returns -EFAULT (some data may have been
* copied).
*
* If @count is smaller than the length of the string, copies @count bytes
* and returns @count.
*/
extern int strncpy_from_user(char *dst, const char __user *src, int count);
/*
* __clear_user: - Zero a block of memory in user space, with less checking.
* @to: Destination address, in user space.
* @n: Number of bytes to zero.
*
* Zero a block of memory in user space. Caller must check
* the specified block with access_ok() before calling this function.
*
* Returns number of bytes that could not be cleared.
* On success, this will be zero.
*/
extern int __clear_user(void __user *mem, int len);
/*
* clear_user: - Zero a block of memory in user space.
* @to: Destination address, in user space.
* @n: Number of bytes to zero.
*
* Zero a block of memory in user space.
*
* Returns number of bytes that could not be cleared.
* On success, this will be zero.
*/
extern int clear_user(void __user *mem, int len);
/*
* strlen_user: - Get the size of a string in user space.
* @str: The string to measure.
* @n: The maximum valid length
*
* Get the size of a NUL-terminated string in user space.
*
* Returns the size of the string INCLUDING the terminating NUL.
* On exception, returns 0.
* If the string is too long, returns a value greater than @n.
*/
extern int strnlen_user(const void __user *str, int len);
#define __copy_from_user(to, from, n) copy_from_user(to, from, n)
#define __copy_to_user(to, from, n) copy_to_user(to, from, n)
extern long __copy_from_user(void *to, const void __user *from, unsigned long n);
extern long __copy_to_user(void __user *to, const void *from, unsigned long n);
extern long __strncpy_from_user(char *dst, const char __user *src, long count);
extern long __strnlen_user(const void __user *str, long len);
extern unsigned long __clear_user(void __user *mem, unsigned long len);
static inline int __access_ok(unsigned long addr, unsigned long size);
/* Teach asm-generic/uaccess.h that we have C functions for these. */
#define __access_ok __access_ok
#define __clear_user __clear_user
#define __copy_to_user __copy_to_user
#define __copy_from_user __copy_from_user
#define __strnlen_user __strnlen_user
#define __strncpy_from_user __strncpy_from_user
#define __copy_to_user_inatomic __copy_to_user
#define __copy_from_user_inatomic __copy_from_user
#define __get_user(x, ptr) \
({ \
const __typeof__(*(ptr)) __user *__private_ptr = (ptr); \
__typeof__(x) __private_val; \
int __private_ret = -EFAULT; \
(x) = (__typeof__(*(__private_ptr)))0; \
if (__copy_from_user((__force void *)&__private_val, (__private_ptr),\
sizeof(*(__private_ptr))) == 0) { \
(x) = (__typeof__(*(__private_ptr))) __private_val; \
__private_ret = 0; \
} \
__private_ret; \
})
#include <asm-generic/uaccess.h>
#define get_user(x, ptr) \
({ \
const __typeof__((*(ptr))) __user *private_ptr = (ptr); \
(access_ok(VERIFY_READ, private_ptr, sizeof(*private_ptr)) ? \
__get_user(x, private_ptr) : ((x) = (__typeof__(*ptr))0, -EFAULT)); \
})
#define __put_user(x, ptr) \
({ \
__typeof__(*(ptr)) __user *__private_ptr = ptr; \
__typeof__(*(__private_ptr)) __private_val; \
int __private_ret = -EFAULT; \
__private_val = (__typeof__(*(__private_ptr))) (x); \
if (__copy_to_user((__private_ptr), &__private_val, \
sizeof(*(__private_ptr))) == 0) { \
__private_ret = 0; \
} \
__private_ret; \
})
#define put_user(x, ptr) \
({ \
__typeof__(*(ptr)) __user *private_ptr = (ptr); \
(access_ok(VERIFY_WRITE, private_ptr, sizeof(*private_ptr)) ? \
__put_user(x, private_ptr) : -EFAULT); \
})
#define strlen_user(str) strnlen_user(str, ~0U >> 1)
struct exception_table_entry
static inline int __access_ok(unsigned long addr, unsigned long size)
{
unsigned long insn;
unsigned long fixup;
};
return __addr_range_nowrap(addr, size) &&
(__under_task_size(addr, size) ||
__access_ok_vsyscall(addr, size) ||
segment_eq(get_fs(), KERNEL_DS));
}
#endif

47
arch/um/kernel/skas/uaccess.c
View File

@ -87,10 +87,10 @@ static int do_op_one_page(unsigned long addr, int len, int is_write,
return n;
}
static int buffer_op(unsigned long addr, int len, int is_write,
int (*op)(unsigned long, int, void *), void *arg)
static long buffer_op(unsigned long addr, int len, int is_write,
int (*op)(unsigned long, int, void *), void *arg)
{
int size, remain, n;
long size, remain, n;
size = min(PAGE_ALIGN(addr) - addr, (unsigned long) len);
remain = len;
@ -139,18 +139,16 @@ static int copy_chunk_from_user(unsigned long from, int len, void *arg)
return 0;
}
int copy_from_user(void *to, const void __user *from, int n)
long __copy_from_user(void *to, const void __user *from, unsigned long n)
{
if (segment_eq(get_fs(), KERNEL_DS)) {
memcpy(to, (__force void*)from, n);
return 0;
}
return access_ok(VERIFY_READ, from, n) ?
buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to):
n;
return buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to);
}
EXPORT_SYMBOL(copy_from_user);
EXPORT_SYMBOL(__copy_from_user);
static int copy_chunk_to_user(unsigned long to, int len, void *arg)
{
@ -161,18 +159,16 @@ static int copy_chunk_to_user(unsigned long to, int len, void *arg)
return 0;
}
int copy_to_user(void __user *to, const void *from, int n)
long __copy_to_user(void __user *to, const void *from, unsigned long n)
{
if (segment_eq(get_fs(), KERNEL_DS)) {
memcpy((__force void *) to, from, n);
return 0;
}
return access_ok(VERIFY_WRITE, to, n) ?
buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from) :
n;
return buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from);
}
EXPORT_SYMBOL(copy_to_user);
EXPORT_SYMBOL(__copy_to_user);
static int strncpy_chunk_from_user(unsigned long from, int len, void *arg)
{
@ -188,9 +184,9 @@ static int strncpy_chunk_from_user(unsigned long from, int len, void *arg)
return 0;
}
int strncpy_from_user(char *dst, const char __user *src, int count)
long __strncpy_from_user(char *dst, const char __user *src, long count)
{
int n;
long n;
char *ptr = dst;
if (segment_eq(get_fs(), KERNEL_DS)) {
@ -198,16 +194,13 @@ int strncpy_from_user(char *dst, const char __user *src, int count)
return strnlen(dst, count);
}
if (!access_ok(VERIFY_READ, src, 1))
return -EFAULT;
n = buffer_op((unsigned long) src, count, 0, strncpy_chunk_from_user,
&ptr);
if (n != 0)
return -EFAULT;
return strnlen(dst, count);
}
EXPORT_SYMBOL(strncpy_from_user);
EXPORT_SYMBOL(__strncpy_from_user);
static int clear_chunk(unsigned long addr, int len, void *unused)
{
@ -215,22 +208,16 @@ static int clear_chunk(unsigned long addr, int len, void *unused)
return 0;
}
int __clear_user(void __user *mem, int len)
{
return buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL);
}
int clear_user(void __user *mem, int len)
unsigned long __clear_user(void __user *mem, unsigned long len)
{
if (segment_eq(get_fs(), KERNEL_DS)) {
memset((__force void*)mem, 0, len);
return 0;
}
return access_ok(VERIFY_WRITE, mem, len) ?
buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL) : len;
return buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL);
}
EXPORT_SYMBOL(clear_user);
EXPORT_SYMBOL(__clear_user);
static int strnlen_chunk(unsigned long str, int len, void *arg)
{
@ -244,7 +231,7 @@ static int strnlen_chunk(unsigned long str, int len, void *arg)
return 0;
}
int strnlen_user(const void __user *str, int len)
long __strnlen_user(const void __user *str, long len)
{
int count = 0, n;
@ -256,4 +243,4 @@ int strnlen_user(const void __user *str, int len)
return count + 1;
return 0;
}
EXPORT_SYMBOL(strnlen_user);
EXPORT_SYMBOL(__strnlen_user);

1
arch/x86/um/asm/checksum.h
View File

@ -3,6 +3,7 @@
#include <linux/string.h>
#include <linux/in6.h>
#include <linux/uaccess.h>
/*
* computes the checksum of a memory block at buff, length len,

2
arch/x86/um/asm/elf.h
View File

@ -200,8 +200,6 @@ typedef elf_greg_t elf_gregset_t[ELF_NGREG];
typedef struct user_i387_struct elf_fpregset_t;
#define task_pt_regs(t) (&(t)->thread.regs)
struct task_struct;
extern int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu);

2
arch/x86/um/asm/processor.h
View File

@ -28,6 +28,8 @@ static inline void rep_nop(void)
#define cpu_relax() rep_nop()
#define cpu_relax_lowlatency() cpu_relax()
#define task_pt_regs(t) (&(t)->thread.regs)
#include <asm/processor-generic.h>
#endif

8
arch/x86/um/asm/segment.h
View File

@ -7,4 +7,12 @@ extern int host_gdt_entry_tls_min;
#define GDT_ENTRY_TLS_MIN host_gdt_entry_tls_min
#define GDT_ENTRY_TLS_MAX (GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1)
typedef struct {
unsigned long seg;
} mm_segment_t;
#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
#define KERNEL_DS MAKE_MM_SEG(~0UL)
#define USER_DS MAKE_MM_SEG(TASK_SIZE)
#endif