mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-14 07:36:43 +07:00
f5a1a536fa
A common pattern for syscall extensions is increasing the size of a
struct passed from userspace, such that the zero-value of the new fields
result in the old kernel behaviour (allowing for a mix of userspace and
kernel vintages to operate on one another in most cases).
While this interface exists for communication in both directions, only
one interface is straightforward to have reasonable semantics for
(userspace passing a struct to the kernel). For kernel returns to
userspace, what the correct semantics are (whether there should be an
error if userspace is unaware of a new extension) is very
syscall-dependent and thus probably cannot be unified between syscalls
(a good example of this problem is [1]).
Previously there was no common lib/ function that implemented
the necessary extension-checking semantics (and different syscalls
implemented them slightly differently or incompletely[2]). Future
patches replace common uses of this pattern to make use of
copy_struct_from_user().
Some in-kernel selftests that insure that the handling of alignment and
various byte patterns are all handled identically to memchr_inv() usage.
[1]: commit 1251201c0d
("sched/core: Fix uclamp ABI bug, clean up and
robustify sched_read_attr() ABI logic and code")
[2]: For instance {sched_setattr,perf_event_open,clone3}(2) all do do
similar checks to copy_struct_from_user() while rt_sigprocmask(2)
always rejects differently-sized struct arguments.
Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20191001011055.19283-2-cyphar@cyphar.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
290 lines
6.9 KiB
C
290 lines
6.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _LINUX_BITOPS_H
|
|
#define _LINUX_BITOPS_H
|
|
#include <asm/types.h>
|
|
#include <linux/bits.h>
|
|
|
|
/* Set bits in the first 'n' bytes when loaded from memory */
|
|
#ifdef __LITTLE_ENDIAN
|
|
# define aligned_byte_mask(n) ((1UL << 8*(n))-1)
|
|
#else
|
|
# define aligned_byte_mask(n) (~0xffUL << (BITS_PER_LONG - 8 - 8*(n)))
|
|
#endif
|
|
|
|
#define BITS_PER_TYPE(type) (sizeof(type) * BITS_PER_BYTE)
|
|
#define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_TYPE(long))
|
|
|
|
extern unsigned int __sw_hweight8(unsigned int w);
|
|
extern unsigned int __sw_hweight16(unsigned int w);
|
|
extern unsigned int __sw_hweight32(unsigned int w);
|
|
extern unsigned long __sw_hweight64(__u64 w);
|
|
|
|
/*
|
|
* Include this here because some architectures need generic_ffs/fls in
|
|
* scope
|
|
*/
|
|
#include <asm/bitops.h>
|
|
|
|
#define for_each_set_bit(bit, addr, size) \
|
|
for ((bit) = find_first_bit((addr), (size)); \
|
|
(bit) < (size); \
|
|
(bit) = find_next_bit((addr), (size), (bit) + 1))
|
|
|
|
/* same as for_each_set_bit() but use bit as value to start with */
|
|
#define for_each_set_bit_from(bit, addr, size) \
|
|
for ((bit) = find_next_bit((addr), (size), (bit)); \
|
|
(bit) < (size); \
|
|
(bit) = find_next_bit((addr), (size), (bit) + 1))
|
|
|
|
#define for_each_clear_bit(bit, addr, size) \
|
|
for ((bit) = find_first_zero_bit((addr), (size)); \
|
|
(bit) < (size); \
|
|
(bit) = find_next_zero_bit((addr), (size), (bit) + 1))
|
|
|
|
/* same as for_each_clear_bit() but use bit as value to start with */
|
|
#define for_each_clear_bit_from(bit, addr, size) \
|
|
for ((bit) = find_next_zero_bit((addr), (size), (bit)); \
|
|
(bit) < (size); \
|
|
(bit) = find_next_zero_bit((addr), (size), (bit) + 1))
|
|
|
|
static inline int get_bitmask_order(unsigned int count)
|
|
{
|
|
int order;
|
|
|
|
order = fls(count);
|
|
return order; /* We could be slightly more clever with -1 here... */
|
|
}
|
|
|
|
static __always_inline unsigned long hweight_long(unsigned long w)
|
|
{
|
|
return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
|
|
}
|
|
|
|
/**
|
|
* rol64 - rotate a 64-bit value left
|
|
* @word: value to rotate
|
|
* @shift: bits to roll
|
|
*/
|
|
static inline __u64 rol64(__u64 word, unsigned int shift)
|
|
{
|
|
return (word << (shift & 63)) | (word >> ((-shift) & 63));
|
|
}
|
|
|
|
/**
|
|
* ror64 - rotate a 64-bit value right
|
|
* @word: value to rotate
|
|
* @shift: bits to roll
|
|
*/
|
|
static inline __u64 ror64(__u64 word, unsigned int shift)
|
|
{
|
|
return (word >> (shift & 63)) | (word << ((-shift) & 63));
|
|
}
|
|
|
|
/**
|
|
* rol32 - rotate a 32-bit value left
|
|
* @word: value to rotate
|
|
* @shift: bits to roll
|
|
*/
|
|
static inline __u32 rol32(__u32 word, unsigned int shift)
|
|
{
|
|
return (word << (shift & 31)) | (word >> ((-shift) & 31));
|
|
}
|
|
|
|
/**
|
|
* ror32 - rotate a 32-bit value right
|
|
* @word: value to rotate
|
|
* @shift: bits to roll
|
|
*/
|
|
static inline __u32 ror32(__u32 word, unsigned int shift)
|
|
{
|
|
return (word >> (shift & 31)) | (word << ((-shift) & 31));
|
|
}
|
|
|
|
/**
|
|
* rol16 - rotate a 16-bit value left
|
|
* @word: value to rotate
|
|
* @shift: bits to roll
|
|
*/
|
|
static inline __u16 rol16(__u16 word, unsigned int shift)
|
|
{
|
|
return (word << (shift & 15)) | (word >> ((-shift) & 15));
|
|
}
|
|
|
|
/**
|
|
* ror16 - rotate a 16-bit value right
|
|
* @word: value to rotate
|
|
* @shift: bits to roll
|
|
*/
|
|
static inline __u16 ror16(__u16 word, unsigned int shift)
|
|
{
|
|
return (word >> (shift & 15)) | (word << ((-shift) & 15));
|
|
}
|
|
|
|
/**
|
|
* rol8 - rotate an 8-bit value left
|
|
* @word: value to rotate
|
|
* @shift: bits to roll
|
|
*/
|
|
static inline __u8 rol8(__u8 word, unsigned int shift)
|
|
{
|
|
return (word << (shift & 7)) | (word >> ((-shift) & 7));
|
|
}
|
|
|
|
/**
|
|
* ror8 - rotate an 8-bit value right
|
|
* @word: value to rotate
|
|
* @shift: bits to roll
|
|
*/
|
|
static inline __u8 ror8(__u8 word, unsigned int shift)
|
|
{
|
|
return (word >> (shift & 7)) | (word << ((-shift) & 7));
|
|
}
|
|
|
|
/**
|
|
* sign_extend32 - sign extend a 32-bit value using specified bit as sign-bit
|
|
* @value: value to sign extend
|
|
* @index: 0 based bit index (0<=index<32) to sign bit
|
|
*
|
|
* This is safe to use for 16- and 8-bit types as well.
|
|
*/
|
|
static inline __s32 sign_extend32(__u32 value, int index)
|
|
{
|
|
__u8 shift = 31 - index;
|
|
return (__s32)(value << shift) >> shift;
|
|
}
|
|
|
|
/**
|
|
* sign_extend64 - sign extend a 64-bit value using specified bit as sign-bit
|
|
* @value: value to sign extend
|
|
* @index: 0 based bit index (0<=index<64) to sign bit
|
|
*/
|
|
static inline __s64 sign_extend64(__u64 value, int index)
|
|
{
|
|
__u8 shift = 63 - index;
|
|
return (__s64)(value << shift) >> shift;
|
|
}
|
|
|
|
static inline unsigned fls_long(unsigned long l)
|
|
{
|
|
if (sizeof(l) == 4)
|
|
return fls(l);
|
|
return fls64(l);
|
|
}
|
|
|
|
static inline int get_count_order(unsigned int count)
|
|
{
|
|
int order;
|
|
|
|
order = fls(count) - 1;
|
|
if (count & (count - 1))
|
|
order++;
|
|
return order;
|
|
}
|
|
|
|
/**
|
|
* get_count_order_long - get order after rounding @l up to power of 2
|
|
* @l: parameter
|
|
*
|
|
* it is same as get_count_order() but with long type parameter
|
|
*/
|
|
static inline int get_count_order_long(unsigned long l)
|
|
{
|
|
if (l == 0UL)
|
|
return -1;
|
|
else if (l & (l - 1UL))
|
|
return (int)fls_long(l);
|
|
else
|
|
return (int)fls_long(l) - 1;
|
|
}
|
|
|
|
/**
|
|
* __ffs64 - find first set bit in a 64 bit word
|
|
* @word: The 64 bit word
|
|
*
|
|
* On 64 bit arches this is a synomyn for __ffs
|
|
* The result is not defined if no bits are set, so check that @word
|
|
* is non-zero before calling this.
|
|
*/
|
|
static inline unsigned long __ffs64(u64 word)
|
|
{
|
|
#if BITS_PER_LONG == 32
|
|
if (((u32)word) == 0UL)
|
|
return __ffs((u32)(word >> 32)) + 32;
|
|
#elif BITS_PER_LONG != 64
|
|
#error BITS_PER_LONG not 32 or 64
|
|
#endif
|
|
return __ffs((unsigned long)word);
|
|
}
|
|
|
|
/**
|
|
* assign_bit - Assign value to a bit in memory
|
|
* @nr: the bit to set
|
|
* @addr: the address to start counting from
|
|
* @value: the value to assign
|
|
*/
|
|
static __always_inline void assign_bit(long nr, volatile unsigned long *addr,
|
|
bool value)
|
|
{
|
|
if (value)
|
|
set_bit(nr, addr);
|
|
else
|
|
clear_bit(nr, addr);
|
|
}
|
|
|
|
static __always_inline void __assign_bit(long nr, volatile unsigned long *addr,
|
|
bool value)
|
|
{
|
|
if (value)
|
|
__set_bit(nr, addr);
|
|
else
|
|
__clear_bit(nr, addr);
|
|
}
|
|
|
|
#ifdef __KERNEL__
|
|
|
|
#ifndef set_mask_bits
|
|
#define set_mask_bits(ptr, mask, bits) \
|
|
({ \
|
|
const typeof(*(ptr)) mask__ = (mask), bits__ = (bits); \
|
|
typeof(*(ptr)) old__, new__; \
|
|
\
|
|
do { \
|
|
old__ = READ_ONCE(*(ptr)); \
|
|
new__ = (old__ & ~mask__) | bits__; \
|
|
} while (cmpxchg(ptr, old__, new__) != old__); \
|
|
\
|
|
old__; \
|
|
})
|
|
#endif
|
|
|
|
#ifndef bit_clear_unless
|
|
#define bit_clear_unless(ptr, clear, test) \
|
|
({ \
|
|
const typeof(*(ptr)) clear__ = (clear), test__ = (test);\
|
|
typeof(*(ptr)) old__, new__; \
|
|
\
|
|
do { \
|
|
old__ = READ_ONCE(*(ptr)); \
|
|
new__ = old__ & ~clear__; \
|
|
} while (!(old__ & test__) && \
|
|
cmpxchg(ptr, old__, new__) != old__); \
|
|
\
|
|
!(old__ & test__); \
|
|
})
|
|
#endif
|
|
|
|
#ifndef find_last_bit
|
|
/**
|
|
* find_last_bit - find the last set bit in a memory region
|
|
* @addr: The address to start the search at
|
|
* @size: The number of bits to search
|
|
*
|
|
* Returns the bit number of the last set bit, or size.
|
|
*/
|
|
extern unsigned long find_last_bit(const unsigned long *addr,
|
|
unsigned long size);
|
|
#endif
|
|
|
|
#endif /* __KERNEL__ */
|
|
#endif
|