Something went wrong. Try again.
(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Something went wrong. Try again.
C
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475// SPDX-License-Identifier: GPL-2.0// Copyright(c) 2018 Linus Torvalds. All rights reserved.// Copyright(c) 2018 Alexei Starovoitov. All rights reserved.// Copyright(c) 2018 Intel Corporation. All rights reserved.
#ifndef _LINUX_NOSPEC_H#define _LINUX_NOSPEC_H
#include <linux/compiler.h>#include <asm/barrier.h>
struct task_struct;
#ifndef barrier_nospec# define barrier_nospec() do { } while (0)#endif
/** * array_index_mask_nospec() - generate a ~0 mask when index < size, 0 otherwise * @index: array element index * @size: number of elements in array * * When @index is out of bounds (@index >= @size), the sign bit will be * set. Extend the sign bit to all bits and invert, giving a result of * zero for an out of bounds index, or ~0 if within bounds [0, @size). */#ifndef array_index_mask_nospecstatic inline unsigned long array_index_mask_nospec(unsigned long index, unsigned long size){ /* * Always calculate and emit the mask even if the compiler * thinks the mask is not needed. The compiler does not take * into account the value of @index under speculation. */ OPTIMIZER_HIDE_VAR(index); return ~(long)(index | (size - 1UL - index)) >> (BITS_PER_LONG - 1);}#endif
/* * array_index_nospec - sanitize an array index after a bounds check * * For a code sequence like: * * if (index < size) { * index = array_index_nospec(index, size); * val = array[index]; * } * * ...if the CPU speculates past the bounds check then * array_index_nospec() will clamp the index within the range of [0, * size). */#define array_index_nospec(index, size) \({ \ typeof(index) _i = (index); \ typeof(size) _s = (size); \ unsigned long _mask = array_index_mask_nospec(_i, _s); \ \ BUILD_BUG_ON(sizeof(_i) > sizeof(long)); \ BUILD_BUG_ON(sizeof(_s) > sizeof(long)); \ \ (typeof(_i)) (_i & _mask); \})
/* Speculation control prctl */int arch_prctl_spec_ctrl_get(struct task_struct *task, unsigned long which);int arch_prctl_spec_ctrl_set(struct task_struct *task, unsigned long which, unsigned long ctrl);/* Speculation control for seccomp enforced mitigation */void arch_seccomp_spec_mitigate(struct task_struct *task);
#endif /* _LINUX_NOSPEC_H */