diff options
Diffstat (limited to 'arch/arm64/kernel/ssbd.c')
-rw-r--r-- | arch/arm64/kernel/ssbd.c | 129 |
1 files changed, 0 insertions, 129 deletions
diff --git a/arch/arm64/kernel/ssbd.c b/arch/arm64/kernel/ssbd.c deleted file mode 100644 index b26955f56750..000000000000 --- a/arch/arm64/kernel/ssbd.c +++ /dev/null @@ -1,129 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * Copyright (C) 2018 ARM Ltd, All Rights Reserved. - */ - -#include <linux/compat.h> -#include <linux/errno.h> -#include <linux/prctl.h> -#include <linux/sched.h> -#include <linux/sched/task_stack.h> -#include <linux/thread_info.h> - -#include <asm/cpufeature.h> - -static void ssbd_ssbs_enable(struct task_struct *task) -{ - u64 val = is_compat_thread(task_thread_info(task)) ? - PSR_AA32_SSBS_BIT : PSR_SSBS_BIT; - - task_pt_regs(task)->pstate |= val; -} - -static void ssbd_ssbs_disable(struct task_struct *task) -{ - u64 val = is_compat_thread(task_thread_info(task)) ? - PSR_AA32_SSBS_BIT : PSR_SSBS_BIT; - - task_pt_regs(task)->pstate &= ~val; -} - -/* - * prctl interface for SSBD - */ -static int ssbd_prctl_set(struct task_struct *task, unsigned long ctrl) -{ - int state = arm64_get_ssbd_state(); - - /* Unsupported */ - if (state == ARM64_SSBD_UNKNOWN) - return -ENODEV; - - /* Treat the unaffected/mitigated state separately */ - if (state == ARM64_SSBD_MITIGATED) { - switch (ctrl) { - case PR_SPEC_ENABLE: - return -EPERM; - case PR_SPEC_DISABLE: - case PR_SPEC_FORCE_DISABLE: - return 0; - } - } - - /* - * Things are a bit backward here: the arm64 internal API - * *enables the mitigation* when the userspace API *disables - * speculation*. So much fun. - */ - switch (ctrl) { - case PR_SPEC_ENABLE: - /* If speculation is force disabled, enable is not allowed */ - if (state == ARM64_SSBD_FORCE_ENABLE || - task_spec_ssb_force_disable(task)) - return -EPERM; - task_clear_spec_ssb_disable(task); - clear_tsk_thread_flag(task, TIF_SSBD); - ssbd_ssbs_enable(task); - break; - case PR_SPEC_DISABLE: - if (state == ARM64_SSBD_FORCE_DISABLE) - return -EPERM; - task_set_spec_ssb_disable(task); - set_tsk_thread_flag(task, TIF_SSBD); - ssbd_ssbs_disable(task); - break; - case PR_SPEC_FORCE_DISABLE: - if (state == ARM64_SSBD_FORCE_DISABLE) - return -EPERM; - task_set_spec_ssb_disable(task); - task_set_spec_ssb_force_disable(task); - set_tsk_thread_flag(task, TIF_SSBD); - ssbd_ssbs_disable(task); - break; - default: - return -ERANGE; - } - - return 0; -} - -int arch_prctl_spec_ctrl_set(struct task_struct *task, unsigned long which, - unsigned long ctrl) -{ - switch (which) { - case PR_SPEC_STORE_BYPASS: - return ssbd_prctl_set(task, ctrl); - default: - return -ENODEV; - } -} - -static int ssbd_prctl_get(struct task_struct *task) -{ - switch (arm64_get_ssbd_state()) { - case ARM64_SSBD_UNKNOWN: - return -ENODEV; - case ARM64_SSBD_FORCE_ENABLE: - return PR_SPEC_DISABLE; - case ARM64_SSBD_KERNEL: - if (task_spec_ssb_force_disable(task)) - return PR_SPEC_PRCTL | PR_SPEC_FORCE_DISABLE; - if (task_spec_ssb_disable(task)) - return PR_SPEC_PRCTL | PR_SPEC_DISABLE; - return PR_SPEC_PRCTL | PR_SPEC_ENABLE; - case ARM64_SSBD_FORCE_DISABLE: - return PR_SPEC_ENABLE; - default: - return PR_SPEC_NOT_AFFECTED; - } -} - -int arch_prctl_spec_ctrl_get(struct task_struct *task, unsigned long which) -{ - switch (which) { - case PR_SPEC_STORE_BYPASS: - return ssbd_prctl_get(task); - default: - return -ENODEV; - } -} |