projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
| 916cda1a MS |
2 | /* |
| 3 | * Copyright IBM Corp. 2016 | |
| 4 | * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com> | |
| 5 | */ | |
| 6 | ||
| 7 | #include <linux/kernel.h> | |
| 8 | #include <linux/syscalls.h> | |
| 9 | #include <linux/signal.h> | |
| 10 | #include <linux/mm.h> | |
| 11 | #include <linux/slab.h> | |
| 12 | #include <asm/guarded_storage.h> | |
| 13 | #include "entry.h" | |
| 14 | ||
| 15 | void exit_thread_gs(void) | |
| 16 | { | |
| 17 | kfree(current->thread.gs_cb); | |
| 18 | kfree(current->thread.gs_bc_cb); | |
| 19 | current->thread.gs_cb = current->thread.gs_bc_cb = NULL; | |
| 20 | } | |
| 21 | ||
| 22 | static int gs_enable(void) | |
| 23 | { | |
| 24 | struct gs_cb *gs_cb; | |
| 25 | ||
| 26 | if (!current->thread.gs_cb) { | |
| 27 | gs_cb = kzalloc(sizeof(*gs_cb), GFP_KERNEL); | |
| 28 | if (!gs_cb) | |
| 29 | return -ENOMEM; | |
| 30 | gs_cb->gsd = 25; | |
| 31 | preempt_disable(); | |
| 32 | __ctl_set_bit(2, 4); | |
| 33 | load_gs_cb(gs_cb); | |
| 34 | current->thread.gs_cb = gs_cb; | |
| 35 | preempt_enable(); | |
| 36 | } | |
| 37 | return 0; | |
| 38 | } | |
| 39 | ||
| 40 | static int gs_disable(void) | |
| 41 | { | |
| 42 | if (current->thread.gs_cb) { | |
| 43 | preempt_disable(); | |
| 44 | kfree(current->thread.gs_cb); | |
| 45 | current->thread.gs_cb = NULL; | |
| 46 | __ctl_clear_bit(2, 4); | |
| 47 | preempt_enable(); | |
| 48 | } | |
| 49 | return 0; | |
| 50 | } | |
| 51 | ||
| 52 | static int gs_set_bc_cb(struct gs_cb __user *u_gs_cb) | |
| 53 | { | |
| 54 | struct gs_cb *gs_cb; | |
| 55 | ||
| 56 | gs_cb = current->thread.gs_bc_cb; | |
| 57 | if (!gs_cb) { | |
| 58 | gs_cb = kzalloc(sizeof(*gs_cb), GFP_KERNEL); | |
| 59 | if (!gs_cb) | |
| 60 | return -ENOMEM; | |
| 61 | current->thread.gs_bc_cb = gs_cb; | |
| 62 | } | |
| 63 | if (copy_from_user(gs_cb, u_gs_cb, sizeof(*gs_cb))) | |
| 64 | return -EFAULT; | |
| 65 | return 0; | |
| 66 | } | |
| 67 | ||
| 68 | static int gs_clear_bc_cb(void) | |
| 69 | { | |
| 70 | struct gs_cb *gs_cb; | |
| 71 | ||
| 72 | gs_cb = current->thread.gs_bc_cb; | |
| 73 | current->thread.gs_bc_cb = NULL; | |
| 74 | kfree(gs_cb); | |
| 75 | return 0; | |
| 76 | } | |
| 77 | ||
| 78 | void gs_load_bc_cb(struct pt_regs *regs) | |
| 79 | { | |
| 80 | struct gs_cb *gs_cb; | |
| 81 | ||
| 82 | preempt_disable(); | |
| 83 | clear_thread_flag(TIF_GUARDED_STORAGE); | |
| 84 | gs_cb = current->thread.gs_bc_cb; | |
| 85 | if (gs_cb) { | |
| 86 | kfree(current->thread.gs_cb); | |
| 87 | current->thread.gs_bc_cb = NULL; | |
| 88 | __ctl_set_bit(2, 4); | |
| 89 | load_gs_cb(gs_cb); | |
| 90 | current->thread.gs_cb = gs_cb; | |
| 91 | } | |
| 92 | preempt_enable(); | |
| 93 | } | |
| 94 | ||
| 95 | static int gs_broadcast(void) | |
| 96 | { | |
| 97 | struct task_struct *sibling; | |
| 98 | ||
| 99 | read_lock(&tasklist_lock); | |
| 100 | for_each_thread(current, sibling) { | |
| 101 | if (!sibling->thread.gs_bc_cb) | |
| 102 | continue; | |
| 103 | if (test_and_set_tsk_thread_flag(sibling, TIF_GUARDED_STORAGE)) | |
| 104 | kick_process(sibling); | |
| 105 | } | |
| 106 | read_unlock(&tasklist_lock); | |
| 107 | return 0; | |
| 108 | } | |
| 109 | ||
| 110 | SYSCALL_DEFINE2(s390_guarded_storage, int, command, | |
| 111 | struct gs_cb __user *, gs_cb) | |
| 112 | { | |
| 113 | if (!MACHINE_HAS_GS) | |
| 114 | return -EOPNOTSUPP; | |
| 115 | switch (command) { | |
| 116 | case GS_ENABLE: | |
| 117 | return gs_enable(); | |
| 118 | case GS_DISABLE: | |
| 119 | return gs_disable(); | |
| 120 | case GS_SET_BC_CB: | |
| 121 | return gs_set_bc_cb(gs_cb); | |
| 122 | case GS_CLEAR_BC_CB: | |
| 123 | return gs_clear_bc_cb(); | |
| 124 | case GS_BROADCAST: | |
| 125 | return gs_broadcast(); | |
| 126 | default: | |
| 127 | return -EINVAL; | |
| 128 | } | |
| 129 | } |