diff options
Diffstat (limited to 'sys/dev/hwt/hwt_hook.c')
| -rw-r--r-- | sys/dev/hwt/hwt_hook.c | 323 |
1 files changed, 323 insertions, 0 deletions
diff --git a/sys/dev/hwt/hwt_hook.c b/sys/dev/hwt/hwt_hook.c new file mode 100644 index 000000000000..258279b14f20 --- /dev/null +++ b/sys/dev/hwt/hwt_hook.c @@ -0,0 +1,323 @@ +/*- + * SPDX-License-Identifier: BSD-2-Clause + * + * Copyright (c) 2023-2025 Ruslan Bukin <br@bsdpad.com> + * + * This work was supported by Innovate UK project 105694, "Digital Security + * by Design (DSbD) Technology Platform Prototype". + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +/* Hardware Trace (HWT) framework. */ + +#include <sys/param.h> +#include <sys/proc.h> +#include <sys/malloc.h> +#include <sys/mman.h> +#include <sys/refcount.h> +#include <sys/hwt.h> + +#include <dev/hwt/hwt_hook.h> +#include <dev/hwt/hwt_context.h> +#include <dev/hwt/hwt_contexthash.h> +#include <dev/hwt/hwt_config.h> +#include <dev/hwt/hwt_thread.h> +#include <dev/hwt/hwt_owner.h> +#include <dev/hwt/hwt_backend.h> +#include <dev/hwt/hwt_record.h> +#include <dev/hwt/hwt_vm.h> + +#define HWT_DEBUG +#undef HWT_DEBUG + +#ifdef HWT_DEBUG +#define dprintf(fmt, ...) printf(fmt, ##__VA_ARGS__) +#else +#define dprintf(fmt, ...) +#endif + +static void +hwt_switch_in(struct thread *td) +{ + struct hwt_context *ctx; + struct hwt_thread *thr; + struct proc *p; + int cpu_id; + + p = td->td_proc; + + cpu_id = PCPU_GET(cpuid); + + ctx = hwt_contexthash_lookup(p); + if (ctx == NULL) + return; + + if (ctx->state != CTX_STATE_RUNNING) { + hwt_ctx_put(ctx); + return; + } + + thr = hwt_thread_lookup(ctx, td); + if (thr == NULL) { + hwt_ctx_put(ctx); + return; + } + + dprintf("%s: thr %p index %d tid %d on cpu_id %d\n", __func__, thr, + thr->thread_id, td->td_tid, cpu_id); + + hwt_backend_configure(ctx, cpu_id, thr->thread_id); + hwt_backend_enable(ctx, cpu_id); + + hwt_ctx_put(ctx); +} + +static void +hwt_switch_out(struct thread *td) +{ + struct hwt_context *ctx; + struct hwt_thread *thr; + struct proc *p; + int cpu_id; + + p = td->td_proc; + + cpu_id = PCPU_GET(cpuid); + + ctx = hwt_contexthash_lookup(p); + if (ctx == NULL) + return; + + if (ctx->state != CTX_STATE_RUNNING) { + hwt_ctx_put(ctx); + return; + } + thr = hwt_thread_lookup(ctx, td); + if (thr == NULL) { + hwt_ctx_put(ctx); + return; + } + + dprintf("%s: thr %p index %d tid %d on cpu_id %d\n", __func__, thr, + thr->thread_id, td->td_tid, cpu_id); + + hwt_backend_disable(ctx, cpu_id); + + hwt_ctx_put(ctx); +} + +static void +hwt_hook_thread_exit(struct thread *td) +{ + struct hwt_context *ctx; + struct hwt_thread *thr; + struct proc *p; + int cpu_id; + + p = td->td_proc; + + cpu_id = PCPU_GET(cpuid); + + ctx = hwt_contexthash_lookup(p); + if (ctx == NULL) + return; + + thr = hwt_thread_lookup(ctx, td); + if (thr == NULL) { + hwt_ctx_put(ctx); + return; + } + + thr->state = HWT_THREAD_STATE_EXITED; + + dprintf("%s: thr %p index %d tid %d on cpu_id %d\n", __func__, thr, + thr->thread_id, td->td_tid, cpu_id); + + if (ctx->state == CTX_STATE_RUNNING) + hwt_backend_disable(ctx, cpu_id); + + hwt_ctx_put(ctx); +} + +static void +hwt_hook_mmap(struct thread *td) +{ + struct hwt_context *ctx; + struct hwt_thread *thr; + struct proc *p; + int pause; + + p = td->td_proc; + + ctx = hwt_contexthash_lookup(p); + if (ctx == NULL) + return; + + /* The ctx state could be any here. */ + + pause = ctx->pause_on_mmap ? 1 : 0; + + thr = hwt_thread_lookup(ctx, td); + if (thr == NULL) { + hwt_ctx_put(ctx); + return; + } + + /* + * msleep(9) atomically releases the mtx lock, so take refcount + * to ensure that thr is not destroyed. + * It could not be destroyed prior to this call as we are holding ctx + * refcnt. + */ + refcount_acquire(&thr->refcnt); + hwt_ctx_put(ctx); + + if (pause) { + HWT_THR_LOCK(thr); + msleep(thr, &thr->mtx, PCATCH, "hwt-mmap", 0); + HWT_THR_UNLOCK(thr); + } + + if (refcount_release(&thr->refcnt)) + hwt_thread_free(thr); +} + +static int +hwt_hook_thread_create(struct thread *td) +{ + struct hwt_record_entry *entry; + struct hwt_context *ctx; + struct hwt_thread *thr; + char path[MAXPATHLEN]; + size_t bufsize; + struct proc *p; + int thread_id, kva_req; + int error; + + p = td->td_proc; + + /* Step 1. Get CTX and collect information needed. */ + ctx = hwt_contexthash_lookup(p); + if (ctx == NULL) + return (ENXIO); + thread_id = atomic_fetchadd_int(&ctx->thread_counter, 1); + bufsize = ctx->bufsize; + kva_req = ctx->hwt_backend->kva_req; + sprintf(path, "hwt_%d_%d", ctx->ident, thread_id); + hwt_ctx_put(ctx); + + /* Step 2. Allocate some memory without holding ctx ref. */ + error = hwt_thread_alloc(&thr, path, bufsize, kva_req); + if (error) { + printf("%s: could not allocate thread, error %d\n", + __func__, error); + return (error); + } + + entry = hwt_record_entry_alloc(); + entry->record_type = HWT_RECORD_THREAD_CREATE; + entry->thread_id = thread_id; + + /* Step 3. Get CTX once again. */ + ctx = hwt_contexthash_lookup(p); + if (ctx == NULL) { + hwt_record_entry_free(entry); + hwt_thread_free(thr); + /* ctx->thread_counter does not matter. */ + return (ENXIO); + } + /* Allocate backend-specific thread data. */ + error = hwt_backend_thread_alloc(ctx, thr); + if (error != 0) { + dprintf("%s: failed to allocate backend thread data\n", + __func__); + return (error); + } + + thr->vm->ctx = ctx; + thr->ctx = ctx; + thr->backend = ctx->hwt_backend; + thr->thread_id = thread_id; + thr->td = td; + + HWT_CTX_LOCK(ctx); + hwt_thread_insert(ctx, thr, entry); + HWT_CTX_UNLOCK(ctx); + + /* Notify userspace. */ + hwt_record_wakeup(ctx); + + hwt_ctx_put(ctx); + + return (0); +} + +static void +hwt_hook_handler(struct thread *td, int func, void *arg) +{ + struct proc *p; + + p = td->td_proc; + if ((p->p_flag2 & P2_HWT) == 0) + return; + + switch (func) { + case HWT_SWITCH_IN: + hwt_switch_in(td); + break; + case HWT_SWITCH_OUT: + hwt_switch_out(td); + break; + case HWT_THREAD_CREATE: + hwt_hook_thread_create(td); + break; + case HWT_THREAD_SET_NAME: + /* TODO. */ + break; + case HWT_THREAD_EXIT: + hwt_hook_thread_exit(td); + break; + case HWT_EXEC: + case HWT_MMAP: + hwt_record_td(td, arg, M_WAITOK | M_ZERO); + hwt_hook_mmap(td); + break; + case HWT_RECORD: + hwt_record_td(td, arg, M_WAITOK | M_ZERO); + break; + }; +} + +void +hwt_hook_load(void) +{ + + hwt_hook = hwt_hook_handler; +} + +void +hwt_hook_unload(void) +{ + + hwt_hook = NULL; +} |