From 978b6924525f07479d670bb6ebc5bc50fb8c01e1 Mon Sep 17 00:00:00 2001 From: Sean McBride Date: Fri, 27 Nov 2020 19:17:00 -0500 Subject: [PATCH] fix: correct assorted bugs --- runtime/include/admissions_info.h | 4 +++ runtime/include/arch/aarch64/context.h | 14 ++++++++ runtime/include/arch/x86_64/context.h | 31 +++++++++++++++++- runtime/src/arch_context.c | 1 + runtime/src/local_runqueue_minheap.c | 2 +- runtime/src/sandbox.c | 33 ++++++++++++------- runtime/src/software_interrupt.c | 5 ++- runtime/src/worker_thread.c | 44 ++++++++++++++++---------- 8 files changed, 104 insertions(+), 30 deletions(-) diff --git a/runtime/include/admissions_info.h b/runtime/include/admissions_info.h index d61ae8c..55211e3 100644 --- a/runtime/include/admissions_info.h +++ b/runtime/include/admissions_info.h @@ -32,6 +32,10 @@ admissions_info_initialize(struct admissions_info *self, int percentile, uint64_ self->percentile = percentile; self->control_index = PERF_WINDOW_BUFFER_SIZE * percentile / 100; +#ifdef LOG_ADMISSIONS_CONTROL + debuglog("Percentile: %d\n", self->percentile); + debuglog("Control Index: %d\n", self->control_index); +#endif #endif } diff --git a/runtime/include/arch/aarch64/context.h b/runtime/include/arch/aarch64/context.h index e83fec6..95f7125 100644 --- a/runtime/include/arch/aarch64/context.h +++ b/runtime/include/arch/aarch64/context.h @@ -1,6 +1,8 @@ #pragma once +#include #include "arch/common.h" +#include "current_sandbox.h" #define ARCH_SIG_JMP_OFF 0x100 /* Based on code generated! */ @@ -16,6 +18,7 @@ static inline void arch_context_init(struct arch_context *actx, reg_t ip, reg_t sp) { assert(actx != NULL); + assert(!software_interrupt_is_enabled()); if (ip == 0 && sp == 0) { actx->variant = ARCH_CONTEXT_VARIANT_UNUSED; @@ -68,6 +71,17 @@ arch_context_switch(struct arch_context *a, struct arch_context *b) /* Assumption: Software Interrupts are disabled by caller */ assert(!software_interrupt_is_enabled()); +#ifndef NDEBUG + /* + * Assumption: In the case of a slow context switch, the caller + * set current_sandbox to the sandbox containing the target context + */ + if (b->variant == ARCH_CONTEXT_VARIANT_SLOW) { + struct sandbox *current = current_sandbox_get(); + assert(current != NULL && b == ¤t->ctxt); + } +#endif + /* if both a and b are NULL, there is no state change */ assert(a != NULL || b != NULL); diff --git a/runtime/include/arch/x86_64/context.h b/runtime/include/arch/x86_64/context.h index 0b5e7f8..cf961fb 100644 --- a/runtime/include/arch/x86_64/context.h +++ b/runtime/include/arch/x86_64/context.h @@ -32,13 +32,15 @@ static void __attribute__((noinline)) arch_context_init(struct arch_context *act */ asm volatile("movq %%rsp, %%rbx\n\t" /* Temporarily save pointer of active stack to B */ "movq %%rax, %%rsp\n\t" /* Set active stack to stack pointer in A(C variable sp) */ - "pushq %%rax\n\t" /* Push A(C variable sp) onto the stack at sp */ + "pushq %%rax\n\t" /* Push A register (C variable sp) onto the stack at sp */ "movq %%rsp, %%rax\n\t" /* Write the incremented stack pointer to A(C variable sp) */ "movq %%rbx, %%rsp\n\t" /* Restore original stack saved in B */ : "=a"(sp) : "a"(sp) : "memory", "cc", "rbx"); } + // FIXME: Is the klobber list correct? + // : "memory", "cc", "rbx", "rsi", "rdi"); actx->regs[UREG_SP] = sp; actx->regs[UREG_IP] = ip; @@ -71,6 +73,33 @@ arch_context_restore(mcontext_t *active_context, struct arch_context *sandbox_co active_context->gregs[REG_RIP] = sandbox_context->regs[UREG_IP] + ARCH_SIG_JMP_OFF; } +/** + * Load a new sandbox that preempted an existing sandbox, restoring only the + * instruction pointer and stack pointer registers. + * I am unclear about setting the BP + * @param active_context - the context of the current worker thread + * @param sandbox_context - the context that we want to restore + */ +static inline void +arch_context_restore_new(mcontext_t *active_context, struct arch_context *sandbox_context) +{ + assert(active_context != NULL); + assert(sandbox_context != NULL); + + /* Assumption: Base Context is only ever used by arch_context_switch */ + assert(sandbox_context != &worker_thread_base_context); + + assert(sandbox_context->regs[UREG_SP]); + assert(sandbox_context->regs[UREG_IP]); + + /* Transitioning from Fast -> Running */ + assert(sandbox_context->variant == ARCH_CONTEXT_VARIANT_FAST); + sandbox_context->variant = ARCH_CONTEXT_VARIANT_RUNNING; + + active_context->gregs[REG_RSP] = sandbox_context->regs[UREG_SP]; + active_context->gregs[REG_RIP] = sandbox_context->regs[UREG_IP]; +} + /** * @param a - the registers and context of the thing running * @param b - the registers and context of what we're switching to diff --git a/runtime/src/arch_context.c b/runtime/src/arch_context.c index c20ff12..5106b03 100644 --- a/runtime/src/arch_context.c +++ b/runtime/src/arch_context.c @@ -14,5 +14,6 @@ void __attribute__((noinline)) __attribute__((noreturn)) arch_context_restore_preempted(void) { pthread_kill(pthread_self(), SIGUSR1); + // if (unlikely(rc != 0)) panic("%s\n", strerror(rc)); panic("Unexpectedly reached code after sending self SIGUSR1\n"); } diff --git a/runtime/src/local_runqueue_minheap.c b/runtime/src/local_runqueue_minheap.c index 05fc340..d93bfc3 100644 --- a/runtime/src/local_runqueue_minheap.c +++ b/runtime/src/local_runqueue_minheap.c @@ -185,7 +185,7 @@ local_runqueue_minheap_preempt(ucontext_t *user_context) * user-level context switch state, so do not enable software interrupts. * TODO: Review the interrupt logic here. Issue #63 */ - arch_context_restore(&user_context->uc_mcontext, &next_sandbox->ctxt); + arch_context_restore_new(&user_context->uc_mcontext, &next_sandbox->ctxt); should_enable_software_interrupt = false; } done: diff --git a/runtime/src/sandbox.c b/runtime/src/sandbox.c index 21bfab7..bf95502 100644 --- a/runtime/src/sandbox.c +++ b/runtime/src/sandbox.c @@ -373,7 +373,6 @@ sandbox_allocate_memory(struct module *module) error_message = "sandbox_allocate_memory - memory allocation failed"; goto alloc_failed; } - sandbox = (struct sandbox *)addr; /* Set the struct sandbox, HTTP Req/Resp buffer, and the initial Wasm Pages as read/write */ errno = 0; @@ -384,6 +383,8 @@ sandbox_allocate_memory(struct module *module) goto set_rw_failed; } + sandbox = (struct sandbox *)addr_rw; + /* Populate Sandbox members */ sandbox->state = SANDBOX_UNINITIALIZED; sandbox->linear_memory_start = (char *)addr + sandbox_size; @@ -411,12 +412,23 @@ sandbox_allocate_stack(struct sandbox *sandbox) { assert(sandbox); assert(sandbox->module); + assert(!software_interrupt_is_enabled()); - errno = 0; + errno = 0; + char *addr = mmap(NULL, sandbox->module->stack_size + /* guard page */ PAGE_SIZE, PROT_NONE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (addr == MAP_FAILED) goto err_stack_allocation_failed; + + /* Set the struct sandbox, HTTP Req/Resp buffer, and the initial Wasm Pages as read/write */ + errno = 0; + char *addr_rw = mmap(addr + /* guard page */ PAGE_SIZE, sandbox->module->stack_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0); + + /* TODO: Fix leak here */ + if (addr_rw == MAP_FAILED) goto err_stack_allocation_failed; + + sandbox->stack_start = addr_rw; sandbox->stack_size = sandbox->module->stack_size; - sandbox->stack_start = mmap(NULL, sandbox->stack_size, PROT_READ | PROT_WRITE, - MAP_PRIVATE | MAP_ANONYMOUS | MAP_GROWSDOWN, -1, 0); - if (sandbox->stack_start == MAP_FAILED) goto err_stack_allocation_failed; done: return 0; @@ -450,8 +462,9 @@ sandbox_set_as_initialized(struct sandbox *sandbox, struct sandbox_request *sand sandbox->state = SANDBOX_SET_AS_INITIALIZED; /* Initialize the sandbox's context, stack, and instruction pointer */ + /* stack_start points to the bottom of the usable stack, so add stack_size to get to top */ arch_context_init(&sandbox->ctxt, (reg_t)current_sandbox_main, - (reg_t)(sandbox->stack_start + sandbox->stack_size)); + (reg_t)sandbox->stack_start + sandbox->stack_size); /* Initialize file descriptors to -1 */ for (int i = 0; i < SANDBOX_MAX_IO_HANDLE_COUNT; i++) sandbox->io_handles[i].file_descriptor = -1; @@ -875,13 +888,11 @@ sandbox_free(struct sandbox *sandbox) module_release(sandbox->module); - void * stkaddr = sandbox->stack_start; - size_t stksz = sandbox->stack_size; - - /* Free Sandbox Stack */ errno = 0; - rc = munmap(stkaddr, stksz); + + /* The stack start is the bottom of the usable stack, but we allocated a guard page below this */ + rc = munmap((char *)sandbox->stack_start - PAGE_SIZE, sandbox->stack_size + PAGE_SIZE); if (rc == -1) { debuglog("Failed to unmap stack of Sandbox %lu\n", sandbox->id); goto err_free_stack_failed; diff --git a/runtime/src/software_interrupt.c b/runtime/src/software_interrupt.c index 90df9fd..a0dce8a 100644 --- a/runtime/src/software_interrupt.c +++ b/runtime/src/software_interrupt.c @@ -129,6 +129,8 @@ sigusr1_handler(siginfo_t *signal_info, ucontext_t *user_context, struct sandbox #ifdef LOG_PREEMPTION debuglog("Total SIGUSR1 Received: %d\n", software_interrupt_SIGUSR_count); + debuglog("Restoring sandbox: %lu, Stack %llu\n", current_sandbox->id, + current_sandbox->ctxt.mctx.gregs[REG_RSP]); #endif arch_mcontext_restore(&user_context->uc_mcontext, ¤t_sandbox->ctxt); @@ -176,7 +178,7 @@ software_interrupt_handle_signals(int signal_type, siginfo_t *signal_info, void case SIGUSR1: { return sigusr1_handler(signal_info, user_context, current_sandbox); } - default: + default: { if (signal_info->si_code == SI_TKILL) { panic("Unexpectedly received signal %d from a thread kill, but we have no handler\n", signal_type); @@ -184,6 +186,7 @@ software_interrupt_handle_signals(int signal_type, siginfo_t *signal_info, void panic("Unexpectedly received signal %d from the kernel, but we have no handler\n", signal_type); } } + } #endif } diff --git a/runtime/src/worker_thread.c b/runtime/src/worker_thread.c index 24d22a7..ac5660b 100644 --- a/runtime/src/worker_thread.c +++ b/runtime/src/worker_thread.c @@ -1,3 +1,4 @@ +#include #include #include #include @@ -102,24 +103,34 @@ worker_thread_switch_to_sandbox(struct sandbox *next_sandbox) sandbox_set_as_running(next_sandbox, next_sandbox->state); #ifdef LOG_CONTEXT_SWITCHES - debuglog("Base Context (%s) > Sandbox %lu (%s)\n", - arch_context_variant_print(worker_thread_base_context.variant), next_sandbox->id, + debuglog("Base Context (@%p) (%s) > Sandbox %lu (@%p) (%s)\n", &worker_thread_base_context, + arch_context_variant_print(worker_thread_base_context.variant), next_sandbox->id, next_context, arch_context_variant_print(next_context->variant)); #endif + /* Assumption: If a slow context switch, current sandbox should be set to the target */ + assert(next_context->variant != ARCH_CONTEXT_VARIANT_SLOW + || ¤t_sandbox_get()->ctxt == next_context); arch_context_switch(NULL, next_context); } else { /* Set the current sandbox to the next */ assert(next_sandbox != current_sandbox); + struct arch_context *current_context = ¤t_sandbox->ctxt; + +#ifdef LOG_CONTEXT_SWITCHES + debuglog("Sandbox %lu (@%p) (%s) > Sandbox %lu (@%p) (%s)\n", current_sandbox->id, + ¤t_sandbox->ctxt, arch_context_variant_print(current_sandbox->ctxt.variant), + next_sandbox->id, &next_sandbox->ctxt, arch_context_variant_print(next_context->variant)); +#endif + worker_thread_transition_exiting_sandbox(current_sandbox); sandbox_set_as_running(next_sandbox, next_sandbox->state); - struct arch_context *current_context = ¤t_sandbox->ctxt; - -#ifdef LOG_CONTEXT_SWITCHES - debuglog("Sandbox %lu > Sandbox %lu\n", current_sandbox->id, next_sandbox->id); +#ifndef NDEBUG + assert(next_context->variant != ARCH_CONTEXT_VARIANT_SLOW + || ¤t_sandbox_get()->ctxt == next_context); #endif /* Switch to the associated context. */ @@ -146,22 +157,21 @@ worker_thread_switch_to_base_context() } #endif - worker_thread_transition_exiting_sandbox(current_sandbox); - /* Assumption: Base Context should never switch to Base Context */ assert(current_sandbox != NULL); - assert(¤t_sandbox->ctxt != &worker_thread_base_context); - - current_sandbox_set(NULL); + struct arch_context *current_context = ¤t_sandbox->ctxt; + assert(current_context != &worker_thread_base_context); #ifdef LOG_CONTEXT_SWITCHES - debuglog("Sandbox %lu (%s) > Base Context (%s)\n", current_sandbox->id, - arch_context_variant_print(current_sandbox->ctxt.variant), + debuglog("Sandbox %lu (@%p) (%s)> Base Context (@%p) (%s)\n", current_sandbox->id, current_context, + arch_context_variant_print(current_sandbox->ctxt.variant), &worker_thread_base_context, arch_context_variant_print(worker_thread_base_context.variant)); #endif - arch_context_switch(¤t_sandbox->ctxt, &worker_thread_base_context); - + worker_thread_transition_exiting_sandbox(current_sandbox); + current_sandbox_set(NULL); + assert(worker_thread_base_context.variant == ARCH_CONTEXT_VARIANT_FAST); + arch_context_switch(current_context, &worker_thread_base_context); software_interrupt_enable(); } @@ -282,7 +292,9 @@ worker_thread_main(void *return_code) worker_thread_start_timestamp = __getcycles(); worker_thread_lock_duration = 0; - /* Initialize Base Context */ + /* Initialize Base Context as unused + * The SP and IP are populated during the first FAST switch away + */ arch_context_init(&worker_thread_base_context, 0, 0); /* Initialize Runqueue Variant */