diff options
Diffstat (limited to 'tools/testing/selftests/x86')
| -rw-r--r-- | tools/testing/selftests/x86/Makefile | 64 | ||||
| -rwxr-xr-x | tools/testing/selftests/x86/check_cc.sh | 16 | ||||
| -rw-r--r-- | tools/testing/selftests/x86/entry_from_vm86.c | 114 | ||||
| -rw-r--r-- | tools/testing/selftests/x86/run_x86_tests.sh | 13 | ||||
| -rw-r--r-- | tools/testing/selftests/x86/sysret_ss_attrs.c | 112 | ||||
| -rw-r--r-- | tools/testing/selftests/x86/thunks.S | 67 | ||||
| -rw-r--r-- | tools/testing/selftests/x86/trivial_32bit_program.c | 4 | ||||
| -rw-r--r-- | tools/testing/selftests/x86/trivial_64bit_program.c | 18 |
8 files changed, 370 insertions, 38 deletions
diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile index ddf63569df5a..caa60d56d7d1 100644 --- a/tools/testing/selftests/x86/Makefile +++ b/tools/testing/selftests/x86/Makefile @@ -1,48 +1,62 @@ -.PHONY: all all_32 all_64 check_build32 clean run_tests +all: -TARGETS_C_BOTHBITS := sigreturn single_step_syscall +include ../lib.mk -BINARIES_32 := $(TARGETS_C_BOTHBITS:%=%_32) +.PHONY: all all_32 all_64 warn_32bit_failure clean + +TARGETS_C_BOTHBITS := sigreturn single_step_syscall sysret_ss_attrs +TARGETS_C_32BIT_ONLY := entry_from_vm86 + +TARGETS_C_32BIT_ALL := $(TARGETS_C_BOTHBITS) $(TARGETS_C_32BIT_ONLY) +BINARIES_32 := $(TARGETS_C_32BIT_ALL:%=%_32) BINARIES_64 := $(TARGETS_C_BOTHBITS:%=%_64) CFLAGS := -O2 -g -std=gnu99 -pthread -Wall -UNAME_P := $(shell uname -p) +UNAME_M := $(shell uname -m) +CAN_BUILD_I386 := $(shell ./check_cc.sh $(CC) trivial_32bit_program.c -m32) +CAN_BUILD_X86_64 := $(shell ./check_cc.sh $(CC) trivial_64bit_program.c) -# Always build 32-bit tests +ifeq ($(CAN_BUILD_I386),1) all: all_32 +TEST_PROGS += $(BINARIES_32) +endif -# If we're on a 64-bit host, build 64-bit tests as well -ifeq ($(shell uname -p),x86_64) +ifeq ($(CAN_BUILD_X86_64),1) all: all_64 +TEST_PROGS += $(BINARIES_64) endif -all_32: check_build32 $(BINARIES_32) +all_32: $(BINARIES_32) all_64: $(BINARIES_64) clean: $(RM) $(BINARIES_32) $(BINARIES_64) -run_tests: - ./run_x86_tests.sh - -$(TARGETS_C_BOTHBITS:%=%_32): %_32: %.c +$(TARGETS_C_32BIT_ALL:%=%_32): %_32: %.c $(CC) -m32 -o $@ $(CFLAGS) $(EXTRA_CFLAGS) $^ -lrt -ldl $(TARGETS_C_BOTHBITS:%=%_64): %_64: %.c $(CC) -m64 -o $@ $(CFLAGS) $(EXTRA_CFLAGS) $^ -lrt -ldl -check_build32: - @if ! $(CC) -m32 -o /dev/null trivial_32bit_program.c; then \ - echo "Warning: you seem to have a broken 32-bit build" 2>&1; \ - echo "environment. If you are using a Debian-like"; \ - echo " distribution, try:"; \ - echo ""; \ - echo " apt-get install gcc-multilib libc6-i386 libc6-dev-i386"; \ - echo ""; \ - echo "If you are using a Fedora-like distribution, try:"; \ - echo ""; \ - echo " yum install glibc-devel.*i686"; \ - exit 1; \ - fi +# x86_64 users should be encouraged to install 32-bit libraries +ifeq ($(CAN_BUILD_I386)$(CAN_BUILD_X86_64),01) +all: warn_32bit_failure + +warn_32bit_failure: + @echo "Warning: you seem to have a broken 32-bit build" 2>&1; \ + echo "environment. This will reduce test coverage of 64-bit" 2>&1; \ + echo "kernels. If you are using a Debian-like distribution," 2>&1; \ + echo "try:"; 2>&1; \ + echo ""; \ + echo " apt-get install gcc-multilib libc6-i386 libc6-dev-i386"; \ + echo ""; \ + echo "If you are using a Fedora-like distribution, try:"; \ + echo ""; \ + echo " yum install glibc-devel.*i686"; \ + exit 0; +endif + +# Some tests have additional dependencies. +sysret_ss_attrs_64: thunks.S diff --git a/tools/testing/selftests/x86/check_cc.sh b/tools/testing/selftests/x86/check_cc.sh new file mode 100755 index 000000000000..172d3293fb7b --- /dev/null +++ b/tools/testing/selftests/x86/check_cc.sh @@ -0,0 +1,16 @@ +#!/bin/sh +# check_cc.sh - Helper to test userspace compilation support +# Copyright (c) 2015 Andrew Lutomirski +# GPL v2 + +CC="$1" +TESTPROG="$2" +shift 2 + +if "$CC" -o /dev/null "$TESTPROG" -O0 "$@" 2>/dev/null; then + echo 1 +else + echo 0 +fi + +exit 0 diff --git a/tools/testing/selftests/x86/entry_from_vm86.c b/tools/testing/selftests/x86/entry_from_vm86.c new file mode 100644 index 000000000000..5c38a187677b --- /dev/null +++ b/tools/testing/selftests/x86/entry_from_vm86.c @@ -0,0 +1,114 @@ +/* + * entry_from_vm86.c - tests kernel entries from vm86 mode + * Copyright (c) 2014-2015 Andrew Lutomirski + * + * This exercises a few paths that need to special-case vm86 mode. + * + * GPL v2. + */ + +#define _GNU_SOURCE + +#include <assert.h> +#include <stdlib.h> +#include <sys/syscall.h> +#include <sys/signal.h> +#include <sys/ucontext.h> +#include <unistd.h> +#include <stdio.h> +#include <string.h> +#include <inttypes.h> +#include <sys/mman.h> +#include <err.h> +#include <stddef.h> +#include <stdbool.h> +#include <errno.h> +#include <sys/vm86.h> + +static unsigned long load_addr = 0x10000; +static int nerrs = 0; + +asm ( + ".pushsection .rodata\n\t" + ".type vmcode_bound, @object\n\t" + "vmcode:\n\t" + "vmcode_bound:\n\t" + ".code16\n\t" + "bound %ax, (2048)\n\t" + "int3\n\t" + "vmcode_sysenter:\n\t" + "sysenter\n\t" + ".size vmcode, . - vmcode\n\t" + "end_vmcode:\n\t" + ".code32\n\t" + ".popsection" + ); + +extern unsigned char vmcode[], end_vmcode[]; +extern unsigned char vmcode_bound[], vmcode_sysenter[]; + +static void do_test(struct vm86plus_struct *v86, unsigned long eip, + const char *text) +{ + long ret; + + printf("[RUN]\t%s from vm86 mode\n", text); + v86->regs.eip = eip; + ret = vm86(VM86_ENTER, v86); + + if (ret == -1 && errno == ENOSYS) { + printf("[SKIP]\tvm86 not supported\n"); + return; + } + + if (VM86_TYPE(ret) == VM86_INTx) { + char trapname[32]; + int trapno = VM86_ARG(ret); + if (trapno == 13) + strcpy(trapname, "GP"); + else if (trapno == 5) + strcpy(trapname, "BR"); + else if (trapno == 14) + strcpy(trapname, "PF"); + else + sprintf(trapname, "%d", trapno); + + printf("[OK]\tExited vm86 mode due to #%s\n", trapname); + } else if (VM86_TYPE(ret) == VM86_UNKNOWN) { + printf("[OK]\tExited vm86 mode due to unhandled GP fault\n"); + } else { + printf("[OK]\tExited vm86 mode due to type %ld, arg %ld\n", + VM86_TYPE(ret), VM86_ARG(ret)); + } +} + +int main(void) +{ + struct vm86plus_struct v86; + unsigned char *addr = mmap((void *)load_addr, 4096, + PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_ANONYMOUS | MAP_PRIVATE, -1,0); + if (addr != (unsigned char *)load_addr) + err(1, "mmap"); + + memcpy(addr, vmcode, end_vmcode - vmcode); + addr[2048] = 2; + addr[2050] = 3; + + memset(&v86, 0, sizeof(v86)); + + v86.regs.cs = load_addr / 16; + v86.regs.ss = load_addr / 16; + v86.regs.ds = load_addr / 16; + v86.regs.es = load_addr / 16; + + assert((v86.regs.cs & 3) == 0); /* Looks like RPL = 0 */ + + /* #BR -- should deliver SIG??? */ + do_test(&v86, vmcode_bound - vmcode, "#BR"); + + /* SYSENTER -- should cause #GP or #UD depending on CPU */ + do_test(&v86, vmcode_sysenter - vmcode, "SYSENTER"); + + return (nerrs == 0 ? 0 : 1); +} diff --git a/tools/testing/selftests/x86/run_x86_tests.sh b/tools/testing/selftests/x86/run_x86_tests.sh deleted file mode 100644 index 3fc19b376812..000000000000 --- a/tools/testing/selftests/x86/run_x86_tests.sh +++ /dev/null @@ -1,13 +0,0 @@ -#!/bin/bash - -# This is deliberately minimal. IMO kselftests should provide a standard -# script here. -./sigreturn_32 || exit 1 -./single_step_syscall_32 || exit 1 - -if [[ "$uname -p" -eq "x86_64" ]]; then - ./sigreturn_64 || exit 1 - ./single_step_syscall_64 || exit 1 -fi - -exit 0 diff --git a/tools/testing/selftests/x86/sysret_ss_attrs.c b/tools/testing/selftests/x86/sysret_ss_attrs.c new file mode 100644 index 000000000000..ce42d5a64009 --- /dev/null +++ b/tools/testing/selftests/x86/sysret_ss_attrs.c @@ -0,0 +1,112 @@ +/* + * sysret_ss_attrs.c - test that syscalls return valid hidden SS attributes + * Copyright (c) 2015 Andrew Lutomirski + * + * This program is free software; you can redistribute it and/or modify + * it under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * On AMD CPUs, SYSRET can return with a valid SS descriptor with with + * the hidden attributes set to an unusable state. Make sure the kernel + * doesn't let this happen. + */ + +#define _GNU_SOURCE + +#include <stdlib.h> +#include <unistd.h> +#include <stdio.h> +#include <string.h> +#include <sys/mman.h> +#include <err.h> +#include <stddef.h> +#include <stdbool.h> +#include <pthread.h> + +static void *threadproc(void *ctx) +{ + /* + * Do our best to cause sleeps on this CPU to exit the kernel and + * re-enter with SS = 0. + */ + while (true) + ; + + return NULL; +} + +#ifdef __x86_64__ +extern unsigned long call32_from_64(void *stack, void (*function)(void)); + +asm (".pushsection .text\n\t" + ".code32\n\t" + "test_ss:\n\t" + "pushl $0\n\t" + "popl %eax\n\t" + "ret\n\t" + ".code64"); +extern void test_ss(void); +#endif + +int main() +{ + /* + * Start a busy-looping thread on the same CPU we're on. + * For simplicity, just stick everything to CPU 0. This will + * fail in some containers, but that's probably okay. + */ + cpu_set_t cpuset; + CPU_ZERO(&cpuset); + CPU_SET(0, &cpuset); + if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0) + printf("[WARN]\tsched_setaffinity failed\n"); + + pthread_t thread; + if (pthread_create(&thread, 0, threadproc, 0) != 0) + err(1, "pthread_create"); + +#ifdef __x86_64__ + unsigned char *stack32 = mmap(NULL, 4096, PROT_READ | PROT_WRITE, + MAP_32BIT | MAP_ANONYMOUS | MAP_PRIVATE, + -1, 0); + if (stack32 == MAP_FAILED) + err(1, "mmap"); +#endif + + printf("[RUN]\tSyscalls followed by SS validation\n"); + + for (int i = 0; i < 1000; i++) { + /* + * Go to sleep and return using sysret (if we're 64-bit + * or we're 32-bit on AMD on a 64-bit kernel). On AMD CPUs, + * SYSRET doesn't fix up the cached SS descriptor, so the + * kernel needs some kind of workaround to make sure that we + * end the system call with a valid stack segment. This + * can be a confusing failure because the SS *selector* + * is the same regardless. + */ + usleep(2); + +#ifdef __x86_64__ + /* + * On 32-bit, just doing a syscall through glibc is enough + * to cause a crash if our cached SS descriptor is invalid. + * On 64-bit, it's not, so try extra hard. + */ + call32_from_64(stack32 + 4088, test_ss); +#endif + } + + printf("[OK]\tWe survived\n"); + +#ifdef __x86_64__ + munmap(stack32, 4096); +#endif + + return 0; +} diff --git a/tools/testing/selftests/x86/thunks.S b/tools/testing/selftests/x86/thunks.S new file mode 100644 index 000000000000..ce8a995bbb17 --- /dev/null +++ b/tools/testing/selftests/x86/thunks.S @@ -0,0 +1,67 @@ +/* + * thunks.S - assembly helpers for mixed-bitness code + * Copyright (c) 2015 Andrew Lutomirski + * + * This program is free software; you can redistribute it and/or modify + * it under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * These are little helpers that make it easier to switch bitness on + * the fly. + */ + + .text + + .global call32_from_64 + .type call32_from_64, @function +call32_from_64: + // rdi: stack to use + // esi: function to call + + // Save registers + pushq %rbx + pushq %rbp + pushq %r12 + pushq %r13 + pushq %r14 + pushq %r15 + pushfq + + // Switch stacks + mov %rsp,(%rdi) + mov %rdi,%rsp + + // Switch to compatibility mode + pushq $0x23 /* USER32_CS */ + pushq $1f + lretq + +1: + .code32 + // Call the function + call *%esi + // Switch back to long mode + jmp $0x33,$1f + .code64 + +1: + // Restore the stack + mov (%rsp),%rsp + + // Restore registers + popfq + popq %r15 + popq %r14 + popq %r13 + popq %r12 + popq %rbp + popq %rbx + + ret + +.size call32_from_64, .-call32_from_64 diff --git a/tools/testing/selftests/x86/trivial_32bit_program.c b/tools/testing/selftests/x86/trivial_32bit_program.c index 2e231beb0a39..fabdf0f51621 100644 --- a/tools/testing/selftests/x86/trivial_32bit_program.c +++ b/tools/testing/selftests/x86/trivial_32bit_program.c @@ -4,6 +4,10 @@ * GPL v2 */ +#ifndef __i386__ +# error wrong architecture +#endif + #include <stdio.h> int main() diff --git a/tools/testing/selftests/x86/trivial_64bit_program.c b/tools/testing/selftests/x86/trivial_64bit_program.c new file mode 100644 index 000000000000..05c6a41b3671 --- /dev/null +++ b/tools/testing/selftests/x86/trivial_64bit_program.c @@ -0,0 +1,18 @@ +/* + * Trivial program to check that we have a valid 64-bit build environment. + * Copyright (c) 2015 Andy Lutomirski + * GPL v2 + */ + +#ifndef __x86_64__ +# error wrong architecture +#endif + +#include <stdio.h> + +int main() +{ + printf("\n"); + + return 0; +} |
