diff options
Diffstat (limited to 'tools/testing/selftests/x86/iopl.c')
| -rw-r--r-- | tools/testing/selftests/x86/iopl.c | 170 |
1 files changed, 147 insertions, 23 deletions
diff --git a/tools/testing/selftests/x86/iopl.c b/tools/testing/selftests/x86/iopl.c index 6aa27f34644c..457b6715542b 100644 --- a/tools/testing/selftests/x86/iopl.c +++ b/tools/testing/selftests/x86/iopl.c @@ -20,47 +20,178 @@ #include <sched.h> #include <sys/io.h> +#include "helpers.h" + static int nerrs = 0; -static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *), - int flags) +static jmp_buf jmpbuf; + +static void sigsegv(int sig, siginfo_t *si, void *ctx_void) { - struct sigaction sa; - memset(&sa, 0, sizeof(sa)); - sa.sa_sigaction = handler; - sa.sa_flags = SA_SIGINFO | flags; - sigemptyset(&sa.sa_mask); - if (sigaction(sig, &sa, 0)) - err(1, "sigaction"); + siglongjmp(jmpbuf, 1); +} +static bool try_outb(unsigned short port) +{ + sethandler(SIGSEGV, sigsegv, SA_RESETHAND); + if (sigsetjmp(jmpbuf, 1) != 0) { + return false; + } else { + asm volatile ("outb %%al, %w[port]" + : : [port] "Nd" (port), "a" (0)); + return true; + } + clearhandler(SIGSEGV); } -static jmp_buf jmpbuf; +static void expect_ok_outb(unsigned short port) +{ + if (!try_outb(port)) { + printf("[FAIL]\toutb to 0x%02hx failed\n", port); + exit(1); + } -static void sigsegv(int sig, siginfo_t *si, void *ctx_void) + printf("[OK]\toutb to 0x%02hx worked\n", port); +} + +static void expect_gp_outb(unsigned short port) { - siglongjmp(jmpbuf, 1); + if (try_outb(port)) { + printf("[FAIL]\toutb to 0x%02hx worked\n", port); + nerrs++; + } + + printf("[OK]\toutb to 0x%02hx failed\n", port); +} + +#define RET_FAULTED 0 +#define RET_FAIL 1 +#define RET_EMUL 2 + +static int try_cli(void) +{ + unsigned long flags; + + sethandler(SIGSEGV, sigsegv, SA_RESETHAND); + if (sigsetjmp(jmpbuf, 1) != 0) { + return RET_FAULTED; + } else { + asm volatile("cli; pushf; pop %[flags]" + : [flags] "=rm" (flags)); + + /* X86_FLAGS_IF */ + if (!(flags & (1 << 9))) + return RET_FAIL; + else + return RET_EMUL; + } + clearhandler(SIGSEGV); +} + +static int try_sti(bool irqs_off) +{ + unsigned long flags; + + sethandler(SIGSEGV, sigsegv, SA_RESETHAND); + if (sigsetjmp(jmpbuf, 1) != 0) { + return RET_FAULTED; + } else { + asm volatile("sti; pushf; pop %[flags]" + : [flags] "=rm" (flags)); + + /* X86_FLAGS_IF */ + if (irqs_off && (flags & (1 << 9))) + return RET_FAIL; + else + return RET_EMUL; + } + clearhandler(SIGSEGV); +} + +static void expect_gp_sti(bool irqs_off) +{ + int ret = try_sti(irqs_off); + + switch (ret) { + case RET_FAULTED: + printf("[OK]\tSTI faulted\n"); + break; + case RET_EMUL: + printf("[OK]\tSTI NOPped\n"); + break; + default: + printf("[FAIL]\tSTI worked\n"); + nerrs++; + } +} + +/* + * Returns whether it managed to disable interrupts. + */ +static bool test_cli(void) +{ + int ret = try_cli(); + + switch (ret) { + case RET_FAULTED: + printf("[OK]\tCLI faulted\n"); + break; + case RET_EMUL: + printf("[OK]\tCLI NOPped\n"); + break; + default: + printf("[FAIL]\tCLI worked\n"); + nerrs++; + return true; + } + + return false; } int main(void) { cpu_set_t cpuset; + CPU_ZERO(&cpuset); CPU_SET(0, &cpuset); if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0) err(1, "sched_setaffinity to CPU 0"); /* Probe for iopl support. Note that iopl(0) works even as nonroot. */ - if (iopl(3) != 0) { + switch(iopl(3)) { + case 0: + break; + case -ENOSYS: + printf("[OK]\tiopl() nor supported\n"); + return 0; + default: printf("[OK]\tiopl(3) failed (%d) -- try running as root\n", errno); return 0; } - /* Restore our original state prior to starting the test. */ + /* Make sure that CLI/STI are blocked even with IOPL level 3 */ + expect_gp_sti(test_cli()); + expect_ok_outb(0x80); + + /* Establish an I/O bitmap to test the restore */ + if (ioperm(0x80, 1, 1) != 0) + err(1, "ioperm(0x80, 1, 1) failed\n"); + + /* Restore our original state prior to starting the fork test. */ if (iopl(0) != 0) err(1, "iopl(0)"); + /* + * Verify that IOPL emulation is disabled and the I/O bitmap still + * works. + */ + expect_ok_outb(0x80); + expect_gp_outb(0xed); + /* Drop the I/O bitmap */ + if (ioperm(0x80, 1, 0) != 0) + err(1, "ioperm(0x80, 1, 0) failed\n"); + pid_t child = fork(); if (child == -1) err(1, "fork"); @@ -90,14 +221,8 @@ int main(void) printf("[RUN]\tparent: write to 0x80 (should fail)\n"); - sethandler(SIGSEGV, sigsegv, 0); - if (sigsetjmp(jmpbuf, 1) != 0) { - printf("[OK]\twrite was denied\n"); - } else { - asm volatile ("outb %%al, $0x80" : : "a" (0)); - printf("[FAIL]\twrite was allowed\n"); - nerrs++; - } + expect_gp_outb(0x80); + expect_gp_sti(test_cli()); /* Test the capability checks. */ printf("\tiopl(3)\n"); @@ -133,4 +258,3 @@ int main(void) done: return nerrs ? 1 : 0; } - |