Merge branch 'x86-iopl-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 iopl updates from Ingo Molnar:
 "This implements a nice simplification of the iopl and ioperm code that
  Thomas Gleixner discovered: we can implement the IO privilege features
  of the iopl system call by using the IO permission bitmap in
  permissive mode, while trapping CLI/STI/POPF/PUSHF uses in user-space
  if they change the interrupt flag.

  This implements that feature, with testing facilities and related
  cleanups"

[ "Simplification" may be an over-statement. The main goal is to avoid
  the cli/sti of iopl by effectively implementing the IO port access
  parts of iopl in terms of ioperm.

  This may end up not workign well in case people actually depend on
  cli/sti being available, or if there are mixed uses of iopl and
  ioperm. We will see..       - Linus ]

* 'x86-iopl-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits)
  x86/ioperm: Fix use of deprecated config option
  x86/entry/32: Clarify register saving in __switch_to_asm()
  selftests/x86/iopl: Extend test to cover IOPL emulation
  x86/ioperm: Extend IOPL config to control ioperm() as well
  x86/iopl: Remove legacy IOPL option
  x86/iopl: Restrict iopl() permission scope
  x86/iopl: Fixup misleading comment
  selftests/x86/ioperm: Extend testing so the shared bitmap is exercised
  x86/ioperm: Share I/O bitmap if identical
  x86/ioperm: Remove bitmap if all permissions dropped
  x86/ioperm: Move TSS bitmap update to exit to user work
  x86/ioperm: Add bitmap sequence number
  x86/ioperm: Move iobitmap data into a struct
  x86/tss: Move I/O bitmap data into a seperate struct
  x86/io: Speedup schedule out of I/O bitmap user
  x86/ioperm: Avoid bitmap allocation if no permissions are set
  x86/ioperm: Simplify first ioperm() invocation logic
  x86/iopl: Cleanup include maze
  x86/tss: Fix and move VMX BUILD_BUG_ON()
  x86/cpu: Unify cpu_init()
  ...

2 files changed, 133 insertions, 12 deletions

diff --git a/tools/testing/selftests/x86/ioperm.c b/tools/testing/selftests/x86/ioperm.c
index 01de41c1b725..57ec5e99edb9 100644
--- a/tools/testing/selftests/x86/ioperm.c
+++ b/tools/testing/selftests/x86/ioperm.c
@@ -131,6 +131,17 @@ int main(void)
 		printf("[RUN]\tchild: check that we inherited permissions\n");
 		expect_ok(0x80);
 		expect_gp(0xed);
+		printf("[RUN]\tchild: Extend permissions to 0x81\n");
+		if (ioperm(0x81, 1, 1) != 0) {
+			printf("[FAIL]\tioperm(0x81, 1, 1) failed (%d)", errno);
+			return 1;
+		}
+		printf("[RUN]\tchild: Drop permissions to 0x80\n");
+		if (ioperm(0x80, 1, 0) != 0) {
+			printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
+			return 1;
+		}
+		expect_gp(0x80);
 		return 0;
 	} else {
 		int status;
@@ -146,8 +157,11 @@ int main(void)
 		}
 	}
 
-	/* Test the capability checks. */
+	/* Verify that the child dropping 0x80 did not affect the parent */
+	printf("\tVerify that unsharing the bitmap worked\n");
+	expect_ok(0x80);
 
+	/* Test the capability checks. */
 	printf("\tDrop privileges\n");
 	if (setresuid(1, 1, 1) != 0) {
 		printf("[WARN]\tDropping privileges failed\n");
diff --git a/tools/testing/selftests/x86/iopl.c b/tools/testing/selftests/x86/iopl.c
index 6aa27f34644c..bab2f6e06b63 100644
--- a/tools/testing/selftests/x86/iopl.c
+++ b/tools/testing/selftests/x86/iopl.c
@@ -35,6 +35,16 @@ static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
 
 }
 
+static void clearhandler(int sig)
+{
+	struct sigaction sa;
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_handler = SIG_DFL;
+	sigemptyset(&sa.sa_mask);
+	if (sigaction(sig, &sa, 0))
+		err(1, "sigaction");
+}
+
 static jmp_buf jmpbuf;
 
 static void sigsegv(int sig, siginfo_t *si, void *ctx_void)
@@ -42,25 +52,128 @@ static void sigsegv(int sig, siginfo_t *si, void *ctx_void)
 	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 void expect_ok_outb(unsigned short port)
+{
+	if (!try_outb(port)) {
+		printf("[FAIL]\toutb to 0x%02hx failed\n", port);
+		exit(1);
+	}
+
+	printf("[OK]\toutb to 0x%02hx worked\n", port);
+}
+
+static void expect_gp_outb(unsigned short port)
+{
+	if (try_outb(port)) {
+		printf("[FAIL]\toutb to 0x%02hx worked\n", port);
+		nerrs++;
+	}
+
+	printf("[OK]\toutb to 0x%02hx failed\n", port);
+}
+
+static bool try_cli(void)
+{
+	sethandler(SIGSEGV, sigsegv, SA_RESETHAND);
+	if (sigsetjmp(jmpbuf, 1) != 0) {
+		return false;
+	} else {
+		asm volatile ("cli");
+		return true;
+	}
+	clearhandler(SIGSEGV);
+}
+
+static bool try_sti(void)
+{
+	sethandler(SIGSEGV, sigsegv, SA_RESETHAND);
+	if (sigsetjmp(jmpbuf, 1) != 0) {
+		return false;
+	} else {
+		asm volatile ("sti");
+		return true;
+	}
+	clearhandler(SIGSEGV);
+}
+
+static void expect_gp_sti(void)
+{
+	if (try_sti()) {
+		printf("[FAIL]\tSTI worked\n");
+		nerrs++;
+	} else {
+		printf("[OK]\tSTI faulted\n");
+	}
+}
+
+static void expect_gp_cli(void)
+{
+	if (try_cli()) {
+		printf("[FAIL]\tCLI worked\n");
+		nerrs++;
+	} else {
+		printf("[OK]\tCLI faulted\n");
+	}
+}
+
 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_cli();
+	expect_gp_sti();
+	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 +203,9 @@ 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_cli();
+	expect_gp_sti();
 
 	/* Test the capability checks. */
 	printf("\tiopl(3)\n");
@@ -133,4 +241,3 @@ int main(void)
 done:
 	return nerrs ? 1 : 0;
 }
-