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

Pull x86 fixes from Ingo Molnar:
 "Misc fixes:

   - fix hotplug bugs
   - fix irq live lock
   - fix various topology handling bugs
   - fix APIC ACK ordering
   - fix PV iopl handling
   - fix speling
   - fix/tweak memcpy_mcsafe() return value
   - fix fbcon bug
   - remove stray prototypes"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/msr: Remove unused native_read_tscp()
  x86/apic: Remove declaration of unused hw_nmi_is_cpu_stuck
  x86/oprofile/nmi: Add missing hotplug FROZEN handling
  x86/hpet: Use proper mask to modify hotplug action
  x86/apic/uv: Fix the hotplug notifier
  x86/apb/timer: Use proper mask to modify hotplug action
  x86/topology: Use total_cpus not nr_cpu_ids for logical packages
  x86/topology: Fix Intel HT disable
  x86/topology: Fix logical package mapping
  x86/irq: Cure live lock in fixup_irqs()
  x86/tsc: Prevent NULL pointer deref in calibrate_delay_is_known()
  x86/apic: Fix suspicious RCU usage in smp_trace_call_function_interrupt()
  x86/iopl: Fix iopl capability check on Xen PV
  x86/iopl/64: Properly context-switch IOPL on Xen PV
  selftests/x86: Add an iopl test
  x86/mm, x86/mce: Fix return type/value for memcpy_mcsafe()
  x86/video: Don't assume all FB devices are PCI devices
  arch/x86/irq: Purge useless handler declarations from hw_irq.h
  x86: Fix misspellings in comments

2 files changed, 136 insertions, 1 deletions

diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index d5ce7d7aae3e..b47ebd170690 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -5,7 +5,7 @@ include ../lib.mk
 .PHONY: all all_32 all_64 warn_32bit_failure clean
 
 TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt ptrace_syscall \
-                        check_initial_reg_state sigreturn ldt_gdt
+                        check_initial_reg_state sigreturn ldt_gdt iopl
 TARGETS_C_32BIT_ONLY := entry_from_vm86 syscall_arg_fault test_syscall_vdso unwind_vdso \
                         test_FCMOV test_FCOMI test_FISTTP \
                         vdso_restorer
diff --git a/tools/testing/selftests/x86/iopl.c b/tools/testing/selftests/x86/iopl.c
new file mode 100644
index 000000000000..c496ca97bc18
--- /dev/null
+++ b/tools/testing/selftests/x86/iopl.c
@@ -0,0 +1,135 @@
+/*
+ * iopl.c - Test case for a Linux on Xen 64-bit bug
+ * Copyright (c) 2015 Andrew Lutomirski
+ */
+
+#define _GNU_SOURCE
+#include <err.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <signal.h>
+#include <setjmp.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdbool.h>
+#include <sched.h>
+#include <sys/io.h>
+
+static int nerrs = 0;
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+                       int flags)
+{
+        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");
+
+}
+
+static jmp_buf jmpbuf;
+
+static void sigsegv(int sig, siginfo_t *si, void *ctx_void)
+{
+        siglongjmp(jmpbuf, 1);
+}
+
+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) {
+                printf("[OK]\tiopl(3) failed (%d) -- try running as root\n",
+                       errno);
+                return 0;
+        }
+
+        /* Restore our original state prior to starting the test. */
+        if (iopl(0) != 0)
+                err(1, "iopl(0)");
+
+        pid_t child = fork();
+        if (child == -1)
+                err(1, "fork");
+
+        if (child == 0) {
+                printf("\tchild: set IOPL to 3\n");
+                if (iopl(3) != 0)
+                        err(1, "iopl");
+
+                printf("[RUN]\tchild: write to 0x80\n");
+                asm volatile ("outb %%al, $0x80" : : "a" (0));
+
+                return 0;
+        } else {
+                int status;
+                if (waitpid(child, &status, 0) != child ||
+                    !WIFEXITED(status)) {
+                        printf("[FAIL]\tChild died\n");
+                        nerrs++;
+                } else if (WEXITSTATUS(status) != 0) {
+                        printf("[FAIL]\tChild failed\n");
+                        nerrs++;
+                } else {
+                        printf("[OK]\tChild succeeded\n");
+                }
+        }
+
+        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++;
+        }
+
+        /* Test the capability checks. */
+        printf("\tiopl(3)\n");
+        if (iopl(3) != 0)
+                err(1, "iopl(3)");
+
+        printf("\tDrop privileges\n");
+        if (setresuid(1, 1, 1) != 0) {
+                printf("[WARN]\tDropping privileges failed\n");
+                goto done;
+        }
+
+        printf("[RUN]\tiopl(3) unprivileged but with IOPL==3\n");
+        if (iopl(3) != 0) {
+                printf("[FAIL]\tiopl(3) should work if iopl is already 3 even if unprivileged\n");
+                nerrs++;
+        }
+
+        printf("[RUN]\tiopl(0) unprivileged\n");
+        if (iopl(0) != 0) {
+                printf("[FAIL]\tiopl(0) should work if iopl is already 3 even if unprivileged\n");
+                nerrs++;
+        }
+
+        printf("[RUN]\tiopl(3) unprivileged\n");
+        if (iopl(3) == 0) {
+                printf("[FAIL]\tiopl(3) should fail if when unprivileged if iopl==0\n");
+                nerrs++;
+        } else {
+                printf("[OK]\tFailed as expected\n");
+        }
+
+done:
+        return nerrs ? 1 : 0;
+}
+