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

Pull x86 asm changes from Ingo Molnar:
 "The biggest changes in this cycle were:

   - Revamp, simplify (and in some cases fix) Time Stamp Counter (TSC)
     primitives.  (Andy Lutomirski)

   - Add new, comprehensible entry and exit handlers written in C.
     (Andy Lutomirski)

   - vm86 mode cleanups and fixes.  (Brian Gerst)

   - 32-bit compat code cleanups.  (Brian Gerst)

  The amount of simplification in low level assembly code is already
  palpable:

     arch/x86/entry/entry_32.S                          | 130 +----
     arch/x86/entry/entry_64.S                          | 197 ++-----

  but more simplifications are planned.

  There's also the usual laudry mix of low level changes - see the
  changelog for details"

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (83 commits)
  x86/asm: Drop repeated macro of X86_EFLAGS_AC definition
  x86/asm/msr: Make wrmsrl() a function
  x86/asm/delay: Introduce an MWAITX-based delay with a configurable timer
  x86/asm: Add MONITORX/MWAITX instruction support
  x86/traps: Weaken context tracking entry assertions
  x86/asm/tsc: Add rdtscll() merge helper
  selftests/x86: Add syscall_nt selftest
  selftests/x86: Disable sigreturn_64
  x86/vdso: Emit a GNU hash
  x86/entry: Remove do_notify_resume(), syscall_trace_leave(), and their TIF masks
  x86/entry/32: Migrate to C exit path
  x86/entry/32: Remove 32-bit syscall audit optimizations
  x86/vm86: Rename vm86->v86flags and v86mask
  x86/vm86: Rename vm86->vm86_info to user_vm86
  x86/vm86: Clean up vm86.h includes
  x86/vm86: Move the vm86 IRQ definitions to vm86.h
  x86/vm86: Use the normal pt_regs area for vm86
  x86/vm86: Eliminate 'struct kernel_vm86_struct'
  x86/vm86: Move fields from 'struct kernel_vm86_struct' to 'struct vm86'
  x86/vm86: Move vm86 fields out of 'thread_struct'
  ...

1 files changed, 130 insertions, 0 deletions

diff --git a/tools/testing/selftests/x86/syscall_arg_fault.c b/tools/testing/selftests/x86/syscall_arg_fault.c
new file mode 100644
index 000000000000..7db4fc9fa09f
--- /dev/null
+++ b/tools/testing/selftests/x86/syscall_arg_fault.c
@@ -0,0 +1,130 @@
+/*
+ * syscall_arg_fault.c - tests faults 32-bit fast syscall stack args
+ * 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.
+ */
+
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/signal.h>
+#include <sys/ucontext.h>
+#include <err.h>
+#include <setjmp.h>
+#include <errno.h>
+
+/* Our sigaltstack scratch space. */
+static unsigned char altstack_data[SIGSTKSZ];
+
+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 volatile sig_atomic_t sig_traps;
+static sigjmp_buf jmpbuf;
+
+static volatile sig_atomic_t n_errs;
+
+static void sigsegv(int sig, siginfo_t *info, void *ctx_void)
+{
+	ucontext_t *ctx = (ucontext_t*)ctx_void;
+
+	if (ctx->uc_mcontext.gregs[REG_EAX] != -EFAULT) {
+		printf("[FAIL]\tAX had the wrong value: 0x%x\n",
+		       ctx->uc_mcontext.gregs[REG_EAX]);
+		n_errs++;
+	} else {
+		printf("[OK]\tSeems okay\n");
+	}
+
+	siglongjmp(jmpbuf, 1);
+}
+
+static void sigill(int sig, siginfo_t *info, void *ctx_void)
+{
+	printf("[SKIP]\tIllegal instruction\n");
+	siglongjmp(jmpbuf, 1);
+}
+
+int main()
+{
+	stack_t stack = {
+		.ss_sp = altstack_data,
+		.ss_size = SIGSTKSZ,
+	};
+	if (sigaltstack(&stack, NULL) != 0)
+		err(1, "sigaltstack");
+
+	sethandler(SIGSEGV, sigsegv, SA_ONSTACK);
+	sethandler(SIGILL, sigill, SA_ONSTACK);
+
+	/*
+	 * Exercise another nasty special case.  The 32-bit SYSCALL
+	 * and SYSENTER instructions (even in compat mode) each
+	 * clobber one register.  A Linux system call has a syscall
+	 * number and six arguments, and the user stack pointer
+	 * needs to live in some register on return.  That means
+	 * that we need eight registers, but SYSCALL and SYSENTER
+	 * only preserve seven registers.  As a result, one argument
+	 * ends up on the stack.  The stack is user memory, which
+	 * means that the kernel can fail to read it.
+	 *
+	 * The 32-bit fast system calls don't have a defined ABI:
+	 * we're supposed to invoke them through the vDSO.  So we'll
+	 * fudge it: we set all regs to invalid pointer values and
+	 * invoke the entry instruction.  The return will fail no
+	 * matter what, and we completely lose our program state,
+	 * but we can fix it up with a signal handler.
+	 */
+
+	printf("[RUN]\tSYSENTER with invalid state\n");
+	if (sigsetjmp(jmpbuf, 1) == 0) {
+		asm volatile (
+			"movl $-1, %%eax\n\t"
+			"movl $-1, %%ebx\n\t"
+			"movl $-1, %%ecx\n\t"
+			"movl $-1, %%edx\n\t"
+			"movl $-1, %%esi\n\t"
+			"movl $-1, %%edi\n\t"
+			"movl $-1, %%ebp\n\t"
+			"movl $-1, %%esp\n\t"
+			"sysenter"
+			: : : "memory", "flags");
+	}
+
+	printf("[RUN]\tSYSCALL with invalid state\n");
+	if (sigsetjmp(jmpbuf, 1) == 0) {
+		asm volatile (
+			"movl $-1, %%eax\n\t"
+			"movl $-1, %%ebx\n\t"
+			"movl $-1, %%ecx\n\t"
+			"movl $-1, %%edx\n\t"
+			"movl $-1, %%esi\n\t"
+			"movl $-1, %%edi\n\t"
+			"movl $-1, %%ebp\n\t"
+			"movl $-1, %%esp\n\t"
+			"syscall\n\t"
+			"pushl $0"	/* make sure we segfault cleanly */
+			: : : "memory", "flags");
+	}
+
+	return 0;
+}