x86/asm/entry: Move the vsyscall code to arch/x86/entry/vsyscall/

The vsyscall code is entry code too, so move it to arch/x86/entry/vsyscall/.

Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 0 insertions, 335 deletions

diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
deleted file mode 100644
index 2dcc6ff6fdcc..000000000000
--- a/arch/x86/kernel/vsyscall_64.c
+++ /dev/null
@@ -1,335 +0,0 @@
-/*
- * Copyright (c) 2012-2014 Andy Lutomirski <luto@amacapital.net>
- *
- * Based on the original implementation which is:
- *  Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
- *  Copyright 2003 Andi Kleen, SuSE Labs.
- *
- *  Parts of the original code have been moved to arch/x86/vdso/vma.c
- *
- * This file implements vsyscall emulation.  vsyscalls are a legacy ABI:
- * Userspace can request certain kernel services by calling fixed
- * addresses.  This concept is problematic:
- *
- * - It interferes with ASLR.
- * - It's awkward to write code that lives in kernel addresses but is
- *   callable by userspace at fixed addresses.
- * - The whole concept is impossible for 32-bit compat userspace.
- * - UML cannot easily virtualize a vsyscall.
- *
- * As of mid-2014, I believe that there is no new userspace code that
- * will use a vsyscall if the vDSO is present.  I hope that there will
- * soon be no new userspace code that will ever use a vsyscall.
- *
- * The code in this file emulates vsyscalls when notified of a page
- * fault to a vsyscall address.
- */
-
-#include <linux/kernel.h>
-#include <linux/timer.h>
-#include <linux/syscalls.h>
-#include <linux/ratelimit.h>
-
-#include <asm/vsyscall.h>
-#include <asm/unistd.h>
-#include <asm/fixmap.h>
-#include <asm/traps.h>
-
-#define CREATE_TRACE_POINTS
-#include "vsyscall_trace.h"
-
-static enum { EMULATE, NATIVE, NONE } vsyscall_mode = EMULATE;
-
-static int __init vsyscall_setup(char *str)
-{
-	if (str) {
-		if (!strcmp("emulate", str))
-			vsyscall_mode = EMULATE;
-		else if (!strcmp("native", str))
-			vsyscall_mode = NATIVE;
-		else if (!strcmp("none", str))
-			vsyscall_mode = NONE;
-		else
-			return -EINVAL;
-
-		return 0;
-	}
-
-	return -EINVAL;
-}
-early_param("vsyscall", vsyscall_setup);
-
-static void warn_bad_vsyscall(const char *level, struct pt_regs *regs,
-			      const char *message)
-{
-	if (!show_unhandled_signals)
-		return;
-
-	printk_ratelimited("%s%s[%d] %s ip:%lx cs:%lx sp:%lx ax:%lx si:%lx di:%lx\n",
-			   level, current->comm, task_pid_nr(current),
-			   message, regs->ip, regs->cs,
-			   regs->sp, regs->ax, regs->si, regs->di);
-}
-
-static int addr_to_vsyscall_nr(unsigned long addr)
-{
-	int nr;
-
-	if ((addr & ~0xC00UL) != VSYSCALL_ADDR)
-		return -EINVAL;
-
-	nr = (addr & 0xC00UL) >> 10;
-	if (nr >= 3)
-		return -EINVAL;
-
-	return nr;
-}
-
-static bool write_ok_or_segv(unsigned long ptr, size_t size)
-{
-	/*
-	 * XXX: if access_ok, get_user, and put_user handled
-	 * sig_on_uaccess_error, this could go away.
-	 */
-
-	if (!access_ok(VERIFY_WRITE, (void __user *)ptr, size)) {
-		siginfo_t info;
-		struct thread_struct *thread = &current->thread;
-
-		thread->error_code	= 6;  /* user fault, no page, write */
-		thread->cr2		= ptr;
-		thread->trap_nr		= X86_TRAP_PF;
-
-		memset(&info, 0, sizeof(info));
-		info.si_signo		= SIGSEGV;
-		info.si_errno		= 0;
-		info.si_code		= SEGV_MAPERR;
-		info.si_addr		= (void __user *)ptr;
-
-		force_sig_info(SIGSEGV, &info, current);
-		return false;
-	} else {
-		return true;
-	}
-}
-
-bool emulate_vsyscall(struct pt_regs *regs, unsigned long address)
-{
-	struct task_struct *tsk;
-	unsigned long caller;
-	int vsyscall_nr, syscall_nr, tmp;
-	int prev_sig_on_uaccess_error;
-	long ret;
-
-	/*
-	 * No point in checking CS -- the only way to get here is a user mode
-	 * trap to a high address, which means that we're in 64-bit user code.
-	 */
-
-	WARN_ON_ONCE(address != regs->ip);
-
-	if (vsyscall_mode == NONE) {
-		warn_bad_vsyscall(KERN_INFO, regs,
-				  "vsyscall attempted with vsyscall=none");
-		return false;
-	}
-
-	vsyscall_nr = addr_to_vsyscall_nr(address);
-
-	trace_emulate_vsyscall(vsyscall_nr);
-
-	if (vsyscall_nr < 0) {
-		warn_bad_vsyscall(KERN_WARNING, regs,
-				  "misaligned vsyscall (exploit attempt or buggy program) -- look up the vsyscall kernel parameter if you need a workaround");
-		goto sigsegv;
-	}
-
-	if (get_user(caller, (unsigned long __user *)regs->sp) != 0) {
-		warn_bad_vsyscall(KERN_WARNING, regs,
-				  "vsyscall with bad stack (exploit attempt?)");
-		goto sigsegv;
-	}
-
-	tsk = current;
-
-	/*
-	 * Check for access_ok violations and find the syscall nr.
-	 *
-	 * NULL is a valid user pointer (in the access_ok sense) on 32-bit and
-	 * 64-bit, so we don't need to special-case it here.  For all the
-	 * vsyscalls, NULL means "don't write anything" not "write it at
-	 * address 0".
-	 */
-	switch (vsyscall_nr) {
-	case 0:
-		if (!write_ok_or_segv(regs->di, sizeof(struct timeval)) ||
-		    !write_ok_or_segv(regs->si, sizeof(struct timezone))) {
-			ret = -EFAULT;
-			goto check_fault;
-		}
-
-		syscall_nr = __NR_gettimeofday;
-		break;
-
-	case 1:
-		if (!write_ok_or_segv(regs->di, sizeof(time_t))) {
-			ret = -EFAULT;
-			goto check_fault;
-		}
-
-		syscall_nr = __NR_time;
-		break;
-
-	case 2:
-		if (!write_ok_or_segv(regs->di, sizeof(unsigned)) ||
-		    !write_ok_or_segv(regs->si, sizeof(unsigned))) {
-			ret = -EFAULT;
-			goto check_fault;
-		}
-
-		syscall_nr = __NR_getcpu;
-		break;
-	}
-
-	/*
-	 * Handle seccomp.  regs->ip must be the original value.
-	 * See seccomp_send_sigsys and Documentation/prctl/seccomp_filter.txt.
-	 *
-	 * We could optimize the seccomp disabled case, but performance
-	 * here doesn't matter.
-	 */
-	regs->orig_ax = syscall_nr;
-	regs->ax = -ENOSYS;
-	tmp = secure_computing();
-	if ((!tmp && regs->orig_ax != syscall_nr) || regs->ip != address) {
-		warn_bad_vsyscall(KERN_DEBUG, regs,
-				  "seccomp tried to change syscall nr or ip");
-		do_exit(SIGSYS);
-	}
-	regs->orig_ax = -1;
-	if (tmp)
-		goto do_ret;  /* skip requested */
-
-	/*
-	 * With a real vsyscall, page faults cause SIGSEGV.  We want to
-	 * preserve that behavior to make writing exploits harder.
-	 */
-	prev_sig_on_uaccess_error = current_thread_info()->sig_on_uaccess_error;
-	current_thread_info()->sig_on_uaccess_error = 1;
-
-	ret = -EFAULT;
-	switch (vsyscall_nr) {
-	case 0:
-		ret = sys_gettimeofday(
-			(struct timeval __user *)regs->di,
-			(struct timezone __user *)regs->si);
-		break;
-
-	case 1:
-		ret = sys_time((time_t __user *)regs->di);
-		break;
-
-	case 2:
-		ret = sys_getcpu((unsigned __user *)regs->di,
-				 (unsigned __user *)regs->si,
-				 NULL);
-		break;
-	}
-
-	current_thread_info()->sig_on_uaccess_error = prev_sig_on_uaccess_error;
-
-check_fault:
-	if (ret == -EFAULT) {
-		/* Bad news -- userspace fed a bad pointer to a vsyscall. */
-		warn_bad_vsyscall(KERN_INFO, regs,
-				  "vsyscall fault (exploit attempt?)");
-
-		/*
-		 * If we failed to generate a signal for any reason,
-		 * generate one here.  (This should be impossible.)
-		 */
-		if (WARN_ON_ONCE(!sigismember(&tsk->pending.signal, SIGBUS) &&
-				 !sigismember(&tsk->pending.signal, SIGSEGV)))
-			goto sigsegv;
-
-		return true;  /* Don't emulate the ret. */
-	}
-
-	regs->ax = ret;
-
-do_ret:
-	/* Emulate a ret instruction. */
-	regs->ip = caller;
-	regs->sp += 8;
-	return true;
-
-sigsegv:
-	force_sig(SIGSEGV, current);
-	return true;
-}
-
-/*
- * A pseudo VMA to allow ptrace access for the vsyscall page.  This only
- * covers the 64bit vsyscall page now. 32bit has a real VMA now and does
- * not need special handling anymore:
- */
-static const char *gate_vma_name(struct vm_area_struct *vma)
-{
-	return "[vsyscall]";
-}
-static struct vm_operations_struct gate_vma_ops = {
-	.name = gate_vma_name,
-};
-static struct vm_area_struct gate_vma = {
-	.vm_start	= VSYSCALL_ADDR,
-	.vm_end		= VSYSCALL_ADDR + PAGE_SIZE,
-	.vm_page_prot	= PAGE_READONLY_EXEC,
-	.vm_flags	= VM_READ | VM_EXEC,
-	.vm_ops		= &gate_vma_ops,
-};
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-#ifdef CONFIG_IA32_EMULATION
-	if (!mm || mm->context.ia32_compat)
-		return NULL;
-#endif
-	if (vsyscall_mode == NONE)
-		return NULL;
-	return &gate_vma;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	struct vm_area_struct *vma = get_gate_vma(mm);
-
-	if (!vma)
-		return 0;
-
-	return (addr >= vma->vm_start) && (addr < vma->vm_end);
-}
-
-/*
- * Use this when you have no reliable mm, typically from interrupt
- * context. It is less reliable than using a task's mm and may give
- * false positives.
- */
-int in_gate_area_no_mm(unsigned long addr)
-{
-	return vsyscall_mode != NONE && (addr & PAGE_MASK) == VSYSCALL_ADDR;
-}
-
-void __init map_vsyscall(void)
-{
-	extern char __vsyscall_page;
-	unsigned long physaddr_vsyscall = __pa_symbol(&__vsyscall_page);
-
-	if (vsyscall_mode != NONE)
-		__set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall,
-			     vsyscall_mode == NATIVE
-			     ? PAGE_KERNEL_VSYSCALL
-			     : PAGE_KERNEL_VVAR);
-
-	BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_PAGE) !=
-		     (unsigned long)VSYSCALL_ADDR);
-}