https://github.com/torvalds/linux
Revision f45b55575cedb7efa782e43f1ea74338456d0381 authored by Eugeni Dodonov on 10 December 2011, 01:16:37 UTC, committed by Keith Packard on 16 December 2011, 16:49:59 UTC
This adds a default setting for semaphores parameter, and enables
semaphores by default on IVB.

For now, as semaphores interaction with VTd causes random issues on
SNB, we do not enable them by default. But they can still be enabled
via the semaphores=1 kernel parameter.

v2: enables semaphores on SNB when IO remapping is disabled, with base
on Keith Packard patch.

CC: Daniel Vetter <daniel.vetter@ffwll.ch>
CC: Ben Widawsky <ben@bwidawsk.net>
CC: Keith Packard <keithp@keithp.com>
CC: Jesse Barnes <jbarnes@virtuousgeek.org>
CC: Chris Wilson <chris@chris-wilson.co.uk>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=42696
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=40564
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=41353
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=38862
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
1 parent 7317c75
Raw File
Tip revision: f45b55575cedb7efa782e43f1ea74338456d0381 authored by Eugeni Dodonov on 10 December 2011, 01:16:37 UTC
drm/i915: enable semaphores on per-device defaults
Tip revision: f45b555
extable.c
/* Rewritten by Rusty Russell, on the backs of many others...
   Copyright (C) 2001 Rusty Russell, 2002 Rusty Russell IBM.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that 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.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
#include <linux/ftrace.h>
#include <linux/memory.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/init.h>

#include <asm/sections.h>
#include <asm/uaccess.h>

/*
 * mutex protecting text section modification (dynamic code patching).
 * some users need to sleep (allocating memory...) while they hold this lock.
 *
 * NOT exported to modules - patching kernel text is a really delicate matter.
 */
DEFINE_MUTEX(text_mutex);

extern struct exception_table_entry __start___ex_table[];
extern struct exception_table_entry __stop___ex_table[];

/* Sort the kernel's built-in exception table */
void __init sort_main_extable(void)
{
	sort_extable(__start___ex_table, __stop___ex_table);
}

/* Given an address, look for it in the exception tables. */
const struct exception_table_entry *search_exception_tables(unsigned long addr)
{
	const struct exception_table_entry *e;

	e = search_extable(__start___ex_table, __stop___ex_table-1, addr);
	if (!e)
		e = search_module_extables(addr);
	return e;
}

static inline int init_kernel_text(unsigned long addr)
{
	if (addr >= (unsigned long)_sinittext &&
	    addr <= (unsigned long)_einittext)
		return 1;
	return 0;
}

int core_kernel_text(unsigned long addr)
{
	if (addr >= (unsigned long)_stext &&
	    addr <= (unsigned long)_etext)
		return 1;

	if (system_state == SYSTEM_BOOTING &&
	    init_kernel_text(addr))
		return 1;
	return 0;
}

/**
 * core_kernel_data - tell if addr points to kernel data
 * @addr: address to test
 *
 * Returns true if @addr passed in is from the core kernel data
 * section.
 *
 * Note: On some archs it may return true for core RODATA, and false
 *  for others. But will always be true for core RW data.
 */
int core_kernel_data(unsigned long addr)
{
	if (addr >= (unsigned long)_sdata &&
	    addr < (unsigned long)_edata)
		return 1;
	return 0;
}

int __kernel_text_address(unsigned long addr)
{
	if (core_kernel_text(addr))
		return 1;
	if (is_module_text_address(addr))
		return 1;
	/*
	 * There might be init symbols in saved stacktraces.
	 * Give those symbols a chance to be printed in
	 * backtraces (such as lockdep traces).
	 *
	 * Since we are after the module-symbols check, there's
	 * no danger of address overlap:
	 */
	if (init_kernel_text(addr))
		return 1;
	return 0;
}

int kernel_text_address(unsigned long addr)
{
	if (core_kernel_text(addr))
		return 1;
	return is_module_text_address(addr);
}

/*
 * On some architectures (PPC64, IA64) function pointers
 * are actually only tokens to some data that then holds the
 * real function address. As a result, to find if a function
 * pointer is part of the kernel text, we need to do some
 * special dereferencing first.
 */
int func_ptr_is_kernel_text(void *ptr)
{
	unsigned long addr;
	addr = (unsigned long) dereference_function_descriptor(ptr);
	if (core_kernel_text(addr))
		return 1;
	return is_module_text_address(addr);
}
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