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Revision ff66135015726696568e998720d9b6afe2d04642 authored by Marco Elver on 12 July 2019, 03:53:56 UTC, committed by Linus Torvalds on 12 July 2019, 18:05:42 UTC 
x86: use static_cpu_has in uaccess region to avoid instrumentation
 
This patch is a pre-requisite for enabling KASAN bitops instrumentation;
using static_cpu_has instead of boot_cpu_has avoids instrumentation of
test_bit inside the uaccess region.  With instrumentation, the KASAN
check would otherwise be flagged by objtool.

For consistency, kernel/signal.c was changed to mirror this change,
however, is never instrumented with KASAN (currently unsupported under
x86 32bit).

Link: http://lkml.kernel.org/r/20190613125950.197667-3-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Raw File
eisa_eeprom.c 
// SPDX-License-Identifier: GPL-2.0-or-later
/* 
 *    EISA "eeprom" support routines
 *
 *    Copyright (C) 2001 Thomas Bogendoerfer <tsbogend at parisc-linux.org>
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <asm/io.h>
#include <linux/uaccess.h>
#include <asm/eisa_eeprom.h>

#define 	EISA_EEPROM_MINOR 241

static loff_t eisa_eeprom_llseek(struct file *file, loff_t offset, int origin)
{
	return fixed_size_llseek(file, offset, origin, HPEE_MAX_LENGTH);
}

static ssize_t eisa_eeprom_read(struct file * file,
			      char __user *buf, size_t count, loff_t *ppos )
{
	unsigned char *tmp;
	ssize_t ret;
	int i;
	
	if (*ppos < 0 || *ppos >= HPEE_MAX_LENGTH)
		return 0;
	
	count = *ppos + count < HPEE_MAX_LENGTH ? count : HPEE_MAX_LENGTH - *ppos;
	tmp = kmalloc(count, GFP_KERNEL);
	if (tmp) {
		for (i = 0; i < count; i++)
			tmp[i] = readb(eisa_eeprom_addr+(*ppos)++);

		if (copy_to_user (buf, tmp, count))
			ret = -EFAULT;
		else
			ret = count;
		kfree (tmp);
	} else
		ret = -ENOMEM;
	
	return ret;
}

static int eisa_eeprom_open(struct inode *inode, struct file *file)
{
	if (file->f_mode & FMODE_WRITE)
		return -EINVAL;
   
	return 0;
}

static int eisa_eeprom_release(struct inode *inode, struct file *file)
{
	return 0;
}

/*
 *	The various file operations we support.
 */
static const struct file_operations eisa_eeprom_fops = {
	.owner =	THIS_MODULE,
	.llseek =	eisa_eeprom_llseek,
	.read =		eisa_eeprom_read,
	.open =		eisa_eeprom_open,
	.release =	eisa_eeprom_release,
};

static struct miscdevice eisa_eeprom_dev = {
	EISA_EEPROM_MINOR,
	"eisa_eeprom",
	&eisa_eeprom_fops
};

static int __init eisa_eeprom_init(void)
{
	int retval;

	if (!eisa_eeprom_addr)
		return -ENODEV;

	retval = misc_register(&eisa_eeprom_dev);
	if (retval < 0) {
		printk(KERN_ERR "EISA EEPROM: cannot register misc device.\n");
		return retval;
	}

	printk(KERN_INFO "EISA EEPROM at 0x%px\n", eisa_eeprom_addr);
	return 0;
}

MODULE_LICENSE("GPL");

module_init(eisa_eeprom_init);
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