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Revision 85a00d9bbfb4704fbf368944b1cb9fed8f1598c5 authored by Peter Jones on 22 September 2010, 20:05:04 UTC, committed by Linus Torvalds on 23 September 2010, 00:22:39 UTC 
efifb: check that the base address is plausible on pci systems
 
Some Apple machines have identical DMI data but different memory
configurations for the video.  Given that, check that the address in our
table is actually within the range of a PCI BAR on a VGA device in the
machine.

This also fixes up the return value from set_system(), which has always
been wrong, but never resulted in bad behavior since there's only ever
been one matching entry in the dmi table.

The patch

1) stops people's machines from crashing when we get their display wrong,
   which seems to be unfortunately inevitable,

2) allows us to support identical dmi data with differing video memory
   configurations

This also adds me as the efifb maintainer, since I've effectively been
acting as such for quite some time.

Signed-off-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent a0c42ba
Raw File
debugfs.c 
/*
 * debugfs.c - ACPI debugfs interface to userspace.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/uaccess.h>
#include <linux/debugfs.h>
#include <acpi/acpi_drivers.h>

#define _COMPONENT		ACPI_SYSTEM_COMPONENT
ACPI_MODULE_NAME("debugfs");


/* /sys/modules/acpi/parameters/aml_debug_output */

module_param_named(aml_debug_output, acpi_gbl_enable_aml_debug_object,
		   bool, 0644);
MODULE_PARM_DESC(aml_debug_output,
		 "To enable/disable the ACPI Debug Object output.");

/* /sys/kernel/debug/acpi/custom_method */

static ssize_t cm_write(struct file *file, const char __user * user_buf,
			size_t count, loff_t *ppos)
{
	static char *buf;
	static int uncopied_bytes;
	struct acpi_table_header table;
	acpi_status status;

	if (!(*ppos)) {
		/* parse the table header to get the table length */
		if (count <= sizeof(struct acpi_table_header))
			return -EINVAL;
		if (copy_from_user(&table, user_buf,
				   sizeof(struct acpi_table_header)))
			return -EFAULT;
		uncopied_bytes = table.length;
		buf = kzalloc(uncopied_bytes, GFP_KERNEL);
		if (!buf)
			return -ENOMEM;
	}

	if (uncopied_bytes < count) {
		kfree(buf);
		return -EINVAL;
	}

	if (copy_from_user(buf + (*ppos), user_buf, count)) {
		kfree(buf);
		return -EFAULT;
	}

	uncopied_bytes -= count;
	*ppos += count;

	if (!uncopied_bytes) {
		status = acpi_install_method(buf);
		kfree(buf);
		if (ACPI_FAILURE(status))
			return -EINVAL;
		add_taint(TAINT_OVERRIDDEN_ACPI_TABLE);
	}

	return count;
}

static const struct file_operations cm_fops = {
	.write = cm_write,
};

int __init acpi_debugfs_init(void)
{
	struct dentry *acpi_dir, *cm_dentry;

	acpi_dir = debugfs_create_dir("acpi", NULL);
	if (!acpi_dir)
		goto err;

	cm_dentry = debugfs_create_file("custom_method", S_IWUGO,
					acpi_dir, NULL, &cm_fops);
	if (!cm_dentry)
		goto err;

	return 0;

err:
	if (acpi_dir)
		debugfs_remove(acpi_dir);
	return -EINVAL;
}
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