linux-stable/arch/x86/kernel/kdebugfs.c
Julia Lawall 41fb433b63 arch/x86/kernel/kdebugfs.c: Ensure a consistent return value in error case
Typically, the return value desired for the failure of a
function with an integer return value is a negative integer.  In
these cases, the return value is sometimes a negative integer
and sometimes 0, due to a subsequent initialization of the
return variable within the loop.

A simplified version of the semantic match that finds this
problem is: (http://coccinelle.lip6.fr/)

//<smpl>
@r exists@
identifier ret;
position p;
constant C;
expression e1,e3,e4;
statement S;
@@

ret = -C
... when != ret = e3
    when any
if@p (...) S
... when any
if (\(ret != 0\|ret < 0\|ret > 0\) || ...) { ... return ...; }
... when != ret = e3
    when any
*if@p (...)
{
  ... when != ret = e4
  return ret;
}
//</smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Link: http://lkml.kernel.org/r/1342284188-19176-7-git-send-email-Julia.Lawall@lip6.fr
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-07-26 15:07:20 +02:00

214 lines
3.9 KiB
C

/*
* Architecture specific debugfs files
*
* Copyright (C) 2007, Intel Corp.
* Huang Ying <ying.huang@intel.com>
*
* This file is released under the GPLv2.
*/
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/stat.h>
#include <linux/io.h>
#include <linux/mm.h>
#include <asm/setup.h>
struct dentry *arch_debugfs_dir;
EXPORT_SYMBOL(arch_debugfs_dir);
#ifdef CONFIG_DEBUG_BOOT_PARAMS
struct setup_data_node {
u64 paddr;
u32 type;
u32 len;
};
static ssize_t setup_data_read(struct file *file, char __user *user_buf,
size_t count, loff_t *ppos)
{
struct setup_data_node *node = file->private_data;
unsigned long remain;
loff_t pos = *ppos;
struct page *pg;
void *p;
u64 pa;
if (pos < 0)
return -EINVAL;
if (pos >= node->len)
return 0;
if (count > node->len - pos)
count = node->len - pos;
pa = node->paddr + sizeof(struct setup_data) + pos;
pg = pfn_to_page((pa + count - 1) >> PAGE_SHIFT);
if (PageHighMem(pg)) {
p = ioremap_cache(pa, count);
if (!p)
return -ENXIO;
} else
p = __va(pa);
remain = copy_to_user(user_buf, p, count);
if (PageHighMem(pg))
iounmap(p);
if (remain)
return -EFAULT;
*ppos = pos + count;
return count;
}
static const struct file_operations fops_setup_data = {
.read = setup_data_read,
.open = simple_open,
.llseek = default_llseek,
};
static int __init
create_setup_data_node(struct dentry *parent, int no,
struct setup_data_node *node)
{
struct dentry *d, *type, *data;
char buf[16];
sprintf(buf, "%d", no);
d = debugfs_create_dir(buf, parent);
if (!d)
return -ENOMEM;
type = debugfs_create_x32("type", S_IRUGO, d, &node->type);
if (!type)
goto err_dir;
data = debugfs_create_file("data", S_IRUGO, d, node, &fops_setup_data);
if (!data)
goto err_type;
return 0;
err_type:
debugfs_remove(type);
err_dir:
debugfs_remove(d);
return -ENOMEM;
}
static int __init create_setup_data_nodes(struct dentry *parent)
{
struct setup_data_node *node;
struct setup_data *data;
int error;
struct dentry *d;
struct page *pg;
u64 pa_data;
int no = 0;
d = debugfs_create_dir("setup_data", parent);
if (!d)
return -ENOMEM;
pa_data = boot_params.hdr.setup_data;
while (pa_data) {
node = kmalloc(sizeof(*node), GFP_KERNEL);
if (!node) {
error = -ENOMEM;
goto err_dir;
}
pg = pfn_to_page((pa_data+sizeof(*data)-1) >> PAGE_SHIFT);
if (PageHighMem(pg)) {
data = ioremap_cache(pa_data, sizeof(*data));
if (!data) {
kfree(node);
error = -ENXIO;
goto err_dir;
}
} else
data = __va(pa_data);
node->paddr = pa_data;
node->type = data->type;
node->len = data->len;
error = create_setup_data_node(d, no, node);
pa_data = data->next;
if (PageHighMem(pg))
iounmap(data);
if (error)
goto err_dir;
no++;
}
return 0;
err_dir:
debugfs_remove(d);
return error;
}
static struct debugfs_blob_wrapper boot_params_blob = {
.data = &boot_params,
.size = sizeof(boot_params),
};
static int __init boot_params_kdebugfs_init(void)
{
struct dentry *dbp, *version, *data;
int error = -ENOMEM;
dbp = debugfs_create_dir("boot_params", NULL);
if (!dbp)
return -ENOMEM;
version = debugfs_create_x16("version", S_IRUGO, dbp,
&boot_params.hdr.version);
if (!version)
goto err_dir;
data = debugfs_create_blob("data", S_IRUGO, dbp,
&boot_params_blob);
if (!data)
goto err_version;
error = create_setup_data_nodes(dbp);
if (error)
goto err_data;
return 0;
err_data:
debugfs_remove(data);
err_version:
debugfs_remove(version);
err_dir:
debugfs_remove(dbp);
return error;
}
#endif /* CONFIG_DEBUG_BOOT_PARAMS */
static int __init arch_kdebugfs_init(void)
{
int error = 0;
arch_debugfs_dir = debugfs_create_dir("x86", NULL);
if (!arch_debugfs_dir)
return -ENOMEM;
#ifdef CONFIG_DEBUG_BOOT_PARAMS
error = boot_params_kdebugfs_init();
#endif
return error;
}
arch_initcall(arch_kdebugfs_init);