From b22da3d8526a935aa31e086e63f60ff3246cb61c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Sat, 09 Dec 2023 07:24:11 +0000
Subject: [PATCH] add stmac read mac form eeprom
---
kernel/drivers/char/mem.c | 150 +++++++++++++++++++++++++++++++++++++++++++++++---
1 files changed, 141 insertions(+), 9 deletions(-)
diff --git a/kernel/drivers/char/mem.c b/kernel/drivers/char/mem.c
index 54b8649..7d483c3 100644
--- a/kernel/drivers/char/mem.c
+++ b/kernel/drivers/char/mem.c
@@ -29,13 +29,17 @@
#include <linux/export.h>
#include <linux/io.h>
#include <linux/uio.h>
-
#include <linux/uaccess.h>
+#include <linux/security.h>
+#include <linux/pseudo_fs.h>
+#include <uapi/linux/magic.h>
+#include <linux/mount.h>
#ifdef CONFIG_IA64
# include <linux/efi.h>
#endif
+#define DEVMEM_MINOR 1
#define DEVPORT_MINOR 4
static inline unsigned long size_inside_page(unsigned long start,
@@ -167,7 +171,7 @@
if (!ptr)
goto failed;
- probe = probe_kernel_read(bounce, ptr, sz);
+ probe = copy_from_kernel_nofault(bounce, ptr, sz);
unxlate_dev_mem_ptr(p, ptr);
if (probe)
goto failed;
@@ -630,7 +634,7 @@
unsigned long i = *ppos;
char __user *tmp = buf;
- if (!access_ok(VERIFY_WRITE, buf, count))
+ if (!access_ok(buf, count))
return -EFAULT;
while (count-- > 0 && i < 65536) {
if (__put_user(inb(i), tmp) < 0)
@@ -648,7 +652,7 @@
unsigned long i = *ppos;
const char __user *tmp = buf;
- if (!access_ok(VERIFY_READ, buf, count))
+ if (!access_ok(buf, count))
return -EFAULT;
while (count-- > 0 && i < 65536) {
char c;
@@ -722,6 +726,33 @@
return written;
}
+static ssize_t read_zero(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ size_t cleared = 0;
+
+ while (count) {
+ size_t chunk = min_t(size_t, count, PAGE_SIZE);
+ size_t left;
+
+ left = clear_user(buf + cleared, chunk);
+ if (unlikely(left)) {
+ cleared += (chunk - left);
+ if (!cleared)
+ return -EFAULT;
+ break;
+ }
+ cleared += chunk;
+ count -= chunk;
+
+ if (signal_pending(current))
+ break;
+ cond_resched();
+ }
+
+ return cleared;
+}
+
static int mmap_zero(struct file *file, struct vm_area_struct *vma)
{
#ifndef CONFIG_MMU
@@ -787,7 +818,7 @@
switch (orig) {
case SEEK_CUR:
offset += file->f_pos;
- /* fall through */
+ fallthrough;
case SEEK_SET:
/* to avoid userland mistaking f_pos=-9 as -EBADF=-9 */
if ((unsigned long long)offset >= -MAX_ERRNO) {
@@ -805,9 +836,65 @@
return ret;
}
+static struct inode *devmem_inode;
+
+#ifdef CONFIG_IO_STRICT_DEVMEM
+void revoke_devmem(struct resource *res)
+{
+ /* pairs with smp_store_release() in devmem_init_inode() */
+ struct inode *inode = smp_load_acquire(&devmem_inode);
+
+ /*
+ * Check that the initialization has completed. Losing the race
+ * is ok because it means drivers are claiming resources before
+ * the fs_initcall level of init and prevent /dev/mem from
+ * establishing mappings.
+ */
+ if (!inode)
+ return;
+
+ /*
+ * The expectation is that the driver has successfully marked
+ * the resource busy by this point, so devmem_is_allowed()
+ * should start returning false, however for performance this
+ * does not iterate the entire resource range.
+ */
+ if (devmem_is_allowed(PHYS_PFN(res->start)) &&
+ devmem_is_allowed(PHYS_PFN(res->end))) {
+ /*
+ * *cringe* iomem=relaxed says "go ahead, what's the
+ * worst that can happen?"
+ */
+ return;
+ }
+
+ unmap_mapping_range(inode->i_mapping, res->start, resource_size(res), 1);
+}
+#endif
+
static int open_port(struct inode *inode, struct file *filp)
{
- return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
+ int rc;
+
+ if (!capable(CAP_SYS_RAWIO))
+ return -EPERM;
+
+ rc = security_locked_down(LOCKDOWN_DEV_MEM);
+ if (rc)
+ return rc;
+
+ if (iminor(inode) != DEVMEM_MINOR)
+ return 0;
+
+ /*
+ * Use a unified address space to have a single point to manage
+ * revocations when drivers want to take over a /dev/mem mapped
+ * range.
+ */
+ inode->i_mapping = devmem_inode->i_mapping;
+ filp->f_mapping = inode->i_mapping;
+
+ return 0;
}
#define zero_lseek null_lseek
@@ -861,6 +948,7 @@
.llseek = zero_lseek,
.write = write_zero,
.read_iter = read_iter_zero,
+ .read = read_zero,
.write_iter = write_iter_zero,
.mmap = mmap_zero,
.get_unmapped_area = get_unmapped_area_zero,
@@ -882,7 +970,7 @@
fmode_t fmode;
} devlist[] = {
#ifdef CONFIG_DEVMEM
- [1] = { "mem", 0, &mem_fops, FMODE_UNSIGNED_OFFSET },
+ [DEVMEM_MINOR] = { "mem", 0, &mem_fops, FMODE_UNSIGNED_OFFSET },
#endif
#ifdef CONFIG_DEVKMEM
[2] = { "kmem", 0, &kmem_fops, FMODE_UNSIGNED_OFFSET },
@@ -893,8 +981,8 @@
#endif
[5] = { "zero", 0666, &zero_fops, 0 },
[7] = { "full", 0666, &full_fops, 0 },
- [8] = { "random", 0666, &random_fops, 0 },
- [9] = { "urandom", 0666, &urandom_fops, 0 },
+ [8] = { "random", 0666, &random_fops, FMODE_NOWAIT },
+ [9] = { "urandom", 0666, &urandom_fops, FMODE_NOWAIT },
#ifdef CONFIG_PRINTK
[11] = { "kmsg", 0644, &kmsg_fops, 0 },
#endif
@@ -936,6 +1024,48 @@
static struct class *mem_class;
+static int devmem_fs_init_fs_context(struct fs_context *fc)
+{
+ return init_pseudo(fc, DEVMEM_MAGIC) ? 0 : -ENOMEM;
+}
+
+static struct file_system_type devmem_fs_type = {
+ .name = "devmem",
+ .owner = THIS_MODULE,
+ .init_fs_context = devmem_fs_init_fs_context,
+ .kill_sb = kill_anon_super,
+};
+
+static int devmem_init_inode(void)
+{
+ static struct vfsmount *devmem_vfs_mount;
+ static int devmem_fs_cnt;
+ struct inode *inode;
+ int rc;
+
+ rc = simple_pin_fs(&devmem_fs_type, &devmem_vfs_mount, &devmem_fs_cnt);
+ if (rc < 0) {
+ pr_err("Cannot mount /dev/mem pseudo filesystem: %d\n", rc);
+ return rc;
+ }
+
+ inode = alloc_anon_inode(devmem_vfs_mount->mnt_sb);
+ if (IS_ERR(inode)) {
+ rc = PTR_ERR(inode);
+ pr_err("Cannot allocate inode for /dev/mem: %d\n", rc);
+ simple_release_fs(&devmem_vfs_mount, &devmem_fs_cnt);
+ return rc;
+ }
+
+ /*
+ * Publish /dev/mem initialized.
+ * Pairs with smp_load_acquire() in revoke_devmem().
+ */
+ smp_store_release(&devmem_inode, inode);
+
+ return 0;
+}
+
static int __init chr_dev_init(void)
{
int minor;
@@ -957,6 +1087,8 @@
*/
if ((minor == DEVPORT_MINOR) && !arch_has_dev_port())
continue;
+ if ((minor == DEVMEM_MINOR) && devmem_init_inode() != 0)
+ continue;
device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor),
NULL, devlist[minor].name);
--
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