From: Andrey Smirnov <andrew.smirnov@gmail.com>
To: barebox@lists.infradead.org
Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Subject: [PATCH v2 18/19] drivers: mem: Create file to access second half of 64-bit memory
Date: Mon, 28 Jan 2019 22:55:48 -0800 [thread overview]
Message-ID: <20190129065549.29161-19-andrew.smirnov@gmail.com> (raw)
In-Reply-To: <20190129065549.29161-1-andrew.smirnov@gmail.com>
In order to allow access to second half of address space on 64-bit
machines, add code that creates /dev/highmem dedicated for that.
Note that due to maximum file size being limited to MAX_LFS_FILESIZE
or 0x7fff_ffff_ffff_ffff bytes at addresses 0x7fff_ffff_ffff_ffff and
0xffff_ffff_ffff_ffff cannot be access through /dev/mem and
/dev/hightmem correspondingly.
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
---
drivers/misc/mem.c | 23 ++++++++++++++++++++---
1 file changed, 20 insertions(+), 3 deletions(-)
diff --git a/drivers/misc/mem.c b/drivers/misc/mem.c
index 2f3316307..e3fb0d04a 100644
--- a/drivers/misc/mem.c
+++ b/drivers/misc/mem.c
@@ -7,6 +7,10 @@
#include <driver.h>
#include <init.h>
+#include <linux/pagemap.h>
+#include <linux/fs.h>
+
+
static struct cdev_operations memops = {
.read = mem_read_nofail,
.write = mem_write,
@@ -21,8 +25,7 @@ static int mem_probe(struct device_d *dev)
dev->priv = cdev;
cdev->name = (char*)dev->resource[0].name;
- cdev->size = min_t(unsigned long long, resource_size(&dev->resource[0]),
- S64_MAX);
+ cdev->size = resource_size(&dev->resource[0]);
cdev->ops = &memops;
cdev->dev = dev;
@@ -38,7 +41,21 @@ static struct driver_d mem_drv = {
static int mem_init(void)
{
- add_mem_device("mem", 0, ~0, IORESOURCE_MEM_WRITEABLE);
+ const resource_size_t size = min_t(unsigned long long,
+ MAX_LFS_FILESIZE,
+ (resource_size_t)~0);
+ add_mem_device("mem", 0, size, IORESOURCE_MEM_WRITEABLE);
+ /*
+ * We can't fit all of 64-bit address space into a single
+ * file, so we create a separate one to allow acces to the
+ * second half
+ */
+ if (IS_ENABLED(CONFIG_CPU_64))
+ add_mem_device("highmem",
+ (resource_size_t)MAX_LFS_FILESIZE + 1,
+ size,
+ IORESOURCE_MEM_WRITEABLE);
+
return platform_driver_register(&mem_drv);
}
device_initcall(mem_init);
--
2.20.1
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next prev parent reply other threads:[~2019-01-29 6:56 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-29 6:55 [PATCH v2 00/19] 32-bit lseek and /dev/mem fixes/improvements Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 01/19] commands: Move mem_parse_options() to lib/misc.c Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 02/19] commands: Get rid of mem_rw_buf Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 03/19] commands: Move /dev/mem driver to drivers/misc Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 04/19] nvmem: Do not use DEVFS_IS_CHARACTER_DEV Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 05/19] common: firmware: Don't use FILE_SIZE_STREAM directly Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 06/19] devfs: Fix incorrect error check for cdev->ops->lseek() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 07/19] fs: Update FILE position in lseek() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 08/19] fs: Drop trivial .lseek() implementaitons in FS drivers Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 09/19] devfs: Drop dev_lseek_default() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 10/19] fs: devfs: Change .lseek callbacks to return 'int' Andrey Smirnov
2019-02-04 14:32 ` Sascha Hauer
2019-01-29 6:55 ` [PATCH v2 11/19] fs: Do not use IS_ERR_VALUE() to validate offset in lseek() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 12/19] fs: Simplify new position calculation " Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 13/19] fs: Share code between mem_write()/mem_read() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 14/19] fs: Avoid division in mem_copy() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 15/19] fs: Report actual data processed by mem_copy() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 16/19] fs: Introduce mem_read_nofail() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 17/19] commands: md: Do not use memmap() Andrey Smirnov
2019-02-04 13:57 ` Sascha Hauer
2019-02-04 19:35 ` Andrey Smirnov
2019-01-29 6:55 ` Andrey Smirnov [this message]
2019-01-29 8:48 ` [PATCH v2 18/19] drivers: mem: Create file to access second half of 64-bit memory Sascha Hauer
2019-01-29 20:40 ` Andrey Smirnov
2019-01-29 21:09 ` Sam Ravnborg
2019-01-31 10:54 ` Peter Mamonov
2019-01-31 12:50 ` Peter Mamonov
2019-02-01 7:47 ` Sascha Hauer
2019-02-01 10:25 ` Peter Mamonov
2019-02-02 1:07 ` Andrey Smirnov
2019-02-02 0:35 ` Andrey Smirnov
2019-02-04 7:40 ` Sascha Hauer
2019-01-31 20:17 ` Andrey Smirnov
2019-02-01 10:14 ` Peter Mamonov
2019-01-29 6:55 ` [PATCH v2 19/19] libfile: Fix incorrect lseek check in open_and_lseek() Andrey Smirnov
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