2014-01-28 13:06:27

by Michel Lespinasse

[permalink] [raw]
Subject: [PATCH 0/2] Google firmware driver updates

Two small fixes for google firmware drivers.

The patches are against v3.13; I am proposing this for inclusion to v3.14.

Michel Lespinasse (2):
firmware: fix google/gsmi duplicate efivars_sysfs_init()
drivers-firmware: google memconsole driver fixes

drivers/firmware/google/gsmi.c | 7 ------
drivers/firmware/google/memconsole.c | 47 ++++++++++++++++++++----------------
2 files changed, 26 insertions(+), 28 deletions(-)

--
1.8.5.3


2014-01-28 13:06:30

by Michel Lespinasse

[permalink] [raw]
Subject: [PATCH 1/2] firmware: fix google/gsmi duplicate efivars_sysfs_init()

Starting in commit e14ab23dde12b80db4c94b684a2e485b72b16af3,
efivars_sysfs_init() is called both by itself as an init function,
and by drivers/firmware/google/gsmi.c gsmi_init().

This results in runtime warnings such as the following:
[ 5.651330] WARNING: at fs/sysfs/dir.c:530 sysfs_add_one+0xbd/0xe0()
[ 5.657699] sysfs: cannot create duplicate filename '/firmware/gsmi/vars'

Fixing this by removing the redundant efivars_sysfs_init() call in
gsmi_init().

Tested: booted, checked that /firmware/gsmi/vars was still present and
showed the expected contents.

Signed-off-by: Michel Lespinasse <[email protected]>
---
drivers/firmware/google/gsmi.c | 7 -------
1 file changed, 7 deletions(-)

diff --git a/drivers/firmware/google/gsmi.c b/drivers/firmware/google/gsmi.c
index e5a67b24587a..f1ab05ea56bb 100644
--- a/drivers/firmware/google/gsmi.c
+++ b/drivers/firmware/google/gsmi.c
@@ -892,13 +892,6 @@ static __init int gsmi_init(void)
goto out_remove_sysfs_files;
}

- ret = efivars_sysfs_init();
- if (ret) {
- printk(KERN_INFO "gsmi: Failed to create efivars files\n");
- efivars_unregister(&efivars);
- goto out_remove_sysfs_files;
- }
-
register_reboot_notifier(&gsmi_reboot_notifier);
register_die_notifier(&gsmi_die_notifier);
atomic_notifier_chain_register(&panic_notifier_list,
--
1.8.5.3

2014-01-28 13:06:45

by Michel Lespinasse

[permalink] [raw]
Subject: [PATCH 2/2] drivers-firmware: google memconsole driver fixes

The google memconsole driver is currently broken upstream, as it tries
to read memory that is described as reserved in /proc/iomem, by
dereferencing a pointer obtained through phys_to_virt(). This triggers
a kernel fault as such regions are unmapped after early boot.

The proper workaround is to use ioremap_cache() / iounmap() around such
accesses.

As some unrelated changes, I also converted some printks to use pr_info()
and added some missing __init annotations.

Tested: booted dbg build, verified I could read /sys/firmware/log

Signed-off-by: Michel Lespinasse <[email protected]>
---
drivers/firmware/google/memconsole.c | 47 ++++++++++++++++++++----------------
1 file changed, 26 insertions(+), 21 deletions(-)

diff --git a/drivers/firmware/google/memconsole.c b/drivers/firmware/google/memconsole.c
index 2a90ba613613..2f569aaed4c7 100644
--- a/drivers/firmware/google/memconsole.c
+++ b/drivers/firmware/google/memconsole.c
@@ -15,6 +15,7 @@
#include <linux/kobject.h>
#include <linux/module.h>
#include <linux/dmi.h>
+#include <linux/io.h>
#include <asm/bios_ebda.h>

#define BIOS_MEMCONSOLE_V1_MAGIC 0xDEADBABE
@@ -41,15 +42,25 @@ struct biosmemcon_ebda {
};
} __packed;

-static char *memconsole_baseaddr;
+static u32 memconsole_baseaddr;
static size_t memconsole_length;

static ssize_t memconsole_read(struct file *filp, struct kobject *kobp,
struct bin_attribute *bin_attr, char *buf,
loff_t pos, size_t count)
{
- return memory_read_from_buffer(buf, count, &pos, memconsole_baseaddr,
- memconsole_length);
+ char *memconsole;
+ ssize_t ret;
+
+ memconsole = ioremap_cache(memconsole_baseaddr, memconsole_length);
+ if (!memconsole) {
+ pr_err("memconsole: ioremap_cache failed\n");
+ return -ENOMEM;
+ }
+ ret = memory_read_from_buffer(buf, count, &pos, memconsole,
+ memconsole_length);
+ iounmap(memconsole);
+ return ret;
}

static struct bin_attribute memconsole_bin_attr = {
@@ -58,43 +69,42 @@ static struct bin_attribute memconsole_bin_attr = {
};


-static void found_v1_header(struct biosmemcon_ebda *hdr)
+static void __init found_v1_header(struct biosmemcon_ebda *hdr)
{
- printk(KERN_INFO "BIOS console v1 EBDA structure found at %p\n", hdr);
- printk(KERN_INFO "BIOS console buffer at 0x%.8x, "
+ pr_info("BIOS console v1 EBDA structure found at %p\n", hdr);
+ pr_info("BIOS console buffer at 0x%.8x, "
"start = %d, end = %d, num = %d\n",
hdr->v1.buffer_addr, hdr->v1.start,
hdr->v1.end, hdr->v1.num_chars);

memconsole_length = hdr->v1.num_chars;
- memconsole_baseaddr = phys_to_virt(hdr->v1.buffer_addr);
+ memconsole_baseaddr = hdr->v1.buffer_addr;
}

-static void found_v2_header(struct biosmemcon_ebda *hdr)
+static void __init found_v2_header(struct biosmemcon_ebda *hdr)
{
- printk(KERN_INFO "BIOS console v2 EBDA structure found at %p\n", hdr);
- printk(KERN_INFO "BIOS console buffer at 0x%.8x, "
+ pr_info("BIOS console v2 EBDA structure found at %p\n", hdr);
+ pr_info("BIOS console buffer at 0x%.8x, "
"start = %d, end = %d, num_bytes = %d\n",
hdr->v2.buffer_addr, hdr->v2.start,
hdr->v2.end, hdr->v2.num_bytes);

memconsole_length = hdr->v2.end - hdr->v2.start;
- memconsole_baseaddr = phys_to_virt(hdr->v2.buffer_addr
- + hdr->v2.start);
+ memconsole_baseaddr = hdr->v2.buffer_addr + hdr->v2.start;
}

/*
* Search through the EBDA for the BIOS Memory Console, and
* set the global variables to point to it. Return true if found.
*/
-static bool found_memconsole(void)
+static bool __init found_memconsole(void)
{
unsigned int address;
size_t length, cur;

address = get_bios_ebda();
if (!address) {
- printk(KERN_INFO "BIOS EBDA non-existent.\n");
+ pr_info("BIOS EBDA non-existent.\n");
return false;
}

@@ -122,7 +132,7 @@ static bool found_memconsole(void)
}
}

- printk(KERN_INFO "BIOS console EBDA structure not found!\n");
+ pr_info("BIOS console EBDA structure not found!\n");
return false;
}

@@ -139,8 +149,6 @@ MODULE_DEVICE_TABLE(dmi, memconsole_dmi_table);

static int __init memconsole_init(void)
{
- int ret;
-
if (!dmi_check_system(memconsole_dmi_table))
return -ENODEV;

@@ -148,10 +156,7 @@ static int __init memconsole_init(void)
return -ENODEV;

memconsole_bin_attr.size = memconsole_length;
-
- ret = sysfs_create_bin_file(firmware_kobj, &memconsole_bin_attr);
-
- return ret;
+ return sysfs_create_bin_file(firmware_kobj, &memconsole_bin_attr);
}

static void __exit memconsole_exit(void)
--
1.8.5.3

2014-01-28 18:36:32

by Mike Waychison

[permalink] [raw]
Subject: Re: [PATCH 0/2] Google firmware driver updates

Thanks Michel!

Acked-by: Mike Waychison <[email protected]>

On Tue, Jan 28, 2014 at 5:06 AM, Michel Lespinasse <[email protected]> wrote:
> Two small fixes for google firmware drivers.
>
> The patches are against v3.13; I am proposing this for inclusion to v3.14.
>
> Michel Lespinasse (2):
> firmware: fix google/gsmi duplicate efivars_sysfs_init()
> drivers-firmware: google memconsole driver fixes
>
> drivers/firmware/google/gsmi.c | 7 ------
> drivers/firmware/google/memconsole.c | 47 ++++++++++++++++++++----------------
> 2 files changed, 26 insertions(+), 28 deletions(-)
>
> --
> 1.8.5.3
>

2014-01-31 09:46:23

by Matt Fleming

[permalink] [raw]
Subject: Re: [PATCH 1/2] firmware: fix google/gsmi duplicate efivars_sysfs_init()

On Tue, 28 Jan, at 05:06:21AM, Michel Lespinasse wrote:
> Starting in commit e14ab23dde12b80db4c94b684a2e485b72b16af3,
> efivars_sysfs_init() is called both by itself as an init function,
> and by drivers/firmware/google/gsmi.c gsmi_init().
>
> This results in runtime warnings such as the following:
> [ 5.651330] WARNING: at fs/sysfs/dir.c:530 sysfs_add_one+0xbd/0xe0()
> [ 5.657699] sysfs: cannot create duplicate filename '/firmware/gsmi/vars'
>
> Fixing this by removing the redundant efivars_sysfs_init() call in
> gsmi_init().
>
> Tested: booted, checked that /firmware/gsmi/vars was still present and
> showed the expected contents.
>
> Signed-off-by: Michel Lespinasse <[email protected]>
> ---
> drivers/firmware/google/gsmi.c | 7 -------
> 1 file changed, 7 deletions(-)

Oops, my bad.

(If it matters: Acked-by: Matt Fleming <[email protected]>)

--
Matt Fleming, Intel Open Source Technology Center