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authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-04-18 22:28:28 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-04-18 22:28:28 +0300
commit5614e7725856ea383f458377980298111439e0fb (patch)
tree82560034c3a17ee18073420406ba1228935e2967 /drivers/firmware/qemu_fw_cfg.c
parent522566376a3f8373fbd5ff75bb8a7a2da701c1a7 (diff)
parentc3b46c73264b03000d1e18b22f5caf63332547c9 (diff)
downloadlinux-5614e7725856ea383f458377980298111439e0fb.tar.xz
Merge 4.6-rc4 into driver-core-next
We want those fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/firmware/qemu_fw_cfg.c')
-rw-r--r--drivers/firmware/qemu_fw_cfg.c24
1 files changed, 23 insertions, 1 deletions
diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
index 7bba76c0206c..d999fe3b1de6 100644
--- a/drivers/firmware/qemu_fw_cfg.c
+++ b/drivers/firmware/qemu_fw_cfg.c
@@ -77,12 +77,28 @@ static inline u16 fw_cfg_sel_endianness(u16 key)
static inline void fw_cfg_read_blob(u16 key,
void *buf, loff_t pos, size_t count)
{
+ u32 glk;
+ acpi_status status;
+
+ /* If we have ACPI, ensure mutual exclusion against any potential
+ * device access by the firmware, e.g. via AML methods:
+ */
+ status = acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk);
+ if (ACPI_FAILURE(status) && status != AE_NOT_CONFIGURED) {
+ /* Should never get here */
+ WARN(1, "fw_cfg_read_blob: Failed to lock ACPI!\n");
+ memset(buf, 0, count);
+ return;
+ }
+
mutex_lock(&fw_cfg_dev_lock);
iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl);
while (pos-- > 0)
ioread8(fw_cfg_reg_data);
ioread8_rep(fw_cfg_reg_data, buf, count);
mutex_unlock(&fw_cfg_dev_lock);
+
+ acpi_release_global_lock(glk);
}
/* clean up fw_cfg device i/o */
@@ -725,12 +741,18 @@ device_param_cb(mmio, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR);
static int __init fw_cfg_sysfs_init(void)
{
+ int ret;
+
/* create /sys/firmware/qemu_fw_cfg/ top level directory */
fw_cfg_top_ko = kobject_create_and_add("qemu_fw_cfg", firmware_kobj);
if (!fw_cfg_top_ko)
return -ENOMEM;
- return platform_driver_register(&fw_cfg_sysfs_driver);
+ ret = platform_driver_register(&fw_cfg_sysfs_driver);
+ if (ret)
+ fw_cfg_kobj_cleanup(fw_cfg_top_ko);
+
+ return ret;
}
static void __exit fw_cfg_sysfs_exit(void)