acpi: Be more ACPI compliant when generating _UID

* Add function to generate unique _UID using CRC32
* Add function to write the _UID based on a device's ACPI path

ACPI devices that have the same _HID must use different _UID.
Linux doesn't care about _UID if it's not used.
Windows 10 verifies the ACPI code on boot and BSODs if two devices
with the same _HID share the same _UID.

Fixes BSOD seen on Windows 10.

Change-Id: I47cd5396060d325f9ce338afced6af021e7ff2b4
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/37695
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>
This commit is contained in:
Patrick Rudolph 2019-12-13 12:16:06 +01:00 committed by Felix Held
parent 5c8ff794a8
commit c83bab62b3
9 changed files with 48 additions and 5 deletions

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@ -2,6 +2,8 @@
This section contains documentation about coreboot on ACPI.
- [SSDT UID generation](uid.md)
## GPIO
- [GPIO toggling in ACPI AML](gpio.md)

14
Documentation/acpi/uid.md Normal file
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@ -0,0 +1,14 @@
# ACPI SSDT \_UID generation
According to the ACPI spec:
> The _UID must be unique across all devices with either a common _HID or _CID.
When generating SSDTs in coreboot the independent drivers don't know
which \_UID is already in use for a specific \_HID or \_CID. To generate
unique \_UIDs the ACPI device's path is hashed and used as ID. As every ACPI
device has a different path, the hash will be also different for every device.
Windows 10 verifies all devices with the same \_HID or \_CID and makes
sure that no \_UID is duplicated. If it is it'll BSOD.

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@ -18,6 +18,8 @@
#include <device/device.h>
#include <device/path.h>
#include <stdlib.h>
#include <crc_byte.h>
#if CONFIG(GENERIC_GPIO_LIB)
#include <gpio.h>
#endif
@ -98,6 +100,19 @@ const char *acpi_device_hid(const struct device *dev)
return NULL;
}
/*
* Generate unique ID based on the ACPI path.
* Collisions on the same _HID are possible but very unlikely.
*/
uint32_t acpi_device_uid(struct device *dev)
{
const char *path = acpi_device_path(dev);
if (!path)
return 0;
return CRC(path, strlen(path), crc32_byte);
}
/* Recursive function to find the root device and print a path from there */
static ssize_t acpi_device_path_fill(const struct device *dev, char *buf,
size_t buf_len, size_t cur)
@ -192,6 +207,13 @@ int acpi_device_status(const struct device *dev)
return ACPI_STATUS_DEVICE_ALL_ON;
}
/* Write the unique _UID based on ACPI device path. */
void acpi_device_write_uid(struct device *dev)
{
acpigen_write_name_integer("_UID", acpi_device_uid(dev));
}
/* ACPI 6.1 section 6.4.3.6: Extended Interrupt Descriptor */
void acpi_device_write_interrupt(const struct acpi_irq *irq)
{

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@ -62,10 +62,12 @@ struct acpi_dp {
struct device;
const char *acpi_device_name(const struct device *dev);
const char *acpi_device_hid(const struct device *dev);
uint32_t acpi_device_uid(struct device *dev);
const char *acpi_device_path(const struct device *dev);
const char *acpi_device_scope(const struct device *dev);
const char *acpi_device_path_join(const struct device *dev, const char *name);
int acpi_device_status(const struct device *dev);
void acpi_device_write_uid(struct device *dev);
/*
* ACPI Descriptor for extended Interrupt()

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@ -117,7 +117,7 @@ static void crb_tpm_fill_ssdt(struct device *dev)
acpigen_write_name_string("_HID", "MSFT0101");
acpigen_write_name_string("_CID", "MSFT0101");
acpigen_write_name_integer("_UID", 1);
acpi_device_write_uid(dev);
acpigen_write_STA(ACPI_STATUS_DEVICE_ALL_ON);

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@ -312,7 +312,8 @@ static void r8168_net_fill_ssdt(struct device *dev)
acpigen_write_scope(path);
acpigen_write_device(acpi_device_name(dev));
acpigen_write_name_string("_HID", R8168_ACPI_HID);
acpigen_write_name_integer("_UID", 0);
acpi_device_write_uid(dev);
if (dev->chip_ops)
acpigen_write_name_string("_DDN", dev->chip_ops->name);

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@ -902,7 +902,7 @@ static void lpc_tpm_fill_ssdt(struct device *dev)
acpigen_write_name("_CID");
acpigen_emit_eisaid("PNP0C31");
acpigen_write_name_integer("_UID", 1);
acpi_device_write_uid(dev);
u32 did_vid = tpm_read_did_vid(0);
if (did_vid > 0 && did_vid < 0xffffffff)

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@ -187,7 +187,8 @@ void generic_wifi_fill_ssdt(struct device *dev,
/* Device */
acpigen_write_scope(path);
acpigen_write_device(acpi_device_name(dev));
acpigen_write_name_integer("_UID", 0);
acpi_device_write_uid(dev);
if (dev->chip_ops)
acpigen_write_name_string("_DDN", dev->chip_ops->name);

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@ -196,7 +196,8 @@ void superio_common_fill_ssdt_generator(struct device *dev)
/* Device */
acpigen_write_device(name);
acpigen_write_name_byte("_UID", 0);
acpi_device_write_uid(dev);
acpigen_write_name_byte("LDN", ldn);
acpigen_write_name_byte("VLDN", vldn);