* [PATCH v4 3/4] x86/efi: Retrieve and assign Apple device properties
[not found] ` <cover.1478506920.git.lukas-JFq808J9C/izQB+pC5nmwQ@public.gmane.org>
@ 2016-11-07 10:09 ` Lukas Wunner
2016-11-07 10:09 ` [PATCH v4 1/4] efi: Add device path parser Lukas Wunner
` (3 subsequent siblings)
4 siblings, 0 replies; 7+ messages in thread
From: Lukas Wunner @ 2016-11-07 10:09 UTC (permalink / raw)
To: linux-efi-u79uwXL29TY76Z2rM5mHXA, Matt Fleming
Cc: Andreas Noever, Peter Jones, Ard Biesheuvel
Apple's EFI drivers supply device properties which are needed to support
Macs optimally. They contain vital information which cannot be obtained
any other way (e.g. Thunderbolt Device ROM). They're also used to convey
the current device state so that OS drivers can pick up where EFI
drivers left (e.g. GPU mode setting).
There's an EFI driver dubbed "AAPL,PathProperties" which implements a
per-device key/value store. Other EFI drivers populate it using a custom
protocol. The macOS bootloader /System/Library/CoreServices/boot.efi
retrieves the properties with the same protocol. The kernel extension
AppleACPIPlatform.kext subsequently merges them into the I/O Kit
registry (see ioreg(8)) where they can be queried by other kernel
extensions and user space.
This commit extends the efistub to retrieve the device properties before
ExitBootServices is called. It assigns them to devices in an fs_initcall
so that they can be queried with the API in <linux/property.h>.
Note that the device properties will only be available if the kernel is
booted with the efistub. Distros should adjust their installers to
always use the efistub on Macs. grub with the "linux" directive will not
work unless the functionality of this commit is duplicated in grub.
(The "linuxefi" directive should work but is not included upstream as of
this writing.)
The custom protocol has GUID 91BD12FE-F6C3-44FB-A5B7-5122AB303AE0 and
looks like this:
typedef struct {
unsigned long version; /* 0x10000 */
efi_status_t (*get) (
IN struct apple_properties_protocol *this,
IN struct efi_dev_path *device,
IN efi_char16_t *property_name,
OUT void *buffer,
IN OUT u32 *buffer_len);
/* EFI_SUCCESS, EFI_NOT_FOUND, EFI_BUFFER_TOO_SMALL */
efi_status_t (*set) (
IN struct apple_properties_protocol *this,
IN struct efi_dev_path *device,
IN efi_char16_t *property_name,
IN void *property_value,
IN u32 property_value_len);
/* allocates copies of property name and value */
/* EFI_SUCCESS, EFI_OUT_OF_RESOURCES */
efi_status_t (*del) (
IN struct apple_properties_protocol *this,
IN struct efi_dev_path *device,
IN efi_char16_t *property_name);
/* EFI_SUCCESS, EFI_NOT_FOUND */
efi_status_t (*get_all) (
IN struct apple_properties_protocol *this,
OUT void *buffer,
IN OUT u32 *buffer_len);
/* EFI_SUCCESS, EFI_BUFFER_TOO_SMALL */
} apple_properties_protocol;
Thanks to Pedro Vilaça for this blog post which was helpful in reverse
engineering Apple's EFI drivers and bootloader:
https://reverse.put.as/2016/06/25/apple-efi-firmware-passwords-and-the-scbo-myth/
If someone at Apple is reading this, please note there's a memory leak
in your implementation of the del() function as the property struct is
freed but the name and value allocations are not.
Neither the macOS bootloader nor Apple's EFI drivers check the protocol
version, but we do to avoid breakage if it's ever changed. It's been the
same since at least OS X 10.6 (2009).
The get_all() function conveniently fills a buffer with all properties
in marshalled form which can be passed to the kernel as a setup_data
payload. The number of device properties is dynamic and can change
between a first invocation of get_all() (to determine the buffer size)
and a second invocation (to retrieve the actual buffer), hence the
peculiar loop which does not finish until the buffer size settles.
The macOS bootloader does the same.
The setup_data payload is later on unmarshalled in an fs_initcall. The
idea is that most buses instantiate devices in "subsys" initcall level
and drivers are usually bound to these devices in "device" initcall
level, so we assign the properties in-between, i.e. in "fs" initcall
level.
This assumes that devices to which properties pertain are instantiated
from a "subsys" initcall or earlier. That should always be the case
since on macOS, AppleACPIPlatformExpert::matchEFIDevicePath() only
supports ACPI and PCI nodes and we've fully scanned those buses during
"subsys" initcall level.
The second assumption is that properties are only needed from a "device"
initcall or later. Seems reasonable to me, but should this ever not work
out, an alternative approach would be to store the property sets e.g. in
a btree early during boot. Then whenever device_add() is called, an EFI
Device Path would have to be constructed for the newly added device,
and looked up in the btree. That way, the property set could be assigned
to the device immediately on instantiation. And this would also work for
devices instantiated in a deferred fashion. It seems like this approach
would be more complicated and require more code. That doesn't seem
justified without a specific use case.
For comparison, the strategy on macOS is to assign properties to objects
in the ACPI namespace (AppleACPIPlatformExpert::mergeEFIProperties()).
That approach is definitely wrong as it fails for devices not present in
the namespace: The NHI EFI driver supplies properties for attached
Thunderbolt devices, yet on Macs with Thunderbolt 1 only one device
level behind the host controller is described in the namespace.
Consequently macOS cannot assign properties for chained devices. With
Thunderbolt 2 they started to describe three device levels behind host
controllers in the namespace but this grossly inflates the SSDT and
still fails if the user daisy-chained more than three devices.
We copy the property names and values from the setup_data payload to
swappable virtual memory and afterwards make the payload available to
the page allocator. This is just for the sake of good housekeeping, it
wouldn't occupy a meaningful amount of physical memory (4444 bytes on my
machine). Only the payload is freed, not the setup_data header since
otherwise we'd break the list linkage and we cannot safely update the
predecessor's ->next link because there's no locking for the list.
The payload is currently not passed on to kexec'ed kernels, same for PCI
ROMs retrieved by setup_efi_pci(). This can be added later if there is
demand by amending setup_efi_state(). The payload can then no longer be
made available to the page allocator of course.
Cc: grub-devel-mXXj517/zsQ@public.gmane.org
Cc: Pedro Vilaça <reverser-P1ImLx+pFc0@public.gmane.org>
Cc: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
Cc: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Cc: Andreas Noever <andreas.noever-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Tested-by: Lukas Wunner <lukas-JFq808J9C/izQB+pC5nmwQ@public.gmane.org> [MacBookPro9,1]
Tested-by: Pierre Moreau <pierre.morrow-GANU6spQydw@public.gmane.org> [MacBookPro11,3]
Signed-off-by: Lukas Wunner <lukas-JFq808J9C/izQB+pC5nmwQ@public.gmane.org>
---
Documentation/kernel-parameters.txt | 5 +
arch/x86/boot/compressed/eboot.c | 65 +++++++++
arch/x86/include/uapi/asm/bootparam.h | 1 +
drivers/firmware/efi/Kconfig | 13 ++
drivers/firmware/efi/Makefile | 1 +
drivers/firmware/efi/apple-properties.c | 248 ++++++++++++++++++++++++++++++++
include/linux/efi.h | 17 +++
7 files changed, 350 insertions(+)
create mode 100644 drivers/firmware/efi/apple-properties.c
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 37babf9..86a31df 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1062,6 +1062,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
dscc4.setup= [NET]
+ dump_apple_properties [X86]
+ Dump name and content of EFI device properties on
+ x86 Macs. Useful for driver authors to determine
+ what data is available or for reverse-engineering.
+
dyndbg[="val"] [KNL,DYNAMIC_DEBUG]
module.dyndbg[="val"]
Enable debug messages at boot time. See
diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index cc69e37..ff01c8f 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -537,6 +537,69 @@ free_handle:
efi_call_early(free_pool, pci_handle);
}
+static void retrieve_apple_device_properties(struct boot_params *boot_params)
+{
+ efi_guid_t guid = APPLE_PROPERTIES_PROTOCOL_GUID;
+ struct setup_data *data, *new;
+ efi_status_t status;
+ u32 size = 0;
+ void *p;
+
+ status = efi_call_early(locate_protocol, &guid, NULL, &p);
+ if (status != EFI_SUCCESS)
+ return;
+
+ if (efi_table_attr(apple_properties_protocol, version, p) != 0x10000) {
+ efi_printk(sys_table, "Unsupported properties proto version\n");
+ return;
+ }
+
+ efi_call_proto(apple_properties_protocol, get_all, p, NULL, &size);
+ if (!size)
+ return;
+
+ do {
+ status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
+ size + sizeof(struct setup_data), &new);
+ if (status != EFI_SUCCESS) {
+ efi_printk(sys_table,
+ "Failed to alloc mem for properties\n");
+ return;
+ }
+
+ status = efi_call_proto(apple_properties_protocol, get_all, p,
+ new->data, &size);
+
+ if (status == EFI_BUFFER_TOO_SMALL)
+ efi_call_early(free_pool, new);
+ } while (status == EFI_BUFFER_TOO_SMALL);
+
+ new->type = SETUP_APPLE_PROPERTIES;
+ new->len = size;
+ new->next = 0;
+
+ data = (struct setup_data *)(unsigned long)boot_params->hdr.setup_data;
+ if (!data)
+ boot_params->hdr.setup_data = (unsigned long)new;
+ else {
+ while (data->next)
+ data = (struct setup_data *)(unsigned long)data->next;
+ data->next = (unsigned long)new;
+ }
+}
+
+static void setup_quirks(struct boot_params *boot_params)
+{
+ efi_char16_t const apple[] = { 'A', 'p', 'p', 'l', 'e', 0 };
+ efi_char16_t *fw_vendor = (efi_char16_t *)(unsigned long)
+ efi_table_attr(efi_system_table, fw_vendor, sys_table);
+
+ if (!memcmp(fw_vendor, apple, sizeof(apple))) {
+ if (IS_ENABLED(CONFIG_APPLE_PROPERTIES))
+ retrieve_apple_device_properties(boot_params);
+ }
+}
+
static efi_status_t
setup_uga32(void **uga_handle, unsigned long size, u32 *width, u32 *height)
{
@@ -1098,6 +1161,8 @@ struct boot_params *efi_main(struct efi_config *c,
setup_efi_pci(boot_params);
+ setup_quirks(boot_params);
+
status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
sizeof(*gdt), (void **)&gdt);
if (status != EFI_SUCCESS) {
diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
index c18ce67..b10bf31 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -7,6 +7,7 @@
#define SETUP_DTB 2
#define SETUP_PCI 3
#define SETUP_EFI 4
+#define SETUP_APPLE_PROPERTIES 5
/* ram_size flags */
#define RAMDISK_IMAGE_START_MASK 0x07FF
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index 893fda4..2e78b0b 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -129,6 +129,19 @@ config EFI_TEST
Say Y here to enable the runtime services support via /dev/efi_test.
If unsure, say N.
+config APPLE_PROPERTIES
+ bool "Apple Device Properties"
+ depends on EFI_STUB && X86
+ select EFI_DEV_PATH_PARSER
+ select UCS2_STRING
+ help
+ Retrieve properties from EFI on Apple Macs and assign them to
+ devices, allowing for improved support of Apple hardware.
+ Properties that would otherwise be missing include the
+ Thunderbolt Device ROM and GPU configuration data.
+
+ If unsure, say Y if you have a Mac. Otherwise N.
+
endmenu
config UEFI_CPER
diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile
index 3e91ae3..ad67342 100644
--- a/drivers/firmware/efi/Makefile
+++ b/drivers/firmware/efi/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_EFI_FAKE_MEMMAP) += fake_mem.o
obj-$(CONFIG_EFI_BOOTLOADER_CONTROL) += efibc.o
obj-$(CONFIG_EFI_TEST) += test/
obj-$(CONFIG_EFI_DEV_PATH_PARSER) += dev-path-parser.o
+obj-$(CONFIG_APPLE_PROPERTIES) += apple-properties.o
arm-obj-$(CONFIG_EFI) := arm-init.o arm-runtime.o
obj-$(CONFIG_ARM) += $(arm-obj-y)
diff --git a/drivers/firmware/efi/apple-properties.c b/drivers/firmware/efi/apple-properties.c
new file mode 100644
index 0000000..c473f4c
--- /dev/null
+++ b/drivers/firmware/efi/apple-properties.c
@@ -0,0 +1,248 @@
+/*
+ * apple-properties.c - EFI device properties on Macs
+ * Copyright (C) 2016 Lukas Wunner <lukas-JFq808J9C/izQB+pC5nmwQ@public.gmane.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2) as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#define pr_fmt(fmt) "apple-properties: " fmt
+
+#include <linux/bootmem.h>
+#include <linux/dmi.h>
+#include <linux/efi.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+#include <linux/ucs2_string.h>
+#include <asm/setup.h>
+
+static bool dump_properties __initdata;
+
+static int __init dump_properties_enable(char *arg)
+{
+ dump_properties = true;
+ return 0;
+}
+
+__setup("dump_apple_properties", dump_properties_enable);
+
+struct dev_header {
+ u32 len;
+ u32 prop_count;
+ struct efi_dev_path path[0];
+ /*
+ * followed by key/value pairs, each key and value preceded by u32 len,
+ * len includes itself, value may be empty (in which case its len is 4)
+ */
+};
+
+struct properties_header {
+ u32 len;
+ u32 version;
+ u32 dev_count;
+ struct dev_header dev_header[0];
+};
+
+static u8 one __initdata = 1;
+
+static void __init unmarshal_key_value_pairs(struct dev_header *dev_header,
+ struct device *dev, void *ptr,
+ struct property_entry entry[])
+{
+ int i;
+
+ for (i = 0; i < dev_header->prop_count; i++) {
+ int remaining = dev_header->len - (ptr - (void *)dev_header);
+ u32 key_len, val_len;
+ char *key;
+
+ if (sizeof(key_len) > remaining)
+ break;
+
+ key_len = *(typeof(key_len) *)ptr;
+ if (key_len + sizeof(val_len) > remaining ||
+ key_len < sizeof(key_len) + sizeof(efi_char16_t) ||
+ *(efi_char16_t *)(ptr + sizeof(key_len)) == 0) {
+ dev_err(dev, "invalid property name len at %#zx\n",
+ ptr - (void *)dev_header);
+ break;
+ }
+
+ val_len = *(typeof(val_len) *)(ptr + key_len);
+ if (key_len + val_len > remaining ||
+ val_len < sizeof(val_len)) {
+ dev_err(dev, "invalid property val len at %#zx\n",
+ ptr - (void *)dev_header + key_len);
+ break;
+ }
+
+ /* 4 bytes to accommodate UTF-8 code points + null byte */
+ key = kzalloc((key_len - sizeof(key_len)) * 4 + 1, GFP_KERNEL);
+ if (!key) {
+ dev_err(dev, "cannot allocate property name\n");
+ break;
+ }
+ ucs2_as_utf8(key, ptr + sizeof(key_len),
+ key_len - sizeof(key_len));
+
+ entry[i].name = key;
+ entry[i].is_array = true;
+ entry[i].length = val_len - sizeof(val_len);
+ entry[i].pointer.raw_data = ptr + key_len + sizeof(val_len);
+ if (!entry[i].length) {
+ /* driver core doesn't accept empty properties */
+ entry[i].length = 1;
+ entry[i].pointer.raw_data = &one;
+ }
+
+ if (dump_properties) {
+ dev_info(dev, "property: %s\n", entry[i].name);
+ print_hex_dump(KERN_INFO, pr_fmt(), DUMP_PREFIX_OFFSET,
+ 16, 1, entry[i].pointer.raw_data,
+ entry[i].length, true);
+ }
+
+ ptr += key_len + val_len;
+ }
+
+ if (i != dev_header->prop_count) {
+ dev_err(dev, "got %d device properties, expected %u\n", i,
+ dev_header->prop_count);
+ print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
+ 16, 1, dev_header, dev_header->len, true);
+ return;
+ }
+
+ dev_info(dev, "assigning %d device properties\n", i);
+}
+
+static int __init unmarshal_devices(struct properties_header *properties)
+{
+ size_t offset = offsetof(struct properties_header, dev_header[0]);
+
+ while (offset + sizeof(struct dev_header) < properties->len) {
+ struct dev_header *dev_header = (void *)properties + offset;
+ struct property_entry *entry = NULL;
+ struct device *dev;
+ size_t len;
+ int ret, i;
+ void *ptr;
+
+ if (offset + dev_header->len > properties->len ||
+ dev_header->len <= sizeof(*dev_header)) {
+ pr_err("invalid len in dev_header at %#zx\n", offset);
+ return -EINVAL;
+ }
+
+ ptr = dev_header->path;
+ len = dev_header->len - sizeof(*dev_header);
+
+ dev = efi_get_device_by_path((struct efi_dev_path **)&ptr, &len);
+ if (IS_ERR(dev)) {
+ pr_err("device path parse error %ld at %#zx:\n",
+ PTR_ERR(dev), ptr - (void *)dev_header);
+ print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
+ 16, 1, dev_header, dev_header->len, true);
+ dev = NULL;
+ goto skip_device;
+ }
+
+ entry = kcalloc(dev_header->prop_count + 1, sizeof(*entry),
+ GFP_KERNEL);
+ if (!entry) {
+ dev_err(dev, "cannot allocate properties\n");
+ goto skip_device;
+ }
+
+ unmarshal_key_value_pairs(dev_header, dev, ptr, entry);
+ if (!entry[0].name)
+ goto skip_device;
+
+ ret = device_add_properties(dev, entry); /* makes deep copy */
+ if (ret)
+ dev_err(dev, "error %d assigning properties\n", ret);
+
+ for (i = 0; entry[i].name; i++)
+ kfree(entry[i].name);
+
+skip_device:
+ kfree(entry);
+ put_device(dev);
+ offset += dev_header->len;
+ }
+
+ return 0;
+}
+
+static int __init map_properties(void)
+{
+ struct properties_header *properties;
+ struct setup_data *data;
+ u32 data_len;
+ u64 pa_data;
+ int ret;
+
+ if (!dmi_match(DMI_SYS_VENDOR, "Apple Inc.") &&
+ !dmi_match(DMI_SYS_VENDOR, "Apple Computer, Inc."))
+ return 0;
+
+ pa_data = boot_params.hdr.setup_data;
+ while (pa_data) {
+ data = ioremap(pa_data, sizeof(*data));
+ if (!data) {
+ pr_err("cannot map setup_data header\n");
+ return -ENOMEM;
+ }
+
+ if (data->type != SETUP_APPLE_PROPERTIES) {
+ pa_data = data->next;
+ iounmap(data);
+ continue;
+ }
+
+ data_len = data->len;
+ iounmap(data);
+
+ data = ioremap(pa_data, sizeof(*data) + data_len);
+ if (!data) {
+ pr_err("cannot map setup_data payload\n");
+ return -ENOMEM;
+ }
+
+ properties = (struct properties_header *)data->data;
+ if (properties->version != 1) {
+ pr_err("unsupported version:\n");
+ print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
+ 16, 1, properties, data_len, true);
+ ret = -ENOTSUPP;
+ } else if (properties->len != data_len) {
+ pr_err("length mismatch, expected %u\n", data_len);
+ print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
+ 16, 1, properties, data_len, true);
+ ret = -EINVAL;
+ } else
+ ret = unmarshal_devices(properties);
+
+ /*
+ * Can only free the setup_data payload but not its header
+ * to avoid breaking the chain of ->next pointers.
+ */
+ data->len = 0;
+ iounmap(data);
+ free_bootmem_late(pa_data + sizeof(*data), data_len);
+
+ return ret;
+ }
+ return 0;
+}
+
+fs_initcall(map_properties);
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 2617672..a07a476 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -443,6 +443,22 @@ typedef struct {
#define EFI_PCI_IO_ATTRIBUTE_VGA_PALETTE_IO_16 0x20000
#define EFI_PCI_IO_ATTRIBUTE_VGA_IO_16 0x40000
+typedef struct {
+ u32 version;
+ u32 get;
+ u32 set;
+ u32 del;
+ u32 get_all;
+} apple_properties_protocol_32_t;
+
+typedef struct {
+ u64 version;
+ u64 get;
+ u64 set;
+ u64 del;
+ u64 get_all;
+} apple_properties_protocol_64_t;
+
/*
* Types and defines for EFI ResetSystem
*/
@@ -592,6 +608,7 @@ void efi_native_runtime_setup(void);
#define EFI_RNG_ALGORITHM_RAW EFI_GUID(0xe43176d7, 0xb6e8, 0x4827, 0xb7, 0x84, 0x7f, 0xfd, 0xc4, 0xb6, 0x85, 0x61)
#define EFI_MEMORY_ATTRIBUTES_TABLE_GUID EFI_GUID(0xdcfa911d, 0x26eb, 0x469f, 0xa2, 0x20, 0x38, 0xb7, 0xdc, 0x46, 0x12, 0x20)
#define EFI_CONSOLE_OUT_DEVICE_GUID EFI_GUID(0xd3b36f2c, 0xd551, 0x11d4, 0x9a, 0x46, 0x00, 0x90, 0x27, 0x3f, 0xc1, 0x4d)
+#define APPLE_PROPERTIES_PROTOCOL_GUID EFI_GUID(0x91bd12fe, 0xf6c3, 0x44fb, 0xa5, 0xb7, 0x51, 0x22, 0xab, 0x30, 0x3a, 0xe0)
/*
* This GUID is used to pass to the kernel proper the struct screen_info
--
2.10.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH v4 1/4] efi: Add device path parser
[not found] ` <cover.1478506920.git.lukas-JFq808J9C/izQB+pC5nmwQ@public.gmane.org>
2016-11-07 10:09 ` [PATCH v4 3/4] x86/efi: Retrieve and assign " Lukas Wunner
@ 2016-11-07 10:09 ` Lukas Wunner
2016-11-07 10:09 ` [PATCH v4 4/4] thunderbolt: Use Device ROM retrieved from EFI Lukas Wunner
` (2 subsequent siblings)
4 siblings, 0 replies; 7+ messages in thread
From: Lukas Wunner @ 2016-11-07 10:09 UTC (permalink / raw)
To: linux-efi-u79uwXL29TY76Z2rM5mHXA, Matt Fleming
Cc: Andreas Noever, Peter Jones, Ard Biesheuvel
We're about to extended the efistub to retrieve device properties from
EFI on Apple Macs. The properties use EFI Device Paths to indicate the
device they belong to. This commit adds a parser which, given an EFI
Device Path, locates the corresponding struct device and returns a
reference to it.
Initially only ACPI and PCI Device Path nodes are supported, these are
the only types needed for Apple device properties (the corresponding
macOS function AppleACPIPlatformExpert::matchEFIDevicePath() does not
support any others). Further node types can be added with little to
moderate effort.
Apple device properties is currently the only use case of this parser,
but Peter Jones intends to use it to match up devices with the
ConInDev/ConOutDev/ErrOutDev variables and add sysfs attributes to these
devices to say the hardware supports using them as console. Thus,
make this parser a separate component which can be selected with config
option EFI_DEV_PATH_PARSER. It can in principle be compiled as a module
if acpi_get_first_physical_node() and acpi_bus_type are exported (and
efi_get_device_by_path() itself is exported).
The dependency on CONFIG_ACPI is needed for acpi_match_device_ids().
It can be removed if an empty inline stub is added for that function.
Cc: Peter Jones <pjones-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
Cc: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Signed-off-by: Lukas Wunner <lukas-JFq808J9C/izQB+pC5nmwQ@public.gmane.org>
---
drivers/firmware/efi/Kconfig | 5 +
drivers/firmware/efi/Makefile | 1 +
drivers/firmware/efi/dev-path-parser.c | 203 +++++++++++++++++++++++++++++++++
include/linux/efi.h | 20 ++++
4 files changed, 229 insertions(+)
create mode 100644 drivers/firmware/efi/dev-path-parser.c
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index c981be1..893fda4 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -133,3 +133,8 @@ endmenu
config UEFI_CPER
bool
+
+config EFI_DEV_PATH_PARSER
+ bool
+ depends on ACPI
+ default n
diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile
index c8a439f..3e91ae3 100644
--- a/drivers/firmware/efi/Makefile
+++ b/drivers/firmware/efi/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_EFI_STUB) += libstub/
obj-$(CONFIG_EFI_FAKE_MEMMAP) += fake_mem.o
obj-$(CONFIG_EFI_BOOTLOADER_CONTROL) += efibc.o
obj-$(CONFIG_EFI_TEST) += test/
+obj-$(CONFIG_EFI_DEV_PATH_PARSER) += dev-path-parser.o
arm-obj-$(CONFIG_EFI) := arm-init.o arm-runtime.o
obj-$(CONFIG_ARM) += $(arm-obj-y)
diff --git a/drivers/firmware/efi/dev-path-parser.c b/drivers/firmware/efi/dev-path-parser.c
new file mode 100644
index 0000000..85d1834
--- /dev/null
+++ b/drivers/firmware/efi/dev-path-parser.c
@@ -0,0 +1,203 @@
+/*
+ * dev-path-parser.c - EFI Device Path parser
+ * Copyright (C) 2016 Lukas Wunner <lukas-JFq808J9C/izQB+pC5nmwQ@public.gmane.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2) as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/acpi.h>
+#include <linux/efi.h>
+#include <linux/pci.h>
+
+struct acpi_hid_uid {
+ struct acpi_device_id hid[2];
+ char uid[11]; /* UINT_MAX + null byte */
+};
+
+static int __init match_acpi_dev(struct device *dev, void *data)
+{
+ struct acpi_hid_uid hid_uid = *(struct acpi_hid_uid *)data;
+ struct acpi_device *adev = to_acpi_device(dev);
+
+ if (acpi_match_device_ids(adev, hid_uid.hid))
+ return 0;
+
+ if (adev->pnp.unique_id)
+ return !strcmp(adev->pnp.unique_id, hid_uid.uid);
+ else
+ return !strcmp("0", hid_uid.uid);
+}
+
+static long __init parse_acpi_path(struct efi_dev_path *node,
+ struct device *parent, struct device **child)
+{
+ struct acpi_hid_uid hid_uid = {};
+ struct device *phys_dev;
+
+ if (node->length != 12)
+ return -EINVAL;
+
+ sprintf(hid_uid.hid[0].id, "%c%c%c%04X",
+ 'A' + ((node->acpi.hid >> 10) & 0x1f) - 1,
+ 'A' + ((node->acpi.hid >> 5) & 0x1f) - 1,
+ 'A' + ((node->acpi.hid >> 0) & 0x1f) - 1,
+ node->acpi.hid >> 16);
+ sprintf(hid_uid.uid, "%u", node->acpi.uid);
+
+ *child = bus_find_device(&acpi_bus_type, NULL, &hid_uid,
+ match_acpi_dev);
+ if (!*child)
+ return -ENODEV;
+
+ phys_dev = acpi_get_first_physical_node(to_acpi_device(*child));
+ if (phys_dev) {
+ get_device(phys_dev);
+ put_device(*child);
+ *child = phys_dev;
+ }
+
+ return 0;
+}
+
+static int __init match_pci_dev(struct device *dev, void *data)
+{
+ unsigned int devfn = *(unsigned int *)data;
+
+ return dev_is_pci(dev) && to_pci_dev(dev)->devfn == devfn;
+}
+
+static long __init parse_pci_path(struct efi_dev_path *node,
+ struct device *parent, struct device **child)
+{
+ unsigned int devfn;
+
+ if (node->length != 6)
+ return -EINVAL;
+ if (!parent)
+ return -EINVAL;
+
+ devfn = PCI_DEVFN(node->pci.dev, node->pci.fn);
+
+ *child = device_find_child(parent, &devfn, match_pci_dev);
+ if (!*child)
+ return -ENODEV;
+
+ return 0;
+}
+
+/*
+ * Insert parsers for further node types here.
+ *
+ * Each parser takes a pointer to the @node and to the @parent (will be NULL
+ * for the first device path node). If a device corresponding to @node was
+ * found below @parent, its reference count should be incremented and the
+ * device returned in @child.
+ *
+ * The return value should be 0 on success or a negative int on failure.
+ * The special return values 0x01 (EFI_DEV_END_INSTANCE) and 0xFF
+ * (EFI_DEV_END_ENTIRE) signal the end of the device path, only
+ * parse_end_path() is supposed to return this.
+ *
+ * Be sure to validate the node length and contents before commencing the
+ * search for a device.
+ */
+
+static long __init parse_end_path(struct efi_dev_path *node,
+ struct device *parent, struct device **child)
+{
+ if (node->length != 4)
+ return -EINVAL;
+ if (node->sub_type != EFI_DEV_END_INSTANCE &&
+ node->sub_type != EFI_DEV_END_ENTIRE)
+ return -EINVAL;
+ if (!parent)
+ return -ENODEV;
+
+ *child = get_device(parent);
+ return node->sub_type;
+}
+
+/**
+ * efi_get_device_by_path - find device by EFI Device Path
+ * @node: EFI Device Path
+ * @len: maximum length of EFI Device Path in bytes
+ *
+ * Parse a series of EFI Device Path nodes at @node and find the corresponding
+ * device. If the device was found, its reference count is incremented and a
+ * pointer to it is returned. The caller needs to drop the reference with
+ * put_device() after use. The @node pointer is updated to point to the
+ * location immediately after the "End of Hardware Device Path" node.
+ *
+ * If another Device Path instance follows, @len is decremented by the number
+ * of bytes consumed. Otherwise @len is set to %0.
+ *
+ * If a Device Path node is malformed or its corresponding device is not found,
+ * @node is updated to point to this offending node and an ERR_PTR is returned.
+ *
+ * If @len is initially %0, the function returns %NULL. Thus, to iterate over
+ * all instances in a path, the following idiom may be used:
+ *
+ * while (!IS_ERR_OR_NULL(dev = efi_get_device_by_path(&node, &len))) {
+ * // do something with dev
+ * put_device(dev);
+ * }
+ * if (IS_ERR(dev))
+ * // report error
+ *
+ * Devices can only be found if they're already instantiated. Most buses
+ * instantiate devices in the "subsys" initcall level, hence the earliest
+ * initcall level in which this function should be called is "fs".
+ *
+ * Returns the device on success or
+ * %ERR_PTR(-ENODEV) if no device was found,
+ * %ERR_PTR(-EINVAL) if a node is malformed or exceeds @len,
+ * %ERR_PTR(-ENOTSUPP) if support for a node type is not yet implemented.
+ */
+struct device * __init efi_get_device_by_path(struct efi_dev_path **node,
+ size_t *len)
+{
+ struct device *parent = NULL, *child;
+ long ret = 0;
+
+ if (!*len)
+ return NULL;
+
+ while (!ret) {
+ if (*len < 4 || *len < (*node)->length)
+ ret = -EINVAL;
+ else if ((*node)->type == EFI_DEV_ACPI &&
+ (*node)->sub_type == EFI_DEV_BASIC_ACPI)
+ ret = parse_acpi_path(*node, parent, &child);
+ else if ((*node)->type == EFI_DEV_HW &&
+ (*node)->sub_type == EFI_DEV_PCI)
+ ret = parse_pci_path(*node, parent, &child);
+ else if (((*node)->type == EFI_DEV_END_PATH ||
+ (*node)->type == EFI_DEV_END_PATH2))
+ ret = parse_end_path(*node, parent, &child);
+ else
+ ret = -ENOTSUPP;
+
+ put_device(parent);
+ if (ret < 0)
+ return ERR_PTR(ret);
+
+ parent = child;
+ *node = (void *)*node + (*node)->length;
+ *len -= (*node)->length;
+ }
+
+ if (ret == EFI_DEV_END_ENTIRE)
+ *len = 0;
+
+ return child;
+}
diff --git a/include/linux/efi.h b/include/linux/efi.h
index f5a821d..2617672 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1148,6 +1148,26 @@ struct efi_generic_dev_path {
u16 length;
} __attribute ((packed));
+struct efi_dev_path {
+ u8 type; /* can be replaced with unnamed */
+ u8 sub_type; /* struct efi_generic_dev_path; */
+ u16 length; /* once we've moved to -std=c11 */
+ union {
+ struct {
+ u32 hid;
+ u32 uid;
+ } acpi;
+ struct {
+ u8 fn;
+ u8 dev;
+ } pci;
+ };
+} __attribute ((packed));
+
+#if IS_ENABLED(CONFIG_EFI_DEV_PATH_PARSER)
+struct device *efi_get_device_by_path(struct efi_dev_path **node, size_t *len);
+#endif
+
static inline void memrange_efi_to_native(u64 *addr, u64 *npages)
{
*npages = PFN_UP(*addr + (*npages<<EFI_PAGE_SHIFT)) - PFN_DOWN(*addr);
--
2.10.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH v4 4/4] thunderbolt: Use Device ROM retrieved from EFI
[not found] ` <cover.1478506920.git.lukas-JFq808J9C/izQB+pC5nmwQ@public.gmane.org>
2016-11-07 10:09 ` [PATCH v4 3/4] x86/efi: Retrieve and assign " Lukas Wunner
2016-11-07 10:09 ` [PATCH v4 1/4] efi: Add device path parser Lukas Wunner
@ 2016-11-07 10:09 ` Lukas Wunner
2016-11-07 10:09 ` [PATCH v4 2/4] efi: Allow bitness-agnostic protocol calls Lukas Wunner
2016-11-12 10:10 ` [PATCH v4 0/4] Apple device properties Matt Fleming
4 siblings, 0 replies; 7+ messages in thread
From: Lukas Wunner @ 2016-11-07 10:09 UTC (permalink / raw)
To: linux-efi-u79uwXL29TY76Z2rM5mHXA, Matt Fleming
Cc: Andreas Noever, Peter Jones, Ard Biesheuvel
Macs with Thunderbolt 1 do not have a unit-specific DROM: The DROM is
empty with uid 0x1000000000000. (Apple started factory-burning a unit-
specific DROM with Thunderbolt 2.)
Instead, the NHI EFI driver supplies a DROM in a device property. Use
it if available. It's only available when booting with the efistub.
If it's not available, silently fall back to our hardcoded DROM.
The size of the DROM is always 256 bytes. The number is hardcoded into
the NHI EFI driver. This commit can deal with an arbitrary size however,
just in case they ever change that.
Background information: The EFI firmware volume contains ROM files for
the NHI, GMUX and several other chips as well as key material. This
strategy allows Apple to deploy ROM or key updates by simply publishing
an EFI firmware update on their website. Drivers do not access those
files directly but rather through a file server via EFI protocol
AC5E4829-A8FD-440B-AF33-9FFE013B12D8. Files are identified by GUID, the
NHI DROM has 339370BD-CFC6-4454-8EF7-704653120818.
The NHI EFI driver amends that file with a unit-specific uid. The uid
has 64 bit but its entropy is much lower: 24 bit represent the model,
24 bit are taken from a serial number, 16 bit are fixed. The NHI EFI
driver obtains the serial number via the DataHub protocol, copies it
into the DROM, calculates the CRC and submits the result as a device
property.
A modification is needed in the resume code where we currently read the
uid of all switches in the hierarchy to detect plug events that occurred
during sleep. On Thunderbolt 1 root switches this will now lead to a
mismatch between the uid of the empty DROM and the EFI DROM. Exempt the
root switch from this check: It's built in, so the uid should never
change. However we continue to *read* the uid of the root switch, this
seems like a good way to test its reachability after resume.
Cc: Pedro Vilaça <reverser-P1ImLx+pFc0@public.gmane.org>
Tested-by: Lukas Wunner <lukas-JFq808J9C/izQB+pC5nmwQ@public.gmane.org> [MacBookPro9,1]
Tested-by: Pierre Moreau <pierre.morrow-GANU6spQydw@public.gmane.org> [MacBookPro11,3]
Signed-off-by: Lukas Wunner <lukas-JFq808J9C/izQB+pC5nmwQ@public.gmane.org>
Acked-by: Andreas Noever <andreas.noever-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
drivers/thunderbolt/Kconfig | 1 +
drivers/thunderbolt/eeprom.c | 43 +++++++++++++++++++++++++++++++++++++++++++
drivers/thunderbolt/switch.c | 2 +-
3 files changed, 45 insertions(+), 1 deletion(-)
diff --git a/drivers/thunderbolt/Kconfig b/drivers/thunderbolt/Kconfig
index c121acc..0056df7 100644
--- a/drivers/thunderbolt/Kconfig
+++ b/drivers/thunderbolt/Kconfig
@@ -1,6 +1,7 @@
menuconfig THUNDERBOLT
tristate "Thunderbolt support for Apple devices"
depends on PCI
+ select APPLE_PROPERTIES
select CRC32
help
Cactus Ridge Thunderbolt Controller driver
diff --git a/drivers/thunderbolt/eeprom.c b/drivers/thunderbolt/eeprom.c
index 2b9602c..6392990 100644
--- a/drivers/thunderbolt/eeprom.c
+++ b/drivers/thunderbolt/eeprom.c
@@ -5,6 +5,7 @@
*/
#include <linux/crc32.h>
+#include <linux/property.h>
#include <linux/slab.h>
#include "tb.h"
@@ -360,6 +361,40 @@ static int tb_drom_parse_entries(struct tb_switch *sw)
}
/**
+ * tb_drom_copy_efi - copy drom supplied by EFI to sw->drom if present
+ */
+static int tb_drom_copy_efi(struct tb_switch *sw, u16 *size)
+{
+ struct device *dev = &sw->tb->nhi->pdev->dev;
+ int len, res;
+
+ len = device_property_read_u8_array(dev, "ThunderboltDROM", NULL, 0);
+ if (len < 0 || len < sizeof(struct tb_drom_header))
+ return -EINVAL;
+
+ sw->drom = kmalloc(len, GFP_KERNEL);
+ if (!sw->drom)
+ return -ENOMEM;
+
+ res = device_property_read_u8_array(dev, "ThunderboltDROM", sw->drom,
+ len);
+ if (res)
+ goto err;
+
+ *size = ((struct tb_drom_header *)sw->drom)->data_len +
+ TB_DROM_DATA_START;
+ if (*size > len)
+ goto err;
+
+ return 0;
+
+err:
+ kfree(sw->drom);
+ sw->drom = NULL;
+ return -EINVAL;
+}
+
+/**
* tb_drom_read - copy drom to sw->drom and parse it
*/
int tb_drom_read(struct tb_switch *sw)
@@ -374,6 +409,13 @@ int tb_drom_read(struct tb_switch *sw)
if (tb_route(sw) == 0) {
/*
+ * Apple's NHI EFI driver supplies a DROM for the root switch
+ * in a device property. Use it if available.
+ */
+ if (tb_drom_copy_efi(sw, &size) == 0)
+ goto parse;
+
+ /*
* The root switch contains only a dummy drom (header only,
* no entries). Hardcode the configuration here.
*/
@@ -418,6 +460,7 @@ int tb_drom_read(struct tb_switch *sw)
if (res)
goto err;
+parse:
header = (void *) sw->drom;
if (header->data_len + TB_DROM_DATA_START != size) {
diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index 9840fde..c6f30b1 100644
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -460,7 +460,7 @@ int tb_switch_resume(struct tb_switch *sw)
tb_sw_warn(sw, "uid read failed\n");
return err;
}
- if (sw->uid != uid) {
+ if (sw != sw->tb->root_switch && sw->uid != uid) {
tb_sw_info(sw,
"changed while suspended (uid %#llx -> %#llx)\n",
sw->uid, uid);
--
2.10.1
^ permalink raw reply related [flat|nested] 7+ messages in thread