The FDT is mapped via a fixmap entry that is at least 2 MB in size and
2 MB aligned on 4 KB page size kernels.
On UEFI systems, the FDT allocation may share this 2 MB mapping with a
reserved region (or another memory region that we should never map),
unless we account for this in the size of the allocation (the alignment
is already 2 MB)
So instead of taking guesses at the needed space, simply allocate 2 MB
immediately. The allocation will be recorded as EFI_LOADER_DATA, and the
kernel only memblock_reserve()'s the actual size of the FDT, so the
unused space will be released back to the kernel.
Reviewed-By: Jeffrey Hugo <jhugo@codeaurora.org>
Tested-by: Richard Ruigrok <rruigrok@codeaurora.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20170404160245.27812-6-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
On arm64, we have made some changes over the past year to the way the
kernel itself is allocated and to how it deals with the initrd and FDT.
This patch brings the allocation logic in the EFI stub in line with that,
which is necessary because the introduction of KASLR has created the
possibility for the initrd to be allocated in a place where the kernel
may not be able to map it. (This is mostly a theoretical scenario, since
it only affects systems where the physical memory footprint exceeds the
size of the linear mapping.)
Since we know the kernel itself will be covered by the linear mapping,
choose a suitably sized window (i.e., based on the size of the linear
region) covering the kernel when allocating memory for the initrd.
The FDT may be anywhere in memory on arm64 now that we map it via the
fixmap, so we can lift the address restriction there completely.
Tested-by: Richard Ruigrok <rruigrok@codeaurora.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Jeffrey Hugo <jhugo@codeaurora.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20170404160245.27812-4-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The UEFI Specification permits Graphics Output Protocol (GOP) instances
without direct framebuffer access. This is indicated in the Mode structure
with a PixelFormat enumeration value of PIXEL_BLT_ONLY. Given that the
kernel does not know how to drive a Blt() only framebuffer (which is only
permitted before ExitBootServices() anyway), we should disregard such
framebuffers when looking for a GOP instance that is suitable for use as
the boot console.
So modify the EFI GOP initialization to not use a PIXEL_BLT_ONLY instance,
preventing attempts later in boot to use an invalid screen_info.lfb_base
address.
Signed-off-by: Eugene Cohen <eugene@hp.com>
[ Moved the Blt() only check into the loop and clarified that Blt() only GOPs are unusable by the kernel. ]
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: <stable@vger.kernel.org> # v4.7+
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: leif.lindholm@linaro.org
Cc: linux-efi@vger.kernel.org
Cc: lorenzo.pieralisi@arm.com
Fixes: 9822504c1f ("efifb: Enable the efi-framebuffer platform driver ...")
Link: http://lkml.kernel.org/r/20170404152744.26687-2-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The Intel Compute Stick STCK1A8LFC and Weibu F3C platforms both
log 2 error messages during boot:
efi: requested map not found.
esrt: ESRT header is not in the memory map.
Searching the web, this seems to affect many other platforms too.
Since these messages are logged as errors, they appear on-screen during
the boot process even when using the "quiet" boot parameter used by
distros.
Demote the ESRT error to a warning so that it does not appear on-screen,
and delete the error logging from efi_mem_desc_lookup; both callsites
of that function log more specific messages upon failure.
Out of curiosity I looked closer at the Weibu F3C. There is no entry in
the UEFI-provided memory map which corresponds to the ESRT pointer, but
hacking the code to map it anyway, the ESRT does appear to be valid with
2 entries.
Signed-off-by: Daniel Drake <drake@endlessm.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Acked-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
This removes the argument list for the erase() callback and replaces it
with a pointer to the backend record details to be removed.
Signed-off-by: Kees Cook <keescook@chromium.org>
Similar to the pstore_info read() callback, there were too many arguments.
This switches to the new struct pstore_record pointer instead. This adds
"reason" and "part" to the record structure as well.
Signed-off-by: Kees Cook <keescook@chromium.org>
The argument list for the pstore_read() interface is unwieldy. This changes
passes the new struct pstore_record instead. The erst backend was already
doing something similar internally.
Signed-off-by: Kees Cook <keescook@chromium.org>
On ARM and arm64, we use a dedicated mm_struct to map the UEFI
Runtime Services regions, which allows us to map those regions
on demand, and in a way that is guaranteed to be compatible
with incoming kernels across kexec.
As it turns out, we don't fully initialize the mm_struct in the
same way as process mm_structs are initialized on fork(), which
results in the following crash on ARM if CONFIG_CPUMASK_OFFSTACK=y
is enabled:
...
EFI Variables Facility v0.08 2004-May-17
Unable to handle kernel NULL pointer dereference at virtual address 00000000
[...]
Process swapper/0 (pid: 1)
...
__memzero()
check_and_switch_context()
virt_efi_get_next_variable()
efivar_init()
efivars_sysfs_init()
do_one_initcall()
...
This is due to a missing call to mm_init_cpumask(), so add it.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: <stable@vger.kernel.org> # v4.5+
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1488395154-29786-1-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The ARM decompressor is finicky when it comes to uninitialized variables
with local linkage, the reason being that it may relocate .text and .bss
independently when executing from ROM. This is only possible if all
references into .bss from .text are absolute, and this happens to be the
case for references emitted under -fpic to symbols with external linkage,
and so all .bss references must involve symbols with external linkage.
When building the ARM stub using clang, the initialized local variable
__chunk_size is optimized into a zero-initialized flag that indicates
whether chunking is in effect or not. This flag is therefore emitted into
.bss, which triggers the ARM decompressor's diagnostics, resulting in a
failed build.
Under UEFI, we never execute the decompressor from ROM, so the diagnostic
makes little sense here. But we can easily work around the issue by making
__chunk_size global instead.
However, given that the file I/O chunking that is controlled by the
__chunk_size variable is intended to work around known bugs on various
x86 implementations of UEFI, we can simply make the chunking an x86
specific feature. This is an improvement by itself, and also removes the
need to parse the efi= options in the stub entirely.
Tested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1486380166-31868-8-git-send-email-ard.biesheuvel@linaro.org
[ Small readability edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Some AArch64 UEFI implementations disable the MMU in ExitBootServices(),
after which unaligned accesses to RAM are no longer supported.
Commit:
abfb7b686a ("efi/libstub/arm*: Pass latest memory map to the kernel")
fixed an issue in the memory map handling of the stub FDT code, but
inadvertently created an issue with such firmware, by moving some
of the FDT manipulation to after the invocation of ExitBootServices().
Given that the stub's libfdt implementation uses the ordinary, accelerated
string functions, which rely on hardware handling of unaligned accesses,
manipulating the FDT with the MMU off may result in alignment faults.
So fix the situation by moving the update_fdt_memmap() call into the
callback function invoked by efi_exit_boot_services() right before it
calls the ExitBootServices() UEFI service (which is arguably a better
place for it anyway)
Note that disabling the MMU in ExitBootServices() is not compliant with
the UEFI spec, and carries great risk due to the fact that switching from
cached to uncached memory accesses halfway through compiler generated code
(i.e., involving a stack) can never be done in a way that is architecturally
safe.
Fixes: abfb7b686a ("efi/libstub/arm*: Pass latest memory map to the kernel")
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Riku Voipio <riku.voipio@linaro.org>
Cc: <stable@vger.kernel.org>
Cc: mark.rutland@arm.com
Cc: linux-efi@vger.kernel.org
Cc: matt@codeblueprint.co.uk
Cc: leif.lindholm@linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1485971102-23330-2-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The build commands for the ARM and arm64 EFI stubs strip the .debug
sections and other sections that may legally contain absolute relocations,
in order to inspect the remaining sections for the presence of such
relocations.
This leaves us without debugging symbols in the stub for no good reason,
considering that these sections are omitted from the kernel binary anyway,
and that these relocations are thus only consumed by users of the ELF
binary, such as debuggers.
So move to 'strip' for performing the relocation check, and if it succeeds,
invoke objcopy as before, but leaving the .debug sections in place. Note
that these sections may refer to ksymtab/kcrctab contents, so leave those
in place as well.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1485868902-20401-11-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
UEFI v2.6 introduces EFI_MEMORY_ATTRIBUTES_TABLE which describes memory
protections that may be applied to the EFI Runtime code and data regions by
the kernel. This enables the kernel to map these regions more strictly thereby
increasing security.
Presently, the only valid bits for the attribute field of a memory descriptor
are EFI_MEMORY_RO and EFI_MEMORY_XP, hence use these bits to update the
mappings in efi_pgd.
The UEFI specification recommends to use this feature instead of
EFI_PROPERTIES_TABLE and hence while updating EFI mappings we first
check for EFI_MEMORY_ATTRIBUTES_TABLE and if it's present we update
the mappings according to this table and hence disregarding
EFI_PROPERTIES_TABLE even if it's published by the firmware. We consider
EFI_PROPERTIES_TABLE only when EFI_MEMORY_ATTRIBUTES_TABLE is absent.
Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Lee, Chun-Yi <jlee@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Cc: Ricardo Neri <ricardo.neri@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1485868902-20401-6-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With the following commit:
4bc9f92e64 ("x86/efi-bgrt: Use efi_mem_reserve() to avoid copying image data")
... efi_bgrt_init() calls into the memblock allocator through
efi_mem_reserve() => efi_arch_mem_reserve() *after* mm_init() has been called.
Indeed, KASAN reports a bad read access later on in efi_free_boot_services():
BUG: KASAN: use-after-free in efi_free_boot_services+0xae/0x24c
at addr ffff88022de12740
Read of size 4 by task swapper/0/0
page:ffffea0008b78480 count:0 mapcount:-127
mapping: (null) index:0x1 flags: 0x5fff8000000000()
[...]
Call Trace:
dump_stack+0x68/0x9f
kasan_report_error+0x4c8/0x500
kasan_report+0x58/0x60
__asan_load4+0x61/0x80
efi_free_boot_services+0xae/0x24c
start_kernel+0x527/0x562
x86_64_start_reservations+0x24/0x26
x86_64_start_kernel+0x157/0x17a
start_cpu+0x5/0x14
The instruction at the given address is the first read from the memmap's
memory, i.e. the read of md->type in efi_free_boot_services().
Note that the writes earlier in efi_arch_mem_reserve() don't splat because
they're done through early_memremap()ed addresses.
So, after memblock is gone, allocations should be done through the "normal"
page allocator. Introduce a helper, efi_memmap_alloc() for this. Use
it from efi_arch_mem_reserve(), efi_free_boot_services() and, for the sake
of consistency, from efi_fake_memmap() as well.
Note that for the latter, the memmap allocations cease to be page aligned.
This isn't needed though.
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: <stable@vger.kernel.org> # v4.9
Cc: Dave Young <dyoung@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Mika Penttilä <mika.penttila@nextfour.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Fixes: 4bc9f92e64 ("x86/efi-bgrt: Use efi_mem_reserve() to avoid copying image data")
Link: http://lkml.kernel.org/r/20170105125130.2815-1-nicstange@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit 4fd06960f1 ("Use the new x86 setup code for i386") introduced a
reference to the make variable LINUX_INCLUDE. That reference got moved
around a bit and copied twice and now there are three references to it.
There has never been a definition of that variable. (Presumably that is
because it started out as a mistyped reference to LINUXINCLUDE.) So this
reference has always been an empty string. Let's remove it before it
spreads any further.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Pull arm64 updates from Catalin Marinas:
- struct thread_info moved off-stack (also touching
include/linux/thread_info.h and include/linux/restart_block.h)
- cpus_have_cap() reworked to avoid __builtin_constant_p() for static
key use (also touching drivers/irqchip/irq-gic-v3.c)
- uprobes support (currently only for native 64-bit tasks)
- Emulation of kernel Privileged Access Never (PAN) using TTBR0_EL1
switching to a reserved page table
- CPU capacity information passing via DT or sysfs (used by the
scheduler)
- support for systems without FP/SIMD (IOW, kernel avoids touching
these registers; there is no soft-float ABI, nor kernel emulation for
AArch64 FP/SIMD)
- handling of hardware watchpoint with unaligned addresses, varied
lengths and offsets from base
- use of the page table contiguous hint for kernel mappings
- hugetlb fixes for sizes involving the contiguous hint
- remove unnecessary I-cache invalidation in flush_cache_range()
- CNTHCTL_EL2 access fix for CPUs with VHE support (ARMv8.1)
- boot-time checks for writable+executable kernel mappings
- simplify asm/opcodes.h and avoid including the 32-bit ARM counterpart
and make the arm64 kernel headers self-consistent (Xen headers patch
merged separately)
- Workaround for broken .inst support in certain binutils versions
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (60 commits)
arm64: Disable PAN on uaccess_enable()
arm64: Work around broken .inst when defective gas is detected
arm64: Add detection code for broken .inst support in binutils
arm64: Remove reference to asm/opcodes.h
arm64: Get rid of asm/opcodes.h
arm64: smp: Prevent raw_smp_processor_id() recursion
arm64: head.S: Fix CNTHCTL_EL2 access on VHE system
arm64: Remove I-cache invalidation from flush_cache_range()
arm64: Enable HIBERNATION in defconfig
arm64: Enable CONFIG_ARM64_SW_TTBR0_PAN
arm64: xen: Enable user access before a privcmd hvc call
arm64: Handle faults caused by inadvertent user access with PAN enabled
arm64: Disable TTBR0_EL1 during normal kernel execution
arm64: Introduce uaccess_{disable,enable} functionality based on TTBR0_EL1
arm64: Factor out TTBR0_EL1 post-update workaround into a specific asm macro
arm64: Factor out PAN enabling/disabling into separate uaccess_* macros
arm64: Update the synchronous external abort fault description
selftests: arm64: add test for unaligned/inexact watchpoint handling
arm64: Allow hw watchpoint of length 3,5,6 and 7
arm64: hw_breakpoint: Handle inexact watchpoint addresses
...
The UEFI stub executes in the context of the firmware, which identity
maps the available system RAM, which implies that only memory below
4 GB can be used for allocations on 32-bit architectures, even on [L]PAE
capable hardware.
So ignore any reported memory above 4 GB in efi_random_alloc(). This
also fixes a reported build problem on ARM under -Os, where the 64-bit
logical shift relies on a software routine that the ARM decompressor does
not provide.
A second [minor] issue is also fixed, where the '+ 1' is moved out of
the shift, where it belongs: the reason for its presence is that a
memory region where start == end should count as a single slot, given
that 'end' takes the desired size and alignment of the allocation into
account.
To clarify the code in this regard, rename start/end to 'first_slot' and
'last_slot', respectively, and introduce 'region_end' to describe the
last usable address of the current region.
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1480010543-25709-2-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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.
Tested-by: Lukas Wunner <lukas@wunner.de> [MacBookPro9,1]
Tested-by: Pierre Moreau <pierre.morrow@free.fr> [MacBookPro11,3]
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Andreas Noever <andreas.noever@gmail.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pedro Vilaça <reverser@put.as>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: grub-devel@gnu.org
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20161112213237.8804-9-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Andreas Noever <andreas.noever@gmail.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20161112213237.8804-7-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Specify a Linux specific UEFI configuration table that carries some
random bits, and use the contents during early boot to seed the kernel's
random number generator. This allows much strong random numbers to be
generated early on.
The entropy is fed to the kernel using add_device_randomness(), which is
documented as being appropriate for being called very early.
Since UEFI configuration tables may also be consumed by kexec'd kernels,
register a reboot notifier that updates the seed in the table.
Note that the config table could be generated by the EFI stub or by any
other UEFI driver or application (e.g., GRUB), but the random seed table
GUID and the associated functionality should be considered an internal
kernel interface (unless it is promoted to ABI later on)
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20161112213237.8804-4-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Adjust the size used in calculations to match the actual size of allocation
that will be performed based on EFI size/alignment constraints.
efi_high_alloc() and efi_low_alloc() use the passed size in bytes directly
to find space in the memory map for the allocation, rather than the actual
allocation size that has been adjusted for size and alignment constraints.
This results in failed allocations and retries in efi_high_alloc(). The
same error is present in efi_low_alloc(), although failure will only happen
if the lowest memory block is small.
Also use EFI_PAGE_SIZE consistently and remove use of EFI_PAGE_SHIFT to
calculate page size.
Signed-off-by: Roy Franz <roy.franz@hpe.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20161112213237.8804-2-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
ptdump_register currently initializes a set of page table information and
registers debugfs. There are uses for the ptdump option without wanting the
debugfs options. Split this out to make it a separate option.
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
When building the ARM kernel with CONFIG_EFI=y, the following build
error may occur when using a less recent version of binutils (2.23 or
older):
STUBCPY drivers/firmware/efi/libstub/lib-sort.stub.o
00000000 R_ARM_ABS32 sort
00000004 R_ARM_ABS32 __ksymtab_strings
drivers/firmware/efi/libstub/lib-sort.stub.o: absolute symbol references not allowed in the EFI stub
(and when building with debug symbols, the list above is much longer, and
contains all the internal references between the .debug sections and the
actual code)
This issue is caused by the fact that objcopy v2.23 or earlier does not
support wildcards in its -R and -j options, which means the following
line from the Makefile:
STUBCOPY_FLAGS-y := -R .debug* -R *ksymtab* -R *kcrctab*
fails to take effect, leaving harmless absolute relocations in the binary
that are indistinguishable from relocations that may cause crashes at
runtime due to the fact that these relocations are resolved at link time
using the virtual address of the kernel, which is always different from
the address at which the EFI firmware loads and invokes the stub.
So, as a workaround, disable debug symbols explicitly when building the
stub for ARM, and strip the ksymtab and kcrctab symbols for the only
exported symbol we currently reuse in the stub, which is 'sort'.
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1476805991-7160-2-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull pstore updates from Kees Cook:
- Fix bug in module unloading
- Switch to always using spinlock over cmpxchg
- Explicitly define pstore backend's supported modes
- Remove bounce buffer from pmsg
- Switch to using memcpy_to/fromio()
- Error checking improvements
* tag 'pstore-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
ramoops: move spin_lock_init after kmalloc error checking
pstore/ram: Use memcpy_fromio() to save old buffer
pstore/ram: Use memcpy_toio instead of memcpy
pstore/pmsg: drop bounce buffer
pstore/ram: Set pstore flags dynamically
pstore: Split pstore fragile flags
pstore/core: drop cmpxchg based updates
pstore/ramoops: fixup driver removal
Mike Galbraith reported that his machine started rebooting during boot
after,
commit 8e80632fb2 ("efi/esrt: Use efi_mem_reserve() and avoid a kmalloc()")
The ESRT table on his machine is 56 bytes and at no point in the
efi_arch_mem_reserve() call path is that size rounded up to
EFI_PAGE_SIZE, nor is the start address on an EFI_PAGE_SIZE boundary.
Since the EFI memory map only deals with whole pages, inserting an EFI
memory region with 56 bytes results in a new entry covering zero
pages, and completely screws up the calculations for the old regions
that were trimmed.
Round all sizes upwards, and start addresses downwards, to the nearest
EFI_PAGE_SIZE boundary.
Additionally, efi_memmap_insert() expects the mem::range::end value to
be one less than the end address for the region.
Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Reported-by: Mike Krinkin <krinkin.m.u@gmail.com>
Tested-by: Mike Krinkin <krinkin.m.u@gmail.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Pull EFI updates from Matt Fleming:
"* Refactor the EFI memory map code into architecture neutral files
and allow drivers to permanently reserve EFI boot services regions
on x86, as well as ARM/arm64 - Matt Fleming
* Add ARM support for the EFI esrt driver - Ard Biesheuvel
* Make the EFI runtime services and efivar API interruptible by
swapping spinlocks for semaphores - Sylvain Chouleur
* Provide the EFI identity mapping for kexec which allows kexec to
work on SGI/UV platforms with requiring the "noefi" kernel command
line parameter - Alex Thorlton
* Add debugfs node to dump EFI page tables on arm64 - Ard Biesheuvel
* Merge the EFI test driver being carried out of tree until now in
the FWTS project - Ivan Hu
* Expand the list of flags for classifying EFI regions as "RAM" on
arm64 so we align with the UEFI spec - Ard Biesheuvel
* Optimise out the EFI mixed mode if it's unsupported (CONFIG_X86_32)
or disabled (CONFIG_EFI_MIXED=n) and switch the early EFI boot
services function table for direct calls, alleviating us from
having to maintain the custom function table - Lukas Wunner
* Miscellaneous cleanups and fixes"
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently, memory regions are only recorded in the memblock memory table
if they have the EFI_MEMORY_WB memory type attribute set. In case the
region is of a reserved type, it is also marked as MEMBLOCK_NOMAP, which
will leave it out of the linear mapping.
However, memory regions may legally have the EFI_MEMORY_WT or EFI_MEMORY_WC
attributes set, and the EFI_MEMORY_WB cleared, in which case the region in
question is obviously backed by normal memory, but is not recorded in the
memblock memory table at all. Since it would be useful to be able to
identify any UEFI reported memory region using memblock_is_memory(), it
makes sense to add all memory to the memblock memory table, and simply mark
it as MEMBLOCK_NOMAP if it lacks the EFI_MEMORY_WB attribute.
While implementing this, let's refactor the code slightly to make it easier
to understand: replace is_normal_ram() with is_memory(), and make it return
true for each region that has any of the WB|WT|WC bits set. (This follows
the AArch64 bindings in the UEFI spec, which state that those are the
attributes that map to normal memory)
Also, replace is_reserve_region() with is_usable_memory(), and only invoke
it if the region in question was identified as memory by is_memory() in the
first place. The net result is the same (only reserved regions that are
backed by memory end up in the memblock memory table with the MEMBLOCK_NOMAP
flag set) but carried out in a more straightforward way.
Finally, we remove the trailing asterisk in the EFI debug output. Keeping it
clutters the code, and it serves no real purpose now that we no longer
temporarily reserve BootServices code and data regions like we did in the
early days of EFI support on arm64 Linux (which it inherited from the x86
implementation)
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
Tested-by: James Morse <james.morse@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
