init_mm isn't a normal mm: it has swapper_pg_dir as its pgd (which
contains kernel mappings) and is used as the active_mm for the idle
thread.
When restoring the pgd after an EFI call, we write current->active_mm
into TTBR0. If the current task is actually the idle thread (e.g. when
initialising the EFI RTC before entering userspace), then the TLB can
erroneously populate itself with junk global entries as a result of
speculative table walks.
When we do eventually return to userspace, the task can end up hitting
these junk mappings leading to lockups, corruption or crashes.
This patch fixes the problem in the same way as the CPU suspend code by
ensuring that we never switch to the init_mm in efi_set_pgd and instead
point TTBR0 at the zero page. A check is also added to cpu_switch_mm to
BUG if we get passed swapper_pg_dir.
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Fixes: f3cdfd239d ("arm64/efi: move SetVirtualAddressMap() to UEFI stub")
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
If UEFI Runtime Services are available, they are preferred over direct
PSCI calls or other methods to reset the system.
For the reset case, we need to hook into machine_restart(), as the
arm_pm_restart function pointer may be overwritten by modules.
Tested-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Now that the create_mapping() code in mm/mmu.c is able to support
setting up kernel page tables at initcall time, we can move the whole
virtmap creation to arm64_enable_runtime_services() instead of having
a distinct stage during early boot. This also allows us to drop the
arm64-specific EFI_VIRTMAP flag.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
When remapping the UEFI memory map using ioremap_cache(), we
have to deal with potential failure. Note that, even if the
common case is for ioremap_cache() to return the existing linear
mapping of the memory map, we cannot rely on that to be always the
case, e.g., in the presence of a mem= kernel parameter.
At the same time, remove a stale comment and move the memmap code
together.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Now that we have moved the call to SetVirtualAddressMap() to the stub,
UEFI has no use for the ID map, so we can drop the code that installs
ID mappings for UEFI memory regions.
Acked-by: Leif Lindholm <leif.lindholm@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Tested-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Now that we are calling SetVirtualAddressMap() from the stub, there is no
need to reserve boot-only memory regions, which implies that there is also
no reason to free them again later.
Acked-by: Leif Lindholm <leif.lindholm@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Tested-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
In order to support kexec, the kernel needs to be able to deal with the
state of the UEFI firmware after SetVirtualAddressMap() has been called.
To avoid having separate code paths for non-kexec and kexec, let's move
the call to SetVirtualAddressMap() to the stub: this will guarantee us
that it will only be called once (since the stub is not executed during
kexec), and ensures that the UEFI state is identical between kexec and
normal boot.
This implies that the layout of the virtual mapping needs to be created
by the stub as well. All regions are rounded up to a naturally aligned
multiple of 64 KB (for compatibility with 64k pages kernels) and recorded
in the UEFI memory map. The kernel proper reads those values and installs
the mappings in a dedicated set of page tables that are swapped in during
UEFI Runtime Services calls.
Acked-by: Leif Lindholm <leif.lindholm@linaro.org>
Acked-by: Matt Fleming <matt.fleming@intel.com>
Tested-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
The early ioremap support introduced by patch bf4b558eba
("arm64: add early_ioremap support") failed to add a call to
early_ioremap_reset() at an appropriate time. Without this call,
invocations of early_ioremap etc. that are done too late will go
unnoticed and may cause corruption.
This is exactly what happened when the first user of this feature
was added in patch f84d02755f ("arm64: add EFI runtime services").
The early mapping of the EFI memory map is unmapped during an early
initcall, at which time the early ioremap support is long gone.
Fix by adding the missing call to early_ioremap_reset() to
setup_arch(), and move the offending early_memunmap() to right after
the point where the early mapping of the EFI memory map is last used.
Fixes: f84d02755f ("arm64: add EFI runtime services")
Cc: <stable@vger.kernel.org>
Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This sets the DMI string, containing system type, serial number,
firmware version etc. as dump stack arch description, so that oopses
and other kernel stack dumps automatically have this information
included, if available.
Tested-by: Leif Lindholm <leif.lindholm@linaro.org>
Acked-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
SMBIOS is important for server hardware vendors. It implements a spec for
providing descriptive information about the platform. Things like serial
numbers, physical layout of the ports, build configuration data, and the like.
Signed-off-by: Yi Li <yi.li@linaro.org>
Tested-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Tested-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
The EFI_CONFIG_TABLES bit already gets set by efi_config_init(),
so there is no reason to set it again after this function returns
successfully.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Instead of reserving the memory regions based on which types we know
need to be reserved, consider only regions of the following types as
free for general use by the OS:
EFI_LOADER_CODE
EFI_LOADER_DATA
EFI_BOOT_SERVICES_CODE
EFI_BOOT_SERVICES_DATA
EFI_CONVENTIONAL_MEMORY
Note that this also fixes a problem with the original code, which would
misidentify a EFI_RUNTIME_SERVICES_DATA region as not reserved if it
does not have the EFI_MEMORY_RUNTIME attribute set. However, it is
perfectly legal for the firmware not to request a virtual mapping for
EFI_RUNTIME_SERVICES_DATA regions that contain configuration tables, in
which case the EFI_MEMORY_RUNTIME attribute would not be set.
Acked-by: Roy Franz <roy.franz@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
In case efi runtime disabled via noefi kernel cmdline
arm64_enter_virtual_mode should error out.
At the same time move early_memunmap(memmap.map, mapsize) to the
beginning of the function or it will leak early mem.
Signed-off-by: Dave Young <dyoung@redhat.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
There's one early memmap leak in uefi_init error path, fix it and
slightly tune the error handling code.
Signed-off-by: Dave Young <dyoung@redhat.com>
Acked-by: Mark Salter <msalter@redhat.com>
Reported-by: Will Deacon <will.deacon@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Pull x86 fixes from Ingo Molnar:
"A couple of EFI fixes, plus misc fixes all around the map"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
efi/arm64: Store Runtime Services revision
firmware: Do not use WARN_ON(!spin_is_locked())
x86_32, entry: Clean up sysenter_badsys declaration
x86/doc: Fix the 'tlb_single_page_flush_ceiling' sysconfig path
x86/mm: Fix sparse 'tlb_single_page_flush_ceiling' warning and make the variable read-mostly
x86/mm: Fix RCU splat from new TLB tracepoints
"efi" global data structure contains "runtime_version" field which must
be assigned in order to use it later in Runtime Services virtual calls
(virt_efi_* functions).
Before this patch "runtime_version" was unassigned (0), so each
Runtime Service virtual call that checks revision would fail.
Signed-off-by: Semen Protsenko <semen.protsenko@linaro.org>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
UEFI provides its own method for marking regions to reserve, via the
memory map which is also used to initialise memblock. So when using the
UEFI memory map, ignore any memreserve entries present in the DT.
Reported-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
If we cannot resolve the virtual address of the UEFI System Table, its
physical offset must be missing from the virtual memory map, and there
is really no point in proceeding with installing the virtual memory map
and the runtime services dispatch table. So back out gracefully.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mark Salter <msalter@redhat.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
According to the UEFI spec section 2.3.6.4, the use of FP/SIMD
instructions is allowed, and should adhere to the AAPCS64 calling
convention, which states that 'only the bottom 64 bits of each value
stored in registers v8-v15 need to be preserved' (section 5.1.2).
This applies equally to UEFI Runtime Services called by the kernel, so
make sure the FP/SIMD register file is preserved in this case. We do this
by enabling the wrappers for UEFI Runtime Services (CONFIG_EFI_RUNTIME_WRAPPERS)
and inserting calls to kernel_neon_begin()and kernel_neon_end() into
these wrappers.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Booting a kernel with CONFIG_EFI enabled on a non-EFI system caused
an oops with the current UEFI support code.
Add the required test to prevent this.
Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
This patch adds EFI runtime support for arm64. This runtime support allows
the kernel to access various EFI runtime services provided by EFI firmware.
Things like reboot, real time clock, EFI boot variables, and others.
This functionality is supported for little endian kernels only. The UEFI
firmware standard specifies that the firmware be little endian. A future
patch is expected to add support for big endian kernels running with
little endian firmware.
Signed-off-by: Mark Salter <msalter@redhat.com>
[ Remove unnecessary cache/tlb maintenance. ]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Will Deacon