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2020-09-16efi/libstub: arm32: Use low allocation for the uncompressed kernelArd Biesheuvel1-141/+37
Before commit d0f9ca9be11f25ef ("ARM: decompressor: run decompressor in place if loaded via UEFI") we were rather limited in the choice of base address for the uncompressed kernel, as we were relying on the logic in the decompressor that blindly rounds down the decompressor execution address to the next multiple of 128 MiB, and decompresses the kernel there. For this reason, we have a lot of complicated memory region handling code, to ensure that this memory window is available, even though it could be occupied by reserved regions or other allocations that may or may not collide with the uncompressed image. Today, we simply pass the target address for the decompressed image to the decompressor directly, and so we can choose a suitable window just by finding a 16 MiB aligned region, while taking TEXT_OFFSET and the region for the swapper page tables into account. So let's get rid of the complicated logic, and instead, use the existing bottom up allocation routine to allocate a suitable window as low as possible, and carve out a memory region that has the right properties. Note that this removes any dependencies on the 'dram_base' argument to handle_kernel_image(), and so this is removed as well. Given that this was the only remaining use of dram_base, the code that produces it is removed entirely as well. Reviewed-by: Maxim Uvarov <maxim.uvarov@linaro.org> Tested-by: Maxim Uvarov <maxim.uvarov@linaro.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-09-16efi/libstub: arm32: Base FDT and initrd placement on image addressArd Biesheuvel1-1/+1
The way we use the base of DRAM in the EFI stub is problematic as it is ill defined what the base of DRAM actually means. There are some restrictions on the placement of FDT and initrd which are defined in terms of dram_base, but given that the placement of the kernel in memory is what defines these boundaries (as on ARM, this is where the linear region starts), it is better to use the image address in these cases, and disregard dram_base altogether. Reviewed-by: Maxim Uvarov <maxim.uvarov@linaro.org> Tested-by: Maxim Uvarov <maxim.uvarov@linaro.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-06-17efi/libstub: arm: Print CPU boot mode and MMU state at bootArd Biesheuvel1-1/+53
On 32-bit ARM, we may boot at HYP mode, or with the MMU and caches off (or both), even though the EFI spec does not actually support this. While booting at HYP mode is something we might tolerate, fiddling with the caches is a more serious issue, as disabling the caches is tricky to do safely from C code, and running without the Dcache makes it impossible to support unaligned memory accesses, which is another explicit requirement imposed by the EFI spec. So take note of the CPU mode and MMU state in the EFI stub diagnostic output so that we can easily diagnose any issues that may arise from this. E.g., EFI stub: Entering in SVC mode with MMU enabled Also, capture the CPSR and SCTLR system register values at EFI stub entry, and after ExitBootServices() returns, and check whether the MMU and Dcache were disabled at any point. If this is the case, a diagnostic message like the following will be emitted: efi: [Firmware Bug]: EFI stub was entered with MMU and Dcache disabled, please fix your firmware! efi: CPSR at EFI stub entry : 0x600001d3 efi: SCTLR at EFI stub entry : 0x00c51838 efi: CPSR after ExitBootServices() : 0x600001d3 efi: SCTLR after ExitBootServices(): 0x00c50838 Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Leif Lindholm <leif@nuviainc.com>
2020-06-01Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-armLinus Torvalds1-39/+6
Pull ARM updates from Russell King: - remove a now unnecessary usage of the KERNEL_DS for sys_oabi_epoll_ctl() - update my email address in a number of drivers - decompressor EFI updates from Ard Biesheuvel - module unwind section handling updates - sparsemem Kconfig cleanups - make act_mm macro respect THREAD_SIZE * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: ARM: 8980/1: Allow either FLATMEM or SPARSEMEM on the multiplatform build ARM: 8979/1: Remove redundant ARCH_SPARSEMEM_DEFAULT setting ARM: 8978/1: mm: make act_mm() respect THREAD_SIZE ARM: decompressor: run decompressor in place if loaded via UEFI ARM: decompressor: move GOT into .data for EFI enabled builds ARM: decompressor: defer loading of the contents of the LC0 structure ARM: decompressor: split off _edata and stack base into separate object ARM: decompressor: move headroom variable out of LC0 ARM: 8976/1: module: allow arch overrides for .init section names ARM: 8975/1: module: fix handling of unwind init sections ARM: 8974/1: use SPARSMEM_STATIC when SPARSEMEM is enabled ARM: 8971/1: replace the sole use of a symbol with its definition ARM: 8969/1: decompressor: simplify libfdt builds Update rmk's email address in various drivers ARM: compat: remove KERNEL_DS usage in sys_oabi_epoll_ctl()
2020-05-19ARM: decompressor: run decompressor in place if loaded via UEFIArd Biesheuvel1-39/+6
The decompressor can load from anywhere in memory, and the only reason the EFI stub code relocates it is to ensure it appears within the first 128 MiB of memory, so that the uncompressed kernel ends up at the right offset in memory. We can short circuit this, and simply jump into the decompressor startup code at the point where it knows where the base of memory lives. This also means there is no need to disable the MMU and caches, create new page tables and re-enable them. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Nicolas Pitre <nico@fluxnic.net>
2020-05-01efi/libstub: Move pr_efi/pr_efi_err into efi namespaceArvind Sankar1-6/+6
Rename pr_efi to efi_info and pr_efi_err to efi_err to make it more obvious that they are part of the EFI stub and not generic printk infra. Suggested-by: Joe Perches <joe@perches.com> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200430182843.2510180-4-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-22efi/libstub/arm: Make efi_entry() an ordinary PE/COFF entrypointArd Biesheuvel1-0/+1
Expose efi_entry() as the PE/COFF entrypoint directly, instead of jumping into a wrapper that fiddles with stack buffers and other stuff that the compiler is much better at. The only reason this code exists is to obtain a pointer to the base of the image, but we can get the same value from the loaded_image protocol, which we already need for other reasons anyway. Update the return type as well, to make it consistent with what is required for a PE/COFF executable entrypoint. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2019-12-25efi/libstub: Rename efi_call_early/_runtime macros to be more intuitiveArd Biesheuvel1-15/+15
The macros efi_call_early and efi_call_runtime are used to call EFI boot services and runtime services, respectively. However, the naming is confusing, given that the early vs runtime distinction may suggest that these are used for calling the same set of services either early or late (== at runtime), while in reality, the sets of services they can be used with are completely disjoint, and efi_call_runtime is also only usable in 'early' code. So do a global sweep to replace all occurrences with efi_bs_call or efi_rt_call, respectively, where BS and RT match the idiom used by the UEFI spec to refer to boot time or runtime services. While at it, use 'func' as the macro parameter name for the function pointers, which is less likely to collide and cause weird build errors. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Cc: Arvind Sankar <nivedita@alum.mit.edu> Cc: Borislav Petkov <bp@alien8.de> Cc: James Morse <james.morse@arm.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191224151025.32482-24-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-25efi/libstub: Remove 'sys_table_arg' from all function prototypesArd Biesheuvel1-15/+11
We have a helper efi_system_table() that gives us the address of the EFI system table in memory, so there is no longer point in passing it around from each function to the next. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Cc: Arvind Sankar <nivedita@alum.mit.edu> Cc: Borislav Petkov <bp@alien8.de> Cc: James Morse <james.morse@arm.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191224151025.32482-20-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-25efi/libstub: Drop sys_table_arg from printk routinesArd Biesheuvel1-8/+6
As a first step towards getting rid of the need to pass around a function parameter 'sys_table_arg' pointing to the EFI system table, remove the references to it in the printing code, which is represents the majority of the use cases. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Cc: Arvind Sankar <nivedita@alum.mit.edu> Cc: Borislav Petkov <bp@alien8.de> Cc: James Morse <james.morse@arm.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191224151025.32482-19-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-11-07arm/efi: EFI soft reservation to memblockDan Williams1-0/+5
UEFI 2.8 defines an EFI_MEMORY_SP attribute bit to augment the interpretation of the EFI Memory Types as "reserved for a specific purpose". The proposed Linux behavior for specific purpose memory is that it is reserved for direct-access (device-dax) by default and not available for any kernel usage, not even as an OOM fallback. Later, through udev scripts or another init mechanism, these device-dax claimed ranges can be reconfigured and hot-added to the available System-RAM with a unique node identifier. This device-dax management scheme implements "soft" in the "soft reserved" designation by allowing some or all of the reservation to be recovered as typical memory. This policy can be disabled at compile-time with CONFIG_EFI_SOFT_RESERVE=n, or runtime with efi=nosoftreserve. For this patch, update the ARM paths that consider EFI_CONVENTIONAL_MEMORY to optionally take the EFI_MEMORY_SP attribute into account as a reservation indicator. Publish the soft reservation as IORES_DESC_SOFT_RESERVED memory, similar to x86. (Based on an original patch by Ard) Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-10-31x86, efi: Never relocate kernel below lowest acceptable addressKairui Song1-1/+1
Currently, kernel fails to boot on some HyperV VMs when using EFI. And it's a potential issue on all x86 platforms. It's caused by broken kernel relocation on EFI systems, when below three conditions are met: 1. Kernel image is not loaded to the default address (LOAD_PHYSICAL_ADDR) by the loader. 2. There isn't enough room to contain the kernel, starting from the default load address (eg. something else occupied part the region). 3. In the memmap provided by EFI firmware, there is a memory region starts below LOAD_PHYSICAL_ADDR, and suitable for containing the kernel. EFI stub will perform a kernel relocation when condition 1 is met. But due to condition 2, EFI stub can't relocate kernel to the preferred address, so it fallback to ask EFI firmware to alloc lowest usable memory region, got the low region mentioned in condition 3, and relocated kernel there. It's incorrect to relocate the kernel below LOAD_PHYSICAL_ADDR. This is the lowest acceptable kernel relocation address. The first thing goes wrong is in arch/x86/boot/compressed/head_64.S. Kernel decompression will force use LOAD_PHYSICAL_ADDR as the output address if kernel is located below it. Then the relocation before decompression, which move kernel to the end of the decompression buffer, will overwrite other memory region, as there is no enough memory there. To fix it, just don't let EFI stub relocate the kernel to any address lower than lowest acceptable address. [ ardb: introduce efi_low_alloc_above() to reduce the scope of the change ] Signed-off-by: Kairui Song <kasong@redhat.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> 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: https://lkml.kernel.org/r/20191029173755.27149-6-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-10-31efi: libstub/arm: Account for firmware reserved memory at the base of RAMArd Biesheuvel1-3/+13
The EFI stubloader for ARM starts out by allocating a 32 MB window at the base of RAM, in order to ensure that the decompressor (which blindly copies the uncompressed kernel into that window) does not overwrite other allocations that are made while running in the context of the EFI firmware. In some cases, (e.g., U-Boot running on the Raspberry Pi 2), this is causing boot failures because this initial allocation conflicts with a page of reserved memory at the base of RAM that contains the SMP spin tables and other pieces of firmware data and which was put there by the bootloader under the assumption that the TEXT_OFFSET window right below the kernel is only used partially during early boot, and will be left alone once the memory reservations are processed and taken into account. So let's permit reserved memory regions to exist in the region starting at the base of RAM, and ending at TEXT_OFFSET - 5 * PAGE_SIZE, which is the window below the kernel that is not touched by the early boot code. Tested-by: Guillaume Gardet <Guillaume.Gardet@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Chester Lin <clin@suse.com> 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: https://lkml.kernel.org/r/20191029173755.27149-5-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-02-04efi: Replace GPL license boilerplate with SPDX headersArd Biesheuvel1-5/+1
Replace all GPL license blurbs with an equivalent SPDX header (most files are GPLv2, some are GPLv2+). While at it, drop some outdated header changelogs as well. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Alexander Graf <agraf@suse.de> Cc: Bjorn Andersson <bjorn.andersson@linaro.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Heinrich Schuchardt <xypron.glpk@gmx.de> Cc: Jeffrey Hugo <jhugo@codeaurora.org> Cc: Lee Jones <lee.jones@linaro.org> Cc: Leif Lindholm <leif.lindholm@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Peter Jones <pjones@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20190202094119.13230-7-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-04-05efi/libstub/arm/arm64: Disable debug prints on 'quiet' cmdline argArd Biesheuvel1-0/+2
The EFI stub currently prints a number of diagnostic messages that do not carry a lot of information. Since these prints are not controlled by 'loglevel' or other command line parameters, and since they appear on the EFI framebuffer as well (if enabled), it would be nice if we could turn them off. So let's add support for the 'quiet' command line parameter in the stub, and disable the non-error prints if it is passed. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Mark Rutland <mark.rutland@arm.com> 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: bhe@redhat.com Cc: bhsharma@redhat.com Cc: bp@alien8.de Cc: eugene@hp.com Cc: evgeny.kalugin@intel.com Cc: jhugo@codeaurora.org Cc: leif.lindholm@linaro.org Cc: linux-efi@vger.kernel.org Cc: roy.franz@cavium.com Cc: rruigrok@codeaurora.org Link: http://lkml.kernel.org/r/20170404160910.28115-2-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-04-05efi/arm32-stub: Allow boot-time allocations in the vmlinux regionArd Biesheuvel1-20/+128
The arm32 kernel decompresses itself to the base of DRAM unconditionally, and so it is the EFI stub's job to ensure that the region is available. Currently, we do this by creating an allocation there, and giving up if that fails. However, any boot services regions occupying this area are not an issue, given that the decompressor executes strictly after the stub calls ExitBootServices(). So let's try a bit harder to proceed if the initial allocation fails, and check whether any memory map entries occupying the region may be considered safe. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org> Reviewed-by: Eugene Cohen <eugene@hp.com> Reviewed-by: Roy Franz <roy.franz@cavium.com> 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/20170404160245.27812-11-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-28efi/arm/libstub: Make screen_info accessible to the UEFI stubArd Biesheuvel1-0/+37
In order to hand over the framebuffer described by the GOP protocol and discovered by the UEFI stub, make struct screen_info accessible by the stub. This involves allocating a loader data buffer and passing it to the kernel proper via a UEFI Configuration Table, since the UEFI stub executes in the context of the decompressor, and cannot access the kernel's copy of struct screen_info directly. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Cc: Borislav Petkov <bp@alien8.de> Cc: David Herrmann <dh.herrmann@gmail.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Peter Jones <pjones@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/1461614832-17633-22-git-send-email-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-22efi/arm: Check for LPAE support before booting a LPAE kernelArd Biesheuvel1-0/+17
A kernel built with support for LPAE cannot boot to a state where it can inform the user about if it has to fail due to missing LPAE support in the hardware. If we happen to be booting via UEFI, we can fail gracefully so check for LPAE support in the hardware on CONFIG_ARM_LPAE builds before entering the kernel proper. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Reviewed-by: Jeremy Linton <jeremy.linton@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> 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/1455712566-16727-9-git-send-email-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-12-14ARM: add UEFI stub supportRoy Franz1-0/+85
This patch adds EFI stub support for the ARM Linux kernel. The EFI stub operates similarly to the x86 and arm64 stubs: it is a shim between the EFI firmware and the normal zImage entry point, and sets up the environment that the zImage is expecting. This includes optionally loading the initrd and device tree from the system partition based on the kernel command line. Signed-off-by: Roy Franz <roy.franz@linaro.org> Tested-by: Ryan Harkin <ryan.harkin@linaro.org> Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>