/* * thunks.S - assembly helpers for mixed-bitness code * Copyright (c) 2015 Andrew Lutomirski * * This program is free software; you can redistribute it and/or modify * it under the terms and conditions of the GNU General Public License, * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope 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. * * These are little helpers that make it easier to switch bitness on * the fly. */ .text .global call32_from_64 .type call32_from_64, @function call32_from_64: // rdi: stack to use // esi: function to call // Save registers pushq %rbx pushq %rbp pushq %r12 pushq %r13 pushq %r14 pushq %r15 pushfq // Switch stacks mov %rsp,(%rdi) mov %rdi,%rsp // Switch to compatibility mode pushq $0x23 /* USER32_CS */ pushq $1f lretq 1: .code32 // Call the function call *%esi // Switch back to long mode jmp $0x33,$1f .code64 1: // Restore the stack mov (%rsp),%rsp // Restore registers popfq popq %r15 popq %r14 popq %r13 popq %r12 popq %rbp popq %rbx ret .size call32_from_64, .-call32_from_64 ion> net-next plumbingsTobias Klauser
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325a59cfc718d13a50fbc746ed9b415c25e92'>codecs/max98925.c
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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2017-02-01 17:45:02 +0000
committerIngo Molnar <mingo@kernel.org>2017-02-01 21:17:49 +0100
commitc8f325a59cfc718d13a50fbc746ed9b415c25e92 (patch)
treed53fbdac9d0781e39a13b2ac6b2bd258cf3b4140 /sound/soc/codecs/max98925.c
parentbf29bddf0417a4783da3b24e8c9e017ac649326f (diff)
efi/fdt: Avoid FDT manipulation after ExitBootServices()
Some AArch64 UEFI implementations disable the MMU in ExitBootServices(), after which unaligned accesses to RAM are no longer supported. Commit: abfb7b686a3e ("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: abfb7b686a3e ("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>
Diffstat (limited to 'sound/soc/codecs/max98925.c')