be4e34b6b5
Recent work related to issue 1723 showed that there is potential to get rid of code duplication in MMU fault handling especially with regard to ARM cpus.
86 lines
2.0 KiB
C++
86 lines
2.0 KiB
C++
/*
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* \brief ARM cpu context initialization
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* \author Stefan Kalkowski
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* \date 2017-04-12
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*/
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/*
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* Copyright (C) 2017 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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#include <util/bit_allocator.h>
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#include <base/internal/unmanaged_singleton.h>
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#include <kernel/cpu.h>
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#include <kernel/thread.h>
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#include <spec/arm/cpu_support.h>
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using namespace Genode;
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Arm_cpu::Context::Context(bool privileged)
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{
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using Psr = Arm_cpu::Psr;
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Psr::access_t v = 0;
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Psr::M::set(v, privileged ? Psr::M::SYS : Psr::M::USR);
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if (Genode::Pic::fast_interrupts()) Psr::I::set(v, 1);
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else Psr::F::set(v, 1);
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Psr::A::set(v, 1);
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cpsr = v;
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cpu_exception = RESET;
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}
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using Asid_allocator = Bit_allocator<256>;
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static Asid_allocator &alloc() {
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return *unmanaged_singleton<Asid_allocator>(); }
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Arm_cpu::Mmu_context::Mmu_context(addr_t table)
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: cidr((uint8_t)alloc().alloc()), ttbr0(Ttbr0::init(table)) { }
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Genode::Arm_cpu::Mmu_context::~Mmu_context()
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{
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/* flush TLB by ASID */
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Cpu::Tlbiasid::write(id());
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alloc().free(id());
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}
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using Thread_fault = Kernel::Thread_fault;
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void Arm_cpu::mmu_fault(Context & c, Thread_fault & fault)
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{
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bool prefetch = c.cpu_exception == Context::PREFETCH_ABORT;
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fault.addr = prefetch ? Ifar::read() : Dfar::read();
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Fsr::access_t fsr = prefetch ? Ifsr::read() : Dfsr::read();
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if (!prefetch && Dfsr::Wnr::get(fsr)) {
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fault.type = Thread_fault::WRITE;
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return;
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}
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Cpu::mmu_fault_status(Fsr::Fs::get(fsr), fault);
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}
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void Arm_cpu::mmu_fault_status(Fsr::access_t fsr, Thread_fault & fault)
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{
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enum {
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FAULT_MASK = 0b11101,
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TRANSLATION = 0b00101,
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PERMISSION = 0b01101,
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};
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switch(fsr & FAULT_MASK) {
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case TRANSLATION: fault.type = Thread_fault::PAGE_MISSING; return;
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case PERMISSION: fault.type = Thread_fault::EXEC; return;
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default: fault.type = Thread_fault::UNKNOWN;
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};
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}
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