mirror of
https://github.com/Atmosphere-NX/Atmosphere.git
synced 2024-11-18 08:11:21 +00:00
319 lines
17 KiB
C++
319 lines
17 KiB
C++
/*
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* Copyright (c) 2018-2020 Atmosphère-NX
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <mesosphere.hpp>
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#include "kern_init_loader_asm.hpp"
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/* Necessary for calculating kernelldr size/base for initial identity mapping */
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extern "C" {
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extern const u8 __start__[];
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extern const u8 __end__[];
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}
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namespace ams::kern::init::loader {
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namespace {
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constexpr size_t KernelResourceRegionSize = 0x1728000;
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constexpr size_t ExtraKernelResourceSize = 0x68000;
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static_assert(ExtraKernelResourceSize + KernelResourceRegionSize == 0x1790000);
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constexpr size_t InitialPageTableRegionSize = 0x200000;
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/* Global Allocator. */
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KInitialPageAllocator g_initial_page_allocator;
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void RelocateKernelPhysically(uintptr_t &base_address, KernelLayout *&layout) {
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/* TODO: Proper secure monitor call. */
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KPhysicalAddress correct_base = KSystemControl::Init::GetKernelPhysicalBaseAddress(base_address);
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if (correct_base != base_address) {
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const uintptr_t diff = GetInteger(correct_base) - base_address;
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const size_t size = layout->rw_end_offset;
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/* Conversion from KPhysicalAddress to void * is safe here, because MMU is not set up yet. */
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std::memmove(reinterpret_cast<void *>(GetInteger(correct_base)), reinterpret_cast<void *>(base_address), size);
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base_address += diff;
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layout = reinterpret_cast<KernelLayout *>(reinterpret_cast<uintptr_t>(layout) + diff);
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}
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}
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void EnsureEntireDataCacheFlushed() {
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/* Flush shared cache. */
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cpu::FlushEntireDataCacheShared();
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cpu::DataSynchronizationBarrier();
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/* Flush local cache. */
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cpu::FlushEntireDataCacheLocal();
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cpu::DataSynchronizationBarrier();
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/* Flush shared cache. */
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cpu::FlushEntireDataCacheShared();
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cpu::DataSynchronizationBarrier();
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/* Invalidate entire instruction cache. */
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cpu::InvalidateEntireInstructionCache();
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/* Invalidate entire TLB. */
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cpu::InvalidateEntireTlb();
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}
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void SetupInitialIdentityMapping(KInitialPageTable &ttbr1_table, uintptr_t base_address, uintptr_t kernel_size, uintptr_t page_table_region, size_t page_table_region_size, KInitialPageTable::IPageAllocator &allocator) {
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/* Make a new page table for TTBR0_EL1. */
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KInitialPageTable ttbr0_table(allocator.Allocate());
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/* Map in an RWX identity mapping for the kernel. */
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constexpr PageTableEntry KernelRWXIdentityAttribute(PageTableEntry::Permission_KernelRWX, PageTableEntry::PageAttribute_NormalMemory, PageTableEntry::Shareable_InnerShareable);
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ttbr0_table.Map(base_address, kernel_size, base_address, KernelRWXIdentityAttribute, allocator);
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/* Map in an RWX identity mapping for ourselves. */
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constexpr PageTableEntry KernelLdrRWXIdentityAttribute(PageTableEntry::Permission_KernelRWX, PageTableEntry::PageAttribute_NormalMemory, PageTableEntry::Shareable_InnerShareable);
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const uintptr_t kernel_ldr_base = util::AlignDown(reinterpret_cast<uintptr_t>(__start__), PageSize);
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const uintptr_t kernel_ldr_size = util::AlignUp(reinterpret_cast<uintptr_t>(__end__), PageSize) - kernel_ldr_base;
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ttbr0_table.Map(kernel_ldr_base, kernel_ldr_size, kernel_ldr_base, KernelRWXIdentityAttribute, allocator);
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/* Map in the page table region as RW- for ourselves. */
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constexpr PageTableEntry PageTableRegionRWAttribute(PageTableEntry::Permission_KernelRW, PageTableEntry::PageAttribute_NormalMemory, PageTableEntry::Shareable_InnerShareable);
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ttbr0_table.Map(page_table_region, page_table_region_size, page_table_region, KernelRWXIdentityAttribute, allocator);
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/* Place the L1 table addresses in the relevant system registers. */
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cpu::SetTtbr0El1(ttbr0_table.GetL1TableAddress());
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cpu::SetTtbr1El1(ttbr1_table.GetL1TableAddress());
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/* Setup MAIR_EL1, TCR_EL1. */
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/* TODO: Define these bits properly elsewhere, document exactly what each bit set is doing .*/
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constexpr u64 MairValue = 0x0000000044FF0400ul;
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constexpr u64 TcrValue = 0x00000011B5193519ul;
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cpu::MemoryAccessIndirectionRegisterAccessor(MairValue).Store();
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cpu::TranslationControlRegisterAccessor(TcrValue).Store();
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/* Perform cpu-specific setup. */
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{
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SavedRegisterState saved_registers;
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SaveRegistersToTpidrEl1(&saved_registers);
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ON_SCOPE_EXIT { VerifyAndClearTpidrEl1(&saved_registers); };
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/* Main ID specific setup. */
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cpu::MainIdRegisterAccessor midr_el1;
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if (midr_el1.GetImplementer() == cpu::MainIdRegisterAccessor::Implementer::ArmLimited) {
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/* ARM limited specific setup. */
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const auto cpu_primary_part = midr_el1.GetPrimaryPartNumber();
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const auto cpu_variant = midr_el1.GetVariant();
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const auto cpu_revision = midr_el1.GetRevision();
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if (cpu_primary_part == cpu::MainIdRegisterAccessor::PrimaryPartNumber::CortexA57) {
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/* Cortex-A57 specific setup. */
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/* Non-cacheable load forwarding enabled. */
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u64 cpuactlr_value = 0x1000000;
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/* Enable the processor to receive instruction cache and TLB maintenance */
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/* operations broadcast from other processors in the cluster; */
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/* set the L2 load/store data prefetch distance to 8 requests; */
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/* set the L2 instruction fetch prefetch distance to 3 requests. */
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u64 cpuectlr_value = 0x1B00000040;
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/* Disable load-pass DMB on certain hardware variants. */
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if (cpu_variant == 0 || (cpu_variant == 1 && cpu_revision <= 1)) {
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cpuactlr_value |= 0x800000000000000;
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}
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/* Set actlr and ectlr. */
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if (cpu::GetCpuActlrEl1() != cpuactlr_value) {
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cpu::SetCpuActlrEl1(cpuactlr_value);
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}
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if (cpu::GetCpuEctlrEl1() != cpuectlr_value) {
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cpu::SetCpuEctlrEl1(cpuectlr_value);
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}
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} else if (cpu_primary_part == cpu::MainIdRegisterAccessor::PrimaryPartNumber::CortexA53) {
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/* Cortex-A53 specific setup. */
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/* Set L1 data prefetch control to allow 5 outstanding prefetches; */
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/* enable device split throttle; */
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/* set the number of independent data prefetch streams to 2; */
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/* disable transient and no-read-allocate hints for loads; */
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/* set write streaming no-allocate threshold so the 128th consecutive streaming */
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/* cache line does not allocate in the L1 or L2 cache. */
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u64 cpuactlr_value = 0x90CA000;
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/* Enable hardware management of data coherency with other cores in the cluster. */
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u64 cpuectlr_value = 0x40;
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/* If supported, enable data cache clean as data cache clean/invalidate. */
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if (cpu_variant != 0 || (cpu_variant == 0 && cpu_revision > 2)) {
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cpuactlr_value |= 0x100000000000;
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}
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/* Set actlr and ectlr. */
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if (cpu::GetCpuActlrEl1() != cpuactlr_value) {
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cpu::SetCpuActlrEl1(cpuactlr_value);
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}
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if (cpu::GetCpuEctlrEl1() != cpuectlr_value) {
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cpu::SetCpuEctlrEl1(cpuectlr_value);
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}
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}
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}
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}
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/* Ensure that the entire cache is flushed. */
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EnsureEntireDataCacheFlushed();
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/* Setup SCTLR_EL1. */
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/* TODO: Define these bits properly elsewhere, document exactly what each bit set is doing .*/
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constexpr u64 SctlrValue = 0x0000000034D5D925ul;
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cpu::SetSctlrEl1(SctlrValue);
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cpu::EnsureInstructionConsistency();
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}
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KVirtualAddress GetRandomKernelBaseAddress(KInitialPageTable &page_table, KPhysicalAddress phys_base_address, size_t kernel_size) {
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/* Define useful values for random generation. */
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constexpr uintptr_t KernelBaseAlignment = 0x200000;
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constexpr uintptr_t KernelBaseRangeMin = 0xFFFFFF8000000000;
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constexpr uintptr_t KernelBaseRangeMax = 0xFFFFFFFFFFE00000;
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constexpr uintptr_t KernelBaseRangeEnd = KernelBaseRangeMax - 1;
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static_assert(util::IsAligned(KernelBaseRangeMin, KernelBaseAlignment));
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static_assert(util::IsAligned(KernelBaseRangeMax, KernelBaseAlignment));
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static_assert(KernelBaseRangeMin <= KernelBaseRangeEnd);
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const uintptr_t kernel_offset = GetInteger(phys_base_address) % KernelBaseAlignment;
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/* Repeatedly generate a random virtual address until we get one that's unmapped in the destination page table. */
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while (true) {
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const KVirtualAddress random_kaslr_slide = KSystemControl::Init::GenerateRandomRange(KernelBaseRangeMin, KernelBaseRangeEnd);
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const KVirtualAddress kernel_region_start = util::AlignDown(GetInteger(random_kaslr_slide), KernelBaseAlignment);
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const KVirtualAddress kernel_region_end = util::AlignUp(GetInteger(kernel_region_start) + kernel_offset + kernel_size, KernelBaseAlignment);
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const size_t kernel_region_size = GetInteger(kernel_region_end) - GetInteger(kernel_region_start);
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/* Make sure the region has not overflowed */
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if (kernel_region_start >= kernel_region_end) {
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continue;
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}
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/* Make sure that the region stays within our intended bounds. */
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if (kernel_region_end > KernelBaseRangeMax) {
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continue;
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}
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/* Validate we can map the range we've selected. */
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if (!page_table.IsFree(kernel_region_start, kernel_region_size)) {
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continue;
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}
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/* Our range is valid! */
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return kernel_region_start + kernel_offset;
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}
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}
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}
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uintptr_t Main(uintptr_t base_address, KernelLayout *layout, uintptr_t ini_base_address) {
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/* Relocate the kernel to the correct physical base address. */
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/* Base address and layout are passed by reference and modified. */
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RelocateKernelPhysically(base_address, layout);
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/* Validate kernel layout. */
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/* TODO: constexpr 0x1000 definition somewhere. */
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/* In stratosphere, this is os::MemoryPageSize. */
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/* We don't have ams::os, this may go in hw:: or something. */
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const uintptr_t rx_offset = layout->rx_offset;
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const uintptr_t rx_end_offset = layout->rx_end_offset;
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const uintptr_t ro_offset = layout->ro_offset;
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const uintptr_t ro_end_offset = layout->ro_end_offset;
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const uintptr_t rw_offset = layout->rw_offset;
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/* UNUSED: const uintptr_t rw_end_offset = layout->rw_end_offset; */
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const uintptr_t bss_end_offset = layout->bss_end_offset;
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MESOSPHERE_ABORT_UNLESS(util::IsAligned(rx_offset, 0x1000));
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MESOSPHERE_ABORT_UNLESS(util::IsAligned(rx_end_offset, 0x1000));
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MESOSPHERE_ABORT_UNLESS(util::IsAligned(ro_offset, 0x1000));
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MESOSPHERE_ABORT_UNLESS(util::IsAligned(ro_end_offset, 0x1000));
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MESOSPHERE_ABORT_UNLESS(util::IsAligned(rw_offset, 0x1000));
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MESOSPHERE_ABORT_UNLESS(util::IsAligned(bss_end_offset, 0x1000));
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const uintptr_t bss_offset = layout->bss_offset;
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const uintptr_t ini_load_offset = layout->ini_load_offset;
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const uintptr_t dynamic_offset = layout->dynamic_offset;
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const uintptr_t init_array_offset = layout->init_array_offset;
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const uintptr_t init_array_end_offset = layout->init_array_end_offset;
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/* Decide if Kernel should have enlarged resource region. */
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const bool use_extra_resources = KSystemControl::Init::ShouldIncreaseThreadResourceLimit();
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const size_t resource_region_size = KernelResourceRegionSize + (use_extra_resources ? ExtraKernelResourceSize : 0);
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static_assert(KernelResourceRegionSize > InitialProcessBinarySizeMax);
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static_assert(KernelResourceRegionSize + ExtraKernelResourceSize > InitialProcessBinarySizeMax);
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/* Setup the INI1 header in memory for the kernel. */
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const uintptr_t ini_end_address = base_address + ini_load_offset + resource_region_size;
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const uintptr_t ini_load_address = ini_end_address - InitialProcessBinarySizeMax;
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if (ini_base_address != ini_load_address) {
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/* The INI is not at the correct address, so we need to relocate it. */
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const InitialProcessBinaryHeader *ini_header = reinterpret_cast<const InitialProcessBinaryHeader *>(ini_base_address);
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if (ini_header->magic == InitialProcessBinaryMagic && ini_header->size <= InitialProcessBinarySizeMax) {
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/* INI is valid, relocate it. */
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std::memmove(reinterpret_cast<void *>(ini_load_address), ini_header, ini_header->size);
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} else {
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/* INI is invalid. Make the destination header invalid. */
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std::memset(reinterpret_cast<void *>(ini_load_address), 0, sizeof(InitialProcessBinaryHeader));
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}
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}
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/* We want to start allocating page tables at ini_end_address. */
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g_initial_page_allocator.Initialize(ini_end_address);
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/* Make a new page table for TTBR1_EL1. */
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KInitialPageTable ttbr1_table(g_initial_page_allocator.Allocate());
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/* Setup initial identity mapping. TTBR1 table passed by reference. */
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SetupInitialIdentityMapping(ttbr1_table, base_address, bss_end_offset, ini_end_address, InitialPageTableRegionSize, g_initial_page_allocator);
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/* Generate a random slide for the kernel's base address. */
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const KVirtualAddress virtual_base_address = GetRandomKernelBaseAddress(ttbr1_table, base_address, bss_end_offset);
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/* Map kernel .text as R-X. */
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constexpr PageTableEntry KernelTextAttribute(PageTableEntry::Permission_KernelRX, PageTableEntry::PageAttribute_NormalMemory, PageTableEntry::Shareable_InnerShareable);
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ttbr1_table.Map(virtual_base_address + rx_offset, rx_end_offset - rx_offset, base_address + rx_offset, KernelTextAttribute, g_initial_page_allocator);
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/* Map kernel .rodata and .rwdata as RW-. */
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/* Note that we will later reprotect .rodata as R-- */
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constexpr PageTableEntry KernelRoDataAttribute(PageTableEntry::Permission_KernelR, PageTableEntry::PageAttribute_NormalMemory, PageTableEntry::Shareable_InnerShareable);
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constexpr PageTableEntry KernelRwDataAttribute(PageTableEntry::Permission_KernelRW, PageTableEntry::PageAttribute_NormalMemory, PageTableEntry::Shareable_InnerShareable);
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ttbr1_table.Map(virtual_base_address + ro_offset, ro_end_offset - ro_offset, base_address + ro_offset, KernelRwDataAttribute, g_initial_page_allocator);
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ttbr1_table.Map(virtual_base_address + rw_offset, bss_end_offset - rw_offset, base_address + rw_offset, KernelRwDataAttribute, g_initial_page_allocator);
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/* Clear kernel .bss. */
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std::memset(GetVoidPointer(virtual_base_address + bss_offset), 0, bss_end_offset - bss_offset);
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/* Apply relocations to the kernel. */
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const Elf::Dyn *kernel_dynamic = reinterpret_cast<const Elf::Dyn *>(GetInteger(virtual_base_address) + dynamic_offset);
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Elf::ApplyRelocations(GetInteger(virtual_base_address), kernel_dynamic);
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/* Reprotect .rodata as R-- */
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ttbr1_table.Reprotect(virtual_base_address + ro_offset, ro_end_offset - ro_offset, KernelRwDataAttribute, KernelRoDataAttribute);
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/* Call the kernel's init array functions. */
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Elf::CallInitArrayFuncs(GetInteger(virtual_base_address) + init_array_offset, GetInteger(virtual_base_address) + init_array_end_offset);
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/* Return the difference between the random virtual base and the physical base. */
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return GetInteger(virtual_base_address) - base_address;
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}
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KPhysicalAddress AllocateKernelInitStack() {
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return g_initial_page_allocator.Allocate() + PageSize;
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}
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uintptr_t GetFinalPageAllocatorState() {
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return g_initial_page_allocator.GetFinalState();
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}
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} |