From f16ede905cb02e9d887f52e2c524cf2ac94e88b3 Mon Sep 17 00:00:00 2001 From: Amelia Coutard <eliottulio.coutard@gmail.com> Date: Mon, 6 Mar 2023 00:40:35 +0100 Subject: [PATCH] Edited os::paging::setup_pages a bit. Notably, the global bit is now set for all hhigher-half memory --- kernel/src/kernel.cpp | 4 ++-- kernel/src/paging.cpp | 22 +++++++++++++--------- kernel/src/paging.hpp | 2 +- 3 files changed, 16 insertions(+), 12 deletions(-) diff --git a/kernel/src/kernel.cpp b/kernel/src/kernel.cpp index e0fff26..9757d4c 100644 --- a/kernel/src/kernel.cpp +++ b/kernel/src/kernel.cpp @@ -209,7 +209,7 @@ extern "C" void kmain(unsigned long magic, os::phys_ptr<const multiboot2::info_s // Allocate memory for segment: std::size_t nb_pages = (std::uint64_t(program_header.p_vaddr) % 0x1000 + program_header.p_memsz + 0x1000 - 1) / 0x1000; for (std::size_t i = 0; i < nb_pages; i++) { - os::paging::setup_page(PML4T, program_header.p_vaddr + i * 0x1000, (program_header.flags & 2) >> 1, 1, true); + os::paging::setup_page(PML4T, program_header.p_vaddr + i * 0x1000, (program_header.flags & 2) >> 1, 1); } // Initialise memory for segment: for (std::size_t i = 0; i < program_header.p_filesz; i++) { @@ -224,7 +224,7 @@ extern "C" void kmain(unsigned long magic, os::phys_ptr<const multiboot2::info_s constexpr std::size_t stack_size = 16 * 0x1000 /* 64KiB */; std::byte * const stack = (std::byte*)0x0000'8000'0000'0000 - stack_size; for (std::size_t i = 0; i < stack_size / 0x1000 /* 64KiB */; i++) { - os::paging::setup_page(PML4T, stack + i * 0x1000, 1, 1, true); + os::paging::setup_page(PML4T, stack + i * 0x1000, 1, 1); } os::print("Loading ring 3 interrupts stack.\n"); diff --git a/kernel/src/paging.cpp b/kernel/src/paging.cpp index 5996b25..dc9ec73 100644 --- a/kernel/src/paging.cpp +++ b/kernel/src/paging.cpp @@ -14,7 +14,7 @@ #include "paging.hpp" #include "serial.hpp" -void os::paging::setup_page(os::paging::PML4T& PML4T, const void* vaddr, bool R_W, bool U_S, bool must_be_unmapped) { +void os::paging::setup_page(os::paging::PML4T& PML4T, const void* vaddr, bool R_W, bool U_S) { const auto indices = os::paging::calc_page_table_indices(vaddr); if (PML4T.contents[indices.pml4e].P == 0) { PML4T.contents[indices.pml4e] = {.P = 1, .R_W = 1, .U_S = U_S, .PWT = 0, .PCD = 0, .base_address = 0, .NX = 0}; @@ -26,22 +26,26 @@ void os::paging::setup_page(os::paging::PML4T& PML4T, const void* vaddr, bool R_ PDPT.contents[indices.pdpe] = {.non_page = {.P = 1, .R_W = 1, .U_S = U_S, .PWT = 0, .PCD = 0, .base_address = 0, .NX = 0}}; const auto PDT_alloc = os::paging::page_allocator.allocate(1); set_base_address(PDPT.contents[indices.pdpe], os::phys_ptr<os::paging::PDT>(PDT_alloc.ptr.get_phys_addr())); + } else { + assert(PDPT.contents[indices.pdpe].non_page.zero == 0, + "Cannot map memory address 0x{} because it is inside a 1GiB page", std::uintptr_t(vaddr)); } os::paging::PDT& PDT = *get_base_address(PDPT.contents[indices.pdpe]); if (PDT.contents[indices.pde].non_page.P == 0) { PDT.contents[indices.pde] = {.non_page = {.P = 1, .R_W = 1, .U_S = U_S, .PWT = 0, .PCD = 0, .base_address = 0, .NX = 0}}; const auto PT_alloc = os::paging::page_allocator.allocate(1); set_base_address(PDT.contents[indices.pde], os::phys_ptr<os::paging::PT>(PT_alloc.ptr.get_phys_addr())); - } - os::paging::PT& PT = *get_base_address(PDT.contents[indices.pde]); - if (PT.contents[indices.pe].P == 0) { - PT.contents[indices.pe] = {.P = 1, .R_W = R_W, .U_S = U_S, .PWT = 0, .PCD = 0, .PAT = 0, .G = 0, .base_address = 0, .NX = 0}; - const auto page_alloc = os::paging::page_allocator.allocate(1); - set_page_base_address(PT.contents[indices.pe], os::phys_ptr<os::paging::page>(page_alloc.ptr.get_phys_addr())); - invlpg(vaddr); } else { - os::assert(!must_be_unmapped, "Memory at address 0x{} has already been mapped.", std::uintptr_t(vaddr)); + assert(PDT.contents[indices.pde].non_page.zero == 0, + "Cannot map memory address 0x{} because it is inside a 2MiB page", std::uintptr_t(vaddr)); } + os::paging::PT& PT = *get_base_address(PDT.contents[indices.pde]); + os::assert(PT.contents[indices.pe].P == 0, "Memory at address 0x{} has already been mapped.", std::uintptr_t(vaddr)); + PT.contents[indices.pe] = + {.P = 1, .R_W = R_W, .U_S = U_S, .PWT = 0, .PCD = 0, .PAT = 0, .G = (indices.pml4e < 128) ? 0ul : 1ul, .base_address = 0, .NX = 0}; + const auto page_alloc = os::paging::page_allocator.allocate(1); + set_page_base_address(PT.contents[indices.pe], os::phys_ptr<os::paging::page>(page_alloc.ptr.get_phys_addr())); + invlpg(vaddr); } namespace { diff --git a/kernel/src/paging.hpp b/kernel/src/paging.hpp index a9a1946..9fcb6ee 100644 --- a/kernel/src/paging.hpp +++ b/kernel/src/paging.hpp @@ -235,7 +235,7 @@ constexpr page_table_indices calc_page_table_indices(const void* ptr) { }; } -void setup_page(PML4T& PML4T, const void* vaddr, bool R_W, bool U_S, bool must_be_unmapped); +void setup_page(PML4T& PML4T, const void* vaddr, bool R_W, bool U_S); // For all present page mappings, calls f(virtual address, physical address, page size in bytes (4KiB, 2MiB or 1GiB)). void on_all_pages(const PML4T& PML4T, void f(page*, phys_ptr<page>, std::size_t)); -- 2.46.0