justin/jsix_import
1
0
Fork 0
Code Issues 1 Pull Requests Actions Packages Projects Releases Wiki Activity

[boot][kernel] Split programs into sections

Browse Source 
To enable setting sections as NX or read-only, the boot program loader
now loads programs as lists of sections, and the kernel args are updated
accordingly. The kernel's loader now just takes a program pointer to
iterate the sections. Also enable NX in IA32_EFER in the bootloader.
This commit is contained in:
Justin C. Miller
2021-01-20 01:25:47 -08:00
parent 14aad62e02
commit cb612c36ea
13 changed files with 140 additions and 61 deletions
Download Patch File Download Diff File Expand all files Collapse all files

38
src/boot/paging.cpp
View File

@@ -15,7 +15,7 @@ using memory::page_size;
using ::memory::pml4e_kernel;
using ::memory::table_entries;
// Flags: 0 0 0 1 0 0 0 0 0 0 1 1 = 0x0103
// Flags: 0 0 0 1 0 0 0 0 0 0 0 1 = 0x0101
// IGN | | | | | | | | +- Present
// | | | | | | | +--- Writeable
// | | | | | | +----- Usermode access (supervisor only)
@@ -26,7 +26,7 @@ using ::memory::table_entries;
// | +---------------- PAT (determining memory type for page)
// +------------------- Global
/// Page table entry flags for entries pointing at a page
constexpr uint16_t page_flags = 0x103;
constexpr uint64_t page_flags = 0x101;
// Flags: 0 0 0 0 1 1 0 0 0 1 0 1 1 = 0x018b
// | IGN | | | | | | | | +- Present
@@ -40,7 +40,7 @@ constexpr uint16_t page_flags = 0x103;
// | +------------------- Global
// +---------------------------- PAT (determining memory type for page)
/// Page table entry flags for entries pointing at a huge page
constexpr uint16_t huge_page_flags = 0x183;
constexpr uint64_t huge_page_flags = 0x18b;
// Flags: 0 0 0 0 0 0 0 0 0 0 1 1 = 0x0003
// IGNORED | | | | | | | +- Present
@@ -52,7 +52,7 @@ constexpr uint16_t huge_page_flags = 0x183;
// | +-------------- Ignored
// +---------------- Reserved 0 (Table pointer, not page)
/// Page table entry flags for entries pointing at another table
constexpr uint16_t table_flags = 0x003;
constexpr uint64_t table_flags = 0x003;
/// Iterator over page table entries.
template <unsigned D = 4>
@@ -191,7 +191,7 @@ allocate_tables(kernel::args::header *args, uefi::boot_services *bs)
status_line status(L"Allocating initial page tables");
static constexpr size_t pd_tables = 256; // number of pages for kernelspace PDs
static constexpr size_t extra_tables = 49; // number of extra pages
static constexpr size_t extra_tables = 64; // number of extra pages
// number of pages for kernelspace PDs + PML4
static constexpr size_t kernel_tables = pd_tables + 1;
@@ -223,23 +223,39 @@ allocate_tables(kernel::args::header *args, uefi::boot_services *bs)
console::print(L" Set up initial mappings, %d spare tables.\r\n", args->table_count);
}
template <typename E>
constexpr bool has_flag(E set, E flag) {
return
(static_cast<uint64_t>(set) & static_cast<uint64_t>(flag)) ==
static_cast<uint64_t>(flag);
}
void
map_pages(
map_section(
kernel::args::header *args,
uintptr_t phys, uintptr_t virt,
size_t size)
const kernel::args::program_section &section)
{
paging::page_table *pml4 =
reinterpret_cast<paging::page_table*>(args->pml4);
size_t pages = memory::bytes_to_pages(size);
size_t pages = memory::bytes_to_pages(section.size);
page_entry_iterator<4> iterator{
virt, pml4,
section.virt_addr, pml4,
args->page_tables,
args->table_count};
using kernel::args::section_flags;
uint64_t flags = page_flags;
if (!has_flag(section.type, section_flags::execute))
flags |= (1ull << 63); // set NX bit
if (has_flag(section.type, section_flags::write))
flags |= 2;
uintptr_t phys = section.phys_addr;
while (true) {
*iterator = phys | page_flags;
*iterator = phys | flags;
if (--pages == 0)
break;