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Kernel/riscv64: Don't use the memory before .text as the initial stack

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This new stack has the same size as the x86_64 prekernel stack (32K).
This commit is contained in:
Sönke Holz 2024-02-15 21:12:06 +01:00 • committed by Jelle Raaijmakers
parent 3b6a300ed7
commit 227818de9b
3 changed files with 8 additions and 10 deletions
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8
Kernel/Arch/riscv64/MMU.cpp
View file

@ -150,20 +150,12 @@ static UNMAP_AFTER_INIT void build_mappings(PageBumpAllocator& allocator, u64* r
auto start_of_kernel_range = VirtualAddress { bit_cast<FlatPtr>(+start_of_kernel_image) }; auto start_of_kernel_range = VirtualAddress { bit_cast<FlatPtr>(+start_of_kernel_image) };
auto end_of_kernel_range = VirtualAddress { bit_cast<FlatPtr>(+end_of_kernel_image) }; auto end_of_kernel_range = VirtualAddress { bit_cast<FlatPtr>(+end_of_kernel_image) };
// FIXME: don't use the memory before `start` as the stack
auto start_of_stack_range = VirtualAddress { bit_cast<FlatPtr>(+start_of_kernel_image) }.offset(-64 * KiB);
auto end_of_stack_range = VirtualAddress { bit_cast<FlatPtr>(+start_of_kernel_image) };
auto start_of_physical_kernel_range = PhysicalAddress { start_of_kernel_range.get() }.offset(-calculate_physical_to_link_time_address_offset()); auto start_of_physical_kernel_range = PhysicalAddress { start_of_kernel_range.get() }.offset(-calculate_physical_to_link_time_address_offset());
auto start_of_physical_stack_range = PhysicalAddress { start_of_stack_range.get() }.offset(-calculate_physical_to_link_time_address_offset());
// FIXME: dont map everything RWX // FIXME: dont map everything RWX
// Map kernel into high virtual memory // Map kernel into high virtual memory
insert_entries_for_memory_range(allocator, root_table, start_of_kernel_range, end_of_kernel_range, start_of_physical_kernel_range, PageTableEntryBits::Readable | PageTableEntryBits::Writeable | PageTableEntryBits::Executable); insert_entries_for_memory_range(allocator, root_table, start_of_kernel_range, end_of_kernel_range, start_of_physical_kernel_range, PageTableEntryBits::Readable | PageTableEntryBits::Writeable | PageTableEntryBits::Executable);
// Map the stack
insert_entries_for_memory_range(allocator, root_table, start_of_stack_range, end_of_stack_range, start_of_physical_stack_range, PageTableEntryBits::Readable | PageTableEntryBits::Writeable);
} }
static UNMAP_AFTER_INIT void setup_kernel_page_directory(u64* root_table) static UNMAP_AFTER_INIT void setup_kernel_page_directory(u64* root_table)

4
Kernel/Arch/riscv64/boot.S
View file

@ -35,8 +35,8 @@ Lclear_bss_loop:
bltu t0, t1, Lclear_bss_loop bltu t0, t1, Lclear_bss_loop
Lclear_bss_done: Lclear_bss_done:
// Let the stack start before .text for now. // Set the stack pointer register to the location defined in the linker script.
lla sp, start lla sp, end_of_initial_stack
// Zero all registers except sp, a0 and a1. // Zero all registers except sp, a0 and a1.
li ra, 0 li ra, 0

6
Kernel/Arch/riscv64/linker.ld
View file

@ -98,6 +98,12 @@ SECTIONS
*(.heap) *(.heap)
} :bss } :bss
. = ALIGN(4K);
start_of_initial_stack = .;
. += 32K;
end_of_initial_stack = .;
/* /*
FIXME: 8MB is enough space for all of the tables required to identity map FIXME: 8MB is enough space for all of the tables required to identity map
physical memory. 8M is wasteful, so this should be properly calculated. physical memory. 8M is wasteful, so this should be properly calculated.