From 1b964278762dde86b0b737bd9a34fec569339f54 Mon Sep 17 00:00:00 2001 From: Felix Morgner Date: Thu, 16 Apr 2026 10:29:30 +0200 Subject: x86_64: use p1204 project layout --- arch/x86_64/pre/src/context_switching/main.cpp | 66 ----------- .../pre/src/context_switching/syscall/main.cpp | 35 ------ .../context_switching/syscall/syscall_enable.cpp | 32 ------ .../context_switching/syscall/syscall_handler.cpp | 121 --------------------- 4 files changed, 254 deletions(-) delete mode 100644 arch/x86_64/pre/src/context_switching/main.cpp delete mode 100644 arch/x86_64/pre/src/context_switching/syscall/main.cpp delete mode 100644 arch/x86_64/pre/src/context_switching/syscall/syscall_enable.cpp delete mode 100644 arch/x86_64/pre/src/context_switching/syscall/syscall_handler.cpp (limited to 'arch/x86_64/pre/src/context_switching') diff --git a/arch/x86_64/pre/src/context_switching/main.cpp b/arch/x86_64/pre/src/context_switching/main.cpp deleted file mode 100644 index 0961499..0000000 --- a/arch/x86_64/pre/src/context_switching/main.cpp +++ /dev/null @@ -1,66 +0,0 @@ -#include - -#include -#include -#include -#include -#include -#include -#include - -namespace teachos::arch::context_switching -{ - namespace - { - constexpr interrupt_descriptor_table::segment_selector KERNEL_CODE_SEGMENT_SELECTOR{ - 1U, interrupt_descriptor_table::segment_selector::REQUEST_LEVEL_KERNEL}; - constexpr kernel::cpu::far_pointer KERNEL_CODE_POINTER{&kernel::cpu::reload_data_segment_registers, - KERNEL_CODE_SEGMENT_SELECTOR}; - constexpr context_switching::interrupt_descriptor_table::segment_selector USER_CODE_SEGMENT_SELECTOR{ - 3U, context_switching::interrupt_descriptor_table::segment_selector::REQUEST_LEVEL_USER}; - constexpr context_switching::interrupt_descriptor_table::segment_selector USER_DATA_SEGMENT_SELECTOR{ - 4U, context_switching::interrupt_descriptor_table::segment_selector::REQUEST_LEVEL_USER}; - - auto reload_gdtr() -> void - { - kernel::cpu::call(KERNEL_CODE_POINTER); - } - } // namespace - - auto initialize_descriptor_tables() -> descriptor_tables - { - bool static initalized = false; - - if (!initalized) - { - kernel::cpu::clear_interrupt_flag(); - - segment_descriptor_table::update_gdtr(); - interrupt_descriptor_table::update_interrupt_descriptor_table_register(); - - reload_gdtr(); - segment_descriptor_table::update_tss_register(); - - kernel::cpu::set_interrupt_flag(); - initalized = true; - } - - descriptor_tables tables = {segment_descriptor_table::get_or_create_gdt(), - interrupt_descriptor_table::get_or_create_interrupt_descriptor_table()}; - return tables; - } - - auto switch_to_user_mode() -> void - { - syscall::enable_syscall(); - switch_context(USER_DATA_SEGMENT_SELECTOR, USER_CODE_SEGMENT_SELECTOR, user::main); - } - - auto switch_context(interrupt_descriptor_table::segment_selector data_segment, - interrupt_descriptor_table::segment_selector code_segment, void (*return_function)()) -> void - { - (void)initialize_descriptor_tables(); - kernel::cpu::set_data_segment_registers(data_segment); - kernel::cpu::set_code_segment_register(data_segment, code_segment, reinterpret_cast(return_function)); - } -} // namespace teachos::arch::context_switching diff --git a/arch/x86_64/pre/src/context_switching/syscall/main.cpp b/arch/x86_64/pre/src/context_switching/syscall/main.cpp deleted file mode 100644 index 10bd087..0000000 --- a/arch/x86_64/pre/src/context_switching/syscall/main.cpp +++ /dev/null @@ -1,35 +0,0 @@ -#include - -namespace teachos::arch::context_switching::syscall -{ - auto syscall(type syscall_number, arguments args) -> response - { - asm volatile("mov %[input], %%rax" - : /* no output from call */ - : [input] "m"(syscall_number) - : "memory"); - - asm volatile("mov %[input], %%rdi " : /* no output from call */ : [input] "m"(args.arg_0) : "memory"); - asm volatile("mov %[input], %%rsi" : /* no output from call */ : [input] "m"(args.arg_1) : "memory"); - asm volatile("mov %[input], %%rdx" : /* no output from call */ : [input] "m"(args.arg_2) : "memory"); - asm volatile("mov %[input], %%r10" : /* no output from call */ : [input] "m"(args.arg_3) : "memory"); - asm volatile("mov %[input], %%r8" : /* no output from call */ : [input] "m"(args.arg_4) : "memory"); - asm volatile("mov %[input], %%r9" : /* no output from call */ : [input] "m"(args.arg_5) : "memory"); - - asm volatile("syscall"); - - arguments values{}; - asm volatile("mov %%rdi, %[output]" : [output] "=m"(values.arg_0)); - asm volatile("mov %%rsi, %[output]" : [output] "=m"(values.arg_1)); - asm volatile("mov %%rdx, %[output]" : [output] "=m"(values.arg_2)); - asm volatile("mov %%r10, %[output]" : [output] "=m"(values.arg_3)); - asm volatile("mov %%r8, %[output]" : [output] "=m"(values.arg_4)); - asm volatile("mov %%r9, %[output]" : [output] "=m"(values.arg_5)); - - error error_code{}; - asm volatile("mov %%al, %[output]" : [output] "=m"(error_code)); - - return {error_code, values}; - } - -} // namespace teachos::arch::context_switching::syscall diff --git a/arch/x86_64/pre/src/context_switching/syscall/syscall_enable.cpp b/arch/x86_64/pre/src/context_switching/syscall/syscall_enable.cpp deleted file mode 100644 index f9f070a..0000000 --- a/arch/x86_64/pre/src/context_switching/syscall/syscall_enable.cpp +++ /dev/null @@ -1,32 +0,0 @@ -#include - -#include -#include -#include - -namespace teachos::arch::context_switching::syscall -{ - namespace - { - constexpr interrupt_descriptor_table::segment_selector KERNEL_CODE_SEGMENT_SELECTOR{ - 1U, interrupt_descriptor_table::segment_selector::REQUEST_LEVEL_KERNEL}; - - constexpr auto IA32_STAR_ADDRESS = 0xC000'0081; - constexpr auto IA32_LSTAR_ADDRESS = 0xC000'0082; - constexpr auto IA32_FMASK_ADDRESS = 0xC000'0084; - - } // namespace - - auto enable_syscall() -> void - { - uint64_t const syscall_function = reinterpret_cast(syscall_handler); - kernel::cpu::write_msr(IA32_LSTAR_ADDRESS, syscall_function); - kernel::cpu::write_msr(IA32_FMASK_ADDRESS, 0U); - - uint64_t const kernel_cs = KERNEL_CODE_SEGMENT_SELECTOR; - uint64_t const star_value = (kernel_cs << 32) | (kernel_cs << 48); - kernel::cpu::write_msr(IA32_STAR_ADDRESS, star_value); - - kernel::cpu::set_efer_bit(kernel::cpu::efer_flags::SCE); - } -} // namespace teachos::arch::context_switching::syscall diff --git a/arch/x86_64/pre/src/context_switching/syscall/syscall_handler.cpp b/arch/x86_64/pre/src/context_switching/syscall/syscall_handler.cpp deleted file mode 100644 index 430d65c..0000000 --- a/arch/x86_64/pre/src/context_switching/syscall/syscall_handler.cpp +++ /dev/null @@ -1,121 +0,0 @@ -#include - -#include -#include -#include -#include -#include -#include - -namespace teachos::arch::context_switching::syscall -{ - - namespace - { - auto write_to_vga_buffer(uint64_t buffer) -> response - { - video::vga::text::write(reinterpret_cast(buffer), - video::vga::text::common_attributes::green_on_black); - video::vga::text::newline(); - return {error::OK}; - } - - auto expand_user_heap() -> response - { - auto static current_heap_end = memory::heap::USER_HEAP_START; - uint64_t const heap_start = current_heap_end; - memory::remap_heap(heap_start, memory::heap::USER_HEAP_SIZE, memory::paging::entry::USER_ACCESSIBLE); - current_heap_end += memory::heap::USER_HEAP_SIZE; - return { - error::OK, - {heap_start, memory::heap::USER_HEAP_SIZE} - }; - } - } // namespace - - auto syscall_handler() -> void - { - // Saving state of rcx and r11 because it is required by sysretq to function. - // Calls to other functions potentially overwrite these registers, because of - // callee saved calling convention. - uint64_t return_instruction_pointer, rflags = {}; - asm volatile("mov %%rcx, %[output]" : [output] "=m"(return_instruction_pointer)); - asm volatile("mov %%r11, %[output]" : [output] "=m"(rflags)); - - uint64_t syscall_number, arg_0, arg_1, arg_2, arg_3, arg_4, arg_5 = {}; - asm volatile("mov %%rdi, %[output]" : [output] "=m"(arg_0)); - asm volatile("mov %%rsi, %[output]" : [output] "=m"(arg_1)); - asm volatile("mov %%rdx, %[output]" : [output] "=m"(arg_2)); - asm volatile("mov %%r10, %[output]" : [output] "=m"(arg_3)); - asm volatile("mov %%r8, %[output]" : [output] "=m"(arg_4)); - asm volatile("mov %%r9, %[output]" : [output] "=m"(arg_5)); - - // RAX is read last, because paired with our type enum, we can use it to check - // if the register has been written by the compiled code between executing the syscall - // and now. - asm volatile("mov %%rax, %[output]" : [output] "=m"(syscall_number)); - - response result; - switch (static_cast(syscall_number)) - { - case type::WRITE: - result = write_to_vga_buffer(arg_0); - break; - case type::EXPAND_HEAP: - result = expand_user_heap(); - break; - case type::ASSERT: - teachos::arch::exception_handling::assert(arg_0, reinterpret_cast(arg_1)); - break; - default: - teachos::arch::exception_handling::panic("[Syscall Handler] Invalid syscall number"); - break; - } - - asm volatile("mov %[input], %%rax" - : /* no output from call */ - : [input] "m"(result.error_code) - : "memory"); - - asm volatile("mov %[input], %%rdi" - : /* no output from call */ - : [input] "m"(result.values.arg_0) - : "memory"); - asm volatile("mov %[input], %%rsi" - : /* no output from call */ - : [input] "m"(result.values.arg_1) - : "memory"); - asm volatile("mov %[input], %%rdx" - : /* no output from call */ - : [input] "m"(result.values.arg_2) - : "memory"); - asm volatile("mov %[input], %%r10" - : /* no output from call */ - : [input] "m"(result.values.arg_3) - : "memory"); - asm volatile("mov %[input], %%r8" - : /* no output from call */ - : [input] "m"(result.values.arg_4) - : "memory"); - asm volatile("mov %[input], %%r9" - : /* no output from call */ - : [input] "m"(result.values.arg_5) - : "memory"); - - asm volatile("mov %[input], %%rcx" - : /* no output from call */ - : [input] "m"(return_instruction_pointer) - : "memory"); - asm volatile("mov %[input], %%r11" - : /* no output from call */ - : [input] "m"(rflags) - : "memory"); - - // Additionally call leave, because x86 allocates stack space for the internal variables. If we do not clean up this - // newly created stack frame the syscall instruction that landed in this syscall_handler, will never return to the - // method that originally called it, because the RIP has not been restored from the previous stack frame. - asm volatile("leave\n" - "sysretq"); - } - -} // namespace teachos::arch::context_switching::syscall -- cgit v1.2.3