diff options
8 files changed, 46 insertions, 54 deletions
diff --git a/arch/x86_64/CMakeLists.txt b/arch/x86_64/CMakeLists.txt index d5fb913..71b1946 100644 --- a/arch/x86_64/CMakeLists.txt +++ b/arch/x86_64/CMakeLists.txt @@ -105,7 +105,6 @@ target_sources("_context" PRIVATE "src/context_switching/interrupt_descriptor_table/interrupt_descriptor_table.cpp" "src/context_switching/interrupt_descriptor_table/ist_offset.cpp" "src/context_switching/interrupt_descriptor_table/segment_selector.cpp" - "src/context_switching/syscall_handler.cpp" ) #[============================================================================[ diff --git a/arch/x86_64/include/arch/context_switching/interrupt_descriptor_table/segment_selector.hpp b/arch/x86_64/include/arch/context_switching/interrupt_descriptor_table/segment_selector.hpp index e8854f9..7bfb563 100644 --- a/arch/x86_64/include/arch/context_switching/interrupt_descriptor_table/segment_selector.hpp +++ b/arch/x86_64/include/arch/context_switching/interrupt_descriptor_table/segment_selector.hpp @@ -82,6 +82,13 @@ namespace teachos::arch::context_switching::interrupt_descriptor_table */ auto operator|=(std::bitset<3U> other) -> void; + /** + * @brief Combines all bits in the underlying data in the correct order to return a raw value containing all bits. + * + * @return Underlying value combined into it's full size. + */ + operator uint16_t() const { return static_cast<uint64_t>(_flags) | (static_cast<uint64_t>(_index) << 3U); } + private: uint8_t _flags : 3 = {}; ///< Underlying bits used to read the flags from. uint16_t _index : 13 = diff --git a/arch/x86_64/include/arch/context_switching/main.hpp b/arch/x86_64/include/arch/context_switching/main.hpp index 5537174..f8477ea 100644 --- a/arch/x86_64/include/arch/context_switching/main.hpp +++ b/arch/x86_64/include/arch/context_switching/main.hpp @@ -46,8 +46,6 @@ namespace teachos::arch::context_switching auto switch_context(interrupt_descriptor_table::segment_selector data_segment, interrupt_descriptor_table::segment_selector code_segment, void (*return_function)()) -> void; - auto setup_syscall() -> void; - } // namespace teachos::arch::context_switching #endif // TEACHOS_ARCH_X86_64_CONTEXT_SWITCHING_MAIN_HPP diff --git a/arch/x86_64/include/arch/context_switching/syscall_handler.hpp b/arch/x86_64/include/arch/context_switching/syscall_handler.hpp deleted file mode 100644 index 5a46924..0000000 --- a/arch/x86_64/include/arch/context_switching/syscall_handler.hpp +++ /dev/null @@ -1,9 +0,0 @@ -#ifndef TEACHOS_ARCH_X86_64_CONTEXT_SWITCHING_SYSCALL_HANDLER_HPP -#define TEACHOS_ARCH_X86_64_CONTEXT_SWITCHING_SYSCALL_HANDLER_HPP - -namespace teachos::arch::context_switching -{ - [[gnu::naked]] - auto syscall_handler() -> void; -} -#endif
\ No newline at end of file diff --git a/arch/x86_64/src/context_switching/main.cpp b/arch/x86_64/src/context_switching/main.cpp index 155d150..f73cb19 100644 --- a/arch/x86_64/src/context_switching/main.cpp +++ b/arch/x86_64/src/context_switching/main.cpp @@ -1,7 +1,6 @@ #include "arch/context_switching/main.hpp" #include "arch/boot/pointers.hpp" -#include "arch/context_switching/syscall_handler.hpp" #include "arch/exception_handling/assert.hpp" #include "arch/kernel/cpu/call.hpp" #include "arch/kernel/cpu/control_register.hpp" @@ -30,6 +29,43 @@ namespace teachos::arch::context_switching auto reload_global_descriptor_table_register() -> void { kernel::cpu::call(KERNEL_CODE_POINTER); } + auto user_mode_main() -> void + { + kernel::cpu::validate_segment_registers(USER_DATA_SEGMENT_SELECTOR, USER_CODE_SEGMENT_SELECTOR); + + video::vga::text::write("Successfully entered user mode!", video::vga::text::common_attributes::green_on_black); + + asm volatile("syscall"); + + kernel::cpu::validate_segment_registers(USER_DATA_SEGMENT_SELECTOR, USER_CODE_SEGMENT_SELECTOR); + + video::vga::text::write("Successfully made a SYSCALL and returned back with SYSRET!", + video::vga::text::common_attributes::green_on_black); + } + + auto syscall_handler() -> void + { + uint64_t dummy{}; + switch (dummy) + { + case 0: + break; + default: + break; + } + + asm volatile("sysretq"); + } + + auto enable_systemcall() -> void + { + uint64_t const syscall_function = reinterpret_cast<uint64_t>(syscall_handler); + kernel::cpu::write_msr(IA32_LSTAR_ADDRESS, syscall_function); + kernel::cpu::write_msr(IA32_FMASK_ADDRESS, 0U); + kernel::cpu::write_msr(IA32_STAR_ADDRESS, KERNEL_CODE_SEGMENT_SELECTOR); + kernel::cpu::set_efer_bit(kernel::cpu::efer_flags::SCE); + } + } // namespace auto initialize_descriptor_tables() -> descriptor_tables @@ -55,17 +91,9 @@ namespace teachos::arch::context_switching return tables; } - auto user_mode_main() -> void - { - kernel::cpu::validate_segment_registers(USER_DATA_SEGMENT_SELECTOR, USER_CODE_SEGMENT_SELECTOR); - - asm volatile("SYSCALL"); - - video::vga::text::write("Successfully entered user mode!", video::vga::text::common_attributes::green_on_black); - } - auto switch_to_user_mode() -> void { + enable_systemcall(); switch_context(USER_DATA_SEGMENT_SELECTOR, USER_CODE_SEGMENT_SELECTOR, user_mode_main); } @@ -77,15 +105,4 @@ namespace teachos::arch::context_switching kernel::cpu::set_code_segment_register(data_segment, code_segment, reinterpret_cast<uint64_t>(return_function)); } - auto setup_syscall() -> void - { - uint64_t const syscall_function = reinterpret_cast<uint64_t>(syscall_handler); - uint64_t const segment_selector = *reinterpret_cast<uint64_t const *>(&KERNEL_CODE_SEGMENT_SELECTOR); - - kernel::cpu::write_msr(IA32_LSTAR_ADDRESS, syscall_function); - kernel::cpu::write_msr(IA32_FMASK_ADDRESS, 0U); - kernel::cpu::write_msr(IA32_STAR_ADDRESS, segment_selector); - kernel::cpu::set_efer_bit(kernel::cpu::efer_flags::SCE); - } - } // namespace teachos::arch::context_switching diff --git a/arch/x86_64/src/context_switching/syscall_handler.cpp b/arch/x86_64/src/context_switching/syscall_handler.cpp deleted file mode 100644 index 283d297..0000000 --- a/arch/x86_64/src/context_switching/syscall_handler.cpp +++ /dev/null @@ -1,19 +0,0 @@ -#include "arch/context_switching/syscall_handler.hpp" - -#include <cstdint> - -namespace teachos::arch::context_switching -{ - auto syscall_handler() -> void - { - uint64_t dummy{}; - switch (dummy) - { - case 0: - break; - default: - break; - } - asm volatile("SYSRET"); - } -} // namespace teachos::arch::context_switching
\ No newline at end of file diff --git a/arch/x86_64/src/kernel/cpu/msr.cpp b/arch/x86_64/src/kernel/cpu/msr.cpp index 6249f8f..9c474a1 100644 --- a/arch/x86_64/src/kernel/cpu/msr.cpp +++ b/arch/x86_64/src/kernel/cpu/msr.cpp @@ -16,7 +16,7 @@ namespace teachos::arch::kernel::cpu auto write_msr(uint32_t msr, uint64_t value) -> void { - uint32_t low = value & 0xFFFFFFFF; + uint32_t low = value; uint32_t high = value >> 32; asm volatile("wrmsr" : /* no output from call */ diff --git a/arch/x86_64/src/kernel/main.cpp b/arch/x86_64/src/kernel/main.cpp index e737d44..05c879e 100644 --- a/arch/x86_64/src/kernel/main.cpp +++ b/arch/x86_64/src/kernel/main.cpp @@ -63,7 +63,6 @@ namespace teachos::arch::kernel memory::heap::global_heap_allocator::register_heap_allocator(memory::heap::heap_allocator_type::LINKED_LIST); // heap_test(); - context_switching::setup_syscall(); context_switching::switch_to_user_mode(); } } // namespace teachos::arch::kernel |