syscall: move the syscall handler to x85_64/

Signed-off-by: Andy-Python-Programmer <[email protected]>

Author: Andy-Python-Programmer

src/aero_kernel/src/arch/x86_64/mod.rs

@@ -21,6 +21,7 @@ pub mod controlregs;
 pub mod gdt;
 pub mod interrupts;
 pub mod signals;
+pub mod syscall;
 pub mod task;
 pub mod tls;
 
@@ -198,6 +199,8 @@ extern "C" fn x86_64_aero_main(boot_info: &'static StivaleStruct) -> ! {
     gdt::init(stack_top_addr);
     log::info!("loaded GDT");
 
+    syscall::init();
+
     // Architecture init is done. Now we can initialize and start the init
     // process in the non-architecture specific part of the kernel.
     crate::aero_main();
@@ -216,6 +219,8 @@ extern "C" fn x86_64_aero_ap_main(ap_id: usize, stack_top_addr: VirtAddr) {
     gdt::init(stack_top_addr);
     log::info!("AP{}: loaded GDT", ap_id);
 
+    syscall::init();
+
     apic::mark_ap_ready(true);
 
     // Wait for the BSP to be ready (after the BSP has initialized

src/aero_kernel/src/arch/x86_64/syscall.rs

@@ -0,0 +1,40 @@
+use raw_cpuid::CpuId;
+
+use crate::arch::gdt::GdtEntryType;
+use crate::utils::io;
+
+extern "C" {
+    fn x86_64_syscall_handler();
+}
+
+/// Initializes support for the `syscall` and `sysret` instructions for the
+/// current CPU.
+pub(super) fn init() {
+    // Check if syscall is supported as it is a required CPU feature for aero to run.
+    let has_syscall = CpuId::new()
+        .get_extended_processor_and_feature_identifiers()
+        .map_or(false, |i| i.has_syscall_sysret());
+
+    assert!(has_syscall);
+
+    unsafe {
+        /*
+         * Enable support for `syscall` and `sysret` instructions if the current
+         * CPU supports them and the target pointer width is 64.
+         */
+        let syscall_base = GdtEntryType::KERNEL_CODE << 3;
+        let sysret_base = (GdtEntryType::USER_CODE32_UNUSED << 3) | 3;
+
+        let star_hi = syscall_base as u32 | ((sysret_base as u32) << 16);
+
+        io::wrmsr(io::IA32_STAR, (star_hi as u64) << 32);
+        io::wrmsr(io::IA32_LSTAR, x86_64_syscall_handler as u64);
+
+        // Clear the trap flag and enable interrupts.
+        io::wrmsr(io::IA32_FMASK, 0x300);
+
+        // Set the EFER.SCE bit to enable the syscall feature
+        let efer = io::rdmsr(io::IA32_EFER);
+        io::wrmsr(io::IA32_EFER, efer | 1);
+    }
+}

src/aero_kernel/src/syscall/handler.asm renamed to src/aero_kernel/src/arch/x86_64/syscall_handler.asm

@@ -15,11 +15,8 @@
 ; You should have received a copy of the GNU General Public License
 ; along with Aero. If not, see <https://www.gnu.org/licenses/>.
 
-extern restore_kernel_fs_base_locked
-extern restore_user_tls
 extern __inner_syscall
-
-global syscall_handler
+global x86_64_syscall_handler
 
 %define TSS_TEMP_USTACK_OFF 0x1c
 %define TSS_RSP0_OFF        0x04
@@ -49,7 +46,7 @@ global syscall_handler
 ;
 ; The instruction also does not save anything on the stack and does
 ; *not* change the RSP.
-syscall_handler:
+x86_64_syscall_handler:
     ; swap the GS base to ensure that it points to the 
     ; kernel PCR.
     swapgs
@@ -112,8 +109,7 @@ syscall_handler:
     add rsp, 8
     pop r11
 
-    pop qword [gs:TSS_TEMP_USTACK_OFF]
-    mov rsp, [gs:TSS_TEMP_USTACK_OFF]
+    pop rsp
 
     swapgs
     o64 sysret

src/aero_kernel/src/arch/x86_64/task.asm

@@ -35,10 +35,15 @@ jump_userland_exec:
     o64 sysret
 
 fork_init:
+    cli
     swapgs
-    jmp iretq_init
+    jmp generic_iretq_init
 
 iretq_init:
+    cli
+    jmp generic_iretq_init
+
+generic_iretq_init:
     ; pop the preserved registers
     pop r15
     pop r14

src/aero_kernel/src/main.rs

@@ -117,8 +117,8 @@ fn aero_main() -> ! {
     time::init();
     log::info!("loaded timer");
 
-    userland::init();
-    log::info!("loaded userland");
+    userland::scheduler::init();
+    log::info!("loaded scheduler");
 
     apic::mark_bsp_ready(true);
 
@@ -171,7 +171,6 @@ fn kernel_main_thread() {
 }
 
 extern "C" fn aero_ap_main(ap_id: usize) -> ! {
-    userland::init_ap();
     log::info!("AP{}: Loaded userland", ap_id);
 
     loop {

src/aero_kernel/src/syscall/mod.rs

@@ -73,13 +73,12 @@ use alloc::vec::Vec;
 pub use fs::*;
 pub use ipc::*;
 pub use process::*;
-use raw_cpuid::CpuId;
 pub use time::*;
 
 use crate::arch::interrupts::InterruptStack;
 use crate::arch::signals;
-use crate::arch::{gdt::GdtEntryType, interrupts};
-use crate::utils::{io, StackHelper};
+use crate::arch::{interrupts};
+use crate::utils::{StackHelper};
 
 pub struct ExecArgs {
     inner: Vec<Box<[u8]>>,
@@ -246,37 +245,3 @@ extern "C" fn __inner_syscall(stack: &mut InterruptStack) {
     crate::arch::signals::syscall_check_signals(result_usize as isize, stack);
     stack.scratch.rax = result_usize;
 }
-
-extern "C" {
-    fn syscall_handler();
-}
-
-pub fn init() {
-    // Check if syscall is supported as it is a required CPU feature for aero to run.
-    let has_syscall = CpuId::new()
-        .get_extended_processor_and_feature_identifiers()
-        .map_or(false, |i| i.has_syscall_sysret());
-
-    assert!(has_syscall);
-
-    unsafe {
-        /*
-         * Enable support for `syscall` and `sysret` instructions if the current
-         * CPU supports them and the target pointer width is 64.
-         */
-        let syscall_base = GdtEntryType::KERNEL_CODE << 3;
-        let sysret_base = (GdtEntryType::USER_CODE32_UNUSED << 3) | 3;
-
-        let star_hi = syscall_base as u32 | ((sysret_base as u32) << 16);
-
-        io::wrmsr(io::IA32_STAR, (star_hi as u64) << 32);
-        io::wrmsr(io::IA32_LSTAR, syscall_handler as u64);
-
-        // Clear the trap flag and enable interrupts.
-        io::wrmsr(io::IA32_FMASK, 0x300);
-
-        // Set the EFER.SCE bit to enable the syscall feature
-        let efer = io::rdmsr(io::IA32_EFER);
-        io::wrmsr(io::IA32_EFER, efer | 1);
-    }
-}

src/aero_kernel/src/userland/mod.rs

@@ -20,8 +20,6 @@
 use crate::fs;
 use crate::fs::Path;
 
-use crate::syscall;
-
 pub mod scheduler;
 pub mod signals;
 pub mod task;
@@ -43,12 +41,3 @@ pub fn run_tests() -> fs::Result<()> {
     scheduler::get_scheduler().exec(utest_inode, None, None);
     Ok(())
 }
-
-pub fn init_ap() {
-    syscall::init();
-}
-
-pub fn init() {
-    scheduler::init();
-    syscall::init();
-}