[guest/exceptions] changed the ABI of exception related logic

We used the sysv64 ABI for exception stuff. This ABI is not available for every target so having it there
unconditionally makes the hyperlight_guest lib not be compilable to said targets. This commit changes the ABI to "C"
(i.e., smt more commonly used) and gates it behind a x86_64 cfg as the assembly code is dependent on 64-bit
architectures.

Signed-off-by: danbugs <[email protected]>

Author: danbugs

src/hyperlight_guest/src/entrypoint.rs

@@ -22,11 +22,11 @@ use hyperlight_common::outb::OutBAction;
 use log::LevelFilter;
 use spin::Once;
 
-use crate::gdt::load_gdt;
+#[cfg(target_arch = "x86_64")]
+use crate::exceptions::{gdt::load_gdt, idtr::load_idt};
 use crate::guest_function_call::dispatch_function;
 use crate::guest_logger::init_logger;
 use crate::host_function_call::outb;
-use crate::idtr::load_idt;
 use crate::{__security_cookie, HEAP_ALLOCATOR, MIN_STACK_ADDRESS, OS_PAGE_SIZE, P_PEB};
 
 #[inline(never)]
@@ -103,9 +103,12 @@ pub extern "win64" fn entrypoint(peb_address: u64, seed: u64, ops: u64, max_log_
             // don't have to change the assembly code.
             MIN_STACK_ADDRESS = (*peb_ptr).gueststackData.minUserStackAddress;
 
-            // Setup GDT and IDT
-            load_gdt();
-            load_idt();
+            #[cfg(target_arch = "x86_64")]
+            {
+                // Setup GDT and IDT
+                load_gdt();
+                load_idt();
+            }
 
             let heap_start = (*peb_ptr).guestheapData.guestHeapBuffer as usize;
             let heap_size = (*peb_ptr).guestheapData.guestHeapSize as usize;

src/hyperlight_guest/src/gdt.rs renamed to src/hyperlight_guest/src/exceptions/gdt.rs

@@ -24,7 +24,7 @@ use crate::entrypoint::abort_with_code_and_message;
 
 /// Exception handler
 #[no_mangle]
-pub extern "sysv64" fn hl_exception_handler(
+pub extern "C" fn hl_exception_handler(
     stack_pointer: u64,
     exception_number: u64,
     page_fault_address: u64,

src/hyperlight_guest/src/interrupt_handlers.rs renamed to src/hyperlight_guest/src/exceptions/handlers.rs

@@ -16,7 +16,7 @@ limitations under the License.
 
 use hyperlight_common::outb::Exception;
 
-use crate::interrupt_entry::{
+use crate::exceptions::interrupt_entry::{
     _do_excp0, _do_excp1, _do_excp10, _do_excp11, _do_excp12, _do_excp13, _do_excp14, _do_excp15,
     _do_excp16, _do_excp17, _do_excp18, _do_excp19, _do_excp2, _do_excp20, _do_excp3, _do_excp30,
     _do_excp4, _do_excp5, _do_excp6, _do_excp7, _do_excp8, _do_excp9,
@@ -96,7 +96,7 @@ pub(crate) fn init_idt() {
     set_idt_entry(Exception::SecurityException as usize, _do_excp30); // Security Exception
 }
 
-fn set_idt_entry(index: usize, handler: unsafe extern "sysv64" fn()) {
+fn set_idt_entry(index: usize, handler: unsafe extern "C" fn()) {
     let handler_addr = handler as *const () as u64;
     unsafe {
         IDT[index] = IdtEntry::new(handler_addr);

src/hyperlight_guest/src/idt.rs renamed to src/hyperlight_guest/src/exceptions/idt.rs

@@ -1,6 +1,6 @@
 use core::ptr::addr_of;
 
-use crate::idt::{init_idt, IdtEntry, IDT};
+use crate::exceptions::idt::{init_idt, IdtEntry, IDT};
 
 #[repr(C, packed)]
 pub struct Idtr {

src/hyperlight_guest/src/idtr.rs renamed to src/hyperlight_guest/src/exceptions/idtr.rs

@@ -19,9 +19,9 @@ limitations under the License.
 
 use core::arch::global_asm;
 
-use crate::interrupt_handlers::hl_exception_handler;
+use crate::exceptions::handlers::hl_exception_handler;
 
-extern "sysv64" {
+extern "C" {
     // Exception handlers
     pub(crate) fn _do_excp0();
     pub(crate) fn _do_excp1();
@@ -119,7 +119,6 @@ macro_rules! generate_exceptions {
             // Common exception handler
             ".global _do_excp_common\n",
             "_do_excp_common:\n",
-            // In SysV ABI, the first argument is passed in rdi
             // rdi is the stack pointer.
             "    mov rdi, rsp\n",
             "    call {hl_exception_handler}\n",
@@ -173,12 +172,10 @@ macro_rules! generate_excp {
             stringify!($num),
             ":\n",
             context_save!(),
-            // In SysV ABI, the second argument is passed in rsi
             // rsi is the exception number.
             "    mov rsi, ",
             stringify!($num),
             "\n",
-            // In SysV ABI, the third argument is passed in rdx
             // rdx is only used for pagefault exception and
             // contains the address that caused the pagefault.
             "    mov rdx, 0\n",
@@ -198,12 +195,10 @@ macro_rules! generate_excp {
             // stack aligned.
             "   push 0\n",
             context_save!(),
-            // In SysV ABI, the second argument is passed in rsi
             // rsi is the exception number.
             "    mov rsi, ",
             stringify!($num),
             "\n",
-            // In SysV ABI, the third argument is passed in rdx
             // rdx is only used for pagefault exception and
             // contains the address that caused the pagefault.
             "    mov rdx, 0\n",

src/hyperlight_guest/src/interrupt_entry.rs renamed to src/hyperlight_guest/src/exceptions/interrupt_entry.rs

@@ -44,11 +44,14 @@ pub mod print;
 pub(crate) mod security_check;
 
 pub mod error;
-pub mod gdt;
-pub mod idt;
-pub mod idtr;
-pub mod interrupt_entry;
-pub mod interrupt_handlers;
+#[cfg(target_arch = "x86_64")]
+pub mod exceptions {
+    pub mod gdt;
+    pub mod handlers;
+    pub mod idt;
+    pub mod idtr;
+    pub mod interrupt_entry;
+}
 pub mod logging;
 
 // Unresolved symbols