Replace iopl with either empty or full PIO bitmap.

src/syscall/driver.rs

@@ -2,7 +2,6 @@ use alloc::sync::Arc;
 
 use crate::{
     context,
-    interrupt::InterruptStack,
     paging::VirtualAddress,
     syscall::error::{Error, Result, EFAULT, EINVAL, EPERM, ESRCH},
 };
@@ -18,32 +17,15 @@ fn enforce_root() -> Result<()> {
 }
 
 #[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))]
-pub fn iopl(level: usize, stack: &mut InterruptStack) -> Result<usize> {
+pub fn iopl(level: usize) -> Result<usize> {
     Err(Error::new(syscall::error::ENOSYS))
 }
 
-#[cfg(target_arch = "x86")]
-pub fn iopl(level: usize, stack: &mut InterruptStack) -> Result<usize> {
+#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
+pub fn iopl(level: usize) -> Result<usize> {
     enforce_root()?;
 
-    if level > 3 {
-        return Err(Error::new(EINVAL));
-    }
-
-    stack.iret.eflags = (stack.iret.eflags & !(3 << 12)) | ((level & 3) << 12);
-
-    Ok(0)
-}
-
-#[cfg(target_arch = "x86_64")]
-pub fn iopl(level: usize, stack: &mut InterruptStack) -> Result<usize> {
-    enforce_root()?;
-
-    if level > 3 {
-        return Err(Error::new(EINVAL));
-    }
-
-    stack.iret.rflags = (stack.iret.rflags & !(3 << 12)) | ((level & 3) << 12);
+    context::current()?.write().set_userspace_io_allowed(level >= 3);
 
     Ok(0)
 }

src/syscall/mod.rs

@@ -20,9 +20,9 @@ use self::{
     usercopy::UserSlice,
 };
 
+use crate::interrupt::InterruptStack;
 use crate::{
     context::{memory::AddrSpace, ContextId},
-    interrupt::InterruptStack,
     scheme::{memory::MemoryScheme, FileHandle, SchemeNamespace},
 };
 
@@ -69,7 +69,6 @@ pub fn syscall(
         d: usize,
         e: usize,
         f: usize,
-        stack: &mut InterruptStack,
     ) -> Result<usize> {
         //SYS_* is declared in kernel/syscall/src/number.rs
         match a & SYS_CLASS {
@@ -191,7 +190,7 @@ pub fn syscall(
                     WaitFlags::from_bits_truncate(d),
                 )
                 .map(ContextId::into),
-                SYS_IOPL => iopl(b, stack),
+                SYS_IOPL => iopl(b),
                 SYS_GETEGID => getegid(),
                 SYS_GETENS => getens(),
                 SYS_GETEUID => geteuid(),
@@ -283,7 +282,7 @@ pub fn syscall(
         }
     }
 
-    let result = inner(a, b, c, d, e, f, stack);
+    let result = inner(a, b, c, d, e, f);
 
     {
         let contexts = crate::context::contexts();