Remove the `AT_NULL` variant

kernel/src/process/process_vm/init_stack/aux_vec.rs

@@ -17,7 +17,6 @@ use crate::prelude::*;
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
 #[repr(u8)]
 pub enum AuxKey {
-    AT_NULL = 0,      /* end of vector */
     AT_IGNORE = 1,    /* entry should be ignored */
     AT_EXECFD = 2,    /* file descriptor of program */
     AT_PHDR = 3,      /* program headers for program */
@@ -49,6 +48,11 @@ pub enum AuxKey {
     AT_SYSINFO_EHDR = 33, /* the start address of the page containing the VDSO */
 }
 
+impl AuxKey {
+    /// A special auxiliary key that denotes the end of the auxiliary vector.
+    pub(super) const AT_NULL: u8 = 0;
+}
+
 #[derive(Clone, Default, Debug)]
 pub struct AuxVec {
     table: BTreeMap<AuxKey, u64>,
@@ -61,18 +65,14 @@ impl AuxVec {
         }
     }
 
-    pub fn set(&mut self, key: AuxKey, val: u64) -> Result<()> {
-        if key == AuxKey::AT_NULL || key == AuxKey::AT_IGNORE {
-            return_errno_with_message!(Errno::EINVAL, "Illegal key");
-        }
+    pub fn set(&mut self, key: AuxKey, val: u64) {
         self.table
             .entry(key)
             .and_modify(|val_mut| *val_mut = val)
             .or_insert(val);
-        Ok(())
     }
 
-    pub fn table(&self) -> &BTreeMap<AuxKey, u64> {
+    pub(super) fn table(&self) -> &BTreeMap<AuxKey, u64> {
         &self.table
     }
 }

kernel/src/process/process_vm/init_stack/mod.rs

@@ -259,7 +259,7 @@ impl InitStackWriter<'_> {
             let random_value = generate_random_for_aux_vec();
             self.write_bytes(&random_value)?
         };
-        self.auxvec.set(AuxKey::AT_RANDOM, random_value_pointer)?;
+        self.auxvec.set(AuxKey::AT_RANDOM, random_value_pointer);
 
         self.adjust_stack_alignment(&envp_pointers, &argv_pointers)?;
         self.write_aux_vec()?;

kernel/src/process/program_loader/elf/load_elf.rs

@@ -74,9 +74,7 @@ pub fn load_elf_to_vmar(
     if let Some(vdso_text_base) = map_vdso_to_vmar(vmar) {
         #[cfg(target_arch = "riscv64")]
         vmar.process_vm().set_vdso_base(vdso_text_base);
-        aux_vec
-            .set(AuxKey::AT_SYSINFO_EHDR, vdso_text_base as u64)
-            .unwrap();
+        aux_vec.set(AuxKey::AT_SYSINFO_EHDR, vdso_text_base as u64);
     }
 
     vmar.process_vm()
@@ -166,7 +164,7 @@ fn map_vmos_and_build_aux_vec(
     } else {
         0
     };
-    aux_vec.set(AuxKey::AT_SECURE, secure)?;
+    aux_vec.set(AuxKey::AT_SECURE, secure);
 
     let entry_point = if let Some(ldso_load_info) = ldso_load_info {
         ldso_load_info.entry_point
@@ -431,7 +429,7 @@ fn init_aux_vec(
 ) -> Result<AuxVec> {
     let mut aux_vec = AuxVec::new();
 
-    aux_vec.set(AuxKey::AT_PAGESZ, PAGE_SIZE as _)?;
+    aux_vec.set(AuxKey::AT_PAGESZ, PAGE_SIZE as _);
 
     let Some(ph_vaddr) = elf_map_range.relocated_addr_of(elf.find_vaddr_of_phdrs()?) else {
         return_errno_with_message!(
@@ -439,9 +437,9 @@ fn init_aux_vec(
             "the ELF program headers are not located in any segments"
         );
     };
-    aux_vec.set(AuxKey::AT_PHDR, ph_vaddr as u64)?;
-    aux_vec.set(AuxKey::AT_PHNUM, elf.ph_count() as u64)?;
-    aux_vec.set(AuxKey::AT_PHENT, elf.ph_ent() as u64)?;
+    aux_vec.set(AuxKey::AT_PHDR, ph_vaddr as u64);
+    aux_vec.set(AuxKey::AT_PHNUM, elf.ph_count() as u64);
+    aux_vec.set(AuxKey::AT_PHENT, elf.ph_ent() as u64);
 
     let Some(entry_vaddr) = elf_map_range.relocated_addr_of(elf.entry_point()) else {
         return_errno_with_message!(
@@ -449,10 +447,10 @@ fn init_aux_vec(
             "the entry point is not located in any segments"
         );
     };
-    aux_vec.set(AuxKey::AT_ENTRY, entry_vaddr as u64)?;
+    aux_vec.set(AuxKey::AT_ENTRY, entry_vaddr as u64);
 
     if let Some(ldso_base) = ldso_base {
-        aux_vec.set(AuxKey::AT_BASE, ldso_base as u64)?;
+        aux_vec.set(AuxKey::AT_BASE, ldso_base as u64);
     }
 
     Ok(aux_vec)