fix riscv syscall ABI. fix store user tp and kernel hartid

kernel/src/arch/riscv32/boot/trap.asm

@@ -15,18 +15,18 @@
     # the kernel stack pointer. If we came from the kernel, sscratch
     # will contain 0, and we should continue on the current stack.
     csrrw sp, (xscratch), sp
-    bnez sp, _save_context
-_restore_kernel_sp:
+    bnez sp, trap_from_user
+trap_from_kernel:
     csrr sp, (xscratch)
+    STORE gp, 0
     # sscratch = previous-sp, sp = kernel-sp
-_save_context:
+trap_from_user:
     # provide room for trap frame
     addi sp, sp, -36 * XLENB
     # save x registers except x2 (sp)
     STORE x1, 1
     STORE x3, 3
-    # tp(x4) = hartid. DON'T change.
-    # STORE x4, 4
+    STORE x4, 4
     STORE x5, 5
     STORE x6, 6
     STORE x7, 7
@@ -55,6 +55,9 @@ _save_context:
     STORE x30, 30
     STORE x31, 31
 
+    # load hartid to gp from sp[36]
+    LOAD gp, 36
+
     # get sp, sstatus, sepc, stval, scause
     # set sscratch = 0
     csrrw s0, (xscratch), x0
@@ -74,11 +77,12 @@ _save_context:
     LOAD s1, 32             # s1 = sstatus
     LOAD s2, 33             # s2 = sepc
     TEST_BACK_TO_KERNEL
-    bnez s0, _restore_context   # s0 = back to kernel?
-_save_kernel_sp:
+    bnez s0, _to_kernel     # s0 = back to kernel?
+_to_user:
     addi s0, sp, 36*XLENB
-    csrw (xscratch), s0         # sscratch = kernel-sp
-_restore_context:
+    csrw (xscratch), s0     # sscratch = kernel-sp
+    STORE gp, 36            # store hartid from gp to sp[36]
+_to_kernel:
     # restore sstatus, sepc
     csrw (xstatus), s1
     csrw (xepc), s2
@@ -86,7 +90,7 @@ _restore_context:
     # restore x registers except x2 (sp)
     LOAD x1, 1
     LOAD x3, 3
-    # LOAD x4, 4
+    LOAD x4, 4
     LOAD x5, 5
     LOAD x6, 6
     LOAD x7, 7
@@ -119,13 +123,13 @@ _restore_context:
 .endm
 
     .section .text
-    .globl __alltraps
-__alltraps:
+    .globl trap_entry
+trap_entry:
     SAVE_ALL
     mv a0, sp
     jal rust_trap
-    .globl __trapret
-__trapret:
+    .globl trap_return
+trap_return:
     RESTORE_ALL
     # return from supervisor call
     XRET

kernel/src/arch/riscv32/context.rs

@@ -19,6 +19,7 @@ pub struct TrapFrame {
     pub sepc: usize, // Supervisor exception program counter, save the trap virtual address (here is used to save the process program entry addr?)
     pub stval: usize, // Supervisor trap value
     pub scause: Mcause, // scause register: record the cause of exception/interrupt/trap
+    pub _hartid: usize, // reserve space
 }
 
 /// Generate the trapframe for building new thread in kernel
@@ -123,7 +124,7 @@ impl InitStack {
 }
 
 extern {
-    fn __trapret();
+    fn trap_return();
 }
 
 #[derive(Debug, Default)]
@@ -137,7 +138,7 @@ struct ContextData {
 impl ContextData {
     fn new(satp: usize) -> Self {
         // satp(asid) just like cr3, save the physical address for Page directory?
-        ContextData { ra: __trapret as usize, satp, ..ContextData::default() }
+        ContextData { ra: trap_return as usize, satp, ..ContextData::default() }
     }
 }
 

kernel/src/arch/riscv32/cpu.rs

@@ -4,13 +4,13 @@ use core::ptr::{read_volatile, write_volatile};
 static mut STARTED: [bool; MAX_CPU_NUM] = [false; MAX_CPU_NUM];
 
 pub unsafe fn set_cpu_id(cpu_id: usize) {
-    asm!("mv tp, $0" : : "r"(cpu_id));
+    asm!("mv gp, $0" : : "r"(cpu_id));
 }
 
 pub fn id() -> usize {
     let cpu_id;
     #[cfg(not(feature = "m_mode"))]
-    unsafe { asm!("mv $0, tp" : "=r"(cpu_id)); }
+    unsafe { asm!("mv $0, gp" : "=r"(cpu_id)); }
     #[cfg(feature = "m_mode")]
     unsafe { asm!("csrr $0, mhartid" : "=r"(cpu_id)); }
     cpu_id

kernel/src/arch/riscv32/interrupt.rs

@@ -24,14 +24,14 @@ mod context;
 */
 pub fn init() {
     extern {
-        fn __alltraps();
+        fn trap_entry();
     }
     unsafe {
         // Set sscratch register to 0, indicating to exception vector that we are
         // presently executing in the kernel
         xscratch::write(0);
         // Set the exception vector address
-        xtvec::write(__alltraps as usize, xtvec::TrapMode::Direct);
+        xtvec::write(trap_entry as usize, xtvec::TrapMode::Direct);
         // Enable IPI
         sie::set_ssoft();
         // Enable serial interrupt
@@ -168,7 +168,7 @@ fn timer() {
 */
 fn syscall(tf: &mut TrapFrame) {
     tf.sepc += 4;   // Must before syscall, because of fork.
-    let ret = crate::syscall::syscall(tf.x[10], [tf.x[11], tf.x[12], tf.x[13], tf.x[14], tf.x[15], tf.x[16]], tf);
+    let ret = crate::syscall::syscall(tf.x[17], [tf.x[10], tf.x[11], tf.x[12], tf.x[13], tf.x[14], tf.x[15]], tf);
     tf.x[10] = ret as usize;
 }
 

user

@@ -1 +1 @@
-Subproject commit f0441d1fe30022acfadced2224b00ed9a29db455
+Subproject commit 5ce1d2f7887b026ab5c5eb60f5aa4fb57390d349