Supervisor trap & claim MSI

build.bat

@@ -11,6 +11,7 @@ clang %CC_OPTS% kernel\lib.c -c -o build\lib.o
 clang %CC_OPTS% kernel\vm.c -c -o build\vm.o
 clang %CC_OPTS% kernel\spinlock.c -c -o build\spinlock.o
 clang %CC_OPTS% kernel\aplic.c -c -o build\aplic.o
+clang %CC_OPTS% kernel\strap.s -c -o build\strap.o
 
 ld.lld -T kernel\linker.lds -o build\kernel.elf ^
 	build\boot.o ^
@@ -20,3 +21,4 @@ ld.lld -T kernel\linker.lds -o build\kernel.elf ^
 	build\vm.o ^
 	build\spinlock.o ^
 	build\aplic.o ^
+	build\strap.o ^

kernel/aplic.c

@@ -1,5 +1,4 @@
 #include "kernel/aplic.h"
-#include "kernel/spinlock.h"
 
 static volatile char* APLIC_M = (volatile char*)0x0c00'0000;
 static volatile char* APLIC_S = (volatile char*)0x0d00'0000;
@@ -109,13 +108,22 @@ void aplic_init()
     
     aplic_w_smsiaddr(APLIC_M, (void*)IMSIC_S);
 
-    uint32_t uart_source = 10;
-    aplic_w_sourcecfg_delegate(APLIC_M, uart_source, 0);
-    aplic_w_sourcecfg_active_high(APLIC_S, uart_source);
-    aplic_w_target_msi(APLIC_S, uart_source, 0, 0, uart_source);
-    aplic_enable_intr(APLIC_S, uart_source);
-
     imsic_w_seithreshold(0);
     imsic_w_seidelivery(EIDELIVERY_ENABLED);
-    imsic_s_seie(uart_source);
+}
+
+void aplic_enable_intr_s(uint32_t source, uint32_t msg)
+{
+    aplic_w_sourcecfg_delegate(APLIC_M, source, 0);
+    aplic_w_sourcecfg_active_high(APLIC_S, source);
+    aplic_w_target_msi(APLIC_S, source, 0, 0, msg);
+    aplic_enable_intr(APLIC_S, source);
+    imsic_s_seie(msg);
+}
+
+uint32_t aplic_claim_msi_s()
+{
+    uint32_t intr;
+    __asm__ volatile("csrrw %0, stopei, zero" : "=r"(intr));
+    return intr >> 16;
 }

kernel/aplic.h

@@ -4,3 +4,5 @@
 
 void aplic_init();
 
+void aplic_enable_intr_s(uint32_t source, uint32_t msg);
+uint32_t aplic_claim_msi_s();

kernel/start.c

@@ -11,29 +11,56 @@ extern uint32_t _bss_start;
 extern uint32_t _bss_end;
 extern uint32_t _ram_end;
 
-void kstrap()
+#define UART_MSI 1
+
+extern uint32_t strap;
+
+void ktrap(uint32_t cause)
 {
-    uint32_t scause;
+    if ((cause & 0x8000'0000) == 0)
-    __asm__ volatile("csrr %0, scause" : "=r"(scause));
-    switch (scause)
     {
-        case 0: panic("kstrap: Instruction address misaligned");
+        switch (cause)
-        case 1: panic("kstrap: Instruction access fault");
+        {
-        case 2: panic("kstrap: Illegal instruction");
+            case 0:  panic("kstrap: Instruction address misaligned");
-        case 3: panic("kstrap: Breakpoint");
+            case 1:  panic("kstrap: Instruction access fault");
-        case 4: panic("kstrap: Load address misaligned");
+            case 2:  panic("kstrap: Illegal instruction");
-        case 5: panic("kstrap: Load access fault");
+            case 3:  panic("kstrap: Breakpoint");
-        case 6: panic("kstrap: Store/AMO address misaligned");
+            case 4:  panic("kstrap: Load address misaligned");
-        case 7: panic("kstrap: Store/AMO access fault");
+            case 5:  panic("kstrap: Load access fault");
-        case 8: panic("kstrap: Environment call from U-mode");
+            case 6:  panic("kstrap: Store/AMO address misaligned");
-        case 9: panic("kstrap: Environment call from S-mode");
+            case 7:  panic("kstrap: Store/AMO access fault");
-        case 12: panic("kstrap: Instruction page fault");
+            case 8:  panic("kstrap: Environment call from U-mode");
-        case 13: panic("kstrap: Load page fault");
+            case 9:  panic("kstrap: Environment call from S-mode");
-        case 14: panic("kstrap: Reserved");
+            case 12: panic("kstrap: Instruction page fault");
-        case 15: panic("kstrap: Store/AMO page fault");
+            case 13: panic("kstrap: Load page fault");
-        case 18: panic("kstrap: Software check");
+            case 14: panic("kstrap: Reserved");
-        case 19: panic("kstrap: Hardware error");
+            case 15: panic("kstrap: Store/AMO page fault");
-        default: panic("kstrap: Unknown");
+            case 18: panic("kstrap: Software check");
+            case 19: panic("kstrap: Hardware error");
+            default: panic("kstrap: Unknown");
+        }
+    }
+    else
+    {
+        cause = cause & 0x7fff'ffff;
+        if (cause == 9)
+        {
+            uint32_t msi = aplic_claim_msi_s();
+            switch (msi)
+            {
+                case UART_MSI:
+                {
+                    volatile char* UART_BASE = (volatile char*)0x1000'0000;
+                    *UART_BASE = *UART_BASE;
+                    break;
+                }
+                default: panic("Unknown MSI");
+            }
+        }
+        else
+        {
+            panic("Interrupt");
+        }
     }
 }
 
@@ -57,9 +84,8 @@ void kstart()
     
     kalloc_init();
     kvm_init();
-    aplic_init();
    
-    panic("kstart: end");
+    panic("kstart: end\n");
 }
 
 void kinit()
@@ -80,7 +106,10 @@ void kinit()
     w_sstatus(SSTATUS_SPIE | SSTATUS_SPP_S);
     w_sie(SIE_SEIE);
     w_sepc(&kstart);
-    w_stvec(&kstrap);
+    w_stvec(&strap);
+    
+    aplic_init();
+    aplic_enable_intr_s(10, UART_MSI);
 
     w_pmpcfg0(PMPCFG_RW | PMPCFG_X | PMPCFG_TOR);
     w_pmpaddr0(((uint32_t)&_ram_end) >> PMPADDR_SHIFT);

kernel/strap.s

@@ -0,0 +1,81 @@
+.option norvc
+.section .text
+
+.global ktrap
+
+.set FRAME_SIZE, 4 * 31
+
+.global strap
+strap:
+    addi        sp, sp, -FRAME_SIZE
+
+    sw          x1,  (0  * 4)(sp)
+    sw          x2,  (1  * 4)(sp)
+    sw          x3,  (2  * 4)(sp)
+    sw          x4,  (3  * 4)(sp)
+    sw          x5,  (4  * 4)(sp)
+    sw          x6,  (5  * 4)(sp)
+    sw          x7,  (6  * 4)(sp)
+    sw          x8,  (7  * 4)(sp)
+    sw          x9,  (8  * 4)(sp)
+    sw          x10, (9  * 4)(sp)
+    sw          x11, (10 * 4)(sp)
+    sw          x12, (11 * 4)(sp)
+    sw          x13, (12 * 4)(sp)
+    sw          x14, (13 * 4)(sp)
+    sw          x15, (14 * 4)(sp)
+    sw          x16, (15 * 4)(sp)
+    sw          x17, (16 * 4)(sp)
+    sw          x18, (17 * 4)(sp)
+    sw          x19, (18 * 4)(sp)
+    sw          x20, (19 * 4)(sp)
+    sw          x21, (20 * 4)(sp)
+    sw          x22, (21 * 4)(sp)
+    sw          x23, (22 * 4)(sp)
+    sw          x24, (23 * 4)(sp)
+    sw          x25, (24 * 4)(sp)
+    sw          x26, (25 * 4)(sp)
+    sw          x27, (26 * 4)(sp)
+    sw          x28, (27 * 4)(sp)
+    sw          x29, (28 * 4)(sp)
+    sw          x30, (29 * 4)(sp)
+    sw          x31, (30 * 4)(sp)
+        
+    csrr        a0, scause
+    call        ktrap
+
+    lw          x1,  (0  * 4)(sp)
+    lw          x2,  (1  * 4)(sp)
+    lw          x3,  (2  * 4)(sp)
+    lw          x4,  (3  * 4)(sp)
+    lw          x5,  (4  * 4)(sp)
+    lw          x6,  (5  * 4)(sp)
+    lw          x7,  (6  * 4)(sp)
+    lw          x8,  (7  * 4)(sp)
+    lw          x9,  (8  * 4)(sp)
+    lw          x10, (9  * 4)(sp)
+    lw          x11, (10 * 4)(sp)
+    lw          x12, (11 * 4)(sp)
+    lw          x13, (12 * 4)(sp)
+    lw          x14, (13 * 4)(sp)
+    lw          x15, (14 * 4)(sp)
+    lw          x16, (15 * 4)(sp)
+    lw          x17, (16 * 4)(sp)
+    lw          x18, (17 * 4)(sp)
+    lw          x19, (18 * 4)(sp)
+    lw          x20, (19 * 4)(sp)
+    lw          x21, (20 * 4)(sp)
+    lw          x22, (21 * 4)(sp)
+    lw          x23, (22 * 4)(sp)
+    lw          x24, (23 * 4)(sp)
+    lw          x25, (24 * 4)(sp)
+    lw          x26, (25 * 4)(sp)
+    lw          x27, (26 * 4)(sp)
+    lw          x28, (27 * 4)(sp)
+    lw          x29, (28 * 4)(sp)
+    lw          x30, (29 * 4)(sp)
+    lw          x31, (30 * 4)(sp)
+    
+    addi        sp, sp, FRAME_SIZE
+    
+    sret

kernel/vm.c

@@ -100,10 +100,10 @@ void kvm_init()
     kvm_map(&_stack_start, &_stack_start, &_stack_end - &_stack_start, VM_RW);
     
     kvm_map((void*)0x1000'0000, (void*)0x1000'0000, PAGE_SIZE, VM_RW); // UART
-    kvm_map((void*)0x0c00'0000, (void*)0x0c00'0000, 0x8000, VM_RW); // APLIC M
+    // kvm_map((void*)0x0c00'0000, (void*)0x0c00'0000, 0x8000, VM_RW); // APLIC M
-    kvm_map((void*)0x0d00'0000, (void*)0x0d00'0000, 0x8000, VM_RW); // APLIC S
+    // kvm_map((void*)0x0d00'0000, (void*)0x0d00'0000, 0x8000, VM_RW); // APLIC S
-    kvm_map((void*)0x2400'0000, (void*)0x2400'0000, 0x1000, VM_RW); // IMSIC M
+    // kvm_map((void*)0x2400'0000, (void*)0x2400'0000, 0x1000, VM_RW); // IMSIC M
-    kvm_map((void*)0x2800'0000, (void*)0x2800'0000, 0x1000, VM_RW); // IMSIC S
+    // kvm_map((void*)0x2800'0000, (void*)0x2800'0000, 0x1000, VM_RW); // IMSIC S
 
     w_satp(SATP_MODE_SV32 | ((uint32_t)kroot >> 12));
     sfence_vma();