Decoupling Architectural-specific Code (#35)

[lunaix-os.git] / lunaix-os / arch / i386 / hart.c

diff --git a/lunaix-os/arch/i386/hart.c b/lunaix-os/arch/i386/hart.c
new file mode 100644 (file)
index 0000000..09bd2b3
--- /dev/null
+++ b/lunaix-os/arch/i386/hart.c
@@ -0,0 +1,60 @@
+#include <lunaix/process.h>
+#include <lunaix/hart_state.h>
+#include <lunaix/mm/vmm.h>
+#include <klibc/string.h>
+
+#include <sys/mm/mempart.h>
+#include <sys/abi.h>
+
+volatile struct x86_tss _tss = { .link = 0,
+                                 .esp0 = 0,
+                                 .ss0 = KDATA_SEG };
+
+bool
+install_hart_transition(ptr_t vm_mnt, struct hart_transition* ht)
+{
+    pte_t pte;
+    if (!vmm_lookupat(vm_mnt, ht->inject, &pte)) {
+        return false;
+    }
+
+    mount_page(PG_MOUNT_4, pte_paddr(pte));
+
+    ptr_t mount_inject = PG_MOUNT_4 + va_offset(ht->inject);
+    memcpy((void*)mount_inject, &ht->transfer, sizeof(ht->transfer));
+    
+    unmount_page(PG_MOUNT_4);
+    return true;
+}
+
+void
+hart_prepare_transition(struct hart_transition* ht, 
+                      ptr_t kstack_tp, ptr_t ustack_pt, 
+                      ptr_t entry, bool to_user) 
+{
+    ptr_t offset = (ptr_t)&ht->transfer.eret - (ptr_t)&ht->transfer;
+    ht->inject = align_stack(kstack_tp - sizeof(ht->transfer));
+
+    ht->transfer.state = (struct hart_state){ 
+                            .registers = { 
+                                .ds = KDATA_SEG,
+                                .es = KDATA_SEG,
+                                .fs = KDATA_SEG,
+                                .gs = KDATA_SEG 
+                            },
+                            .execp = (struct exec_param*)(ht->inject + offset)
+                        };
+    
+    int code_seg = KCODE_SEG, data_seg = KDATA_SEG;
+    int mstate = cpu_ldstate();
+    if (to_user) {
+        code_seg = UCODE_SEG, data_seg = UDATA_SEG;
+        mstate |= 0x200;   // enable interrupt
+    }
+
+    ht->transfer.eret = (struct exec_param) {
+                            .cs = code_seg, .eip = entry, 
+                            .ss = data_seg, .esp = align_stack(ustack_pt),
+                            .eflags = mstate
+                        };
+}
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