amd64: barely boot into kernel code

1 files changed, 27 insertions, 0 deletions

diff --git a/src/kernel/arch/amd64/sysenter.c b/src/kernel/arch/amd64/sysenter.c
new file mode 100644
index 0000000..e42ec7d
--- /dev/null
+++ b/src/kernel/arch/amd64/sysenter.c
@@ -0,0 +1,27 @@
+#include <kernel/arch/generic.h>
+#include <kernel/arch/amd64/sysenter.h>
+#include <kernel/proc.h>
+#include <shared/syscalls.h>
+
+struct registers _sysexit_regs;
+
+void sysexit(struct registers regs) {
+	_sysexit_regs = regs;
+	_sysexit_regs.ecx = (uintptr_t) regs.esp;
+	_sysexit_regs.edx = (uintptr_t) regs.eip;
+	_sysexit_real();
+	__builtin_unreachable();
+}
+
+_Noreturn void sysenter_stage2(void) {
+	kprintf("ring0 again!\n");
+	struct registers *regs = &process_current->regs;
+
+	*regs = _sysexit_regs; // save the registers
+	regs->esp = (userptr_t) regs->ecx; // fix them up
+	regs->eip = (userptr_t) regs->edx;
+
+	_syscall(regs->eax, regs->ebx,
+	         regs->esi, regs->edi, (uintptr_t)regs->ebp);
+	process_switch_any();
+}