Kernel: Pull apart CPU.h

This does not add any functional changes

Kernel/Arch/x86/ASM_wrapper.h

@@ -0,0 +1,154 @@
+/*
+ * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Types.h>
+
+namespace Kernel {
+
+ALWAYS_INLINE void cli()
+{
+    asm volatile("cli" ::
+                     : "memory");
+}
+ALWAYS_INLINE void sti()
+{
+    asm volatile("sti" ::
+                     : "memory");
+}
+ALWAYS_INLINE FlatPtr cpu_flags()
+{
+    FlatPtr flags;
+    asm volatile(
+        "pushf\n"
+        "pop %0\n"
+        : "=rm"(flags)::"memory");
+    return flags;
+}
+
+ALWAYS_INLINE void set_fs(u16 segment)
+{
+    asm volatile(
+        "mov %%ax, %%fs" ::"a"(segment)
+        : "memory");
+}
+
+ALWAYS_INLINE void set_gs(u16 segment)
+{
+    asm volatile(
+        "mov %%ax, %%gs" ::"a"(segment)
+        : "memory");
+}
+
+ALWAYS_INLINE u16 get_fs()
+{
+    u16 fs;
+    asm("mov %%fs, %%eax"
+        : "=a"(fs));
+    return fs;
+}
+
+ALWAYS_INLINE u16 get_gs()
+{
+    u16 gs;
+    asm("mov %%gs, %%eax"
+        : "=a"(gs));
+    return gs;
+}
+
+ALWAYS_INLINE u32 read_fs_u32(u32 offset)
+{
+    u32 val;
+    asm volatile(
+        "movl %%fs:%a[off], %k[val]"
+        : [val] "=r"(val)
+        : [off] "ir"(offset));
+    return val;
+}
+
+ALWAYS_INLINE FlatPtr read_fs_ptr(u32 offset)
+{
+    return read_fs_u32(offset);
+}
+
+ALWAYS_INLINE void write_fs_u32(u32 offset, u32 val)
+{
+    asm volatile(
+        "movl %k[val], %%fs:%a[off]" ::[off] "ir"(offset), [val] "ir"(val)
+        : "memory");
+}
+
+ALWAYS_INLINE bool are_interrupts_enabled()
+{
+    return cpu_flags() & 0x200;
+}
+
+FlatPtr read_cr0();
+FlatPtr read_cr2();
+FlatPtr read_cr3();
+FlatPtr read_cr4();
+u64 read_xcr0();
+
+void write_cr0(FlatPtr);
+void write_cr3(FlatPtr);
+void write_cr4(FlatPtr);
+void write_xcr0(u64);
+
+void flush_idt();
+
+ALWAYS_INLINE void load_task_register(u16 selector)
+{
+    asm("ltr %0" ::"r"(selector));
+}
+
+FlatPtr read_dr0();
+void write_dr0(FlatPtr);
+FlatPtr read_dr1();
+void write_dr1(FlatPtr);
+FlatPtr read_dr2();
+void write_dr2(FlatPtr);
+FlatPtr read_dr3();
+void write_dr3(FlatPtr);
+FlatPtr read_dr6();
+void write_dr6(FlatPtr);
+FlatPtr read_dr7();
+void write_dr7(FlatPtr);
+
+ALWAYS_INLINE static bool is_kernel_mode()
+{
+    u16 cs;
+    asm volatile(
+        "mov %%cs, %[cs] \n"
+        : [cs] "=g"(cs));
+    return (cs & 3) == 0;
+}
+
+ALWAYS_INLINE void read_tsc(u32& lsw, u32& msw)
+{
+    asm volatile("rdtsc"
+                 : "=d"(msw), "=a"(lsw));
+}
+
+ALWAYS_INLINE u64 read_tsc()
+{
+    u32 lsw;
+    u32 msw;
+    read_tsc(lsw, msw);
+    return ((u64)msw << 32) | lsw;
+}
+
+void stac();
+void clac();
+
+[[noreturn]] ALWAYS_INLINE void halt_this()
+{
+    for (;;) {
+        asm volatile("cli; hlt");
+    }
+}
+
+}