Changes in kernel/arch/amd64/src/boot/multiboot2.S [17aa6d1:bae43dc] in mainline

File:

• kernel/arch/amd64/src/boot/multiboot2.S (modified) (3 diffs)

kernel/arch/amd64/src/boot/multiboot2.S

@@ -35 +35 @@
 #include <genarch/multiboot/multiboot2.h>
 
+#define START_STACK  (BOOT_OFFSET - BOOT_STACK_SIZE)
+
 .section K_TEXT_START, "ax"
 
@@ -78 +80 @@
                 .word MULTIBOOT2_FLAGS_REQUIRED
                 .long tag_entry_address_end - tag_entry_address_start
-                .long multiboot_image_start
+                .long multiboot2_image_start
         tag_entry_address_end:
 
@@ -120 +122 @@
         tag_terminator_end:
 multiboot2_header_end:
+
+SYMBOL(multiboot2_image_start)
+        cli
+        cld
+
+        /* Initialize stack pointer */
+        movl $START_STACK, %esp
+
+        /*
+         * Initialize Global Descriptor Table and
+         * Interrupt Descriptor Table registers
+         */
+        lgdtl bootstrap_gdtr
+        lidtl bootstrap_idtr
+
+        /* Kernel data + stack */
+        movw $GDT_SELECTOR(KDATA_DES), %cx
+        movw %cx, %es
+        movw %cx, %ds
+        movw %cx, %ss
+
+        /*
+         * Simics seems to remove hidden part of GS on entering user mode
+         * when _visible_ part of GS does not point to user-mode segment.
+         */
+        movw $GDT_SELECTOR(UDATA_DES), %cx
+        movw %cx, %fs
+        movw %cx, %gs
+
+        jmpl $GDT_SELECTOR(KTEXT32_DES), $multiboot2_meeting_point
+        multiboot2_meeting_point:
+
+        /*
+         * Protected 32-bit. We want to reuse the code-seg descriptor,
+         * the Default operand size must not be 1 when entering long mode.
+         */
+
+        /* Save multiboot arguments */
+        movl %eax, multiboot_eax
+        movl %ebx, multiboot_ebx
+
+        movl $(INTEL_CPUID_EXTENDED), %eax
+        cpuid
+        cmp $(INTEL_CPUID_EXTENDED), %eax
+        ja extended_cpuid_supported
+
+                jmp pm_error_halt
+
+        extended_cpuid_supported:
+
+        movl $(AMD_CPUID_EXTENDED), %eax
+        cpuid
+        bt $(AMD_EXT_LONG_MODE), %edx
+        jc long_mode_supported
+
+                jmp pm_error_halt
+
+        long_mode_supported:
+
+        bt $(AMD_EXT_NOEXECUTE), %edx
+        jc noexecute_supported
+
+                jmp pm_error_halt
+
+        noexecute_supported:
+
+        movl $(INTEL_CPUID_STANDARD), %eax
+        cpuid
+        bt $(INTEL_FXSAVE), %edx
+        jc fx_supported
+
+                jmp pm_error_halt
+
+        fx_supported:
+
+        bt $(INTEL_SSE2), %edx
+        jc sse2_supported
+
+                jmp pm_error_halt
+
+        sse2_supported:
+
+        /*
+         * Enable 64-bit page translation entries - CR4.PAE = 1.
+         * Paging is not enabled until after long mode is enabled.
+         */
+
+        movl %cr4, %eax
+        orl $CR4_PAE, %eax
+        movl %eax, %cr4
+
+        /* Set up paging tables */
+        leal ptl_0, %eax
+        movl %eax, %cr3
+
+        /* Enable long mode */
+        movl $AMD_MSR_EFER, %ecx
+        rdmsr                     /* read EFER */
+        orl $AMD_LME, %eax        /* set LME = 1 */
+        wrmsr
+
+        /* Enable paging to activate long mode (set CR0.PG = 1) */
+        movl %cr0, %eax
+        orl $CR0_PG, %eax
+        movl %eax, %cr0
+
+        /* At this point we are in compatibility mode */
+        jmpl $GDT_SELECTOR(KTEXT_DES), $start64
+
+pm_error_halt:
+        cli
+        hlt1:
+                hlt
+                jmp hlt1
+
+.code64
+
+start64:
+
+        /*
+         * Long mode.
+         */
+
+        movq $(PA2KA(START_STACK)), %rsp
+
+        /* Create the first stack frame */
+        pushq $0
+        movq %rsp, %rbp
+
+        /* Call amd64_pre_main(multiboot_eax, multiboot_ebx) */
+        movl multiboot_eax, %edi
+        movl multiboot_ebx, %esi
+
+#ifdef MEMORY_MODEL_large
+        movabsq $amd64_pre_main, %rax
+        callq *%rax
+#else
+        callq amd64_pre_main
+#endif
+
+        /* Call main_bsp() */
+#ifdef MEMORY_MODEL_large
+        movabsq $main_bsp, %rax
+        callq *%rax
+#else
+        callq main_bsp
+#endif
+
+        /* Not reached */
+        cli
+        hlt0:
+                hlt
+                jmp hlt0