tests/tcg/x86_64: add a PVH crt.o for x86_64 system tests

Instead of doing the full real to 64 bit dance we are attempting to
leverage Xen's PVH boot spec to go from 32 bit to 64 bit.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

tests/tcg/i386/Makefile.softmmu-target

@@ -14,6 +14,7 @@ CRT_OBJS=boot.o
 
 ifeq ($(TARGET_X86_64), y)
 CRT_PATH=$(X64_SYSTEM_SRC)
+CFLAGS=-march=x86-64
 LINK_SCRIPT=$(X64_SYSTEM_SRC)/kernel.ld
 LDFLAGS=-Wl,-T$(LINK_SCRIPT) -Wl,-melf_x86_64
 else

tests/tcg/x86_64/system/boot.S

@@ -0,0 +1,277 @@
+/*
+ * x86_64 boot and support code
+ *
+ * Copyright 2019 Linaro
+ *
+ * This work is licensed under the terms of the GNU GPL, version 3 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ * Unlike the i386 version we instead use Xen's PVHVM booting header
+ * which should drop us automatically into 32 bit mode ready to go. I've
+ * nabbed bits of the Linux kernel setup to achieve this.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+        .section .head
+
+#define ELFNOTE_START(name, type, flags)	\
+.pushsection .note.name, flags,@note	;	\
+  .balign 4				;	\
+  .long 2f - 1f		/* namesz */	;	\
+  .long 4484f - 3f	/* descsz */	;	\
+  .long type				;	\
+1:.asciz #name				;	\
+2:.balign 4				;	\
+3:
+
+#define ELFNOTE_END				\
+4484:.balign 4				;	\
+.popsection				;
+
+#define ELFNOTE(name, type, desc)		\
+	ELFNOTE_START(name, type, "")		\
+		desc			;	\
+	ELFNOTE_END
+
+#define XEN_ELFNOTE_ENTRY          1
+#define XEN_ELFNOTE_HYPERCALL_PAGE 2
+#define XEN_ELFNOTE_VIRT_BASE      3
+#define XEN_ELFNOTE_PADDR_OFFSET   4
+#define XEN_ELFNOTE_PHYS32_ENTRY  18
+
+#define __ASM_FORM(x)	x
+#define __ASM_FORM_RAW(x)     x
+#define __ASM_FORM_COMMA(x) x,
+#define __ASM_SEL(a,b)           __ASM_FORM(b)
+#define __ASM_SEL_RAW(a,b)      __ASM_FORM_RAW(b)
+#define _ASM_PTR	__ASM_SEL(.long, .quad)
+
+	ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE,      _ASM_PTR 0x100000)
+	ELFNOTE(Xen, XEN_ELFNOTE_ENTRY,          _ASM_PTR _start)
+	ELFNOTE(Xen, XEN_ELFNOTE_PHYS32_ENTRY,   _ASM_PTR _start)    /* entry == virtbase */
+	ELFNOTE(Xen, XEN_ELFNOTE_PADDR_OFFSET,   _ASM_PTR 0)
+
+       /*
+	* Entry point for PVH guests.
+	*
+	* Xen ABI specifies the following register state when we come here:
+	*
+	* - `ebx`: contains the physical memory address where the loader has placed
+	*          the boot start info structure.
+	* - `cr0`: bit 0 (PE) must be set. All the other writeable bits are cleared.
+	* - `cr4`: all bits are cleared.
+	* - `cs `: must be a 32-bit read/execute code segment with a base of ‘0’
+	*          and a limit of ‘0xFFFFFFFF’. The selector value is unspecified.
+	* - `ds`, `es`: must be a 32-bit read/write data segment with a base of
+	*               ‘0’ and a limit of ‘0xFFFFFFFF’. The selector values are all
+	*               unspecified.
+	* - `tr`: must be a 32-bit TSS (active) with a base of '0' and a limit
+	*         of '0x67'.
+	* - `eflags`: bit 17 (VM) must be cleared. Bit 9 (IF) must be cleared.
+	*             Bit 8 (TF) must be cleared. Other bits are all unspecified.
+	*
+	* All other processor registers and flag bits are unspecified. The OS is in
+	* charge of setting up it's own stack, GDT and IDT.
+	*/
+        .code32
+        .section .text
+
+.global _start
+_start:
+	cld
+        lgdt gdtr
+
+        ljmp $0x8,$.Lloadcs
+.Lloadcs:
+        mov $0x10,%eax
+        mov %eax,%ds
+        mov %eax,%es
+        mov %eax,%fs
+        mov %eax,%gs
+        mov %eax,%ss
+
+	/* Enable PAE mode (bit 5). */
+	mov %cr4, %eax
+	btsl $5, %eax
+	mov %eax, %cr4
+
+#define MSR_EFER		0xc0000080 /* extended feature register */
+
+	/* Enable Long mode. */
+	mov $MSR_EFER, %ecx
+	rdmsr
+	btsl $8, %eax
+	wrmsr
+
+	/* Enable paging */
+	mov $.Lpml4, %ecx
+	mov %ecx, %cr3
+
+	mov %cr0, %eax
+	btsl $31, %eax
+	mov %eax, %cr0
+
+	/* Jump to 64-bit mode. */
+        lgdt gdtr64
+        ljmp $0x8,$.Lenter64
+
+        .code64
+        .section .text
+.Lenter64:
+
+
+	// Setup stack ASAP
+	movq $stack_end,%rsp
+
+        /* don't worry about stack frame, assume everthing is garbage when we return */
+	call main
+
+        /* output any non-zero result in eax to isa-debug-exit device */
+        test %al, %al
+        jz 1f
+        out %ax, $0xf4
+
+1:      /* QEMU ACPI poweroff */
+	mov $0x604,%edx
+	mov $0x2000,%eax
+	out %ax,%dx
+	hlt
+	jmp 1b
+
+        /*
+         * Helper Functions
+         *
+         * x86_64 calling convention is rdi, rsi, rdx, rcx, r8, r9
+         */
+
+        /* Output a single character to serial port */
+        .global __sys_outc
+__sys_outc:
+        pushq %rax
+        mov %rax, %rdx
+	out %al,$0xE9
+        popq %rax
+        ret
+
+	/* Interrupt Descriptor Table */
+
+        .section .data
+        .align 16
+
+idt_00: .int 0, 0
+idt_01: .int 0, 0
+idt_02: .int 0, 0
+idt_03: .int 0, 0
+idt_04: .int 0, 0
+idt_05: .int 0, 0
+idt_06: .int 0, 0 /* intr_6_opcode, Invalid Opcode */
+idt_07: .int 0, 0
+idt_08: .int 0, 0
+idt_09: .int 0, 0
+idt_0A: .int 0, 0
+idt_0B: .int 0, 0
+idt_0C: .int 0, 0
+idt_0D: .int 0, 0
+idt_0E: .int 0, 0
+idt_0F: .int 0, 0
+idt_10: .int 0, 0
+idt_11: .int 0, 0
+idt_12: .int 0, 0
+idt_13: .int 0, 0
+idt_14: .int 0, 0
+idt_15: .int 0, 0
+idt_16: .int 0, 0
+idt_17: .int 0, 0
+idt_18: .int 0, 0
+idt_19: .int 0, 0
+idt_1A: .int 0, 0
+idt_1B: .int 0, 0
+idt_1C: .int 0, 0
+idt_1D: .int 0, 0
+idt_1E: .int 0, 0
+idt_1F: .int 0, 0
+
+
+	/*
+	 * Global Descriptor Table (GDT)
+	 *
+	 * This describes various memory areas (segments) through
+	 * segment descriptors. In 32 bit mode each segment each
+	 * segement is associated with segment registers which are
+	 * implicitly (or explicitly) referenced depending on the
+	 * instruction. However in 64 bit mode selectors are flat and
+	 * segmented addressing isn't used.
+	 */
+gdt:
+        .short 0
+gdtr:
+        .short gdt_en - gdt - 1
+        .int gdt
+
+        // Code cs:
+        .short 0xFFFF
+        .short 0
+        .byte 0
+        .byte 0x9b
+        .byte 0xCF
+        .byte 0
+
+        // Data  ds:, ss:, es:, fs:, and gs:
+        .short 0xFFFF
+        .short 0
+        .byte 0
+        .byte 0x93
+        .byte 0xCF
+        .byte 0
+gdt_en:
+
+gdt64:
+        .short 0
+gdtr64:
+        .short gdt64_en - gdt64 - 1
+        .int gdt64
+
+        // Code
+        .short 0xFFFF
+        .short 0
+        .byte 0
+        .byte 0x9b
+        .byte 0xAF
+        .byte 0
+
+        // Data
+        .short 0xFFFF
+        .short 0
+        .byte 0
+        .byte 0x93
+        .byte 0xCF
+        .byte 0
+gdt64_en:
+
+	.section .bss
+        .align 16
+
+stack: .space 65536
+stack_end:
+
+	.section .data
+
+.align 4096
+.Lpd:
+i = 0
+        .rept 512 * 4
+        .quad 0x1e7 | (i << 21)
+        i = i + 1
+        .endr
+
+.align 4096
+.Lpdp:
+        .quad .Lpd + 7 + 0 * 4096 /* 0-1 GB */
+        .quad .Lpd + 7 + 1 * 4096 /* 1-2 GB */
+        .quad .Lpd + 7 + 2 * 4096 /* 2-3 GB */
+        .quad .Lpd + 7 + 3 * 4096 /* 3-4 GB */
+
+.align 4096
+.Lpml4:
+        .quad .Lpdp + 7 /* 0-512 GB */

tests/tcg/x86_64/system/kernel.ld

@@ -0,0 +1,33 @@
+PHDRS {
+	text PT_LOAD FLAGS(5);          /* R_E */
+	note PT_NOTE FLAGS(0);          /* ___ */
+}
+
+SECTIONS {
+	. = 0x100000;
+
+	.text : {
+		__load_st = .;
+		*(.head)
+		*(.text)
+	} :text
+
+	.rodata : {
+		*(.rodata)
+	} :text
+
+        /* Keep build ID and PVH notes in same section */
+        .notes :  {
+               *(.note.*)
+        } :note
+
+        .data : {
+		*(.data)
+		__load_en = .;
+	} :text
+
+	.bss : {
+		*(.bss)
+		__bss_en = .;
+	}
+}