[PATCH 7/8] x86: enable 64-bit kernel boot from 64-bit U-Boot

[aiden.park at intel.com <aiden.park@intel.com>]

From: Aiden Park <aiden.park@intel.com>

Signed-off-by: Aiden Park <aiden.park@intel.com>
---
 arch/x86/cpu/x86_64/Makefile     |  2 +-
 arch/x86/cpu/x86_64/call64.S     | 21 +++++++++++++++++++++
 arch/x86/cpu/x86_64/cpu.c        | 10 ++++++++++
 arch/x86/include/asm/bootparam.h | 10 +++++++++-
 arch/x86/include/asm/zimage.h    |  2 +-
 arch/x86/lib/bootm.c             | 10 +++++++---
 arch/x86/lib/zimage.c            | 24 ++++++++++++++++--------
 7 files changed, 65 insertions(+), 14 deletions(-)
 create mode 100644 arch/x86/cpu/x86_64/call64.S

diff --git a/arch/x86/cpu/x86_64/Makefile b/arch/x86/cpu/x86_64/Makefile
index 400f0ffe39..951e503a1f 100644
--- a/arch/x86/cpu/x86_64/Makefile
+++ b/arch/x86/cpu/x86_64/Makefile
@@ -3,4 +3,4 @@
 # Written by Simon Glass <sjg@chromium.org>
 #
 
-obj-y += cpu.o interrupts.o setjmp.o
+obj-y += cpu.o interrupts.o setjmp.o call64.o
diff --git a/arch/x86/cpu/x86_64/call64.S b/arch/x86/cpu/x86_64/call64.S
new file mode 100644
index 0000000000..e2cfe15080
--- /dev/null
+++ b/arch/x86/cpu/x86_64/call64.S
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2020 Intel Corporation <www.intel.com>
+ */
+
+.code64
+.globl cpu_call64
+cpu_call64:
+	/*
+	 * cpu_call64(ulong pgtable, ulong setup_base, ulong target)
+	 *
+	 * rdi - pgtable (unused - already in 64-bit with paging)
+	 * rsi - setup_base
+	 * rdx - target
+	 *
+	 */
+	cli
+	mov	%rdx, %rcx
+	mov	%rsi, %rdx
+	call	*%rcx
+	ret
diff --git a/arch/x86/cpu/x86_64/cpu.c b/arch/x86/cpu/x86_64/cpu.c
index 90925e46ea..0730c43f1c 100644
--- a/arch/x86/cpu/x86_64/cpu.c
+++ b/arch/x86/cpu/x86_64/cpu.c
@@ -7,6 +7,7 @@
 #include <common.h>
 #include <cpu_func.h>
 #include <debug_uart.h>
+#include <asm/cpu.h>
 
 /*
  * Global declaration of gd.
@@ -67,3 +68,12 @@ int x86_cpu_reinit_f(void)
 {
 	return 0;
 }
+
+int cpu_jump_to_64bit(ulong setup_base, ulong load_address)
+{
+	ulong target = load_address + 0x200;
+
+	cpu_call64(0, setup_base, target);
+
+	return -EFAULT;
+}
diff --git a/arch/x86/include/asm/bootparam.h b/arch/x86/include/asm/bootparam.h
index d961dddc9e..73c94a33ec 100644
--- a/arch/x86/include/asm/bootparam.h
+++ b/arch/x86/include/asm/bootparam.h
@@ -59,7 +59,15 @@ struct setup_header {
 	__u32	initrd_addr_max;
 	__u32	kernel_alignment;
 	__u8	relocatable_kernel;
-	__u8	_pad2[3];
+	__u8	min_alignment;
+	__u16	xloadflags;
+#define XLF_KERNEL_64			BIT(0)
+#define XLF_CAN_BE_LOADED_ABOVE_4G	BIT(1)
+#define XLF_EFI_HANDOVER_32		BIT(2)
+#define XLF_EFI_HANDOVER_64		BIT(3)
+#define XLF_EFI_KEXEC			BIT(4)
+#define XLF_5LEVEL			BIT(5)
+#define XLF_5LEVEL_ENABLED		BIT(6)
 	__u32	cmdline_size;
 	__u32	hardware_subarch;
 	__u64	hardware_subarch_data;
diff --git a/arch/x86/include/asm/zimage.h b/arch/x86/include/asm/zimage.h
index 80e128ccf3..cadeb04168 100644
--- a/arch/x86/include/asm/zimage.h
+++ b/arch/x86/include/asm/zimage.h
@@ -31,7 +31,7 @@
 #define ZIMAGE_LOAD_ADDR   0x10000
 
 struct boot_params *load_zimage(char *image, unsigned long kernel_size,
-				ulong *load_addressp);
+				ulong *load_addressp, bool *image_64bit);
 int setup_zimage(struct boot_params *setup_base, char *cmd_line, int auto_boot,
 		 unsigned long initrd_addr, unsigned long initrd_size);
 void setup_video(struct screen_info *screen_info);
diff --git a/arch/x86/lib/bootm.c b/arch/x86/lib/bootm.c
index 07d8f1f279..ebed9e4605 100644
--- a/arch/x86/lib/bootm.c
+++ b/arch/x86/lib/bootm.c
@@ -74,6 +74,7 @@ static int boot_prep_linux(bootm_headers_t *images)
 	void *data = NULL;
 	size_t len;
 	int ret;
+	bool image_64bit;
 
 #ifdef CONFIG_OF_LIBFDT
 	if (images->ft_len) {
@@ -116,7 +117,8 @@ static int boot_prep_linux(bootm_headers_t *images)
 		ulong load_address;
 		char *base_ptr;
 
-		base_ptr = (char *)load_zimage(data, len, &load_address);
+		base_ptr = (char *)load_zimage(data, len, &load_address,
+					       &image_64bit);
 		if (!base_ptr) {
 			puts("## Kernel loading failed ...\n");
 			goto error;
@@ -124,6 +126,10 @@ static int boot_prep_linux(bootm_headers_t *images)
 		images->os.load = load_address;
 		cmd_line_dest = base_ptr + COMMAND_LINE_OFFSET;
 		images->ep = (ulong)base_ptr;
+#if CONFIG_IS_ENABLED(X86_64)
+		if (image_64bit)
+			images->os.arch = IH_ARCH_X86_64;
+#endif
 	} else if (images->ep) {
 		cmd_line_dest = (void *)images->ep + COMMAND_LINE_OFFSET;
 	} else {
@@ -164,9 +170,7 @@ int boot_linux_kernel(ulong setup_base, ulong load_address, bool image_64bit)
 		 * TODO(sjg at chromium.org): Support booting both 32-bit and
 		 * 64-bit kernels from 64-bit U-Boot.
 		 */
-#if !CONFIG_IS_ENABLED(X86_64)
 		return cpu_jump_to_64bit(setup_base, load_address);
-#endif
 	} else {
 		/*
 		* Set %ebx, %ebp, and %edi to 0, %esi to point to the
diff --git a/arch/x86/lib/zimage.c b/arch/x86/lib/zimage.c
index ffc09630b7..c84e2d39b2 100644
--- a/arch/x86/lib/zimage.c
+++ b/arch/x86/lib/zimage.c
@@ -129,7 +129,7 @@ static int setup_device_tree(struct setup_header *hdr, const void *fdt_blob)
 }
 
 struct boot_params *load_zimage(char *image, unsigned long kernel_size,
-				ulong *load_addressp)
+				ulong *load_addressp, bool *image_64bit)
 {
 	struct boot_params *setup_base;
 	int setup_size;
@@ -179,6 +179,9 @@ struct boot_params *load_zimage(char *image, unsigned long kernel_size,
 	big_image = (bootproto >= 0x0200) &&
 		    (hdr->loadflags & BIG_KERNEL_FLAG);
 
+	/* Determine 64-bit kernel */
+	*image_64bit = (hdr->xloadflags & XLF_KERNEL_64) ? true : false;
+
 	/* Determine load address */
 	if (big_image)
 		*load_addressp = BZIMAGE_LOAD_ADDR;
@@ -313,12 +316,13 @@ void __setup_pcat_compatibility(void)
 int do_zboot(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
 {
 	struct boot_params *base_ptr;
-	void *bzImage_addr = NULL;
+	void *bzimage_addr = NULL;
 	ulong load_address;
 	char *s;
-	ulong bzImage_size = 0;
+	ulong bzimage_size = 0;
 	ulong initrd_addr = 0;
 	ulong initrd_size = 0;
+	bool image_64bit;
 
 	disable_interrupts();
 
@@ -333,11 +337,11 @@ int do_zboot(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
 	}
 
 	if (s)
-		bzImage_addr = (void *)simple_strtoul(s, NULL, 16);
+		bzimage_addr = (void *)simple_strtoul(s, NULL, 16);
 
 	if (argc >= 3) {
 		/* argv[2] holds the size of the bzImage */
-		bzImage_size = simple_strtoul(argv[2], NULL, 16);
+		bzimage_size = simple_strtoul(argv[2], NULL, 16);
 	}
 
 	if (argc >= 4)
@@ -346,8 +350,13 @@ int do_zboot(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
 		initrd_size = simple_strtoul(argv[4], NULL, 16);
 
 	/* Lets look for */
-	base_ptr = load_zimage(bzImage_addr, bzImage_size, &load_address);
+	base_ptr = load_zimage(bzimage_addr, bzimage_size, &load_address,
+			       &image_64bit);
+#if !CONFIG_IS_ENABLED(X86_64)
+	image_64bit = false;
+#endif
 
+	/* we assume that the kernel is in place */
 	if (!base_ptr) {
 		puts("## Kernel loading failed ...\n");
 		return -1;
@@ -358,8 +367,7 @@ int do_zboot(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
 		return -1;
 	}
 
-	/* we assume that the kernel is in place */
-	return boot_linux_kernel((ulong)base_ptr, load_address, false);
+	return boot_linux_kernel((ulong)base_ptr, load_address, image_64bit);
 }
 
 U_BOOT_CMD(
-- 
2.20.1