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

Simon Glass sjg at chromium.org
Sun Apr 26 22:15:52 CEST 2020


Hi Aiden,

On Tue, 21 Apr 2020 at 18:45, <aiden.park at intel.com> wrote:
>
> From: Aiden Park <aiden.park at intel.com>
>
> Signed-off-by: Aiden Park <aiden.park at 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 at 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);

Please put a 'p' on the end, so image_64bitp, since it a return value.

>  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)

if (CONFIG_IS_ENABLED(X86_64) && 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)

if()

>                 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)

image_64bitp

>  {
>         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;
> +

Drop ()

In fact I suspect you can do:

*image_64bit = hdr->xloadflags & XLF_KERNEL_64)

>         /* 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;

Good change, but really should be in a separate patch.

>         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)

if()

But why not just set it always?

> +       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
>

Regards,
Simon


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