Re: [PATCH 8/8] x86: put 64bit bzImage high

Eric W. Biederman
2012-11-17T06:33:37Z

Yinghai Lu <yinghai@kernel.org> writes:

> also need to make sure pass right 64bit start address to go there
> directly later.

There are some silly things here but I think the clean way to handle
this is to create a kexec/arch/i386/kexec-bzImage64.c that handles
loading a bzImage with a 64bit entry point.

That should keep the code simpler and easier to read. Although it will
probably introduce a bit more code.

Eric

> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> ---
> kexec/arch/i386/kexec-bzImage.c | 53 ++++++++++++++++++++++++++++++++++++--
> 1 files changed, 50 insertions(+), 3 deletions(-)
>
> diff --git a/kexec/arch/i386/kexec-bzImage.c b/kexec/arch/i386/kexec-bzImage.c
> index 6998587..3e705ca 100644
> --- a/kexec/arch/i386/kexec-bzImage.c
> +++ b/kexec/arch/i386/kexec-bzImage.c
> @@ -18,8 +18,10 @@
> */
>
> #define _GNU_SOURCE
> +#include <stddef.h>
> #include <stdio.h>
> #include <string.h>
> +#include <limits.h>
> #include <stdlib.h>
> #include <errno.h>
> #include <sys/types.h>
> @@ -35,6 +37,7 @@
> #include "../../kexec-elf.h"
> #include "../../kexec-syscall.h"
> #include "kexec-x86.h"
> +#include "../x86_64/kexec-x86_64.h"
> #include "x86-linux-setup.h"
> #include "crashdump-x86.h"
> #include <arch/options.h>
> @@ -111,12 +114,15 @@ int do_bzImage_load(struct kexec_info *info,
> size_t size;
> int kern16_size;
> unsigned long setup_base, setup_size;
> + struct entry64_regs regs64;
> struct entry32_regs regs32;
> struct entry16_regs regs16;
> unsigned int relocatable_kernel = 0;
> unsigned long kernel32_load_addr;
> char *modified_cmdline;
> unsigned long cmdline_end;
> + unsigned long code64_start_offset = 0;
> + unsigned long kernel64_load_addr = 0;
>
> /*
> * Find out about the file I am about to load.
> @@ -154,6 +160,13 @@ int do_bzImage_load(struct kexec_info *info,
> dbgprintf("bzImage is relocatable\n");
> }
>
> + if (setup_header.protocol_version >= 0x020C) {
> + code64_start_offset = setup_header.code64_start_offset;
> + if (code64_start_offset)
> + dbgprintf("code64_start_offset: 0x%lx\n",
> + code64_start_offset);
> + }
> +
> /* Can't use bzImage for crash dump purposes with real mode entry */
> if((info->kexec_flags & KEXEC_ON_CRASH) && real_mode_entry) {
> fprintf(stderr, "Can't use bzImage for crash dump purposes"
> @@ -250,7 +263,26 @@ int do_bzImage_load(struct kexec_info *info,
> kernel32_max_addr = real_mode->initrd_addr_max;
> }
>
> - kernel32_load_addr = add_buffer(info, kernel + kern16_size,
> + if (!real_mode_entry && code64_start_offset) {
> + /* align to 1G to avoid cross the PUD_SIZE boundary */
> + kernel64_load_addr = add_buffer(
> + info, kernel + kern16_size,
> + size, size, 1UL<<30,
> + 1UL<<32, ULONG_MAX,
> + -1);
> + if (!kernel64_load_addr)
> + kernel64_load_addr = add_buffer(
> + info, kernel + kern16_size,
> + size, size, 1UL<<30,
> + 1UL<<30, 1UL<<32,
> + -1);
> + if (kernel64_load_addr)
> + kernel64_load_addr += code64_start_offset;
> + }
> +
> + if (!kernel64_load_addr)
> + kernel32_load_addr = add_buffer(
> + info, kernel + kern16_size,
> size, size, kern_align,
> 0x100000, kernel32_max_addr,
> 1);
> @@ -260,8 +292,11 @@ int do_bzImage_load(struct kexec_info *info,
> add_segment(info, kernel + kern16_size, size,
> kernel32_load_addr, size);
> }
> -
> - dbgprintf("Loaded 32bit kernel at 0x%lx\n", kernel32_load_addr);
> +
> + if (kernel64_load_addr)
> + dbgprintf("Loaded 64bit kernel at 0x%lx\n", kernel64_load_addr);
> + else
> + dbgprintf("Loaded 32bit kernel at 0x%lx\n", kernel32_load_addr);
>
> /* Tell the kernel what is going on */
> setup_linux_bootloader_parameters(info, real_mode, setup_base,
> @@ -271,6 +306,16 @@ int do_bzImage_load(struct kexec_info *info,
> /* Get the initial register values */
> elf_rel_get_symbol(&info->rhdr, "entry16_regs", &regs16, sizeof(regs16));
> elf_rel_get_symbol(&info->rhdr, "entry32_regs", &regs32, sizeof(regs32));
> + if (kernel64_load_addr) {
> + elf_rel_get_symbol(&info->rhdr, "entry64_regs", &regs64, sizeof(regs64));
> + regs64.rbx = 0; /* Bootstrap processor */
> + regs64.rsi = setup_base; /* Pointer to the parameters */
> + regs64.rip = kernel64_load_addr; /* the entry point */
> + regs64.rsp = elf_rel_get_addr(&info->rhdr, "stack_end"); /* Stack, unused */
> + elf_rel_set_symbol(&info->rhdr, "entry64_regs", &regs64, sizeof(regs64));
> +
> + goto cmd_line;
> + }
> /*
>
> * Initialize the 32bit start information.
> @@ -320,6 +365,8 @@ int do_bzImage_load(struct kexec_info *info,
> elf_rel_set_symbol(&info->rhdr, "entry16_regs", &regs16, sizeof(regs16));
> elf_rel_set_symbol(&info->rhdr, "entry16_debug_regs", &regs16, sizeof(regs16));
> elf_rel_set_symbol(&info->rhdr, "entry32_regs", &regs32, sizeof(regs32));
> +
> +cmd_line:
> cmdline_end = setup_base + kern16_size + command_line_len - 1;
> elf_rel_set_symbol(&info->rhdr, "cmdline_end", &cmdline_end,
> sizeof(unsigned long));