Re: [PATCH 29/42] x86: Find correct 64 bit ramdisk address for microcode early update

[Kees Cook]

On Tue, Jul 7, 2015 at 1:20 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
> When using kexec with 64bit kernel, bzImage and ramdisk could be
> loaded above 4G. We need this to get correct ramdisk adress.
>
> Make get_ramdisk_image() global and use it for early microcode updating.

This looks correct, thanks!

Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>

-Kees

>
> -v2: update changelog.
>
> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
> ---
>  arch/x86/include/asm/setup.h                |  3 +++
>  arch/x86/kernel/cpu/microcode/amd_early.c   | 10 +++++-----
>  arch/x86/kernel/cpu/microcode/intel_early.c |  8 ++++----
>  arch/x86/kernel/setup.c                     | 28 ++++++++++++++--------------
>  4 files changed, 26 insertions(+), 23 deletions(-)
>
> diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
> index 3e5aa41..496515b 100644
> --- a/arch/x86/include/asm/setup.h
> +++ b/arch/x86/include/asm/setup.h
> @@ -119,6 +119,9 @@ void *extend_brk(size_t size, size_t align);
>         RESERVE_BRK(name, sizeof(type) * entries)
>
>  extern void probe_roms(void);
> +u64 get_ramdisk_image(struct boot_params *bp);
> +u64 get_ramdisk_size(struct boot_params *bp);
> +
>  #ifdef __i386__
>
>  asmlinkage void __init i386_start_kernel(void);
> diff --git a/arch/x86/kernel/cpu/microcode/amd_early.c b/arch/x86/kernel/cpu/microcode/amd_early.c
> index e8a215a..4c579c7 100644
> --- a/arch/x86/kernel/cpu/microcode/amd_early.c
> +++ b/arch/x86/kernel/cpu/microcode/amd_early.c
> @@ -51,12 +51,12 @@ static struct cpio_data __init find_ucode_in_initrd(void)
>          */
>         p       = (struct boot_params *)__pa_nodebug(&boot_params);
>         path    = (char *)__pa_nodebug(ucode_path);
> -       start   = (void *)p->hdr.ramdisk_image;
> -       size    = p->hdr.ramdisk_size;
> +       start   = (void *)(unsigned long)get_ramdisk_image(p);
> +       size    = get_ramdisk_size(p);
>  #else
>         path    = ucode_path;
> -       start   = (void *)(boot_params.hdr.ramdisk_image + PAGE_OFFSET);
> -       size    = boot_params.hdr.ramdisk_size;
> +       start   = (void *)(get_ramdisk_image(&boot_params) + PAGE_OFFSET);
> +       size    = get_ramdisk_size(&boot_params);
>  #endif
>
>         return find_cpio_data(path, start, size, &offset);
> @@ -396,7 +396,7 @@ int __init save_microcode_in_initrd_amd(void)
>          */
>         if (relocated_ramdisk)
>                 container = (u8 *)(__va(relocated_ramdisk) +
> -                            (cont - boot_params.hdr.ramdisk_image));
> +                            (cont - get_ramdisk_size(&boot_params)));
>         else
>                 container = cont_va;
>
> diff --git a/arch/x86/kernel/cpu/microcode/intel_early.c b/arch/x86/kernel/cpu/microcode/intel_early.c
> index 8187b72..c85dcb2 100644
> --- a/arch/x86/kernel/cpu/microcode/intel_early.c
> +++ b/arch/x86/kernel/cpu/microcode/intel_early.c
> @@ -736,16 +736,16 @@ void __init load_ucode_intel_bsp(void)
>         struct boot_params *p;
>
>         p       = (struct boot_params *)__pa_nodebug(&boot_params);
> -       start   = p->hdr.ramdisk_image;
> -       size    = p->hdr.ramdisk_size;
> +       start   = get_ramdisk_image(p);
> +       size    = get_ramdisk_size(p);
>
>         _load_ucode_intel_bsp(
>                         (struct mc_saved_data *)__pa_nodebug(&mc_saved_data),
>                         (unsigned long *)__pa_nodebug(&mc_saved_in_initrd),
>                         start, size);
>  #else
> -       start   = boot_params.hdr.ramdisk_image + PAGE_OFFSET;
> -       size    = boot_params.hdr.ramdisk_size;
> +       start   = get_ramdisk_image(&boot_params) + PAGE_OFFSET;
> +       size    = get_ramdisk_size(&boot_params);
>
>         _load_ucode_intel_bsp(&mc_saved_data, mc_saved_in_initrd, start, size);
>  #endif
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 80f874b..2d808e6 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -300,19 +300,19 @@ u64 relocated_ramdisk;
>
>  #ifdef CONFIG_BLK_DEV_INITRD
>
> -static u64 __init get_ramdisk_image(void)
> +u64 __init get_ramdisk_image(struct boot_params *bp)
>  {
> -       u64 ramdisk_image = boot_params.hdr.ramdisk_image;
> +       u64 ramdisk_image = bp->hdr.ramdisk_image;
>
> -       ramdisk_image |= (u64)boot_params.ext_ramdisk_image << 32;
> +       ramdisk_image |= (u64)bp->ext_ramdisk_image << 32;
>
>         return ramdisk_image;
>  }
> -static u64 __init get_ramdisk_size(void)
> +u64 __init get_ramdisk_size(struct boot_params *bp)
>  {
> -       u64 ramdisk_size = boot_params.hdr.ramdisk_size;
> +       u64 ramdisk_size = bp->hdr.ramdisk_size;
>
> -       ramdisk_size |= (u64)boot_params.ext_ramdisk_size << 32;
> +       ramdisk_size |= (u64)bp->ext_ramdisk_size << 32;
>
>         return ramdisk_size;
>  }
> @@ -321,8 +321,8 @@ static u64 __init get_ramdisk_size(void)
>  static void __init relocate_initrd(void)
>  {
>         /* Assume only end is not page aligned */
> -       u64 ramdisk_image = get_ramdisk_image();
> -       u64 ramdisk_size  = get_ramdisk_size();
> +       u64 ramdisk_image = get_ramdisk_image(&boot_params);
> +       u64 ramdisk_size  = get_ramdisk_size(&boot_params);
>         u64 area_size     = PAGE_ALIGN(ramdisk_size);
>         unsigned long slop, clen, mapaddr;
>         char *p, *q;
> @@ -360,8 +360,8 @@ static void __init relocate_initrd(void)
>                 ramdisk_size  -= clen;
>         }
>
> -       ramdisk_image = get_ramdisk_image();
> -       ramdisk_size  = get_ramdisk_size();
> +       ramdisk_image = get_ramdisk_image(&boot_params);
> +       ramdisk_size  = get_ramdisk_size(&boot_params);
>         printk(KERN_INFO "Move RAMDISK from [mem %#010llx-%#010llx] to"
>                 " [mem %#010llx-%#010llx]\n",
>                 ramdisk_image, ramdisk_image + ramdisk_size - 1,
> @@ -371,8 +371,8 @@ static void __init relocate_initrd(void)
>  static void __init early_reserve_initrd(void)
>  {
>         /* Assume only end is not page aligned */
> -       u64 ramdisk_image = get_ramdisk_image();
> -       u64 ramdisk_size  = get_ramdisk_size();
> +       u64 ramdisk_image = get_ramdisk_image(&boot_params);
> +       u64 ramdisk_size  = get_ramdisk_size(&boot_params);
>         u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
>
>         if (!boot_params.hdr.type_of_loader ||
> @@ -384,8 +384,8 @@ static void __init early_reserve_initrd(void)
>  static void __init reserve_initrd(void)
>  {
>         /* Assume only end is not page aligned */
> -       u64 ramdisk_image = get_ramdisk_image();
> -       u64 ramdisk_size  = get_ramdisk_size();
> +       u64 ramdisk_image = get_ramdisk_image(&boot_params);
> +       u64 ramdisk_size  = get_ramdisk_size(&boot_params);
>         u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
>         u64 mapped_size;
>
> --
> 1.8.4.5
>



-- 
Kees Cook
Chrome OS Security
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/