Re: [PATCH v4] efi: Avoid calling boot services after ExitBootServices()

[Ross Lagerwall <ross.lagerwall@citrix.com>]

ping

On 06/02/2015 10:38 AM, Ross Lagerwall wrote:
> After the first call to ExitBootServices(), avoid calling any boot
> services by setting setting efi_bs to NULL and halting in blexit().
>
> Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
> ---
>
> * Separated halt into an arch hook.
> * Applies on top of the first patch from v3.
> * Tested on x86, not sure if the ARM version is correct.
>
>   xen/arch/arm/efi/efi-boot.h |  5 +++++
>   xen/arch/x86/efi/efi-boot.h |  7 +++++++
>   xen/common/efi/boot.c       | 13 ++++++++++---
>   3 files changed, 22 insertions(+), 3 deletions(-)
>
> diff --git a/xen/arch/arm/efi/efi-boot.h b/xen/arch/arm/efi/efi-boot.h
> index 3297f27..47efdfc 100644
> --- a/xen/arch/arm/efi/efi-boot.h
> +++ b/xen/arch/arm/efi/efi-boot.h
> @@ -522,6 +522,11 @@ static void __init efi_arch_blexit(void)
>           efi_bs->FreePool(memmap);
>   }
>
> +static void __init efi_arch_halt(void)
> +{
> +    stop_cpu();
> +}
> +
>   static void __init efi_arch_load_addr_check(EFI_LOADED_IMAGE *loaded_image)
>   {
>       if ( (unsigned long)loaded_image->ImageBase & ((1 << 12) - 1) )
> diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
> index cd14c19..9f41793 100644
> --- a/xen/arch/x86/efi/efi-boot.h
> +++ b/xen/arch/x86/efi/efi-boot.h
> @@ -614,6 +614,13 @@ static void __init efi_arch_blexit(void)
>           efi_bs->FreePages(ucode.addr, PFN_UP(ucode.size));
>   }
>
> +static void __init efi_arch_halt(void)
> +{
> +    local_irq_disable();
> +    for ( ; ; )
> +        halt();
> +}
> +
>   static void __init efi_arch_load_addr_check(EFI_LOADED_IMAGE *loaded_image)
>   {
>       xen_phys_start = (UINTN)loaded_image->ImageBase;
> diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
> index 60c1b8d..4b816f2 100644
> --- a/xen/common/efi/boot.c
> +++ b/xen/common/efi/boot.c
> @@ -216,6 +216,9 @@ static void __init noreturn blexit(const CHAR16 *str)
>           PrintStr((CHAR16 *)str);
>       PrintStr(newline);
>
> +    if ( !efi_bs )
> +        efi_arch_halt();
> +
>       if ( cfg.addr )
>           efi_bs->FreePages(cfg.addr, PFN_UP(cfg.size));
>       if ( kernel.addr )
> @@ -1063,8 +1066,10 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
>       for ( retry = 0; ; retry = 1 )
>       {
>           efi_memmap_size = map_alloc_size;
> -        status = efi_bs->GetMemoryMap(&efi_memmap_size, efi_memmap, &map_key,
> -                                      &efi_mdesc_size, &mdesc_ver);
> +        status = SystemTable->BootServices->GetMemoryMap(&efi_memmap_size,
> +                                                         efi_memmap, &map_key,
> +                                                         &efi_mdesc_size,
> +                                                         &mdesc_ver);
>           if ( EFI_ERROR(status) )
>               PrintErrMesg(L"Cannot obtain memory map", status);
>
> @@ -1073,7 +1078,9 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
>
>           efi_arch_pre_exit_boot();
>
> -        status = efi_bs->ExitBootServices(ImageHandle, map_key);
> +        status = SystemTable->BootServices->ExitBootServices(ImageHandle,
> +                                                             map_key);
> +        efi_bs = NULL;
>           if ( status != EFI_INVALID_PARAMETER || retry )
>               break;
>       }
>