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Date: Mon, 21 Jan 2013 13:54:30 -0700
From: Dave Jiang <dave.jiang@...el.com>
To: Matt Fleming <matt@...sole-pimps.org>
CC: linux-kernel@...r.kernel.org, linux-efi@...r.kernel.org,
Tim Gardner <rtg.canonical@...il.com>,
Matthew Garrett <mjg59@...f.ucam.org>,
"H. Peter Anvin" <hpa@...or.com>, Olof Johansson <olof@...om.net>,
Tony Luck <tony.luck@...el.com>,
Steve Langasek <steve.langasek@...onical.com>,
Colin Ian King <colin.king@...onical.com>,
Matt Fleming <matt.fleming@...el.com>,
David Airlie <airlied@...ux.ie>,
Corentin Chary <corentincj@...aif.net>,
Peter Jones <pjones@...hat.com>,
Konrad Rzeszutek Wilk <konrad@...nel.org>,
"Rafael J. Wysocki" <rjw@...k.pl>, stable@...r.kernel.org,
"Dorau, Lukasz" <lukasz.dorau@...el.com>
Subject: Re: [PATCH 1/2] efi: Make 'efi_enabled' a function to query EFI facilities
On 01/21/2013 01:40 PM, Matt Fleming wrote:
> From: Matt Fleming <matt.fleming@...el.com>
>
> Originally 'efi_enabled' indicated whether a kernel was booted from
> EFI firmware. Over time its semantics have changed, and it now
> indicates whether or not we are booted on an EFI machine with
> bit-native firmware, e.g. 64-bit kernel with 64-bit firmware.
>
> But users actually want to query 'efi_enabled' for different reasons -
> what they really want access to is the list of available EFI
> facilities.
>
> For instance, the x86 reboot code needs to know whether it can invoke
> the ResetSystem() function provided by the EFI runtime services, while
> the ACPI OSL code wants to know whether the EFI config tables were
> mapped successfully. There are also checks in some of the platform
> driver code to simply see if they're running on an EFI machine (which
> would make it a bad idea to do BIOS-y things).
>
> Cc: David Airlie <airlied@...ux.ie>
> Cc: H. Peter Anvin <hpa@...or.com>
> Cc: Corentin Chary <corentincj@...aif.net>
> Cc: Matthew Garrett <mjg59@...f.ucam.org>
> Cc: Dave Jiang <dave.jiang@...el.com>
> Cc: Olof Johansson <olof@...om.net>
> Cc: Peter Jones <pjones@...hat.com>
> Cc: Colin Ian King <colin.king@...onical.com>
> Cc: Steve Langasek <steve.langasek@...onical.com>
> Cc: Tony Luck <tony.luck@...el.com>
> Cc: Konrad Rzeszutek Wilk <konrad@...nel.org>
> Cc: Rafael J. Wysocki <rjw@...k.pl>
> Cc: stable@...r.kernel.org
> Signed-off-by: Matt Fleming <matt.fleming@...el.com>
> ---
> arch/x86/include/asm/efi.h | 1 +
> arch/x86/kernel/reboot.c | 2 +-
> arch/x86/kernel/setup.c | 28 ++++++++---------
> arch/x86/platform/efi/efi.c | 56 ++++++++++++++++++++--------------
> drivers/acpi/osl.c | 2 +-
> drivers/firmware/dmi_scan.c | 2 +-
> drivers/firmware/efivars.c | 4 +--
> drivers/firmware/iscsi_ibft_find.c | 2 +-
> drivers/gpu/drm/radeon/radeon_device.c | 3 +-
> drivers/platform/x86/ibm_rtl.c | 2 +-
> drivers/scsi/isci/init.c | 2 +-
> include/linux/efi.h | 24 +++++++++++----
> init/main.c | 4 +--
> 13 files changed, 78 insertions(+), 54 deletions(-)
>
<snipped>
> diff --git a/drivers/scsi/isci/init.c b/drivers/scsi/isci/init.c
> index b74050b..9ac1e9d 100644
> --- a/drivers/scsi/isci/init.c
> +++ b/drivers/scsi/isci/init.c
> @@ -633,7 +633,7 @@ static int __devinit isci_pci_probe(struct pci_dev *pdev, const struct pci_devic
> return -ENOMEM;
> pci_set_drvdata(pdev, pci_info);
>
> - if (efi_enabled)
> + if (efi_enabled(EFI_RUNTIME_SERVICES))
> orom = isci_get_efi_var(pdev);
>
> if (!orom)
I think that here we may need to be checking efi_enabled(EFI_BOOT)
instead. We are interested in the kernel was booted from EFI and that
EFI variables support is present. Or is getting efi variable part of
runtime services?
> diff --git a/include/linux/efi.h b/include/linux/efi.h
> index 8b84916..7a9498a 100644
> --- a/include/linux/efi.h
> +++ b/include/linux/efi.h
> @@ -618,18 +618,30 @@ extern int __init efi_setup_pcdp_console(char *);
> #endif
>
> /*
> - * We play games with efi_enabled so that the compiler will, if possible, remove
> - * EFI-related code altogether.
> + * We play games with efi_enabled so that the compiler will, if
> + * possible, remove EFI-related code altogether.
> */
> +#define EFI_BOOT 0 /* Were we booted from EFI? */
> +#define EFI_SYSTEM_TABLES 1 /* Can we use EFI system tables? */
> +#define EFI_CONFIG_TABLES 2 /* Can we use EFI config tables? */
> +#define EFI_RUNTIME_SERVICES 3 /* Can we use runtime services? */
> +#define EFI_MEMMAP 4 /* Can we use EFI memory map? */
> +#define EFI_64BIT 5 /* Is the firmware 64-bit? */
> +
> #ifdef CONFIG_EFI
> # ifdef CONFIG_X86
> - extern int efi_enabled;
> - extern bool efi_64bit;
> +extern int efi_enabled(int facility);
> # else
> -# define efi_enabled 1
> +static inline int efi_enabled(int facility)
> +{
> + return 1;
> +}
> # endif
> #else
> -# define efi_enabled 0
> +static inline int efi_enabled(int facility)
> +{
> + return 0;
> +}
> #endif
>
> /*
> diff --git a/init/main.c b/init/main.c
> index 85d69df..cd30179 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -604,7 +604,7 @@ asmlinkage void __init start_kernel(void)
> pidmap_init();
> anon_vma_init();
> #ifdef CONFIG_X86
> - if (efi_enabled)
> + if (efi_enabled(EFI_RUNTIME_SERVICES))
> efi_enter_virtual_mode();
> #endif
> thread_info_cache_init();
> @@ -632,7 +632,7 @@ asmlinkage void __init start_kernel(void)
> acpi_early_init(); /* before LAPIC and SMP init */
> sfi_init_late();
>
> - if (efi_enabled) {
> + if (efi_enabled(EFI_RUNTIME_SERVICES)) {
> efi_late_init();
> efi_free_boot_services();
> }
--
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