linux-kernel - Re: [PATCH v5 09/14] efi: passing kexec necessary efi data via setup

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Message-ID: <20131211121352.GB29980@console-pimps.org>
Date:	Wed, 11 Dec 2013 12:13:52 +0000
From:	Matt Fleming <matt@...sole-pimps.org>
To:	Dave Young <dyoung@...hat.com>
Cc:	linux-kernel@...r.kernel.org, linux-efi@...r.kernel.org,
	x86@...nel.org, mjg59@...f.ucam.org, hpa@...or.com,
	James.Bottomley@...senPartnership.com, vgoyal@...hat.com,
	ebiederm@...ssion.com, horms@...ge.net.au,
	kexec@...ts.infradead.org, bp@...en8.de, greg@...ah.com,
	toshi.kani@...com
Subject: Re: [PATCH v5 09/14] efi: passing kexec necessary efi data via
 setup_data

On Mon, 09 Dec, at 05:42:22PM, Dave Young wrote:
> Add a new setup_data type SETUP_EFI for kexec use.
> Passing the saved fw_vendor, runtime, config tables and efi runtime mappings.
> 
> When entering virtual mode, directly mapping the efi runtime ragions which
> we passed in previously. And skip the step to call SetVirtualAddressMap.
> 
> Specially for HP z420 workstation we need save the smbios physical address.
> The kernel boot sequence proceeds in the following order.  Step 2
> requires efi.smbios to be the physical address.  However, I found that on
> HP z420 EFI system table has a virtual address of SMBIOS in step 1.  Hence,
> we need set it back to the physical address with the smbios in
> efi_setup_data.  (When it is still the physical address, it simply sets
> the same value.)
> 
> 1. efi_init() - Set efi.smbios from EFI system table
> 2. dmi_scan_machine() - Temporary map efi.smbios to access SMBIOS table
> 3. efi_enter_virtual_mode() - Map EFI ranges
> 
> Tested on ovmf+qemu, lenovo thinkpad, a dell laptop and an
> HP z420 workstation.
> 
> v2: refresh based on previous patch changes, code cleanup.
> v3: use ioremap instead of phys_to_virt for efi_setup
> v5: improve some code structure per comments from Matt
>     Boris: improve code structure, spell fix, etc.
>     Improve changelog from Toshi.
>     change the variable efi_setup to the physical address of efi setup_data
>     instead of the ioremapped virt address
> 
> Signed-off-by: Dave Young <dyoung@...hat.com>
> ---
>  arch/x86/include/asm/efi.h            |  11 ++
>  arch/x86/include/uapi/asm/bootparam.h |   1 +
>  arch/x86/kernel/setup.c               |   3 +
>  arch/x86/platform/efi/efi.c           | 195 ++++++++++++++++++++++++++++++----
>  4 files changed, 187 insertions(+), 23 deletions(-)

[...]

> @@ -115,6 +116,25 @@ static int __init setup_storage_paranoia(char *arg)
>  }
>  early_param("efi_no_storage_paranoia", setup_storage_paranoia);
>  
> +void __init parse_efi_setup(u64 phys_addr)
> +{
> +	struct setup_data *sd;
> +
> +	if (!efi_enabled(EFI_64BIT)) {
> +		pr_warn("SETUP_EFI not supported on 32-bit\n");
> +		return;
> +	}
> +
> +	sd = early_memremap(phys_addr, sizeof(struct setup_data));
> +	if (!sd) {
> +		pr_warn("efi: early_memremap setup_data failed\n");

You shouldn't need the "efi:" prefix in the message.

> @@ -676,6 +766,8 @@ void __init efi_init(void)
>  		efi.systab->hdr.revision >> 16,
>  		efi.systab->hdr.revision & 0xffff, vendor);
>  
> +	efi_reuse_config(efi.systab->tables, efi.systab->nr_tables);
> +

Please check the return value.

>  	if (efi_config_init(arch_tables))
>  		return;
>  
> @@ -886,6 +978,50 @@ out_krealloc:
>  }
>  
>  /*
> + * Map efi regions which was passed via setup_data. The virt_addr is a fixed
> + * addr which was used in first kernel in case kexec boot.
> + */
> +static int __init map_regions_fixed(void)
> +{
> +	int i, s, ret = 0;
> +	u64 end, systab;
> +	unsigned long size;
> +	efi_memory_desc_t *md;
> +	struct efi_setup_data *data;
> +
> +	s = sizeof(*data) + nr_efi_runtime_map * sizeof(data->map[0]);
> +	data = early_memremap(efi_setup, s);
> +	if (!data) {
> +		ret = -ENOMEM;
> +		goto out;
> +	}
> +	for (i = 0, md = data->map; i < nr_efi_runtime_map; i++, md++) {
> +		efi_map_region_fixed(md); /* FIXME: add error handling */

Oops. Please fix this ;-)

-- 
Matt Fleming, Intel Open Source Technology Center
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