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Date: Wed, 22 Jul 2015 11:58:49 +0100
From: Matt Fleming <matt@...eblueprint.co.uk>
To: Yinghai Lu <yinghai@...nel.org>
Cc: Kees Cook <keescook@...omium.org>,
"H. Peter Anvin" <hpa@...or.com>, Baoquan He <bhe@...hat.com>,
linux-kernel@...r.kernel.org,
Matt Fleming <matt.fleming@...el.com>,
linux-efi@...r.kernel.org, Dave Young <dyoung@...hat.com>
Subject: Re: [PATCH 31/42] x86, efi: Copy SETUP_EFI data and access directly
(Pulling in Dave since he wrote the code)
On Tue, 07 Jul, at 01:20:17PM, Yinghai Lu wrote:
> The copy will be in __initdata, and it is small.
>
> We can use pointer to access the setup_data instead of using early_memmap
> everywhere.
Is that the only advantage to copying the data, that we save ourselves
the overhead of calling early_memremap()? That seems fair enough, I just
want to be clear.
> Cc: Matt Fleming <matt.fleming@...el.com>
> Cc: linux-efi@...r.kernel.org
> Signed-off-by: Yinghai Lu <yinghai@...nel.org>
> ---
> arch/x86/include/asm/efi.h | 2 +-
> arch/x86/platform/efi/efi.c | 13 ++-----------
> arch/x86/platform/efi/efi_64.c | 10 +++++++++-
> arch/x86/platform/efi/quirks.c | 23 ++++++-----------------
> 4 files changed, 18 insertions(+), 30 deletions(-)
>
> diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
> index 155162e..a3e3aee 100644
> --- a/arch/x86/include/asm/efi.h
> +++ b/arch/x86/include/asm/efi.h
> @@ -116,7 +116,7 @@ struct efi_setup_data {
> u64 reserved[8];
> };
>
> -extern u64 efi_setup;
> +extern struct efi_setup_data *efi_setup;
>
> #ifdef CONFIG_EFI
>
> diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> index cfba30f..33036ce 100644
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -68,7 +68,7 @@ static efi_config_table_type_t arch_tables[] __initdata = {
> {NULL_GUID, NULL, NULL},
> };
>
> -u64 efi_setup; /* efi setup_data physical address */
> +struct efi_setup_data *efi_setup __initdata; /* cached efi setup_data pointer */
>
> static int add_efi_memmap __initdata;
> static int __init setup_add_efi_memmap(char *arg)
> @@ -257,20 +257,13 @@ static int __init efi_systab_init(void *phys)
> {
> if (efi_enabled(EFI_64BIT)) {
> efi_system_table_64_t *systab64;
> - struct efi_setup_data *data = NULL;
> + struct efi_setup_data *data = efi_setup;
> u64 tmp = 0;
>
> - if (efi_setup) {
> - data = early_memremap(efi_setup, sizeof(*data));
> - if (!data)
> - return -ENOMEM;
> - }
> systab64 = early_memremap((unsigned long)phys,
> sizeof(*systab64));
> if (systab64 == NULL) {
> pr_err("Couldn't map the system table!\n");
> - if (data)
> - early_memunmap(data, sizeof(*data));
> return -ENOMEM;
> }
>
> @@ -303,8 +296,6 @@ static int __init efi_systab_init(void *phys)
> tmp |= data ? data->tables : systab64->tables;
>
> early_memunmap(systab64, sizeof(*systab64));
> - if (data)
> - early_memunmap(data, sizeof(*data));
> #ifdef CONFIG_X86_32
> if (tmp >> 32) {
> pr_err("EFI data located above 4GB, disabling EFI.\n");
> diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
> index a0ac0f9..a255491 100644
> --- a/arch/x86/platform/efi/efi_64.c
> +++ b/arch/x86/platform/efi/efi_64.c
> @@ -295,9 +295,17 @@ void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
> return (void __iomem *)__va(phys_addr);
> }
>
> +static struct efi_setup_data efi_setup_data __initdata;
> +
> void __init parse_efi_setup(u64 phys_addr, u32 data_len)
> {
> - efi_setup = phys_addr + sizeof(struct setup_data);
> + struct efi_setup_data *data;
> +
> + data = early_memremap(phys_addr + sizeof(struct setup_data),
> + sizeof(*data));
> + efi_setup_data = *data;
> + early_memunmap(data, sizeof(*data));
> + efi_setup = &efi_setup_data;
> }
>
> void __init efi_runtime_mkexec(void)
> diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
> index 1c7380d..45fec7d 100644
> --- a/arch/x86/platform/efi/quirks.c
> +++ b/arch/x86/platform/efi/quirks.c
> @@ -203,9 +203,8 @@ void __init efi_free_boot_services(void)
> */
> int __init efi_reuse_config(u64 tables, int nr_tables)
> {
> - int i, sz, ret = 0;
> + int i, sz;
> void *p, *tablep;
> - struct efi_setup_data *data;
>
> if (!efi_setup)
> return 0;
> @@ -213,22 +212,15 @@ int __init efi_reuse_config(u64 tables, int nr_tables)
> if (!efi_enabled(EFI_64BIT))
> return 0;
>
> - data = early_memremap(efi_setup, sizeof(*data));
> - if (!data) {
> - ret = -ENOMEM;
> - goto out;
> - }
> -
> - if (!data->smbios)
> - goto out_memremap;
> + if (!efi_setup->smbios)
> + return 0;
>
> sz = sizeof(efi_config_table_64_t);
>
> p = tablep = early_memremap(tables, nr_tables * sz);
> if (!p) {
> pr_err("Could not map Configuration table!\n");
> - ret = -ENOMEM;
> - goto out_memremap;
> + return -ENOMEM;
> }
>
> for (i = 0; i < efi.systab->nr_tables; i++) {
> @@ -237,15 +229,12 @@ int __init efi_reuse_config(u64 tables, int nr_tables)
> guid = ((efi_config_table_64_t *)p)->guid;
>
> if (!efi_guidcmp(guid, SMBIOS_TABLE_GUID))
> - ((efi_config_table_64_t *)p)->table = data->smbios;
> + ((efi_config_table_64_t *)p)->table = efi_setup->smbios;
> p += sz;
> }
> early_memunmap(tablep, nr_tables * sz);
>
> -out_memremap:
> - early_memunmap(data, sizeof(*data));
> -out:
> - return ret;
> + return 0;
> }
>
> void __init efi_apply_memmap_quirks(void)
> --
> 1.8.4.5
>
> --
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--
Matt Fleming, Intel Open Source Technology Center
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