Re: [PATCH V3 1/4] efi/x86: move efi bgrt init code to early init code

[Ard Biesheuvel]

On 18 January 2017 at 19:24, Bhupesh Sharma <bhsharma@xxxxxxxxxx> wrote:
> On Wed, Jan 18, 2017 at 7:30 PM, Ard Biesheuvel
> <ard.biesheuvel@xxxxxxxxxx> wrote:
>> On 18 January 2017 at 13:48, Dave Young <dyoung@xxxxxxxxxx> wrote:
>>> Before invoking the arch specific handler, efi_mem_reserve() reserves
>>> the given memory region through memblock.
>>>
>>> efi_bgrt_init will call efi_mem_reserve after mm_init(), at that time
>>> memblock is dead and it should not be used any more.
>>>
>>> efi bgrt code depend on acpi intialization to get the bgrt acpi table,
>>> moving bgrt parsing to acpi early boot code can make sure efi_mem_reserve
>>> in efi bgrt code still use memblock safely.
>>>
>>> Signed-off-by: Dave Young <dyoung@xxxxxxxxxx>
>>
>> This patch looks fine to me know
>>
>> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
>>
>> but before applying it, I'd like
>>
>> - Bhupesh to confirm that this patch is a move in the right direction
>> with regard to enabling BGRT on arm64/ACPI,
>
> I gave the changes from Dave a try on top of the following combination:
> 4.10-rc3 + efi/next patches not available in 4.10-rc3 + Nicolai's patches
>
> and was able to get the BGRT table working properly with OVMF on a
> QEMU-x86_64 machine. So you can add my tested-by for this patch
> series.
>
> I think this is the right direction for the ARM64 BGRT handling
> patches as well and I will post a RFC in two phases as suggested by
> Ard, once Dave's patches are accepted (in efi/next?).
>

Thanks!

>
>> - an ack from the ACPI maintainers (cc'ed)
>>

Rafael, Len? Any objections?

If not, I will go ahead and queue this for v4.11


>>> --->>> v1->v2: efi_bgrt_init: check table length first before copying bgrt table
>>>         error checking in drivers/acpi/bgrt.c
>>> v2->v3: drop #ifdef added before; efi-bgrt.h build warning fix
>>>         since only changed this patch, so I just only resend this one.
>>>  arch/x86/kernel/acpi/boot.c      |    9 +++++
>>>  arch/x86/platform/efi/efi-bgrt.c |   59 ++++++++++++++++-----------------------
>>>  arch/x86/platform/efi/efi.c      |    5 ---
>>>  drivers/acpi/bgrt.c              |   28 +++++++++++++-----
>>>  include/linux/efi-bgrt.h         |   11 +++----
>>>  init/main.c                      |    1
>>>  6 files changed, 59 insertions(+), 54 deletions(-)
>>>
>>> --- linux-x86.orig/arch/x86/kernel/acpi/boot.c
>>> +++ linux-x86/arch/x86/kernel/acpi/boot.c
>>> @@ -35,6 +35,7 @@
>>>  #include <linux/bootmem.h>
>>>  #include <linux/ioport.h>
>>>  #include <linux/pci.h>
>>> +#include <linux/efi-bgrt.h>
>>>
>>>  #include <asm/irqdomain.h>
>>>  #include <asm/pci_x86.h>
>>> @@ -1557,6 +1558,12 @@ int __init early_acpi_boot_init(void)
>>>         return 0;
>>>  }
>>>
>>> +static int __init acpi_parse_bgrt(struct acpi_table_header *table)
>>> +{
>>> +       efi_bgrt_init(table);
>>> +       return 0;
>>> +}
>>> +
>>>  int __init acpi_boot_init(void)
>>>  {
>>>         /* those are executed after early-quirks are executed */
>>> @@ -1581,6 +1588,8 @@ int __init acpi_boot_init(void)
>>>         acpi_process_madt();
>>>
>>>         acpi_table_parse(ACPI_SIG_HPET, acpi_parse_hpet);
>>> +       if (IS_ENABLED(CONFIG_ACPI_BGRT))
>>> +               acpi_table_parse(ACPI_SIG_BGRT, acpi_parse_bgrt);
>>>
>>>         if (!acpi_noirq)
>>>                 x86_init.pci.init = pci_acpi_init;
>>> --- linux-x86.orig/arch/x86/platform/efi/efi-bgrt.c
>>> +++ linux-x86/arch/x86/platform/efi/efi-bgrt.c
>>> @@ -19,8 +19,7 @@
>>>  #include <linux/efi.h>
>>>  #include <linux/efi-bgrt.h>
>>>
>>> -struct acpi_table_bgrt *bgrt_tab;
>>> -void *__initdata bgrt_image;
>>> +struct acpi_table_bgrt bgrt_tab;
>>>  size_t __initdata bgrt_image_size;
>>>
>>>  struct bmp_header {
>>> @@ -28,66 +27,58 @@ struct bmp_header {
>>>         u32 size;
>>>  } __packed;
>>>
>>> -void __init efi_bgrt_init(void)
>>> +void __init efi_bgrt_init(struct acpi_table_header *table)
>>>  {
>>> -       acpi_status status;
>>>         void *image;
>>>         struct bmp_header bmp_header;
>>> +       struct acpi_table_bgrt *bgrt = &bgrt_tab;
>>>
>>>         if (acpi_disabled)
>>>                 return;
>>>
>>> -       status = acpi_get_table("BGRT", 0,
>>> -                               (struct acpi_table_header **)&bgrt_tab);
>>> -       if (ACPI_FAILURE(status))
>>> -               return;
>>> -
>>> -       if (bgrt_tab->header.length < sizeof(*bgrt_tab)) {
>>> +       if (table->length < sizeof(bgrt_tab)) {
>>>                 pr_notice("Ignoring BGRT: invalid length %u (expected %zu)\n",
>>> -                      bgrt_tab->header.length, sizeof(*bgrt_tab));
>>> +                      table->length, sizeof(bgrt_tab));
>>>                 return;
>>>         }
>>> -       if (bgrt_tab->version != 1) {
>>> +       *bgrt = *(struct acpi_table_bgrt *)table;
>>> +       if (bgrt->version != 1) {
>>>                 pr_notice("Ignoring BGRT: invalid version %u (expected 1)\n",
>>> -                      bgrt_tab->version);
>>> -               return;
>>> +                      bgrt->version);
>>> +               goto out;
>>>         }
>>> -       if (bgrt_tab->status & 0xfe) {
>>> +       if (bgrt->status & 0xfe) {
>>>                 pr_notice("Ignoring BGRT: reserved status bits are non-zero %u\n",
>>> -                      bgrt_tab->status);
>>> -               return;
>>> +                      bgrt->status);
>>> +               goto out;
>>>         }
>>> -       if (bgrt_tab->image_type != 0) {
>>> +       if (bgrt->image_type != 0) {
>>>                 pr_notice("Ignoring BGRT: invalid image type %u (expected 0)\n",
>>> -                      bgrt_tab->image_type);
>>> -               return;
>>> +                      bgrt->image_type);
>>> +               goto out;
>>>         }
>>> -       if (!bgrt_tab->image_address) {
>>> +       if (!bgrt->image_address) {
>>>                 pr_notice("Ignoring BGRT: null image address\n");
>>> -               return;
>>> +               goto out;
>>>         }
>>>
>>> -       image = memremap(bgrt_tab->image_address, sizeof(bmp_header), MEMREMAP_WB);
>>> +       image = early_memremap(bgrt->image_address, sizeof(bmp_header));
>>>         if (!image) {
>>>                 pr_notice("Ignoring BGRT: failed to map image header memory\n");
>>> -               return;
>>> +               goto out;
>>>         }
>>>
>>>         memcpy(&bmp_header, image, sizeof(bmp_header));
>>> -       memunmap(image);
>>> +       early_memunmap(image, sizeof(bmp_header));
>>>         if (bmp_header.id != 0x4d42) {
>>>                 pr_notice("Ignoring BGRT: Incorrect BMP magic number 0x%x (expected 0x4d42)\n",
>>>                         bmp_header.id);
>>> -               return;
>>> +               goto out;
>>>         }
>>>         bgrt_image_size = bmp_header.size;
>>> +       efi_mem_reserve(bgrt->image_address, bgrt_image_size);
>>>
>>> -       bgrt_image = memremap(bgrt_tab->image_address, bmp_header.size, MEMREMAP_WB);
>>> -       if (!bgrt_image) {
>>> -               pr_notice("Ignoring BGRT: failed to map image memory\n");
>>> -               bgrt_image = NULL;
>>> -               return;
>>> -       }
>>> -
>>> -       efi_mem_reserve(bgrt_tab->image_address, bgrt_image_size);
>>> +       return;
>>> +out:
>>> +       memset(bgrt, 0, sizeof(bgrt_tab));
>>>  }
>>> --- linux-x86.orig/drivers/acpi/bgrt.c
>>> +++ linux-x86/drivers/acpi/bgrt.c
>>> @@ -15,40 +15,41 @@
>>>  #include <linux/sysfs.h>
>>>  #include <linux/efi-bgrt.h>
>>>
>>> +static void *bgrt_image;
>>>  static struct kobject *bgrt_kobj;
>>>
>>>  static ssize_t show_version(struct device *dev,
>>>                             struct device_attribute *attr, char *buf)
>>>  {
>>> -       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->version);
>>> +       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.version);
>>>  }
>>>  static DEVICE_ATTR(version, S_IRUGO, show_version, NULL);
>>>
>>>  static ssize_t show_status(struct device *dev,
>>>                            struct device_attribute *attr, char *buf)
>>>  {
>>> -       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->status);
>>> +       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.status);
>>>  }
>>>  static DEVICE_ATTR(status, S_IRUGO, show_status, NULL);
>>>
>>>  static ssize_t show_type(struct device *dev,
>>>                          struct device_attribute *attr, char *buf)
>>>  {
>>> -       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->image_type);
>>> +       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.image_type);
>>>  }
>>>  static DEVICE_ATTR(type, S_IRUGO, show_type, NULL);
>>>
>>>  static ssize_t show_xoffset(struct device *dev,
>>>                             struct device_attribute *attr, char *buf)
>>>  {
>>> -       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->image_offset_x);
>>> +       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.image_offset_x);
>>>  }
>>>  static DEVICE_ATTR(xoffset, S_IRUGO, show_xoffset, NULL);
>>>
>>>  static ssize_t show_yoffset(struct device *dev,
>>>                             struct device_attribute *attr, char *buf)
>>>  {
>>> -       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->image_offset_y);
>>> +       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.image_offset_y);
>>>  }
>>>  static DEVICE_ATTR(yoffset, S_IRUGO, show_yoffset, NULL);
>>>
>>> @@ -84,15 +85,24 @@ static int __init bgrt_init(void)
>>>  {
>>>         int ret;
>>>
>>> -       if (!bgrt_image)
>>> +       if (!bgrt_tab.image_address)
>>>                 return -ENODEV;
>>>
>>> +       bgrt_image = memremap(bgrt_tab.image_address, bgrt_image_size,
>>> +                             MEMREMAP_WB);
>>> +       if (!bgrt_image) {
>>> +               pr_notice("Ignoring BGRT: failed to map image memory\n");
>>> +               return -ENOMEM;
>>> +       }
>>> +
>>>         bin_attr_image.private = bgrt_image;
>>>         bin_attr_image.size = bgrt_image_size;
>>>
>>>         bgrt_kobj = kobject_create_and_add("bgrt", acpi_kobj);
>>> -       if (!bgrt_kobj)
>>> -               return -EINVAL;
>>> +       if (!bgrt_kobj) {
>>> +               ret = -EINVAL;
>>> +               goto out_memmap;
>>> +       }
>>>
>>>         ret = sysfs_create_group(bgrt_kobj, &bgrt_attribute_group);
>>>         if (ret)
>>> @@ -102,6 +112,8 @@ static int __init bgrt_init(void)
>>>
>>>  out_kobject:
>>>         kobject_put(bgrt_kobj);
>>> +out_memmap:
>>> +       memunmap(bgrt_image);
>>>         return ret;
>>>  }
>>>  device_initcall(bgrt_init);
>>> --- linux-x86.orig/include/linux/efi-bgrt.h
>>> +++ linux-x86/include/linux/efi-bgrt.h
>>> @@ -1,20 +1,19 @@
>>>  #ifndef _LINUX_EFI_BGRT_H
>>>  #define _LINUX_EFI_BGRT_H
>>>
>>> -#ifdef CONFIG_ACPI_BGRT
>>> -
>>>  #include <linux/acpi.h>
>>>
>>> -void efi_bgrt_init(void);
>>> +#ifdef CONFIG_ACPI_BGRT
>>> +
>>> +void efi_bgrt_init(struct acpi_table_header *table);
>>>
>>>  /* The BGRT data itself; only valid if bgrt_image != NULL. */
>>> -extern void *bgrt_image;
>>>  extern size_t bgrt_image_size;
>>> -extern struct acpi_table_bgrt *bgrt_tab;
>>> +extern struct acpi_table_bgrt bgrt_tab;
>>>
>>>  #else /* !CONFIG_ACPI_BGRT */
>>>
>>> -static inline void efi_bgrt_init(void) {}
>>> +static inline void efi_bgrt_init(struct acpi_table_header *table) {}
>>>
>>>  #endif /* !CONFIG_ACPI_BGRT */
>>>
>>> --- linux-x86.orig/arch/x86/platform/efi/efi.c
>>> +++ linux-x86/arch/x86/platform/efi/efi.c
>>> @@ -542,11 +542,6 @@ void __init efi_init(void)
>>>                 efi_print_memmap();
>>>  }
>>>
>>> -void __init efi_late_init(void)
>>> -{
>>> -       efi_bgrt_init();
>>> -}
>>> -
>>>  void __init efi_set_executable(efi_memory_desc_t *md, bool executable)
>>>  {
>>>         u64 addr, npages;
>>> --- linux-x86.orig/init/main.c
>>> +++ linux-x86/init/main.c
>>> @@ -663,7 +663,6 @@ asmlinkage __visible void __init start_k
>>>         sfi_init_late();
>>>
>>>         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
>>> -               efi_late_init();
>>>                 efi_free_boot_services();
>>>         }
>>>

>> - an ack from the ACPI maintainers (cc'ed)
>>
>> Thanks,
>> Ard.
>>
>>
>>> ---
>>> v1->v2: efi_bgrt_init: check table length first before copying bgrt table
>>>         error checking in drivers/acpi/bgrt.c
>>> v2->v3: drop #ifdef added before; efi-bgrt.h build warning fix
>>>         since only changed this patch, so I just only resend this one.
>>>  arch/x86/kernel/acpi/boot.c      |    9 +++++
>>>  arch/x86/platform/efi/efi-bgrt.c |   59 ++++++++++++++++-----------------------
>>>  arch/x86/platform/efi/efi.c      |    5 ---
>>>  drivers/acpi/bgrt.c              |   28 +++++++++++++-----
>>>  include/linux/efi-bgrt.h         |   11 +++----
>>>  init/main.c                      |    1
>>>  6 files changed, 59 insertions(+), 54 deletions(-)
>>>
>>> --- linux-x86.orig/arch/x86/kernel/acpi/boot.c
>>> +++ linux-x86/arch/x86/kernel/acpi/boot.c
>>> @@ -35,6 +35,7 @@
>>>  #include <linux/bootmem.h>
>>>  #include <linux/ioport.h>
>>>  #include <linux/pci.h>
>>> +#include <linux/efi-bgrt.h>
>>>
>>>  #include <asm/irqdomain.h>
>>>  #include <asm/pci_x86.h>
>>> @@ -1557,6 +1558,12 @@ int __init early_acpi_boot_init(void)
>>>         return 0;
>>>  }
>>>
>>> +static int __init acpi_parse_bgrt(struct acpi_table_header *table)
>>> +{
>>> +       efi_bgrt_init(table);
>>> +       return 0;
>>> +}
>>> +
>>>  int __init acpi_boot_init(void)
>>>  {
>>>         /* those are executed after early-quirks are executed */
>>> @@ -1581,6 +1588,8 @@ int __init acpi_boot_init(void)
>>>         acpi_process_madt();
>>>
>>>         acpi_table_parse(ACPI_SIG_HPET, acpi_parse_hpet);
>>> +       if (IS_ENABLED(CONFIG_ACPI_BGRT))
>>> +               acpi_table_parse(ACPI_SIG_BGRT, acpi_parse_bgrt);
>>>
>>>         if (!acpi_noirq)
>>>                 x86_init.pci.init = pci_acpi_init;
>>> --- linux-x86.orig/arch/x86/platform/efi/efi-bgrt.c
>>> +++ linux-x86/arch/x86/platform/efi/efi-bgrt.c
>>> @@ -19,8 +19,7 @@
>>>  #include <linux/efi.h>
>>>  #include <linux/efi-bgrt.h>
>>>
>>> -struct acpi_table_bgrt *bgrt_tab;
>>> -void *__initdata bgrt_image;
>>> +struct acpi_table_bgrt bgrt_tab;
>>>  size_t __initdata bgrt_image_size;
>>>
>>>  struct bmp_header {
>>> @@ -28,66 +27,58 @@ struct bmp_header {
>>>         u32 size;
>>>  } __packed;
>>>
>>> -void __init efi_bgrt_init(void)
>>> +void __init efi_bgrt_init(struct acpi_table_header *table)
>>>  {
>>> -       acpi_status status;
>>>         void *image;
>>>         struct bmp_header bmp_header;
>>> +       struct acpi_table_bgrt *bgrt = &bgrt_tab;
>>>
>>>         if (acpi_disabled)
>>>                 return;
>>>
>>> -       status = acpi_get_table("BGRT", 0,
>>> -                               (struct acpi_table_header **)&bgrt_tab);
>>> -       if (ACPI_FAILURE(status))
>>> -               return;
>>> -
>>> -       if (bgrt_tab->header.length < sizeof(*bgrt_tab)) {
>>> +       if (table->length < sizeof(bgrt_tab)) {
>>>                 pr_notice("Ignoring BGRT: invalid length %u (expected %zu)\n",
>>> -                      bgrt_tab->header.length, sizeof(*bgrt_tab));
>>> +                      table->length, sizeof(bgrt_tab));
>>>                 return;
>>>         }
>>> -       if (bgrt_tab->version != 1) {
>>> +       *bgrt = *(struct acpi_table_bgrt *)table;
>>> +       if (bgrt->version != 1) {
>>>                 pr_notice("Ignoring BGRT: invalid version %u (expected 1)\n",
>>> -                      bgrt_tab->version);
>>> -               return;
>>> +                      bgrt->version);
>>> +               goto out;
>>>         }
>>> -       if (bgrt_tab->status & 0xfe) {
>>> +       if (bgrt->status & 0xfe) {
>>>                 pr_notice("Ignoring BGRT: reserved status bits are non-zero %u\n",
>>> -                      bgrt_tab->status);
>>> -               return;
>>> +                      bgrt->status);
>>> +               goto out;
>>>         }
>>> -       if (bgrt_tab->image_type != 0) {
>>> +       if (bgrt->image_type != 0) {
>>>                 pr_notice("Ignoring BGRT: invalid image type %u (expected 0)\n",
>>> -                      bgrt_tab->image_type);
>>> -               return;
>>> +                      bgrt->image_type);
>>> +               goto out;
>>>         }
>>> -       if (!bgrt_tab->image_address) {
>>> +       if (!bgrt->image_address) {
>>>                 pr_notice("Ignoring BGRT: null image address\n");
>>> -               return;
>>> +               goto out;
>>>         }
>>>
>>> -       image = memremap(bgrt_tab->image_address, sizeof(bmp_header), MEMREMAP_WB);
>>> +       image = early_memremap(bgrt->image_address, sizeof(bmp_header));
>>>         if (!image) {
>>>                 pr_notice("Ignoring BGRT: failed to map image header memory\n");
>>> -               return;
>>> +               goto out;
>>>         }
>>>
>>>         memcpy(&bmp_header, image, sizeof(bmp_header));
>>> -       memunmap(image);
>>> +       early_memunmap(image, sizeof(bmp_header));
>>>         if (bmp_header.id != 0x4d42) {
>>>                 pr_notice("Ignoring BGRT: Incorrect BMP magic number 0x%x (expected 0x4d42)\n",
>>>                         bmp_header.id);
>>> -               return;
>>> +               goto out;
>>>         }
>>>         bgrt_image_size = bmp_header.size;
>>> +       efi_mem_reserve(bgrt->image_address, bgrt_image_size);
>>>
>>> -       bgrt_image = memremap(bgrt_tab->image_address, bmp_header.size, MEMREMAP_WB);
>>> -       if (!bgrt_image) {
>>> -               pr_notice("Ignoring BGRT: failed to map image memory\n");
>>> -               bgrt_image = NULL;
>>> -               return;
>>> -       }
>>> -
>>> -       efi_mem_reserve(bgrt_tab->image_address, bgrt_image_size);
>>> +       return;
>>> +out:
>>> +       memset(bgrt, 0, sizeof(bgrt_tab));
>>>  }
>>> --- linux-x86.orig/drivers/acpi/bgrt.c
>>> +++ linux-x86/drivers/acpi/bgrt.c
>>> @@ -15,40 +15,41 @@
>>>  #include <linux/sysfs.h>
>>>  #include <linux/efi-bgrt.h>
>>>
>>> +static void *bgrt_image;
>>>  static struct kobject *bgrt_kobj;
>>>
>>>  static ssize_t show_version(struct device *dev,
>>>                             struct device_attribute *attr, char *buf)
>>>  {
>>> -       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->version);
>>> +       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.version);
>>>  }
>>>  static DEVICE_ATTR(version, S_IRUGO, show_version, NULL);
>>>
>>>  static ssize_t show_status(struct device *dev,
>>>                            struct device_attribute *attr, char *buf)
>>>  {
>>> -       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->status);
>>> +       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.status);
>>>  }
>>>  static DEVICE_ATTR(status, S_IRUGO, show_status, NULL);
>>>
>>>  static ssize_t show_type(struct device *dev,
>>>                          struct device_attribute *attr, char *buf)
>>>  {
>>> -       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->image_type);
>>> +       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.image_type);
>>>  }
>>>  static DEVICE_ATTR(type, S_IRUGO, show_type, NULL);
>>>
>>>  static ssize_t show_xoffset(struct device *dev,
>>>                             struct device_attribute *attr, char *buf)
>>>  {
>>> -       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->image_offset_x);
>>> +       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.image_offset_x);
>>>  }
>>>  static DEVICE_ATTR(xoffset, S_IRUGO, show_xoffset, NULL);
>>>
>>>  static ssize_t show_yoffset(struct device *dev,
>>>                             struct device_attribute *attr, char *buf)
>>>  {
>>> -       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->image_offset_y);
>>> +       return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.image_offset_y);
>>>  }
>>>  static DEVICE_ATTR(yoffset, S_IRUGO, show_yoffset, NULL);
>>>
>>> @@ -84,15 +85,24 @@ static int __init bgrt_init(void)
>>>  {
>>>         int ret;
>>>
>>> -       if (!bgrt_image)
>>> +       if (!bgrt_tab.image_address)
>>>                 return -ENODEV;
>>>
>>> +       bgrt_image = memremap(bgrt_tab.image_address, bgrt_image_size,
>>> +                             MEMREMAP_WB);
>>> +       if (!bgrt_image) {
>>> +               pr_notice("Ignoring BGRT: failed to map image memory\n");
>>> +               return -ENOMEM;
>>> +       }
>>> +
>>>         bin_attr_image.private = bgrt_image;
>>>         bin_attr_image.size = bgrt_image_size;
>>>
>>>         bgrt_kobj = kobject_create_and_add("bgrt", acpi_kobj);
>>> -       if (!bgrt_kobj)
>>> -               return -EINVAL;
>>> +       if (!bgrt_kobj) {
>>> +               ret = -EINVAL;
>>> +               goto out_memmap;
>>> +       }
>>>
>>>         ret = sysfs_create_group(bgrt_kobj, &bgrt_attribute_group);
>>>         if (ret)
>>> @@ -102,6 +112,8 @@ static int __init bgrt_init(void)
>>>
>>>  out_kobject:
>>>         kobject_put(bgrt_kobj);
>>> +out_memmap:
>>> +       memunmap(bgrt_image);
>>>         return ret;
>>>  }
>>>  device_initcall(bgrt_init);
>>> --- linux-x86.orig/include/linux/efi-bgrt.h
>>> +++ linux-x86/include/linux/efi-bgrt.h
>>> @@ -1,20 +1,19 @@
>>>  #ifndef _LINUX_EFI_BGRT_H
>>>  #define _LINUX_EFI_BGRT_H
>>>
>>> -#ifdef CONFIG_ACPI_BGRT
>>> -
>>>  #include <linux/acpi.h>
>>>
>>> -void efi_bgrt_init(void);
>>> +#ifdef CONFIG_ACPI_BGRT
>>> +
>>> +void efi_bgrt_init(struct acpi_table_header *table);
>>>
>>>  /* The BGRT data itself; only valid if bgrt_image != NULL. */
>>> -extern void *bgrt_image;
>>>  extern size_t bgrt_image_size;
>>> -extern struct acpi_table_bgrt *bgrt_tab;
>>> +extern struct acpi_table_bgrt bgrt_tab;
>>>
>>>  #else /* !CONFIG_ACPI_BGRT */
>>>
>>> -static inline void efi_bgrt_init(void) {}
>>> +static inline void efi_bgrt_init(struct acpi_table_header *table) {}
>>>
>>>  #endif /* !CONFIG_ACPI_BGRT */
>>>
>>> --- linux-x86.orig/arch/x86/platform/efi/efi.c
>>> +++ linux-x86/arch/x86/platform/efi/efi.c
>>> @@ -542,11 +542,6 @@ void __init efi_init(void)
>>>                 efi_print_memmap();
>>>  }
>>>
>>> -void __init efi_late_init(void)
>>> -{
>>> -       efi_bgrt_init();
>>> -}
>>> -
>>>  void __init efi_set_executable(efi_memory_desc_t *md, bool executable)
>>>  {
>>>         u64 addr, npages;
>>> --- linux-x86.orig/init/main.c
>>> +++ linux-x86/init/main.c
>>> @@ -663,7 +663,6 @@ asmlinkage __visible void __init start_k
>>>         sfi_init_late();
>>>
>>>         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
>>> -               efi_late_init();
>>>                 efi_free_boot_services();
>>>         }
>>>