linux.git/drivers/firmware/efi, branch v6.9 Linux kernel source tree efi/unaccepted: touch soft lockup during memory accept 2024-04-24T17:11:34+00:00 Chen Yu yu.c.chen@intel.com 2024-04-10T10:23:01+00:00 1c5a1627f48105cbab81d25ec2f72232bfaa8185 Commit 50e782a86c98 ("efi/unaccepted: Fix soft lockups caused by parallel memory acceptance") has released the spinlock so other CPUs can do memory acceptance in parallel and not triggers softlockup on other CPUs. However the softlock up was intermittent shown up if the memory of the TD guest is large, and the timeout of softlockup is set to 1 second: RIP: 0010:_raw_spin_unlock_irqrestore Call Trace: ? __hrtimer_run_queues <IRQ> ? hrtimer_interrupt ? watchdog_timer_fn ? __sysvec_apic_timer_interrupt ? __pfx_watchdog_timer_fn ? sysvec_apic_timer_interrupt </IRQ> ? __hrtimer_run_queues <TASK> ? hrtimer_interrupt ? asm_sysvec_apic_timer_interrupt ? _raw_spin_unlock_irqrestore ? __sysvec_apic_timer_interrupt ? sysvec_apic_timer_interrupt accept_memory try_to_accept_memory do_huge_pmd_anonymous_page get_page_from_freelist __handle_mm_fault __alloc_pages __folio_alloc ? __tdx_hypercall handle_mm_fault vma_alloc_folio do_user_addr_fault do_huge_pmd_anonymous_page exc_page_fault ? __do_huge_pmd_anonymous_page asm_exc_page_fault __handle_mm_fault When the local irq is enabled at the end of accept_memory(), the softlockup detects that the watchdog on single CPU has not been fed for a while. That is to say, even other CPUs will not be blocked by spinlock, the current CPU might be stunk with local irq disabled for a while, which hurts not only nmi watchdog but also softlockup. Chao Gao pointed out that the memory accept could be time costly and there was similar report before. Thus to avoid any softlocup detection during this stage, give the softlockup a flag to skip the timeout check at the end of accept_memory(), by invoking touch_softlockup_watchdog(). Reported-by: Hossain, Md Iqbal <md.iqbal.hossain@intel.com> Signed-off-by: Chen Yu <yu.c.chen@intel.com> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Fixes: 50e782a86c98 ("efi/unaccepted: Fix soft lockups caused by parallel memory acceptance") Signed-off-by: Ard Biesheuvel <ardb@kernel.org> 
Commit 50e782a86c98 ("efi/unaccepted: Fix soft lockups caused by
parallel memory acceptance") has released the spinlock so other CPUs can
do memory acceptance in parallel and not triggers softlockup on other
CPUs.

However the softlock up was intermittent shown up if the memory of the
TD guest is large, and the timeout of softlockup is set to 1 second:

 RIP: 0010:_raw_spin_unlock_irqrestore
 Call Trace:
 ? __hrtimer_run_queues
 <IRQ>
 ? hrtimer_interrupt
 ? watchdog_timer_fn
 ? __sysvec_apic_timer_interrupt
 ? __pfx_watchdog_timer_fn
 ? sysvec_apic_timer_interrupt
 </IRQ>
 ? __hrtimer_run_queues
 <TASK>
 ? hrtimer_interrupt
 ? asm_sysvec_apic_timer_interrupt
 ? _raw_spin_unlock_irqrestore
 ? __sysvec_apic_timer_interrupt
 ? sysvec_apic_timer_interrupt
 accept_memory
 try_to_accept_memory
 do_huge_pmd_anonymous_page
 get_page_from_freelist
 __handle_mm_fault
 __alloc_pages
 __folio_alloc
 ? __tdx_hypercall
 handle_mm_fault
 vma_alloc_folio
 do_user_addr_fault
 do_huge_pmd_anonymous_page
 exc_page_fault
 ? __do_huge_pmd_anonymous_page
 asm_exc_page_fault
 __handle_mm_fault

When the local irq is enabled at the end of accept_memory(), the
softlockup detects that the watchdog on single CPU has not been fed for
a while. That is to say, even other CPUs will not be blocked by
spinlock, the current CPU might be stunk with local irq disabled for a
while, which hurts not only nmi watchdog but also softlockup.

Chao Gao pointed out that the memory accept could be time costly and
there was similar report before. Thus to avoid any softlocup detection
during this stage, give the softlockup a flag to skip the timeout check
at the end of accept_memory(), by invoking touch_softlockup_watchdog().

Reported-by: Hossain, Md Iqbal <md.iqbal.hossain@intel.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Fixes: 50e782a86c98 ("efi/unaccepted: Fix soft lockups caused by parallel memory acceptance")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
x86/efistub: Reinstate soft limit for initrd loading 2024-03-28T15:19:46+00:00 Ard Biesheuvel ardb@kernel.org 2024-03-28T14:49:48+00:00 decd347c2a75d32984beb8807d470b763a53b542 Commit 8117961d98fb2 ("x86/efi: Disregard setup header of loaded image") dropped the memcopy of the image's setup header into the boot_params struct provided to the core kernel, on the basis that EFI boot does not need it and should rely only on a single protocol to interface with the boot chain. It is also a prerequisite for being able to increase the section alignment to 4k, which is needed to enable memory protections when running in the boot services. So only the setup_header fields that matter to the core kernel are populated explicitly, and everything else is ignored. One thing was overlooked, though: the initrd_addr_max field in the setup_header is not used by the core kernel, but it is used by the EFI stub itself when it loads the initrd, where its default value of INT_MAX is used as the soft limit for memory allocation. This means that, in the old situation, the initrd was virtually always loaded in the lower 2G of memory, but now, due to initrd_addr_max being 0x0, the initrd may end up anywhere in memory. This should not be an issue principle, as most systems can deal with this fine. However, it does appear to tickle some problems in older UEFI implementations, where the memory ends up being corrupted, resulting in errors when unpacking the initramfs. So set the initrd_addr_max field to INT_MAX like it was before. Fixes: 8117961d98fb2 ("x86/efi: Disregard setup header of loaded image") Reported-by: Radek Podgorny <radek@podgorny.cz> Closes: https://lore.kernel.org/all/a99a831a-8ad5-4cb0-bff9-be637311f771@podgorny.cz Signed-off-by: Ard Biesheuvel <ardb@kernel.org> 
Commit

  8117961d98fb2 ("x86/efi: Disregard setup header of loaded image")

dropped the memcopy of the image's setup header into the boot_params
struct provided to the core kernel, on the basis that EFI boot does not
need it and should rely only on a single protocol to interface with the
boot chain. It is also a prerequisite for being able to increase the
section alignment to 4k, which is needed to enable memory protections
when running in the boot services.

So only the setup_header fields that matter to the core kernel are
populated explicitly, and everything else is ignored. One thing was
overlooked, though: the initrd_addr_max field in the setup_header is not
used by the core kernel, but it is used by the EFI stub itself when it
loads the initrd, where its default value of INT_MAX is used as the soft
limit for memory allocation.

This means that, in the old situation, the initrd was virtually always
loaded in the lower 2G of memory, but now, due to initrd_addr_max being
0x0, the initrd may end up anywhere in memory. This should not be an
issue principle, as most systems can deal with this fine. However, it
does appear to tickle some problems in older UEFI implementations, where
the memory ends up being corrupted, resulting in errors when unpacking
the initramfs.

So set the initrd_addr_max field to INT_MAX like it was before.

Fixes: 8117961d98fb2 ("x86/efi: Disregard setup header of loaded image")
Reported-by: Radek Podgorny <radek@podgorny.cz>
Closes: https://lore.kernel.org/all/a99a831a-8ad5-4cb0-bff9-be637311f771@podgorny.cz
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
efi/libstub: Cast away type warning in use of max() 2024-03-28T15:18:57+00:00 Ard Biesheuvel ardb@kernel.org 2024-03-26T10:15:25+00:00 61d130f261a3c15ae2c4b6f3ac3517d5d5b78855 Avoid a type mismatch warning in max() by switching to max_t() and providing the type explicitly. Fixes: 3cb4a4827596abc82e ("efi/libstub: fix efi_random_alloc() ...") Signed-off-by: Ard Biesheuvel <ardb@kernel.org> 
Avoid a type mismatch warning in max() by switching to max_t() and
providing the type explicitly.

Fixes: 3cb4a4827596abc82e ("efi/libstub: fix efi_random_alloc() ...")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Merge tag 'efi-fixes-for-v6.9-2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi 2024-03-24T20:54:06+00:00 Linus Torvalds torvalds@linux-foundation.org 2024-03-24T20:54:06+00:00 ab8de2dbfc9ec912f2762f3b813437a4c4f56251 Pull EFI fixes from Ard Biesheuvel: - Fix logic that is supposed to prevent placement of the kernel image below LOAD_PHYSICAL_ADDR - Use the firmware stack in the EFI stub when running in mixed mode - Clear BSS only once when using mixed mode - Check efi.get_variable() function pointer for NULL before trying to call it * tag 'efi-fixes-for-v6.9-2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi: efi: fix panic in kdump kernel x86/efistub: Don't clear BSS twice in mixed mode x86/efistub: Call mixed mode boot services on the firmware's stack efi/libstub: fix efi_random_alloc() to allocate memory at alloc_min or higher address 
Pull EFI fixes from Ard Biesheuvel:

 - Fix logic that is supposed to prevent placement of the kernel image
   below LOAD_PHYSICAL_ADDR

 - Use the firmware stack in the EFI stub when running in mixed mode

 - Clear BSS only once when using mixed mode

 - Check efi.get_variable() function pointer for NULL before trying to
   call it

* tag 'efi-fixes-for-v6.9-2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  efi: fix panic in kdump kernel
  x86/efistub: Don't clear BSS twice in mixed mode
  x86/efistub: Call mixed mode boot services on the firmware's stack
  efi/libstub: fix efi_random_alloc() to allocate memory at alloc_min or higher address
efi: fix panic in kdump kernel 2024-03-24T08:28:33+00:00 Oleksandr Tymoshenko ovt@google.com 2024-03-23T06:33:33+00:00 62b71cd73d41ddac6b1760402bbe8c4932e23531 Check if get_next_variable() is actually valid pointer before calling it. In kdump kernel this method is set to NULL that causes panic during the kexec-ed kernel boot. Tested with QEMU and OVMF firmware. Fixes: bad267f9e18f ("efi: verify that variable services are supported") Signed-off-by: Oleksandr Tymoshenko <ovt@google.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> 
Check if get_next_variable() is actually valid pointer before
calling it. In kdump kernel this method is set to NULL that causes
panic during the kexec-ed kernel boot.

Tested with QEMU and OVMF firmware.

Fixes: bad267f9e18f ("efi: verify that variable services are supported")
Signed-off-by: Oleksandr Tymoshenko <ovt@google.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
x86/efistub: Don't clear BSS twice in mixed mode 2024-03-24T08:28:33+00:00 Ard Biesheuvel ardb@kernel.org 2024-03-22T16:01:45+00:00 df7ecce842b846a04d087ba85fdb79a90e26a1b0 Clearing BSS should only be done once, at the very beginning. efi_pe_entry() is the entrypoint from the firmware, which may not clear BSS and so it is done explicitly. However, efi_pe_entry() is also used as an entrypoint by the mixed mode startup code, in which case BSS will already have been cleared, and doing it again at this point will corrupt global variables holding the firmware's GDT/IDT and segment selectors. So make the memset() conditional on whether the EFI stub is running in native mode. Fixes: b3810c5a2cc4a666 ("x86/efistub: Clear decompressor BSS in native EFI entrypoint") Signed-off-by: Ard Biesheuvel <ardb@kernel.org> 
Clearing BSS should only be done once, at the very beginning.
efi_pe_entry() is the entrypoint from the firmware, which may not clear
BSS and so it is done explicitly. However, efi_pe_entry() is also used
as an entrypoint by the mixed mode startup code, in which case BSS will
already have been cleared, and doing it again at this point will corrupt
global variables holding the firmware's GDT/IDT and segment selectors.

So make the memset() conditional on whether the EFI stub is running in
native mode.

Fixes: b3810c5a2cc4a666 ("x86/efistub: Clear decompressor BSS in native EFI entrypoint")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Merge tag 'fbdev-for-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev 2024-03-22T17:09:08+00:00 Linus Torvalds torvalds@linux-foundation.org 2024-03-22T17:09:08+00:00 4f55aa85a8746e5e255c46c98c031e143605e2a0 Pull fbdev updates from Helge Deller: - Allow console fonts up to 64x128 pixels (Samuel Thibault) - Prevent division-by-zero in fb monitor code (Roman Smirnov) - Drop Renesas ARM platforms from Mobile LCDC framebuffer driver (Geert Uytterhoeven) - Various code cleanups in viafb, uveafb and mb862xxfb drivers by Aleksandr Burakov, Li Zhijian and Michael Ellerman * tag 'fbdev-for-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev: fbdev: panel-tpo-td043mtea1: Convert sprintf() to sysfs_emit() fbmon: prevent division by zero in fb_videomode_from_videomode() fbcon: Increase maximum font width x height to 64 x 128 fbdev: viafb: fix typo in hw_bitblt_1 and hw_bitblt_2 fbdev: mb862xxfb: Fix defined but not used error fbdev: uvesafb: Convert sprintf/snprintf to sysfs_emit fbdev: Restrict FB_SH_MOBILE_LCDC to SuperH 
Pull fbdev updates from Helge Deller:

 - Allow console fonts up to 64x128 pixels (Samuel Thibault)

 - Prevent division-by-zero in fb monitor code (Roman Smirnov)

 - Drop Renesas ARM platforms from Mobile LCDC framebuffer driver (Geert
   Uytterhoeven)

 - Various code cleanups in viafb, uveafb and mb862xxfb drivers by
   Aleksandr Burakov, Li Zhijian and Michael Ellerman

* tag 'fbdev-for-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev:
  fbdev: panel-tpo-td043mtea1: Convert sprintf() to sysfs_emit()
  fbmon: prevent division by zero in fb_videomode_from_videomode()
  fbcon: Increase maximum font width x height to 64 x 128
  fbdev: viafb: fix typo in hw_bitblt_1 and hw_bitblt_2
  fbdev: mb862xxfb: Fix defined but not used error
  fbdev: uvesafb: Convert sprintf/snprintf to sysfs_emit
  fbdev: Restrict FB_SH_MOBILE_LCDC to SuperH
efi/libstub: fix efi_random_alloc() to allocate memory at alloc_min or higher address 2024-03-22T13:08:42+00:00 KONDO KAZUMA(近藤　和真) kazuma-kondo@nec.com 2024-03-22T10:47:02+00:00 3cb4a4827596abc82e55b80364f509d0fefc3051 Following warning is sometimes observed while booting my servers: [ 3.594838] DMA: preallocated 4096 KiB GFP_KERNEL pool for atomic allocations [ 3.602918] swapper/0: page allocation failure: order:10, mode:0xcc1(GFP_KERNEL|GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0-1 ... [ 3.851862] DMA: preallocated 1024 KiB GFP_KERNEL|GFP_DMA pool for atomic allocation If 'nokaslr' boot option is set, the warning always happens. On x86, ZONE_DMA is small zone at the first 16MB of physical address space. When this problem happens, most of that space seems to be used by decompressed kernel. Thereby, there is not enough space at DMA_ZONE to meet the request of DMA pool allocation. The commit 2f77465b05b1 ("x86/efistub: Avoid placing the kernel below LOAD_PHYSICAL_ADDR") tried to fix this problem by introducing lower bound of allocation. But the fix is not complete. efi_random_alloc() allocates pages by following steps. 1. Count total available slots ('total_slots') 2. Select a slot ('target_slot') to allocate randomly 3. Calculate a starting address ('target') to be included target_slot 4. Allocate pages, which starting address is 'target' In step 1, 'alloc_min' is used to offset the starting address of memory chunk. But in step 3 'alloc_min' is not considered at all. As the result, 'target' can be miscalculated and become lower than 'alloc_min'. When KASLR is disabled, 'target_slot' is always 0 and the problem happens everytime if the EFI memory map of the system meets the condition. Fix this problem by calculating 'target' considering 'alloc_min'. Cc: linux-efi@vger.kernel.org Cc: Tom Englund <tomenglund26@gmail.com> Cc: linux-kernel@vger.kernel.org Fixes: 2f77465b05b1 ("x86/efistub: Avoid placing the kernel below LOAD_PHYSICAL_ADDR") Signed-off-by: Kazuma Kondo <kazuma-kondo@nec.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> 
Following warning is sometimes observed while booting my servers:
  [    3.594838] DMA: preallocated 4096 KiB GFP_KERNEL pool for atomic allocations
  [    3.602918] swapper/0: page allocation failure: order:10, mode:0xcc1(GFP_KERNEL|GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0-1
  ...
  [    3.851862] DMA: preallocated 1024 KiB GFP_KERNEL|GFP_DMA pool for atomic allocation

If 'nokaslr' boot option is set, the warning always happens.

On x86, ZONE_DMA is small zone at the first 16MB of physical address
space. When this problem happens, most of that space seems to be used by
decompressed kernel. Thereby, there is not enough space at DMA_ZONE to
meet the request of DMA pool allocation.

The commit 2f77465b05b1 ("x86/efistub: Avoid placing the kernel below
LOAD_PHYSICAL_ADDR") tried to fix this problem by introducing lower
bound of allocation.

But the fix is not complete.

efi_random_alloc() allocates pages by following steps.
1. Count total available slots ('total_slots')
2. Select a slot ('target_slot') to allocate randomly
3. Calculate a starting address ('target') to be included target_slot
4. Allocate pages, which starting address is 'target'

In step 1, 'alloc_min' is used to offset the starting address of memory
chunk. But in step 3 'alloc_min' is not considered at all.  As the
result, 'target' can be miscalculated and become lower than 'alloc_min'.

When KASLR is disabled, 'target_slot' is always 0 and the problem
happens everytime if the EFI memory map of the system meets the
condition.

Fix this problem by calculating 'target' considering 'alloc_min'.

Cc: linux-efi@vger.kernel.org
Cc: Tom Englund <tomenglund26@gmail.com>
Cc: linux-kernel@vger.kernel.org
Fixes: 2f77465b05b1 ("x86/efistub: Avoid placing the kernel below LOAD_PHYSICAL_ADDR")
Signed-off-by: Kazuma Kondo <kazuma-kondo@nec.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Merge tag 'driver-core-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core 2024-03-21T20:34:15+00:00 Linus Torvalds torvalds@linux-foundation.org 2024-03-21T20:34:15+00:00 241590e5a1d1b6219c8d3045c167f2fbcc076cbb Pull driver core updates from Greg KH: "Here is the "big" set of driver core and kernfs changes for 6.9-rc1. Nothing all that crazy here, just some good updates that include: - automatic attribute group hiding from Dan Williams (he fixed up my horrible attempt at doing this.) - kobject lock contention fixes from Eric Dumazet - driver core cleanups from Andy - kernfs rcu work from Tejun - fw_devlink changes to resolve some reported issues - other minor changes, all details in the shortlog All of these have been in linux-next for a long time with no reported issues" * tag 'driver-core-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (28 commits) device: core: Log warning for devices pending deferred probe on timeout driver: core: Use dev_* instead of pr_* so device metadata is added driver: core: Log probe failure as error and with device metadata of: property: fw_devlink: Add support for "post-init-providers" property driver core: Add FWLINK_FLAG_IGNORE to completely ignore a fwnode link driver core: Adds flags param to fwnode_link_add() debugfs: fix wait/cancellation handling during remove device property: Don't use "proxy" headers device property: Move enum dev_dma_attr to fwnode.h driver core: Move fw_devlink stuff to where it belongs driver core: Drop unneeded 'extern' keyword in fwnode.h firmware_loader: Suppress warning on FW_OPT_NO_WARN flag sysfs:Addresses documentation in sysfs_merge_group and sysfs_unmerge_group. firmware_loader: introduce __free() cleanup hanler platform-msi: Remove usage of the deprecated ida_simple_xx() API sysfs: Introduce DEFINE_SIMPLE_SYSFS_GROUP_VISIBLE() sysfs: Document new "group visible" helpers sysfs: Fix crash on empty group attributes array sysfs: Introduce a mechanism to hide static attribute_groups sysfs: Introduce a mechanism to hide static attribute_groups ... 
Pull driver core updates from Greg KH:
 "Here is the "big" set of driver core and kernfs changes for 6.9-rc1.

  Nothing all that crazy here, just some good updates that include:

   - automatic attribute group hiding from Dan Williams (he fixed up my
     horrible attempt at doing this.)

   - kobject lock contention fixes from Eric Dumazet

   - driver core cleanups from Andy

   - kernfs rcu work from Tejun

   - fw_devlink changes to resolve some reported issues

   - other minor changes, all details in the shortlog

  All of these have been in linux-next for a long time with no reported
  issues"

* tag 'driver-core-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (28 commits)
  device: core: Log warning for devices pending deferred probe on timeout
  driver: core: Use dev_* instead of pr_* so device metadata is added
  driver: core: Log probe failure as error and with device metadata
  of: property: fw_devlink: Add support for "post-init-providers" property
  driver core: Add FWLINK_FLAG_IGNORE to completely ignore a fwnode link
  driver core: Adds flags param to fwnode_link_add()
  debugfs: fix wait/cancellation handling during remove
  device property: Don't use "proxy" headers
  device property: Move enum dev_dma_attr to fwnode.h
  driver core: Move fw_devlink stuff to where it belongs
  driver core: Drop unneeded 'extern' keyword in fwnode.h
  firmware_loader: Suppress warning on FW_OPT_NO_WARN flag
  sysfs:Addresses documentation in sysfs_merge_group and sysfs_unmerge_group.
  firmware_loader: introduce __free() cleanup hanler
  platform-msi: Remove usage of the deprecated ida_simple_xx() API
  sysfs: Introduce DEFINE_SIMPLE_SYSFS_GROUP_VISIBLE()
  sysfs: Document new "group visible" helpers
  sysfs: Fix crash on empty group attributes array
  sysfs: Introduce a mechanism to hide static attribute_groups
  sysfs: Introduce a mechanism to hide static attribute_groups
  ...
Merge tag 'efi-fixes-for-v6.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi 2024-03-17T19:26:04+00:00 Linus Torvalds torvalds@linux-foundation.org 2024-03-17T19:26:04+00:00 906a93befec826475ab3d4facacc57a0b0a002a5 Pull EFI fix from Ard Biesheuvel: "This fixes an oversight on my part in the recent EFI stub rework for x86, which is needed to get Linux/x86 distro builds signed again for secure boot by Microsoft. For this reason, most of this work is being backported to v6.1, which is therefore also affected by this regression. - Explicitly wipe BSS in the native EFI entrypoint, so that globals shared with the legacy decompressor are zero-initialized correctly" * tag 'efi-fixes-for-v6.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi: x86/efistub: Clear decompressor BSS in native EFI entrypoint 
Pull EFI fix from Ard Biesheuvel:
 "This fixes an oversight on my part in the recent EFI stub rework for
  x86, which is needed to get Linux/x86 distro builds signed again for
  secure boot by Microsoft. For this reason, most of this work is being
  backported to v6.1, which is therefore also affected by this
  regression.

   - Explicitly wipe BSS in the native EFI entrypoint, so that globals
     shared with the legacy decompressor are zero-initialized correctly"

* tag 'efi-fixes-for-v6.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  x86/efistub: Clear decompressor BSS in native EFI entrypoint