When running with return thunks enabled under 32-bit EFI, the system
crashes with:

  kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
  BUG: unable to handle page fault for address: 000000005bc02900
  #PF: supervisor instruction fetch in kernel mode
  #PF: error_code(0x0011) - permissions violation
  PGD 18f7063 P4D 18f7063 PUD 18ff063 PMD 190e063 PTE 800000005bc02063
  Oops: 0011 [#1] PREEMPT SMP PTI
  CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.19.0-rc6+ #166
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:0x5bc02900
  Code: Unable to access opcode bytes at RIP 0x5bc028d6.
  RSP: 0018:ffffffffb3203e10 EFLAGS: 00010046
  RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000048
  RDX: 000000000190dfac RSI: 0000000000001710 RDI: 000000007eae823b
  RBP: ffffffffb3203e70 R08: 0000000001970000 R09: ffffffffb3203e28
  R10: 747563657865206c R11: 6c6977203a696665 R12: 0000000000001710
  R13: 0000000000000030 R14: 0000000001970000 R15: 0000000000000001
  FS:  0000000000000000(0000) GS:ffff8e013ca00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0018 ES: 0018 CR0: 0000000080050033
  CR2: 000000005bc02900 CR3: 0000000001930000 CR4: 00000000000006f0
  Call Trace:
   ? efi_set_virtual_address_map+0x9c/0x175
   efi_enter_virtual_mode+0x4a6/0x53e
   start_kernel+0x67c/0x71e
   x86_64_start_reservations+0x24/0x2a
   x86_64_start_kernel+0xe9/0xf4
   secondary_startup_64_no_verify+0xe5/0xeb

That's because it cannot jump to the return thunk from the 32-bit code.

Using a naked RET and marking it as safe allows the system to proceed
booting.

Fixes: aa3d480315ba ("x86: Use return-thunk in asm code")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: <stable@vger.kernel.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Rather than waiting for the bots to fix these one-by-one,
fix all occurences of "the the" throughout arch/x86.

Signed-off-by: Bo Liu <liubo03@inspur.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lore.kernel.org/r/20220527061400.5694-1-liubo03@inspur.com

Pull x86 platform updates from Borislav Petkov:

 - A couple of changes enabling SGI UV5 support

* tag 'x86_platform_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/platform/uv: Log gap hole end size
  x86/platform/uv: Update TSC sync state for UV5
  x86/platform/uv: Update NMI Handler for UV5

Pull x86 cleanups from Borislav Petkov:

 - Serious sanitization and cleanup of the whole APERF/MPERF and
   frequency invariance code along with removing the need for
   unnecessary IPIs

 - Finally remove a.out support

 - The usual trivial cleanups and fixes all over x86

* tag 'x86_cleanups_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits)
  x86: Remove empty files
  x86/speculation: Add missing srbds=off to the mitigations= help text
  x86/prctl: Remove pointless task argument
  x86/aperfperf: Make it correct on 32bit and UP kernels
  x86/aperfmperf: Integrate the fallback code from show_cpuinfo()
  x86/aperfmperf: Replace arch_freq_get_on_cpu()
  x86/aperfmperf: Replace aperfmperf_get_khz()
  x86/aperfmperf: Store aperf/mperf data for cpu frequency reads
  x86/aperfmperf: Make parts of the frequency invariance code unconditional
  x86/aperfmperf: Restructure arch_scale_freq_tick()
  x86/aperfmperf: Put frequency invariance aperf/mperf data into a struct
  x86/aperfmperf: Untangle Intel and AMD frequency invariance init
  x86/aperfmperf: Separate AP/BP frequency invariance init
  x86/smp: Move APERF/MPERF code where it belongs
  x86/aperfmperf: Dont wake idle CPUs in arch_freq_get_on_cpu()
  x86/process: Fix kernel-doc warning due to a changed function name
  x86: Remove a.out support
  x86/mm: Replace nodes_weight() with nodes_empty() where appropriate
  x86: Replace cpumask_weight() with cpumask_empty() where appropriate
  x86/pkeys: Remove __arch_set_user_pkey_access() declaration
  ...

Pull EFI updates from Ard Biesheuvel:

 - Allow runtime services to be re-enabled at boot on RT kernels.

 - Provide access to secrets injected into the boot image by CoCo
   hypervisors (COnfidential COmputing)

 - Use DXE services on x86 to make the boot image executable after
   relocation, if needed.

 - Prefer mirrored memory for randomized allocations.

 - Only randomize the placement of the kernel image on arm64 if the
   loader has not already done so.

 - Add support for obtaining the boot hartid from EFI on RISC-V.

* tag 'efi-next-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  riscv/efi_stub: Add support for RISCV_EFI_BOOT_PROTOCOL
  efi: stub: prefer mirrored memory for randomized allocations
  efi/arm64: libstub: run image in place if randomized by the loader
  efi: libstub: pass image handle to handle_kernel_image()
  efi: x86: Set the NX-compatibility flag in the PE header
  efi: libstub: ensure allocated memory to be executable
  efi: libstub: declare DXE services table
  efi: Add missing prototype for efi_capsule_setup_info
  docs: security: Add secrets/coco documentation
  efi: Register efi_secret platform device if EFI secret area is declared
  virt: Add efi_secret module to expose confidential computing secrets
  efi: Save location of EFI confidential computing area
  efi: Allow to enable EFI runtime services by default on RT

SYM_CODE_START*() doesn't get auto-validated and needs an UNWIND hint
to get checked, add one.

  vmlinux.o: warning: objtool: pvh_start_xen()+0x0: unreachable

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220408094718.321246297@infradead.org

Confidential computing (coco) hardware such as AMD SEV (Secure Encrypted
Virtualization) allows a guest owner to inject secrets into the VMs
memory without the host/hypervisor being able to read them.

Firmware support for secret injection is available in OVMF, which
reserves a memory area for secret injection and includes a pointer to it
the in EFI config table entry LINUX_EFI_COCO_SECRET_TABLE_GUID.

If EFI exposes such a table entry, uefi_init() will keep a pointer to
the EFI config table entry in efi.coco_secret, so it can be used later
by the kernel (specifically drivers/virt/coco/efi_secret).  It will also
appear in the kernel log as "CocoSecret=ADDRESS"; for example:

    [    0.000000] efi: EFI v2.70 by EDK II
    [    0.000000] efi: CocoSecret=0x7f22e680 SMBIOS=0x7f541000 ACPI=0x7f77e000 ACPI 2.0=0x7f77e014 MEMATTR=0x7ea0c018

The new functionality can be enabled with CONFIG_EFI_COCO_SECRET=y.

Signed-off-by: Dov Murik <dovmurik@linux.ibm.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Link: https://lore.kernel.org/r/20220412212127.154182-2-dovmurik@linux.ibm.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

In some cases, x86 code calls cpumask_weight() to check if any bit of a
given cpumask is set.

This can be done more efficiently with cpumask_empty() because
cpumask_empty() stops traversing the cpumask as soon as it finds first set
bit, while cpumask_weight() counts all bits unconditionally.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
Link: https://lore.kernel.org/r/20220210224933.379149-17-yury.norov@gmail.com

Update NMI handler for UV5 hardware. A platform register changed, and
UV5 only uses one of the two NMI methods used on previous hardware.

Signed-off-by: Mike Travis <mike.travis@hpe.com>
Signed-off-by: Steve Wahl <steve.wahl@hpe.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220406195149.228164-2-steve.wahl@hpe.com

The current annotation relies on not running objtool on the file; this
won't work when running objtool on vmlinux.o. Instead explicitly mark
__efi64_thunk() to be ignored.

This preserves the status quo, which is somewhat unfortunate. Luckily
this code is hardly ever used.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154317.402118218@infradead.org