Merge tag 'efi-fixes-for-v6.9-2' of git:https://git.kernel.org/pub/scm/linu…

…x/kernel/git/efi/efi

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:https://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

arch/x86/boot/compressed/efi_mixed.S

@@ -49,6 +49,11 @@ SYM_FUNC_START(startup_64_mixed_mode)
  lea efi32_boot_args(%rip), %rdx
  mov 0(%rdx), %edi
  mov 4(%rdx), %esi
+
+ /* Switch to the firmware's stack */
+ movl efi32_boot_sp(%rip), %esp
+ andl $~7, %esp
+
 #ifdef CONFIG_EFI_HANDOVER_PROTOCOL
  mov 8(%rdx), %edx // saved bootparams pointer
  test %edx, %edx
@@ -254,6 +259,9 @@ SYM_FUNC_START_LOCAL(efi32_entry)
  /* Store firmware IDT descriptor */
  sidtl (efi32_boot_idt - 1b)(%ebx)
 
+ /* Store firmware stack pointer */
+ movl %esp, (efi32_boot_sp - 1b)(%ebx)
+
  /* Store boot arguments */
  leal (efi32_boot_args - 1b)(%ebx), %ebx
  movl %ecx, 0(%ebx)
@@ -318,5 +326,6 @@ SYM_DATA_END(efi32_boot_idt)
 
 SYM_DATA_LOCAL(efi32_boot_cs, .word 0)
 SYM_DATA_LOCAL(efi32_boot_ds, .word 0)
+SYM_DATA_LOCAL(efi32_boot_sp, .long 0)
 SYM_DATA_LOCAL(efi32_boot_args, .long 0, 0, 0)
 SYM_DATA(efi_is64, .byte 1)

drivers/firmware/efi/efi.c

@@ -203,6 +203,8 @@ static bool generic_ops_supported(void)
 
  name_size = sizeof(name);
 
+ if (!efi.get_next_variable)
+ return false;
  status = efi.get_next_variable(&name_size, &name, &guid);
  if (status == EFI_UNSUPPORTED)
  return false;

drivers/firmware/efi/libstub/randomalloc.c

@@ -120,7 +120,7 @@ efi_status_t efi_random_alloc(unsigned long size,
  continue;
  }
 
- target = round_up(md->phys_addr, align) + target_slot * align;
+ target = round_up(max(md->phys_addr, alloc_min), align) + target_slot * align;
  pages = size / EFI_PAGE_SIZE;
 
  status = efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS,

drivers/firmware/efi/libstub/x86-stub.c

@@ -476,7 +476,8 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
  efi_status_t status;
  char *cmdline_ptr;
 
- memset(_bss, 0, _ebss - _bss);
+ if (efi_is_native())
+ memset(_bss, 0, _ebss - _bss);
 
  efi_system_table = sys_table_arg;