Arvind Sankar 105cb9544b efi/x86: Move efi stub globals from .bss to .data ... Commit 3ee372ccce ("x86/boot/compressed/64: Remove .bss/.pgtable from bzImage") removed the .bss section from the bzImage. However, while a PE loader is required to zero-initialize the .bss section before calling the PE entry point, the EFI handover protocol does not currently document any requirement that .bss be initialized by the bootloader prior to calling the handover entry. When systemd-boot is used to boot a unified kernel image [1], the image is constructed by embedding the bzImage as a .linux section in a PE executable that contains a small stub loader from systemd together with additional sections and potentially an initrd. As the .bss section within the bzImage is no longer explicitly present as part of the file, it is not initialized before calling the EFI handover entry. Furthermore, as the size of the embedded .linux section is only the size of the bzImage file itself, the .bss section's memory may not even have been allocated. In particular, this can result in efi_disable_pci_dma being true even when it was not specified via the command line or configuration option, which in turn causes crashes while booting on some systems. To avoid issues, place all EFI stub global variables into the .data section instead of .bss. As of this writing, only boolean flags for a few command line arguments and the sys_table pointer were in .bss and will now move into the .data section. [1] https://systemd.io/BOOT_LOADER_SPECIFICATION/#type-2-efi-unified-kernel-images Fixes: 3ee372ccce ("x86/boot/compressed/64: Remove .bss/.pgtable from bzImage") Reported-by: Sergey Shatunov <me@prok.pw> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200406180614.429454-1-nivedita@alum.mit.edu Link: https://lore.kernel.org/r/20200409130434.6736-4-ardb@kernel.org		2020-04-14 08:32:13 +02:00
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arm32-stub.c	efi/libstub/arm: Make efi_entry() an ordinary PE/COFF entrypoint	2020-02-22 23:37:37 +01:00
arm64-stub.c	arm64 fixes:	2020-04-09 11:04:16 -07:00
arm-stub.c	efi/libstub/arm: Fix spurious message that an initrd was loaded	2020-03-29 12:08:18 +02:00
efi-stub-helper.c	efi/libstub/x86: Make loaded_image protocol handling mixed mode safe	2020-02-23 21:59:42 +01:00
efistub.h	efi/x86: Move efi stub globals from .bss to .data	2020-04-14 08:32:13 +02:00
fdt.c	efi/libstub: Simplify efi_high_alloc() and rename to efi_allocate_pages()	2020-02-23 21:57:15 +01:00
file.c	efi/libstub: Fix error message in handle_cmdline_files()	2020-02-23 21:57:31 +01:00
gop.c	efi/libstub: Rename efi_call_early/_runtime macros to be more intuitive	2019-12-25 10:49:25 +01:00
hidden.h	efi/libstub: Use hidden visibility for all source files	2020-02-23 21:57:12 +01:00
Makefile	Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2020-03-31 10:28:35 -07:00
mem.c	efi/libstub: Describe efi_relocate_kernel()	2020-02-23 21:57:15 +01:00
pci.c	efi: Allow disabling PCI busmastering on bridges during boot	2020-01-10 18:55:04 +01:00
random.c	efi/libstub: Describe RNG functions	2020-02-23 21:57:19 +01:00
randomalloc.c	efi/libstub: Move efi_random_alloc() into separate source file	2020-02-23 21:57:15 +01:00
secureboot.c	efi/libstub: Rename efi_call_early/_runtime macros to be more intuitive	2019-12-25 10:49:25 +01:00
skip_spaces.c	efi/libstub: Clean up command line parsing routine	2020-02-23 21:57:15 +01:00
string.c	efi/libstub: Clean up command line parsing routine	2020-02-23 21:57:15 +01:00
tpm.c	efi/libstub: Rename efi_call_early/_runtime macros to be more intuitive	2019-12-25 10:49:25 +01:00
x86-stub.c	efi/x86: Move efi stub globals from .bss to .data	2020-04-14 08:32:13 +02:00