diff options
Diffstat (limited to 'debian/patches/bugfix/x86/x86-efistub-Don-t-clear-BSS-twice-in-mixed-mode.patch')
| -rw-r--r-- | debian/patches/bugfix/x86/x86-efistub-Don-t-clear-BSS-twice-in-mixed-mode.patch | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/debian/patches/bugfix/x86/x86-efistub-Don-t-clear-BSS-twice-in-mixed-mode.patch b/debian/patches/bugfix/x86/x86-efistub-Don-t-clear-BSS-twice-in-mixed-mode.patch new file mode 100644 index 000000000..2624812c5 --- /dev/null +++ b/debian/patches/bugfix/x86/x86-efistub-Don-t-clear-BSS-twice-in-mixed-mode.patch @@ -0,0 +1,41 @@ +From: Ard Biesheuvel <ardb@kernel.org> +Date: Fri, 22 Mar 2024 17:01:45 +0100 +Subject: x86/efistub: Don't clear BSS twice in mixed mode +Origin: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/commit?id=3a2a828d252f4280e15e61e0666644f1fadcf6c4 + +[ Upstream commit 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> +Signed-off-by: Sasha Levin <sashal@kernel.org> +--- + drivers/firmware/efi/libstub/x86-stub.c | 3 ++- + 1 file changed, 2 insertions(+), 1 deletion(-) + +diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c +index aa07051459f5..dc50dda40239 100644 +--- a/drivers/firmware/efi/libstub/x86-stub.c ++++ b/drivers/firmware/efi/libstub/x86-stub.c +@@ -434,7 +434,8 @@ 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; + +-- +2.43.0 + |