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| author | Arvind Sankar <nivedita@alum.mit.edu> | 2020-01-09 16:02:17 +0100 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2020-02-19 17:28:57 +0100 |
| commit | 3ee372ccce4d4e7c610748d0583979d3ed3a0cf4 (patch) | |
| tree | 77833933e077a371650a1becb8fe62e0acfd8688 /arch/x86/boot | |
| parent | x86/boot/compressed/64: Use 32-bit (zero-extended) MOV for z_output_len (diff) | |
| download | linux-3ee372ccce4d4e7c610748d0583979d3ed3a0cf4.tar.xz linux-3ee372ccce4d4e7c610748d0583979d3ed3a0cf4.zip | |
x86/boot/compressed/64: Remove .bss/.pgtable from bzImage
Commit
5b11f1cee579 ("x86, boot: straighten out ranges to copy/zero in
compressed/head*.S")
introduced a separate .pgtable section, splitting it out from the rest
of .bss. This section was added without the writeable flag, marking it
as read-only. This results in the linker putting the .rela.dyn section
(containing bogus dynamic relocations from head_64.o) after the .bss and
.pgtable sections.
When objcopy is used to convert compressed/vmlinux into a binary for
the bzImage:
$ objcopy -O binary -R .note -R .comment -S arch/x86/boot/compressed/vmlinux \
arch/x86/boot/vmlinux.bin
the .bss and .pgtable sections get materialized as ~176KiB of zero
bytes in the binary in order to place .rela.dyn at the correct location.
Fix this by marking .pgtable as writeable. This moves the .rela.dyn
section up in the ELF image layout so that .bss and .pgtable are the
last allocated sections and so don't appear in bzImage.
[ bp: Massage commit message. ]
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200109150218.16544-1-nivedita@alum.mit.edu
Diffstat (limited to 'arch/x86/boot')
| -rw-r--r-- | arch/x86/boot/compressed/head_64.S | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 68f31c48d6c2..c8ee6eff13ef 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -645,7 +645,7 @@ SYM_DATA_END_LABEL(boot_stack, SYM_L_LOCAL, boot_stack_end) /* * Space for page tables (not in .bss so not zeroed) */ - .section ".pgtable","a",@nobits + .section ".pgtable","aw",@nobits .balign 4096 SYM_DATA_LOCAL(pgtable, .fill BOOT_PGT_SIZE, 1, 0) |