x86/vmlinux: Drop unneeded linker script discard of .eh_frame

Now that .eh_frame sections for the files in setup.elf and realmode.elf
are not generated anymore, the linker scripts don't need the special
output section name /DISCARD/ any more.

Remove the one in the main kernel linker script as well, since there are
no .eh_frame sections already, and fix up a comment referencing .eh_frame.

Update the comment in asm/dwarf2.h referring to .eh_frame so it continues
to make sense, as well as being more specific.

 [ bp: Touch up commit message. ]

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Link: https://lkml.kernel.org/r/20200224232129.597160-3-nivedita@alum.mit.edu
This commit is contained in:
Arvind Sankar 2020-02-24 18:21:29 -05:00 committed by Borislav Petkov
parent 003602ad55
commit 6f8f0dc980
5 changed files with 4 additions and 14 deletions

View File

@ -73,9 +73,4 @@ SECTIONS
#endif
. = ALIGN(PAGE_SIZE); /* keep ZO size page aligned */
_end = .;
/* Discard .eh_frame to save some space */
/DISCARD/ : {
*(.eh_frame)
}
}

View File

@ -52,7 +52,6 @@ SECTIONS
_end = .;
/DISCARD/ : {
*(.eh_frame)
*(.note*)
}

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@ -42,8 +42,8 @@
* Emit CFI data in .debug_frame sections, not .eh_frame sections.
* The latter we currently just discard since we don't do DWARF
* unwinding at runtime. So only the offline DWARF information is
* useful to anyone. Note we should not use this directive if
* vmlinux.lds.S gets changed so it doesn't discard .eh_frame.
* useful to anyone. Note we should not use this directive if we
* ever decide to enable DWARF unwinding at runtime.
*/
.cfi_sections .debug_frame
#else

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@ -313,8 +313,8 @@ SECTIONS
. = ALIGN(8);
/*
* .exit.text is discard at runtime, not link time, to deal with
* references from .altinstructions and .eh_frame
* .exit.text is discarded at runtime, not link time, to deal with
* references from .altinstructions
*/
.exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) {
EXIT_TEXT
@ -412,9 +412,6 @@ SECTIONS
DWARF_DEBUG
DISCARDS
/DISCARD/ : {
*(.eh_frame)
}
}

View File

@ -71,7 +71,6 @@ SECTIONS
/DISCARD/ : {
*(.note*)
*(.debug*)
*(.eh_frame*)
}
#include "pasyms.h"