From 6f8f0dc980028e98ae339876a8403edae4d20e39 Mon Sep 17 00:00:00 2001 From: Arvind Sankar Date: Mon, 24 Feb 2020 18:21:29 -0500 Subject: [PATCH] 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 Signed-off-by: Borislav Petkov Reviewed-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Reviewed-by: Kees Cook Tested-by: Nathan Chancellor Link: https://lkml.kernel.org/r/20200224232129.597160-3-nivedita@alum.mit.edu --- arch/x86/boot/compressed/vmlinux.lds.S | 5 ----- arch/x86/boot/setup.ld | 1 - arch/x86/include/asm/dwarf2.h | 4 ++-- arch/x86/kernel/vmlinux.lds.S | 7 ++----- arch/x86/realmode/rm/realmode.lds.S | 1 - 5 files changed, 4 insertions(+), 14 deletions(-) diff --git a/arch/x86/boot/compressed/vmlinux.lds.S b/arch/x86/boot/compressed/vmlinux.lds.S index 469dcf800a2c..508cfa6828c5 100644 --- a/arch/x86/boot/compressed/vmlinux.lds.S +++ b/arch/x86/boot/compressed/vmlinux.lds.S @@ -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) - } } diff --git a/arch/x86/boot/setup.ld b/arch/x86/boot/setup.ld index 3da1c37c6dd5..24c95522f231 100644 --- a/arch/x86/boot/setup.ld +++ b/arch/x86/boot/setup.ld @@ -52,7 +52,6 @@ SECTIONS _end = .; /DISCARD/ : { - *(.eh_frame) *(.note*) } diff --git a/arch/x86/include/asm/dwarf2.h b/arch/x86/include/asm/dwarf2.h index ae391f609840..f71a0cce9373 100644 --- a/arch/x86/include/asm/dwarf2.h +++ b/arch/x86/include/asm/dwarf2.h @@ -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 diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index e3296aa028fe..5cab3a29adcb 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -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) - } } diff --git a/arch/x86/realmode/rm/realmode.lds.S b/arch/x86/realmode/rm/realmode.lds.S index 64d135d1ee63..63aa51875ba0 100644 --- a/arch/x86/realmode/rm/realmode.lds.S +++ b/arch/x86/realmode/rm/realmode.lds.S @@ -71,7 +71,6 @@ SECTIONS /DISCARD/ : { *(.note*) *(.debug*) - *(.eh_frame*) } #include "pasyms.h"