hollalinux
/
linux-sg2042
mirror of https://github.com/sophgo/linux-riscv.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

ARM: 8894/1: boot: Replace open-coded nop with macro 

This open-coded nop as mov r0, r0 is a development history
artifact.

First commit b11fe38883
("ARM: 6663/1: make Thumb2 kernel entry point more similar
to the ARM one") moved the code around so that the nops
would come before the conditional thumb instructions, as it
turned out that some boot loaders were patching the initial
nop instructions in the kernel. At this point it is clear
that all mov r0,r0 are open-coded nops.

Then commit 81a0bc39ea ("ARM: add UEFI stub support")
moved things around and defined __nop for EFI support and
missed this open-coded nop.

commit 06a4b6d009
("ARM: 8677/1: boot/compressed: fix decompressor header
layout for v7-M") makes all invocations of __nop be wide,
but that is fine, because this is what we want: the
mov r0,r0 is inside ifndef CONFIG_THUMB2_KERNEL.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Acked-by: Roy Franz <rfranz@marvell.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
This commit is contained in:
Linus Walleij 2019-07-16 12:33:14 +01:00 committed by Russell King
parent 20699a42c0
commit 6583d8298e
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/arm/boot/compressed/head.S
View File

@ -169,7 +169,7 @@ start:
__nop
.endr
#ifndef CONFIG_THUMB2_KERNEL
mov r0, r0
__nop
#else
AR_CLASS( sub pc, pc, #3 ) @ A/R: switch to Thumb2 mode
M_CLASS( nop.w ) @ M: already in Thumb2 mode