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| author |   Linus Walleij <linus.walleij@linaro.org> | 2019-07-16 12:33:14 +0100 |
|---|---|---|
| committer |   Russell King <rmk+kernel@armlinux.org.uk> | 2019-08-23 11:39:30 +0100 |
| commit | 6583d8298e5981876603b35926b5832f7e99a122 (patch) | |
| tree | 96c72eae7af99f7639ea0dabcccb3aa4951295f0 /arch/arm/boot/compressed/head.S | |
| parent | ARM: 8893/1: boot: Explain the 8 nops (diff) | |
| download | linux-dev-6583d8298e5981876603b35926b5832f7e99a122.tar.xz linux-dev-6583d8298e5981876603b35926b5832f7e99a122.zip | |
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 b11fe38883d1
("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 81a0bc39ea19 ("ARM: add UEFI stub support")
moved things around and defined __nop for EFI support and
missed this open-coded nop.
commit 06a4b6d009a1
("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>
Diffstat (limited to 'arch/arm/boot/compressed/head.S')
| -rw-r--r-- | arch/arm/boot/compressed/head.S | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index 544450c90673..93dffed0ac6e 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -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 |