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Message-Id: <20201112200718.2747316-1-jiancai@google.com>
Date: Thu, 12 Nov 2020 12:07:17 -0800
From: Jian Cai <jiancai@...gle.com>
To: unlisted-recipients:; (no To-header on input)
Cc: ndesaulniers@...gle.com, ardb@...nel.org, manojgupta@...gle.com,
llozano@...gle.com, clang-built-linux@...glegroups.com,
Jian Cai <jiancai@...gle.com>,
Russell King <linux@...linux.org.uk>,
Nathan Chancellor <natechancellor@...il.com>,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH v3] Make iwmmxt.S support Clang's integrated assembler
This patch replaces 6 IWMMXT instructions Clang's integrated assembler
does not support in iwmmxt.S using macros, while making sure GNU
assembler still emit the same instructions. This should be easier than
providing full IWMMXT support in Clang. This is one of the last bits of
kernel code that could be compiled but not assembled with clang. Once
all of it works with IAS, we no longer need to special-case 32-bit Arm
in Kbuild, or turn off CONFIG_IWMMXT when build-testing.
"Intel Wireless MMX Technology - Developer Guide - August, 2002" should
be referenced for the encoding schemes of these extensions.
Link: https://github.com/ClangBuiltLinux/linux/issues/975
Suggested-by: Nick Desaulniers <ndesaulniers@...gle.com>
Suggested-by: Ard Biesheuvel <ardb@...nel.org>
Acked-by: Ard Biesheuvel <ardb@...nel.org>
Signed-off-by: Jian Cai <jiancai@...gle.com>
---
Thanks Ard for the writeup.
Changes v2 -> v3:
Add rationale in the commit log to further highlight the necessity of
this change based on ardb@...nel.org's suggestion.
arch/arm/kernel/iwmmxt.S | 89 ++++++++++++++++++++--------------------
1 file changed, 45 insertions(+), 44 deletions(-)
diff --git a/arch/arm/kernel/iwmmxt.S b/arch/arm/kernel/iwmmxt.S
index 0dcae787b004..d2b4ac06e4ed 100644
--- a/arch/arm/kernel/iwmmxt.S
+++ b/arch/arm/kernel/iwmmxt.S
@@ -16,6 +16,7 @@
#include <asm/thread_info.h>
#include <asm/asm-offsets.h>
#include <asm/assembler.h>
+#include "iwmmxt.h"
#if defined(CONFIG_CPU_PJ4) || defined(CONFIG_CPU_PJ4B)
#define PJ4(code...) code
@@ -113,33 +114,33 @@ concan_save:
concan_dump:
- wstrw wCSSF, [r1, #MMX_WCSSF]
- wstrw wCASF, [r1, #MMX_WCASF]
- wstrw wCGR0, [r1, #MMX_WCGR0]
- wstrw wCGR1, [r1, #MMX_WCGR1]
- wstrw wCGR2, [r1, #MMX_WCGR2]
- wstrw wCGR3, [r1, #MMX_WCGR3]
+ wstrw wCSSF, r1, MMX_WCSSF
+ wstrw wCASF, r1, MMX_WCASF
+ wstrw wCGR0, r1, MMX_WCGR0
+ wstrw wCGR1, r1, MMX_WCGR1
+ wstrw wCGR2, r1, MMX_WCGR2
+ wstrw wCGR3, r1, MMX_WCGR3
1: @ MUP? wRn
tst r2, #0x2
beq 2f
- wstrd wR0, [r1, #MMX_WR0]
- wstrd wR1, [r1, #MMX_WR1]
- wstrd wR2, [r1, #MMX_WR2]
- wstrd wR3, [r1, #MMX_WR3]
- wstrd wR4, [r1, #MMX_WR4]
- wstrd wR5, [r1, #MMX_WR5]
- wstrd wR6, [r1, #MMX_WR6]
- wstrd wR7, [r1, #MMX_WR7]
- wstrd wR8, [r1, #MMX_WR8]
- wstrd wR9, [r1, #MMX_WR9]
- wstrd wR10, [r1, #MMX_WR10]
- wstrd wR11, [r1, #MMX_WR11]
- wstrd wR12, [r1, #MMX_WR12]
- wstrd wR13, [r1, #MMX_WR13]
- wstrd wR14, [r1, #MMX_WR14]
- wstrd wR15, [r1, #MMX_WR15]
+ wstrd wR0, r1, MMX_WR0
+ wstrd wR1, r1, MMX_WR1
+ wstrd wR2, r1, MMX_WR2
+ wstrd wR3, r1, MMX_WR3
+ wstrd wR4, r1, MMX_WR4
+ wstrd wR5, r1, MMX_WR5
+ wstrd wR6, r1, MMX_WR6
+ wstrd wR7, r1, MMX_WR7
+ wstrd wR8, r1, MMX_WR8
+ wstrd wR9, r1, MMX_WR9
+ wstrd wR10, r1, MMX_WR10
+ wstrd wR11, r1, MMX_WR11
+ wstrd wR12, r1, MMX_WR12
+ wstrd wR13, r1, MMX_WR13
+ wstrd wR14, r1, MMX_WR14
+ wstrd wR15, r1, MMX_WR15
2: teq r0, #0 @ anything to load?
reteq lr @ if not, return
@@ -147,30 +148,30 @@ concan_dump:
concan_load:
@ Load wRn
- wldrd wR0, [r0, #MMX_WR0]
- wldrd wR1, [r0, #MMX_WR1]
- wldrd wR2, [r0, #MMX_WR2]
- wldrd wR3, [r0, #MMX_WR3]
- wldrd wR4, [r0, #MMX_WR4]
- wldrd wR5, [r0, #MMX_WR5]
- wldrd wR6, [r0, #MMX_WR6]
- wldrd wR7, [r0, #MMX_WR7]
- wldrd wR8, [r0, #MMX_WR8]
- wldrd wR9, [r0, #MMX_WR9]
- wldrd wR10, [r0, #MMX_WR10]
- wldrd wR11, [r0, #MMX_WR11]
- wldrd wR12, [r0, #MMX_WR12]
- wldrd wR13, [r0, #MMX_WR13]
- wldrd wR14, [r0, #MMX_WR14]
- wldrd wR15, [r0, #MMX_WR15]
+ wldrd wR0, r0, MMX_WR0
+ wldrd wR1, r0, MMX_WR1
+ wldrd wR2, r0, MMX_WR2
+ wldrd wR3, r0, MMX_WR3
+ wldrd wR4, r0, MMX_WR4
+ wldrd wR5, r0, MMX_WR5
+ wldrd wR6, r0, MMX_WR6
+ wldrd wR7, r0, MMX_WR7
+ wldrd wR8, r0, MMX_WR8
+ wldrd wR9, r0, MMX_WR9
+ wldrd wR10, r0, MMX_WR10
+ wldrd wR11, r0, MMX_WR11
+ wldrd wR12, r0, MMX_WR12
+ wldrd wR13, r0, MMX_WR13
+ wldrd wR14, r0, MMX_WR14
+ wldrd wR15, r0, MMX_WR15
@ Load wCx
- wldrw wCSSF, [r0, #MMX_WCSSF]
- wldrw wCASF, [r0, #MMX_WCASF]
- wldrw wCGR0, [r0, #MMX_WCGR0]
- wldrw wCGR1, [r0, #MMX_WCGR1]
- wldrw wCGR2, [r0, #MMX_WCGR2]
- wldrw wCGR3, [r0, #MMX_WCGR3]
+ wldrw wCSSF, r0, MMX_WCSSF
+ wldrw wCASF, r0, MMX_WCASF
+ wldrw wCGR0, r0, MMX_WCGR0
+ wldrw wCGR1, r0, MMX_WCGR1
+ wldrw wCGR2, r0, MMX_WCGR2
+ wldrw wCGR3, r0, MMX_WCGR3
@ clear CUP/MUP (only if r1 != 0)
teq r1, #0
--
2.29.2.299.gdc1121823c-goog
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