[PATCH stable 5.4 02/11] ARM: 8990/1: use VFP assembler mnemonics in register load/store macros

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Florian Fainelli

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Jun 29, 2022, 2:02:43 PM6/29/22
to sta...@vger.kernel.org, Stefan Agner, Russell King, Florian Fainelli, Russell King, Herbert Xu, David S. Miller, Tony Lindgren, Hans Ulli Kroll, Ard Biesheuvel, Nick Desaulniers, Nicolas Pitre, Andre Przywara, Greg Kroah-Hartman, Catalin Marinas, Jian Cai, moderated list:ARM PORT, open list, open list:CRYPTO API, open list:OMAP2+ SUPPORT, open list:CLANG/LLVM BUILD SUPPORT, Sasha Levin
From: Stefan Agner <ste...@agner.ch>

commit ee440336e5ef977c397afdb72cbf9c6b8effc8ea upstream

The integrated assembler of Clang 10 and earlier do not allow to access
the VFP registers through the coprocessor load/store instructions:
<instantiation>:4:6: error: invalid operand for instruction
LDC p11, cr0, [r10],#32*4 @ FLDMIAD r10!, {d0-d15}
^

This has been addressed with Clang 11 [0]. However, to support earlier
versions of Clang and for better readability use of VFP assembler
mnemonics still is preferred.

Replace the coprocessor load/store instructions with explicit assembler
mnemonics to accessing the floating point coprocessor registers. Use
assembler directives to select the appropriate FPU version.

This allows to build these macros with GNU assembler as well as with
Clang's built-in assembler.

[0] https://reviews.llvm.org/D59733

Link: https://github.com/ClangBuiltLinux/linux/issues/905

Signed-off-by: Stefan Agner <ste...@agner.ch>
Signed-off-by: Russell King <rmk+k...@armlinux.org.uk>
Signed-off-by: Florian Fainelli <f.fai...@gmail.com>
---
arch/arm/include/asm/vfpmacros.h | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/arch/arm/include/asm/vfpmacros.h b/arch/arm/include/asm/vfpmacros.h
index 628c336e8e3b..947ee5395e1f 100644
--- a/arch/arm/include/asm/vfpmacros.h
+++ b/arch/arm/include/asm/vfpmacros.h
@@ -19,23 +19,25 @@

@ read all the working registers back into the VFP
.macro VFPFLDMIA, base, tmp
+ .fpu vfpv2
#if __LINUX_ARM_ARCH__ < 6
- LDC p11, cr0, [\base],#33*4 @ FLDMIAX \base!, {d0-d15}
+ fldmiax \base!, {d0-d15}
#else
- LDC p11, cr0, [\base],#32*4 @ FLDMIAD \base!, {d0-d15}
+ vldmia \base!, {d0-d15}
#endif
#ifdef CONFIG_VFPv3
+ .fpu vfpv3
#if __LINUX_ARM_ARCH__ <= 6
ldr \tmp, =elf_hwcap @ may not have MVFR regs
ldr \tmp, [\tmp, #0]
tst \tmp, #HWCAP_VFPD32
- ldclne p11, cr0, [\base],#32*4 @ FLDMIAD \base!, {d16-d31}
+ vldmiane \base!, {d16-d31}
addeq \base, \base, #32*4 @ step over unused register space
#else
VFPFMRX \tmp, MVFR0 @ Media and VFP Feature Register 0
and \tmp, \tmp, #MVFR0_A_SIMD_MASK @ A_SIMD field
cmp \tmp, #2 @ 32 x 64bit registers?
- ldcleq p11, cr0, [\base],#32*4 @ FLDMIAD \base!, {d16-d31}
+ vldmiaeq \base!, {d16-d31}
addne \base, \base, #32*4 @ step over unused register space
#endif
#endif
@@ -44,22 +46,23 @@
@ write all the working registers out of the VFP
.macro VFPFSTMIA, base, tmp
#if __LINUX_ARM_ARCH__ < 6
- STC p11, cr0, [\base],#33*4 @ FSTMIAX \base!, {d0-d15}
+ fstmiax \base!, {d0-d15}
#else
- STC p11, cr0, [\base],#32*4 @ FSTMIAD \base!, {d0-d15}
+ vstmia \base!, {d0-d15}
#endif
#ifdef CONFIG_VFPv3
+ .fpu vfpv3
#if __LINUX_ARM_ARCH__ <= 6
ldr \tmp, =elf_hwcap @ may not have MVFR regs
ldr \tmp, [\tmp, #0]
tst \tmp, #HWCAP_VFPD32
- stclne p11, cr0, [\base],#32*4 @ FSTMIAD \base!, {d16-d31}
+ vstmiane \base!, {d16-d31}
addeq \base, \base, #32*4 @ step over unused register space
#else
VFPFMRX \tmp, MVFR0 @ Media and VFP Feature Register 0
and \tmp, \tmp, #MVFR0_A_SIMD_MASK @ A_SIMD field
cmp \tmp, #2 @ 32 x 64bit registers?
- stcleq p11, cr0, [\base],#32*4 @ FSTMIAD \base!, {d16-d31}
+ vstmiaeq \base!, {d16-d31}
addne \base, \base, #32*4 @ step over unused register space
#endif
#endif
--
2.25.1

gre...@linuxfoundation.org

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Jun 30, 2022, 9:30:22 AM6/30/22
to andre.p...@arm.com, ar...@kernel.org, caij...@gmail.com, catalin...@arm.com, clang-bu...@googlegroups.com, da...@davemloft.net, f.fai...@gmail.com, gre...@linuxfoundation.org, her...@gondor.apana.org.au, linux-ar...@lists.infradead.org, li...@armlinux.org.uk, ndesau...@google.com, ni...@fluxnic.net, rmk+k...@armlinux.org.uk, sas...@kernel.org, ste...@agner.ch, to...@atomide.com, ulli....@googlemail.com, stable-...@vger.kernel.org

This is a note to let you know that I've just added the patch titled

ARM: 8990/1: use VFP assembler mnemonics in register load/store macros

to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
arm-8990-1-use-vfp-assembler-mnemonics-in-register-load-store-macros.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <sta...@vger.kernel.org> know about it.


From foo@baz Thu Jun 30 03:27:07 PM CEST 2022
From: Florian Fainelli <f.fai...@gmail.com>
Date: Wed, 29 Jun 2022 11:02:18 -0700
Subject: ARM: 8990/1: use VFP assembler mnemonics in register load/store macros
To: sta...@vger.kernel.org
Cc: Stefan Agner <ste...@agner.ch>, Russell King <rmk+k...@armlinux.org.uk>, Florian Fainelli <f.fai...@gmail.com>, Russell King <li...@armlinux.org.uk>, Herbert Xu <her...@gondor.apana.org.au>, "David S. Miller" <da...@davemloft.net>, Tony Lindgren <to...@atomide.com>, Hans Ulli Kroll <ulli....@googlemail.com>, Ard Biesheuvel <ar...@kernel.org>, Nick Desaulniers <ndesau...@google.com>, Nicolas Pitre <ni...@fluxnic.net>, Andre Przywara <andre.p...@arm.com>, Greg Kroah-Hartman <gre...@linuxfoundation.org>, Catalin Marinas <catalin...@arm.com>, Jian Cai <caij...@gmail.com>, linux-ar...@lists.infradead.org (moderated list:ARM PORT), linux-...@vger.kernel.org (open list), linux-...@vger.kernel.org (open list:CRYPTO API), linux...@vger.kernel.org (open list:OMAP2+ SUPPORT), clang-bu...@googlegroups.com (open list:CLANG/LLVM BUILD SUPPORT), Sasha Levin <sas...@kernel.org>
Message-ID: <20220629180227.34...@gmail.com>

From: Stefan Agner <ste...@agner.ch>

commit ee440336e5ef977c397afdb72cbf9c6b8effc8ea upstream

The integrated assembler of Clang 10 and earlier do not allow to access
the VFP registers through the coprocessor load/store instructions:
<instantiation>:4:6: error: invalid operand for instruction
LDC p11, cr0, [r10],#32*4 @ FLDMIAD r10!, {d0-d15}
^

This has been addressed with Clang 11 [0]. However, to support earlier
versions of Clang and for better readability use of VFP assembler
mnemonics still is preferred.

Replace the coprocessor load/store instructions with explicit assembler
mnemonics to accessing the floating point coprocessor registers. Use
assembler directives to select the appropriate FPU version.

This allows to build these macros with GNU assembler as well as with
Clang's built-in assembler.

[0] https://reviews.llvm.org/D59733

Link: https://github.com/ClangBuiltLinux/linux/issues/905

Signed-off-by: Stefan Agner <ste...@agner.ch>
Signed-off-by: Russell King <rmk+k...@armlinux.org.uk>
Signed-off-by: Florian Fainelli <f.fai...@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
arch/arm/include/asm/vfpmacros.h | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)

Patches currently in stable-queue which might be from f.fai...@gmail.com are

queue-5.4/arm-8971-1-replace-the-sole-use-of-a-symbol-with-its-definition.patch
queue-5.4/arm-omap2-drop-unnecessary-adrl.patch
queue-5.4/arm-8933-1-replace-sun-solaris-style-flag-on-section-directive.patch
queue-5.4/crypto-arm-sha256-neon-avoid-adrl-pseudo-instruction.patch
queue-5.4/arm-9029-1-make-iwmmxt.s-support-clang-s-integrated-assembler.patch
queue-5.4/net-mscc-ocelot-allow-unregistered-ip-multicast-flooding.patch
queue-5.4/crypto-arm-sha512-neon-avoid-adrl-pseudo-instruction.patch
queue-5.4/arm-8989-1-use-.fpu-assembler-directives-instead-of-assembler-arguments.patch
queue-5.4/crypto-arm-ghash-ce-define-fpu-before-fpu-registers-are-referenced.patch
queue-5.4/arm-8929-1-use-apsr_nzcv-instead-of-r15-as-mrc-operand.patch
queue-5.4/crypto-arm-use-kconfig-based-compiler-checks-for-crypto-opcodes.patch
queue-5.4/arm-8990-1-use-vfp-assembler-mnemonics-in-register-load-store-macros.patch
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