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From: Mark Brown <broonie@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>
Cc: Julien Grall <julien@xen.org>,
	Zhang Lei <zhang.lei@jp.fujitsu.com>,
	Julien Grall <julien.grall@arm.com>,
	Mark Brown <broonie@kernel.org>,
	Dave Martin <dave.martin@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	Daniel Kiss <Daniel.Kiss@arm.com>
Subject: [PATCH v4 3/8] arm64/fpsimdmacros: Allow the macro "for" to be used in more cases
Date: Fri, 28 Aug 2020 19:11:50 +0100	[thread overview]
Message-ID: <20200828181155.17745-4-broonie@kernel.org> (raw)
In-Reply-To: <20200828181155.17745-1-broonie@kernel.org>

From: Julien Grall <julien.grall@arm.com>

The current version of the macro "for" is not able to work when the
counter is used to generate registers using mnemonics. This is because
gas is not able to evaluate the expression generated if used in
register's name (i.e x\n).

Gas offers a way to evaluate macro arguments by using % in front of
them under the alternate macro mode.

The implementation of "for" is updated to use the alternate macro mode
and %, so we can use the macro in more cases. As the alternate macro
mode may have side-effects, this is disabled when expanding the body.

While it is enough to prefix the argument of the macro "__for_body"
with %, the arguments of "__for" are also prefixed to get a more
bearable value in case of compilation error.

Suggested-by: Dave Martin <dave.martin@arm.com>
Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/include/asm/fpsimdmacros.h | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/fpsimdmacros.h b/arch/arm64/include/asm/fpsimdmacros.h
index 636e9d9c7929..75293f111a6b 100644
--- a/arch/arm64/include/asm/fpsimdmacros.h
+++ b/arch/arm64/include/asm/fpsimdmacros.h
@@ -166,19 +166,23 @@
 
 .macro __for from:req, to:req
 	.if (\from) == (\to)
-		_for__body \from
+		_for__body %\from
 	.else
-		__for \from, (\from) + ((\to) - (\from)) / 2
-		__for (\from) + ((\to) - (\from)) / 2 + 1, \to
+		__for %\from, %((\from) + ((\to) - (\from)) / 2)
+		__for %((\from) + ((\to) - (\from)) / 2 + 1), %\to
 	.endif
 .endm
 
 .macro _for var:req, from:req, to:req, insn:vararg
 	.macro _for__body \var:req
+		.noaltmacro
 		\insn
+		.altmacro
 	.endm
 
+	.altmacro
 	__for \from, \to
+	.noaltmacro
 
 	.purgem _for__body
 .endm
-- 
2.20.1


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  parent reply	other threads:[~2020-08-28 18:16 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-28 18:11 [PATCH v4 0/8] arm64/sve: First steps towards optimizing syscalls Mark Brown
2020-08-28 18:11 ` [PATCH v4 1/8] arm64/fpsimd: Update documentation of do_sve_acc Mark Brown
2020-08-28 18:11 ` [PATCH v4 2/8] arm64/signal: Update the comment in preserve_sve_context Mark Brown
2020-08-28 18:11 ` Mark Brown [this message]
2020-09-21 12:38   ` [PATCH v4 3/8] arm64/fpsimdmacros: Allow the macro "for" to be used in more cases Will Deacon
2020-09-21 16:53     ` Dave Martin
2020-09-21 18:09       ` Mark Brown
2020-09-22 13:51         ` Dave Martin
2020-09-22 13:59           ` Mark Brown
2020-09-22 14:07             ` Dave Martin
2020-08-28 18:11 ` [PATCH v4 4/8] arm64/fpsimdmacros: Introduce a macro to update ZCR_EL1.LEN Mark Brown
2020-08-28 18:11 ` [PATCH v4 5/8] arm64/sve: Implement a helper to flush SVE registers Mark Brown
2020-08-28 18:11 ` [PATCH v4 6/8] arm64/sve: Implement a helper to load SVE registers from FPSIMD state Mark Brown
2020-08-28 18:11 ` [PATCH v4 7/8] arm64/sve: Don't disable SVE on syscalls return Mark Brown
2020-09-21 12:36   ` Will Deacon
2020-09-21 18:03     ` Mark Brown
2020-09-22 14:03       ` Dave Martin
2020-09-22 16:04         ` Mark Brown
2020-08-28 18:11 ` [PATCH v4 8/8] arm64/sve: Rework SVE trap access to use TIF_SVE_NEEDS_FLUSH Mark Brown
2020-09-21 12:42 ` [PATCH v4 0/8] arm64/sve: First steps towards optimizing syscalls Will Deacon
2020-09-21 12:56   ` Mark Brown
2020-09-21 13:08     ` Will Deacon
2020-09-21 18:17 ` Will Deacon

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