Re: [PATCH v2 0/2] arm64: tlb: add support for TLBI RANGE instructions

From: Zhenyu Ye <yezhenyu2@huawei.com>
To: Catalin Marinas <catalin.marinas@arm.com>, <maz@kernel.org>,
	<steven.price@arm.com>, <guohanjun@huawei.com>, <will@kernel.org>,
	<olof@lixom.net>, <suzuki.poulose@arm.com>
Cc: <linux-kernel@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<zhangshaokun@hisilicon.com>, <prime.zeng@hisilicon.com>,
	<linux-arch@vger.kernel.org>, <kuhn.chenqun@huawei.com>,
	<xiexiangyou@huawei.com>, <linux-mm@kvack.org>, <arm@kernel.org>
Subject: Re: [PATCH v2 0/2] arm64: tlb: add support for TLBI RANGE instructions
Date: Mon, 13 Jul 2020 20:41:31 +0800	[thread overview]
Message-ID: <2edcf1ce-38d4-82b2-e500-51f742cae357@huawei.com> (raw)
In-Reply-To: <20200713122123.GC15829@gaia>

Hi Catalin,

On 2020/7/13 20:21, Catalin Marinas wrote:
> On Fri, Jul 10, 2020 at 08:11:19PM +0100, Catalin Marinas wrote:
>> On Fri, 10 Jul 2020 17:44:18 +0800, Zhenyu Ye wrote:
>>> NOTICE: this series are based on the arm64 for-next/tlbi branch:
>>> git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/tlbi
>>>
>>> --
>>> ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a
>>> range of input addresses. This series add support for this feature.
>>>
>>> [...]
>>
>> Applied to arm64 (for-next/tlbi), thanks!
>>
>> [1/2] arm64: tlb: Detect the ARMv8.4 TLBI RANGE feature
>>       https://git.kernel.org/arm64/c/a2fd755f77ff
>> [2/2] arm64: tlb: Use the TLBI RANGE feature in arm64
>>       https://git.kernel.org/arm64/c/db34a081d273
> 
> I'm dropping these two patches from for-next/tlbi and for-next/core.
> They need a check on whether binutils supports the new "tlbi rva*"
> instructions, otherwise the build mail fail.
> 
> I kept the latest incarnation of these patches on devel/tlbi-range for
> reference.
> 

Should we add a check for the binutils version? Just like:

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index fad573883e89..d5fb6567e0d2 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1300,6 +1300,20 @@ config ARM64_AMU_EXTN
 	  correctly reflect reality. Most commonly, the value read will be 0,
 	  indicating that the counter is not enabled.

+config ARM64_TLBI_RANGE
+	bool "Enable support for tlbi range feature"
+	default y
+	depends on AS_HAS_TLBI_RANGE
+	help
+	  ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a
+	  range of input addresses.
+
+	  The feature introduces new assembly instructions, and they were
+	  support when binutils >= 2.30.
+
+config AS_HAS_TLBI_RANGE
+	def_bool $(as-option, -Wa$(comma)-march=armv8.4-a)
+
 endmenu

 menu "ARMv8.5 architectural features"

Then uses the check in the loop:

	while (pages > 0) {
		if (!IS_ENABLED(CONFIG_ARM64_TLBI_RANGE) ||
		   !cpus_have_const_cap(ARM64_HAS_TLBI_RANGE) ||


If this is ok, I could send a new series soon.

Thanks,
Zhenyu


