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Message-ID: <0319d84e-ec4c-45a6-9edd-a606809371d8@sifive.com>
Date: Fri, 29 Mar 2024 13:02:56 -0500
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Subject: Re: [PATCH v4 10/15] x86: Implement ARCH_HAS_KERNEL_FPU_SUPPORT
To: Dave Hansen <dave.hansen@intel.com>,
 Andrew Morton <akpm@linux-foundation.org>, x86@kernel.org
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
 linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org,
 Christoph Hellwig <hch@lst.de>, loongarch@lists.linux.dev,
 amd-gfx@lists.freedesktop.org, Borislav Petkov <bp@alien8.de>,
 Dave Hansen <dave.hansen@linux.intel.com>, Ingo Molnar <mingo@redhat.com>,
 Thomas Gleixner <tglx@linutronix.de>, linux-arm-kernel@lists.infradead.org
References: <20240329072441.591471-1-samuel.holland@sifive.com>
 <20240329072441.591471-11-samuel.holland@sifive.com>
 <d2c3cd78-cdc6-4a39-9804-4f30402751b1@intel.com>
From: Samuel Holland <samuel.holland@sifive.com>
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In-Reply-To: <d2c3cd78-cdc6-4a39-9804-4f30402751b1@intel.com>
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On 2024-03-29 12:28 PM, Dave Hansen wrote:
> On 3/29/24 00:18, Samuel Holland wrote:
>> +#
>> +# CFLAGS for compiling floating point code inside the kernel.
>> +#
>> +CC_FLAGS_FPU := -msse -msse2
>> +ifdef CONFIG_CC_IS_GCC
>> +# Stack alignment mismatch, proceed with caution.
>> +# GCC < 7.1 cannot compile code using `double` and -mpreferred-stack-boundary=3
>> +# (8B stack alignment).
>> +# See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
>> +#
>> +# The "-msse" in the first argument is there so that the
>> +# -mpreferred-stack-boundary=3 build error:
>> +#
>> +#  -mpreferred-stack-boundary=3 is not between 4 and 12
>> +#
>> +# can be triggered. Otherwise gcc doesn't complain.
>> +CC_FLAGS_FPU += -mhard-float
>> +CC_FLAGS_FPU += $(call cc-option,-msse -mpreferred-stack-boundary=3,-mpreferred-stack-boundary=4)
>> +endif
> 
> I was expecting to see this (now duplicate) hunk come _out_ of
> lib/Makefile somewhere in the series.
> 
> Did I miss that, or is there something keeping the duplicate there?

This hunk is removed in patch 15/15, after the conversion of lib/test_fpu.c:

https://lore.kernel.org/linux-kernel/20240329072441.591471-16-samuel.holland@sifive.com/

Regards,
Samuel