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From: Vaibhav Rustagi <vaibhavrustagi@google.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
	Vivek Goyal <vgoyal@redhat.com>,
	Vaibhav Rustagi <vaibhavrustagi@google.com>,
	Nick Desaulniers <ndesaulniers@google.com>,
	stable@vger.kernel.org
Subject: [PATCH 1/2] x86/purgatory: add -mno-sse, -mno-mmx, -mno-sse2 to Makefile
Date: Wed, 17 Jul 2019 17:02:05 -0700	[thread overview]
Message-ID: <20190718000206.121392-2-vaibhavrustagi@google.com> (raw)
In-Reply-To: <20190718000206.121392-1-vaibhavrustagi@google.com>

Compiling the purgatory code with clang results in using of mmx
registers.

$ objdump -d arch/x86/purgatory/purgatory.ro | grep xmm

     112:	0f 28 00             	movaps (%rax),%xmm0
     115:	0f 11 07             	movups %xmm0,(%rdi)
     122:	0f 28 00             	movaps (%rax),%xmm0
     125:	0f 11 47 10          	movups %xmm0,0x10(%rdi)

Add -mno-sse, -mno-mmx, -mno-sse2 to avoid generating SSE instructions.

Signed-off-by: Vaibhav Rustagi <vaibhavrustagi@google.com>
---
 arch/x86/purgatory/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index 3cf302b26332..3589ec4a28c7 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -20,6 +20,7 @@ KCOV_INSTRUMENT := n
 # sure how to relocate those. Like kexec-tools, use custom flags.
 
 KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes -fno-zero-initialized-in-bss -fno-builtin -ffreestanding -c -Os -mcmodel=large
+KBUILD_CFLAGS += -mno-mmx -mno-sse -mno-sse2
 KBUILD_CFLAGS += -m$(BITS)
 KBUILD_CFLAGS += $(call cc-option,-fno-PIE)
 
-- 
2.22.0.510.g264f2c817a-goog


  reply	other threads:[~2019-07-18  0:02 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-18  0:02 [PATCH 0/2] Support kexec/kdump for clang built kernel Vaibhav Rustagi
2019-07-18  0:02 ` Vaibhav Rustagi [this message]
2019-07-18  0:47   ` [PATCH 1/2] x86/purgatory: add -mno-sse, -mno-mmx, -mno-sse2 to Makefile Greg KH
2019-07-18 21:34   ` Nick Desaulniers
2019-07-19  8:17     ` Peter Zijlstra
2019-07-22 21:12       ` Nick Desaulniers
2019-07-18  0:02 ` [PATCH 2/2] x86/purgatory: do not use __builtin_memcpy and __builtin_memset Vaibhav Rustagi
2019-07-18  0:47   ` Greg KH
2019-07-18 21:56   ` Nick Desaulniers
2019-07-18 21:29 ` [PATCH 0/2] Support kexec/kdump for clang built kernel Nick Desaulniers

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