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From: "H.J. Lu" <hjl.tools@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: Andy Lutomirski <luto@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Kees Cook <keescook@chromium.org>,
	Thomas Lendacky <Thomas.Lendacky@amd.com>,
	Sami Tolvanen <samitolvanen@google.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H . Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: [PATCH 1/2] x86: Discard .note.gnu.property sections in vDSO
Date: Fri, 24 Jan 2020 10:18:18 -0800	[thread overview]
Message-ID: <20200124181819.4840-2-hjl.tools@gmail.com> (raw)
In-Reply-To: <20200124181819.4840-1-hjl.tools@gmail.com>

With the command-line option, -mx86-used-note=yes, the x86 assembler
in binutils 2.32 and above generates a program property note in a note
section, .note.gnu.property, to encode used x86 ISAs and features.  X86
kernel vDSO linker script only contains a signle NOTE segment:

PHDRS
{
 text PT_LOAD FLAGS(5) FILEHDR PHDRS; /* PF_R|PF_X */
 dynamic PT_DYNAMIC FLAGS(4); /* PF_R */
 note PT_NOTE FLAGS(4); /* PF_R */
 eh_frame_hdr 0x6474e550;
}

which may not be incompatible with note.gnu.property sections.  Since
note.gnu.property section in vDSO is not used by dynamic linker, this
patch discards .note.gnu.property sections in vDSO by adding

/DISCARD/ : {
 *(.note.gnu.property)
}

before .notes sections.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
---
 arch/x86/entry/vdso/vdso-layout.lds.S | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/entry/vdso/vdso-layout.lds.S b/arch/x86/entry/vdso/vdso-layout.lds.S
index 93c6dc7812d0..b604da6cc024 100644
--- a/arch/x86/entry/vdso/vdso-layout.lds.S
+++ b/arch/x86/entry/vdso/vdso-layout.lds.S
@@ -52,6 +52,10 @@ SECTIONS
 		*(.gnu.linkonce.b.*)
 	}						:text
 
+	/* .note.gnu.property sections should be discarded */
+	/DISCARD/ : {
+		*(.note.gnu.property)
+	}
 	.note		: { *(.note.*) }		:text	:note
 
 	.eh_frame_hdr	: { *(.eh_frame_hdr) }		:text	:eh_frame_hdr
-- 
2.24.1


  reply	other threads:[~2020-01-24 18:18 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-24 18:18 [PATCH 0/2] x86: Discard .note.gnu.property sections H.J. Lu
2020-01-24 18:18 ` H.J. Lu [this message]
2020-01-24 18:18 ` [PATCH 2/2] x86: Discard .note.gnu.property sections in vmlinux H.J. Lu
2020-01-27 23:34   ` Kees Cook
2020-01-30 17:51     ` H.J. Lu
2020-01-30 19:51       ` Kees Cook
2020-01-30 20:04         ` H.J. Lu
2020-01-30 20:08           ` Kees Cook
2020-01-30 20:20             ` H.J. Lu
2020-01-30 20:48               ` [PATCH] Discard .note.gnu.property sections in generic NOTES H.J. Lu
2020-01-30 22:09                 ` Kees Cook
2020-01-30 22:06               ` [PATCH 2/2] x86: Discard .note.gnu.property sections in vmlinux Kees Cook

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