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From: Kees Cook <keescook@chromium.org>
To: Borislav Petkov <bp@alien8.de>
Cc: Kees Cook <keescook@chromium.org>,
	Rick Edgecombe <rick.p.edgecombe@intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Will Deacon <will@kernel.org>,
	linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org,
	linux-ia64@vger.kernel.org, linux-s390@vger.kernel.org,
	linux-c6x-dev@linux-c6x.org,
	Yoshinori Sato <ysato@users.sourceforge.jp>,
	Michal Simek <monstr@monstr.eu>,
	linux-parisc@vger.kernel.org, linux-xtensa@linux-xtensa.org,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 02/29] powerpc: Remove PT_NOTE workaround
Date: Thu, 10 Oct 2019 17:05:42 -0700	[thread overview]
Message-ID: <20191011000609.29728-3-keescook@chromium.org> (raw)
In-Reply-To: <20191011000609.29728-1-keescook@chromium.org>

In preparation for moving NOTES into RO_DATA, remove the PT_NOTE
workaround since the kernel requires at least gcc 4.6 now.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/powerpc/kernel/vmlinux.lds.S | 24 ++----------------------
 1 file changed, 2 insertions(+), 22 deletions(-)

diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index 81e672654789..a3c8492b2b19 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -20,20 +20,6 @@ ENTRY(_stext)
 PHDRS {
 	kernel PT_LOAD FLAGS(7); /* RWX */
 	note PT_NOTE FLAGS(0);
-	dummy PT_NOTE FLAGS(0);
-
-	/* binutils < 2.18 has a bug that makes it misbehave when taking an
-	   ELF file with all segments at load address 0 as input.  This
-	   happens when running "strip" on vmlinux, because of the AT() magic
-	   in this linker script.  People using GCC >= 4.2 won't run into
-	   this problem, because the "build-id" support will put some data
-	   into the "notes" segment (at a non-zero load address).
-
-	   To work around this, we force some data into both the "dummy"
-	   segment and the kernel segment, so the dummy segment will get a
-	   non-zero load address.  It's not enough to always create the
-	   "notes" segment, since if nothing gets assigned to it, its load
-	   address will be zero.  */
 }
 
 #ifdef CONFIG_PPC64
@@ -178,14 +164,8 @@ SECTIONS
 	EXCEPTION_TABLE(0)
 
 	NOTES :kernel :note
-
-	/* The dummy segment contents for the bug workaround mentioned above
-	   near PHDRS.  */
-	.dummy : AT(ADDR(.dummy) - LOAD_OFFSET) {
-		LONG(0)
-		LONG(0)
-		LONG(0)
-	} :kernel :dummy
+	/* Restore program header away from PT_NOTE. */
+	.dummy : { *(.dummy) } :kernel
 
 /*
  * Init sections discarded at runtime
-- 
2.17.1


  parent reply	other threads:[~2019-10-11  0:07 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-11  0:05 [PATCH v2 00/29] vmlinux.lds.h: Refactor EXCEPTION_TABLE and NOTES Kees Cook
2019-10-11  0:05 ` [PATCH v2 01/29] powerpc: Rename "notes" PT_NOTE to "note" Kees Cook
2019-10-11  6:00   ` Michael Ellerman
2019-10-11  8:25   ` Segher Boessenkool
2019-10-11 16:11     ` Kees Cook
2019-10-11 16:25       ` Segher Boessenkool
2019-10-15 16:54         ` Borislav Petkov
2019-10-15 17:36           ` Kees Cook
2019-10-29 21:15           ` Kees Cook
2019-10-30  1:01             ` Segher Boessenkool
2019-11-04  8:59               ` Borislav Petkov
2019-10-11  0:05 ` Kees Cook [this message]
2019-10-11  6:07   ` [PATCH v2 02/29] powerpc: Remove PT_NOTE workaround Michael Ellerman
2019-10-11 16:09     ` Kees Cook
2019-10-11  0:05 ` [PATCH v2 03/29] powerpc: Rename PT_LOAD identifier "kernel" to "text" Kees Cook
2019-10-11  6:07   ` Michael Ellerman
2019-10-11  0:05 ` [PATCH v2 04/29] alpha: " Kees Cook
2019-10-11  0:05 ` [PATCH v2 05/29] ia64: Rename PT_LOAD identifier "code" " Kees Cook
2019-10-11  0:05 ` [PATCH v2 06/29] s390: Move RO_DATA into "text" PT_LOAD Program Header Kees Cook
2019-10-16  8:25   ` Heiko Carstens
2019-10-11  0:05 ` [PATCH v2 07/29] x86: Restore "text" Program Header with dummy section Kees Cook
2019-10-11  0:05 ` [PATCH v2 08/29] vmlinux.lds.h: Provide EMIT_PT_NOTE to indicate export of .notes Kees Cook
2019-10-11  0:05 ` [PATCH v2 09/29] vmlinux.lds.h: Move Program Header restoration into NOTES macro Kees Cook
2019-10-11  0:05 ` [PATCH v2 10/29] vmlinux.lds.h: Move NOTES into RO_DATA Kees Cook
2019-10-11  0:05 ` [PATCH v2 11/29] vmlinux.lds.h: Replace RODATA with RO_DATA Kees Cook
2019-11-11 16:58   ` Geert Uytterhoeven
2019-11-11 17:23     ` Kees Cook
2019-11-11 18:08       ` Geert Uytterhoeven
2019-11-12  9:07         ` Borislav Petkov
2019-11-12  9:13           ` Geert Uytterhoeven
2019-11-12 20:55         ` Kees Cook
2019-10-11  0:05 ` [PATCH v2 12/29] vmlinux.lds.h: Replace RO_DATA_SECTION " Kees Cook
2019-10-11  7:49   ` Geert Uytterhoeven
2019-10-11  0:05 ` [PATCH v2 13/29] vmlinux.lds.h: Replace RW_DATA_SECTION with RW_DATA Kees Cook
2019-10-11  7:49   ` Geert Uytterhoeven
2019-10-11  0:05 ` [PATCH v2 14/29] vmlinux.lds.h: Allow EXCEPTION_TABLE to live in RO_DATA Kees Cook
2019-10-11  0:05 ` [PATCH v2 15/29] x86: Actually use _etext for end of text segment Kees Cook
2019-10-11  0:05 ` [PATCH v2 16/29] x86: Move EXCEPTION_TABLE to RO_DATA segment Kees Cook
2019-10-11  0:05 ` [PATCH v2 17/29] alpha: " Kees Cook
2019-10-11  0:05 ` [PATCH v2 18/29] arm64: " Kees Cook
2019-10-11  0:05 ` [PATCH v2 19/29] c6x: " Kees Cook
2019-10-11  0:06 ` [PATCH v2 20/29] h8300: " Kees Cook
2019-10-11  0:06 ` [PATCH v2 21/29] ia64: " Kees Cook
2019-10-11  0:06 ` [PATCH v2 22/29] microblaze: " Kees Cook
2019-10-11  0:06 ` [PATCH v2 23/29] parisc: " Kees Cook
2019-10-12  9:50   ` Helge Deller
2019-10-11  0:06 ` [PATCH v2 24/29] powerpc: " Kees Cook
2019-10-11  0:06 ` [PATCH v2 25/29] xtensa: " Kees Cook
2019-10-14  7:41   ` Max Filippov
2019-10-11  0:06 ` [PATCH v2 26/29] x86/mm: Remove redundant &s on addresses Kees Cook
2019-10-11  0:06 ` [PATCH v2 27/29] x86/mm: Report which part of kernel image is freed Kees Cook
2019-10-11  0:06 ` [PATCH v2 28/29] x86/mm: Report actual image regions in /proc/iomem Kees Cook
2019-10-11  0:06 ` [PATCH v2 29/29] x86: Use INT3 instead of NOP for linker fill bytes Kees Cook
2019-10-16  8:28 ` [PATCH v2 00/29] vmlinux.lds.h: Refactor EXCEPTION_TABLE and NOTES Heiko Carstens

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