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Re: [PATCH] MIPS: Octeon: add option to ignore PT_NOTE section

To: linux-mips@linux-mips.org
Subject: Re: [PATCH] MIPS: Octeon: add option to ignore PT_NOTE section
From: philby john <pjohn@mvista.com>
Date: Thu, 14 Apr 2011 23:26:55 +0530
Cc: David Daney <ddaney@caviumnetworks.com>
In-reply-to: <4DA5DF7A.1030207@caviumnetworks.com>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <1302710833.14458.1.camel@localhost.localdomain> <4DA5DF7A.1030207@caviumnetworks.com>
Sender: linux-mips-bounce@linux-mips.org
From: David Daney <ddaney@caviumnetworks.com>
Date: Wed, 13 Apr 2011 20:46:32 +0530
Subject: [PATCH] MIPS: Octeon: add option to ignore PT_NOTE section

Some early Octeon bootloaders cannot process PT_NOTE program
headers as reported in numerous sections of the web, here is
an example http://www.spinics.net/lists/mips/msg37799.html
Loading usually fails with such an error ...
Error allocating memory for elf image!

The work around usually is to strip the .notes section by using
such a command $mips-gnu-strip -R .notes vmlinux -o fixed-vmlinux
It is expected that the vmlinux image got after compilation be
bootable. Add a Kconfig option to ignore the PT_NOTE section.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Philby John <pjohn@mvista.com>
---
 arch/mips/cavium-octeon/Kconfig |    8 ++++++++
 arch/mips/kernel/vmlinux.lds.S  |    6 ++++++
 2 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/arch/mips/cavium-octeon/Kconfig b/arch/mips/cavium-octeon/Kconfig
index caae228..ddecee3 100644
--- a/arch/mips/cavium-octeon/Kconfig
+++ b/arch/mips/cavium-octeon/Kconfig
@@ -90,6 +90,14 @@ config CAVIUM_OCTEON_LOCK_L2_MEMCPY
        help
          Lock the kernel's implementation of memcpy() into L2.
 
+config DISABLE_ELF_NOTE_HEADER
+       bool "Disable the creation of the ELF PT_NOTE program header in vmlinux"
+       depends on CPU_CAVIUM_OCTEON
+       help
+         Some early Octeon bootloaders cannot process PT_NOTE program
+         headers.  Select y to omit these headers so that the kernel
+         can be loaded with older bootloaders.
+
 config ARCH_SPARSEMEM_ENABLE
        def_bool y
        select SPARSEMEM_STATIC
diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S
index 832afbb..0536910 100644
--- a/arch/mips/kernel/vmlinux.lds.S
+++ b/arch/mips/kernel/vmlinux.lds.S
@@ -8,7 +8,9 @@ OUTPUT_ARCH(mips)
 ENTRY(kernel_entry)
 PHDRS {
        text PT_LOAD FLAGS(7);  /* RWX */
+#ifndef CONFIG_DISABLE_ELF_NOTE_HEADER
        note PT_NOTE FLAGS(4);  /* R__ */
+#endif
 }
 
 #ifdef CONFIG_32BIT
@@ -62,7 +64,11 @@ SECTIONS
                __stop___dbe_table = .;
        }
 
+#ifndef CONFIG_DISABLE_ELF_NOTE_HEADER
        NOTES :text :note
+#else
+       NOTES :text
+#endif
        .dummy : { *(.dummy) } :text
 
        RODATA
-- 
1.7.4




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