This is a note to let you know that I've just added the patch titled
arm64: vdso: prevent ld from aligning PT_LOAD segments to 64k
to the 3.13-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm64-vdso-prevent-ld-from-aligning-pt_load-segments-to-64k.patch
and it can be found in the queue-3.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 40507403485fcb56b83d6ddfc954e9b08305054c Mon Sep 17 00:00:00 2001
From: Will Deacon <will.deacon@xxxxxxx>
Date: Tue, 4 Feb 2014 14:41:26 +0000
Subject: arm64: vdso: prevent ld from aligning PT_LOAD segments to 64k
From: Will Deacon <will.deacon@xxxxxxx>
commit 40507403485fcb56b83d6ddfc954e9b08305054c upstream.
Whilst the text segment for our VDSO is marked as PT_LOAD in the ELF
headers, it is mapped by the kernel and not actually subject to
demand-paging. ld doesn't realise this, and emits a p_align field of 64k
(the maximum supported page size), which conflicts with the load address
picked by the kernel on 4k systems, which will be 4k aligned. This
causes GDB to fail with "Failed to read a valid object file image from
memory" when attempting to load the VDSO.
This patch passes the -n option to ld, which prevents it from aligning
PT_LOAD segments to the maximum page size.
Reported-by: Kyle McMartin <kyle@xxxxxxxxxx>
Acked-by: Kyle McMartin <kyle@xxxxxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/kernel/vdso/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/arm64/kernel/vdso/Makefile
+++ b/arch/arm64/kernel/vdso/Makefile
@@ -48,7 +48,7 @@ $(obj-vdso): %.o: %.S
# Actual build commands
quiet_cmd_vdsold = VDSOL $@
- cmd_vdsold = $(CC) $(c_flags) -Wl,-T $^ -o $@
+ cmd_vdsold = $(CC) $(c_flags) -Wl,-n -Wl,-T $^ -o $@
quiet_cmd_vdsoas = VDSOA $@
cmd_vdsoas = $(CC) $(a_flags) -c -o $@ $<
Patches currently in stable-queue which might be from will.deacon@xxxxxxx are
queue-3.13/arm64-vdso-fix-coarse-clock-handling.patch
queue-3.13/arm64-vdso-update-wtm-fields-for-clock_monotonic_coarse.patch
queue-3.13/arm64-add-dsb-after-icache-flush-in-__flush_icache_all.patch
queue-3.13/arm64-vdso-prevent-ld-from-aligning-pt_load-segments-to-64k.patch
queue-3.13/arm64-atomics-fix-use-of-acquire-release-for-full-barrier-semantics.patch
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