From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Fri, 29 Jul 2016 10:06:35 +0100 Subject: [PATCH] arm64: vmlinux.lds: make __rela_offset and __dynsym_offset ABSOLUTE In-Reply-To: <1469715314-23260-1-git-send-email-ard.biesheuvel@linaro.org> References: <1469715314-23260-1-git-send-email-ard.biesheuvel@linaro.org> Message-ID: <20160729090634.GA16593@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Ard, On Thu, Jul 28, 2016 at 04:15:14PM +0200, Ard Biesheuvel wrote: > Due to the untyped KIMAGE_VADDR constant, the linker may not notice > that the __rela_offset and __dynsym_offset expressions are absolute > values (i.e., are not subject to relocation). This does not matter for > KASLR, but it does confuse kallsyms in relative mode, since it uses > the lowest non-absolute symbol address as the anchor point, and expects > all other symbol addresses to be within 4 GB of it. > > Fix this by qualifying these expressions as ABSOLUTE() explicitly. > > Fixes: 0cd3defe0af4 ("arm64: kernel: perform relocation processing from ID map") > Signed-off-by: Ard Biesheuvel > --- > arch/arm64/kernel/vmlinux.lds.S | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S > index 89d6e177ecbd..d49492179967 100644 > --- a/arch/arm64/kernel/vmlinux.lds.S > +++ b/arch/arm64/kernel/vmlinux.lds.S > @@ -184,9 +184,9 @@ SECTIONS > *(.hash) > } > > - __rela_offset = ADDR(.rela) - KIMAGE_VADDR; > + __rela_offset = ABSOLUTE(ADDR(.rela) - KIMAGE_VADDR); > __rela_size = SIZEOF(.rela); > - __dynsym_offset = ADDR(.dynsym) - KIMAGE_VADDR; > + __dynsym_offset = ABSOLUTE(ADDR(.dynsym) - KIMAGE_VADDR); You removed the __dynsym_offset entry entirely in "arm64: relocatable: suppress R_AARCH64_ABS64 relocations in vmlinux", so I'll drop this part of the patch and assume you'll do a separate backport for stable. Ok? Will