From mboxrd@z Thu Jan 1 00:00:00 1970 From: matthias.bgg@gmail.com (Matthias Brugger) Date: Mon, 23 Oct 2017 23:32:11 +0200 Subject: [PATCH] ARM: compressed: discard ksym/kcrctab input section In-Reply-To: References: <20170908153143.27279-1-ard.biesheuvel@linaro.org> <33486b3e-8221-92b0-7e18-859be7d0a74b@suse.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 10/21/2017 10:14 AM, Ard Biesheuvel wrote: > On 21 October 2017 at 08:56, Matthias Brugger wrote: >> On 09/08/2017 05:31 PM, Ard Biesheuvel wrote: >>> As it turns out, building the ARM kernel with EFI support pulls in >>> a couple of sections that we don't really need in the decompressor. >>> This is due to the fact the the UEFI stub uses sort() to sort the UEFI >>> memory map, which is an exported symbol pulled in from lib/sort.c. >>> >>> Before commit e4bae4d0b5f3 ("arm/efi: Split zImage code and data into >>> separate PE/COFF sections"), this resulted in the following layout >>> for the decompressor ELF binary. >>> >>> [Nr] Name Type Addr Off Size ES Flg Lk Inf Al >>> [ 0] NULL 00000000 000000 000000 00 0 0 0 >>> [ 1] .text PROGBITS 00000000 010000 009b3c 00 AX 0 0 512 >>> [ 2] .rodata PROGBITS 00009b3c 019b3c 001684 00 A 0 0 4 >>> [ 3] __ksymtab_strings PROGBITS 0000b1c0 01b1c0 000005 00 A 0 0 1 >>> [ 4] .data PROGBITS 0000b1c8 01b1c8 000020 00 WA 0 0 8 >>> [ 5] ___ksymtab+sort PROGBITS 0000b1e8 01b1e8 000008 00 WA 0 0 4 >>> [ 6] .piggydata PROGBITS 0000b1f0 01b1f0 77ac38 00 A 0 0 1 >>> [ 7] .got.plt PROGBITS 00785e28 795e28 00000c 04 WA 0 0 4 >>> [ 8] .got PROGBITS 00785e34 795e34 000028 00 WA 0 0 4 >>> [ 9] .pad PROGBITS 00785e5c 795e5c 000004 00 WA 0 0 1 >>> [10] .bss NOBITS 00785e60 795e60 00001c 00 WA 0 0 4 >>> [11] .stack NOBITS 00785e80 795e60 001000 00 WA 0 0 1 >>> >>> Commit e4bae4d0b5f3 made some changes to the linker script to allow the >>> UEFI firmware to map the decompressor with strict R-X/RW- permissions >>> before invoking it. Unfortunately, this turns out to break the boot on >>> some systems, because the linker now also moves the ksymtab/kcrctab >>> sections around, resulting in .piggydata to appear misaligned. >>> >>> [Nr] Name Type Addr Off Size ES Flg Lk Inf Al >>> [ 0] NULL 00000000 000000 000000 00 0 0 0 >>> [ 1] .text PROGBITS 00000000 010000 00a93c 00 AX 0 0 4096 >>> [ 2] .rodata PROGBITS 0000a93c 01a93c 001684 00 A 0 0 4 >>> [ 3] __ksymtab_strings PROGBITS 0000bfc0 01bfc0 000005 00 A 0 0 1 >>> [ 4] .piggydata PROGBITS 0000bfc5 01bfc5 77ac47 00 A 0 0 1 >>> [ 5] .got.plt PROGBITS 00786c0c 796c0c 00000c 04 WA 0 0 4 >>> [ 6] .got PROGBITS 00786c18 796c18 000028 00 WA 0 0 4 >>> [ 7] .pad PROGBITS 00786c40 796c40 000008 00 WA 0 0 1 >>> [ 8] .data PROGBITS 00787000 797000 000200 00 WA 0 0 4096 >>> [ 9] ___ksymtab+sort PROGBITS 00787200 797200 000008 00 WA 0 0 4 >>> [10] .bss NOBITS 00787208 797208 00001c 00 WA 0 0 4 >>> [11] .stack NOBITS 00787228 797208 001000 00 WA 0 0 1 >>> >>> So let's align piggydata explicitly, and discard these sections from the >>> binary. >>> >>> Cc: Russell King >>> Fixes: e4bae4d0b5f3 ("arm/efi: Split zImage code and data into separate ...") >>> Tested-by: Gregory CLEMENT >>> Signed-off-by: Ard Biesheuvel >>> --- >>> arch/arm/boot/compressed/piggy.S | 1 + >>> arch/arm/boot/compressed/vmlinux.lds.S | 1 + >>> 2 files changed, 2 insertions(+) >>> >> >> This fixes the boot regression on bananapi-r2. >> Thanks! Feel free to add: >> >> Tested-by: Matthias Brugger >> > > Thanks for confirming Matthias. Could you please check whether this > patch from Arnd > > https://marc.info/?l=linux-kernel&m=150852980119217&w=2 > > fixes the issue as well? (after reverting this one) > For the record, gcc7 has a alignment problem which was fixed for PR82445 [1]. I tried to boot with the aforementioned patch from Arnd and the fixed gcc, but that didn't help. Regards, Matthias [1] https://github.com/gcc-mirror/gcc/commit/f59996b56aaa1c1d62a16cbb4010775b624cbde0