From 2d6f74f797f26e14bdd672b3547ad29199bbb6b8 Mon Sep 17 00:00:00 2001 From: Vasily Gorbik Date: Thu, 28 Jun 2018 07:39:24 +0200 Subject: [PATCH] s390/decompressor: correct EXCLUDE_FILE construct The following linker construct is problematic with linkers of binutils < 2.28: EXCLUDE_FILE (*piggy.o) *(.rodata.*) from 8f1732fc2a11dc of binutils: "though the linker accepts this without complaint the EXCLUDE_FILE part is silently ignored and has no effect." Silent ignoring of EXCLUDE_FILE construct made .rodata.compressed be part of .rodata, and in case of .rodata.compressed following some unaligned data, input_len would also become unaligned. from arch/s390/boot/compressed/vmlinux.map: .rodata.compressed 0x0000000000012fea 0x4d57e7 arch/s390/boot/compressed/piggy.o 0x0000000000012fea input_len 0x0000000000012fee input_data input_len is later used here: arch/s390/boot/compressed/misc.c:113 __decompress(input_data, input_len, NULL, NULL, output, 0, NULL, error); asm generated by gcc looks like: .loc 3 113 0 egfrl %r11,input_len from what assembler generates invalid (the second operand must be aligned on a doubleword boundary): 0x00000000000129b4 <+148>: c4 bc 00 00 03 1b lgfrl %r11,0x12fea hence specification exception is recognized. To avoid an issue use EXCLUDE_FILE construct which is recognized by older linkers (since at least binutils-2_11) *(EXCLUDE_FILE (*piggy.o) .rodata.compressed) Also ensure that .rodata.compressed is at least doubleword aligned. Fixes: 89b5202e81df ("s390/decompressor: support uncompressed kernel") Reported-by: Halil Pasic Acked-by: Heiko Carstens Signed-off-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky --- arch/s390/boot/compressed/vmlinux.lds.S | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/s390/boot/compressed/vmlinux.lds.S b/arch/s390/boot/compressed/vmlinux.lds.S index 93ab95cf16fb..b16ac8b3c439 100644 --- a/arch/s390/boot/compressed/vmlinux.lds.S +++ b/arch/s390/boot/compressed/vmlinux.lds.S @@ -26,7 +26,7 @@ SECTIONS .rodata : { _rodata = . ; *(.rodata) /* read-only data */ - EXCLUDE_FILE (*piggy.o) *(.rodata.*) + *(EXCLUDE_FILE (*piggy.o) .rodata.compressed) _erodata = . ; } .data : { @@ -38,6 +38,8 @@ SECTIONS startup_continue = 0x100000; #ifdef CONFIG_KERNEL_UNCOMPRESSED . = 0x100000; +#else + . = ALIGN(8); #endif .rodata.compressed : { *(.rodata.compressed) -- 2.11.0