From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-x230.google.com (mail-wm0-x230.google.com [IPv6:2a00:1450:400c:c09::230]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 6C38D1A0E76 for ; Wed, 20 Jan 2016 20:06:00 +1100 (AEDT) Received: by mail-wm0-x230.google.com with SMTP id u188so175653940wmu.1 for ; Wed, 20 Jan 2016 01:06:00 -0800 (PST) From: Ard Biesheuvel To: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, keescook@chromium.org, akpm@linux-foundation.org, mingo@kernel.org, hpa@zytor.com, heiko.carstens@de.ibm.com, benh@kernel.crashing.org, mpe@ellerman.id.au, mmarek@suse.cz, rusty@rustcorp.com.au Cc: Ard Biesheuvel Subject: [PATCH 3/4] s390: enable text relative kallsyms for 64-bit targets Date: Wed, 20 Jan 2016 10:05:37 +0100 Message-Id: <1453280738-18721-4-git-send-email-ard.biesheuvel@linaro.org> In-Reply-To: <1453280738-18721-1-git-send-email-ard.biesheuvel@linaro.org> References: <1453280738-18721-1-git-send-email-ard.biesheuvel@linaro.org> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , This enables the newly introduced text-relative kallsyms support when building 64-bit targets. This cuts the size of the kallsyms address table in half, reducing the memory footprint of the kernel .rodata section by about 250 KB for a defconfig build. Signed-off-by: Ard Biesheuvel --- BEFORE: ======= $ size vmlinux text data bss dec hex filename 12329586 3107008 14727792 30164386 1cc45a2 vmlinux $ readelf -S .tmp_kallsyms2.o There are 9 section headers, starting at offset 0x125b50: Section Headers: [Nr] Name Type Address Offset Size EntSize Flags Link Info Align ... [ 4] .rodata PROGBITS 0000000000000000 00000040 0000000000125ad0 0000000000000000 A 0 0 8 [ 5] .rela.rodata RELA 0000000000000000 00125f28 000000000015ead8 0000000000000018 7 4 8 [ 6] .shstrtab STRTAB 0000000000000000 00125b10 0000000000000039 0000000000000000 0 0 1 ... $ ls -l arch/s390/boot/bzImage -rwxrwxr-x 1 ard ard 5234224 Jan 20 08:22 arch/s390/boot/bzImage AFTER: ====== $ size vmlinux text data bss dec hex filename 12088114 3102912 14727792 29918818 1c88662 vmlinux $ readelf -S .tmp_kallsyms2.o There are 8 section headers, starting at offset 0xeb428: Section Headers: [Nr] Name Type Address Offset ... [ 4] .rodata PROGBITS 0000000000000000 00000040 00000000000eb3b0 0000000000000000 A 0 0 8 [ 5] .shstrtab STRTAB 0000000000000000 000eb3f0 0000000000000034 0000000000000000 0 0 1 ... $ ls -l arch/s390/boot/bzImage -rwxrwxr-x 1 ard ard 5224256 Jan 20 08:23 arch/s390/boot/bzImage --- arch/s390/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index dbeeb3a049f2..588160fd1db0 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -149,6 +149,7 @@ config S390 select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_SYSCALL_TRACEPOINTS select HAVE_VIRT_CPU_ACCOUNTING + select KALLSYMS_TEXT_RELATIVE if 64BIT select MODULES_USE_ELF_RELA select NO_BOOTMEM select OLD_SIGACTION -- 2.5.0