From patchwork Sun Aug 20 18:19:00 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vitaly Chikunov X-Patchwork-Id: 715270 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 68B37EE4993 for ; Sun, 20 Aug 2023 18:31:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230345AbjHTSbw (ORCPT ); Sun, 20 Aug 2023 14:31:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33884 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231433AbjHTSbt (ORCPT ); Sun, 20 Aug 2023 14:31:49 -0400 X-Greylist: delayed 454 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Sun, 20 Aug 2023 11:27:04 PDT Received: from vmicros1.altlinux.org (vmicros1.altlinux.org [194.107.17.57]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 602DDAF; Sun, 20 Aug 2023 11:27:03 -0700 (PDT) Received: from imap.altlinux.org (imap.altlinux.org [194.107.17.38]) by vmicros1.altlinux.org (Postfix) with ESMTP id EF0FC72C981; Sun, 20 Aug 2023 21:19:27 +0300 (MSK) Received: from beacon.altlinux.org (unknown [193.43.10.9]) by imap.altlinux.org (Postfix) with ESMTPSA id E459836D0165; Sun, 20 Aug 2023 21:19:27 +0300 (MSK) From: Vitaly Chikunov To: Willy Tarreau , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [RFC] tools/nolibc: x86_64: Make it compile with -pie Date: Sun, 20 Aug 2023 21:19:00 +0300 Message-Id: <20230820181900.3786107-1-vt@altlinux.org> X-Mailer: git-send-email 2.33.8 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Use RIP-relative addressing when setting `environ` and `_auxv` in startup code. Some toolchains have `-pie` enabled by default. On them or when -pie is specified manually gcc produces error like this: ld: /tmp/cci0uPcR.o: relocation R_X86_64_32S against symbol `environ' can not be used when making a PIE object; recompile with -fPIE ld: failed to set dynamic section sizes: bad value This is because asm() startup code accesses there pointers with absolute addressing. This may inspire others to fix the problem for other architectures too. Signed-off-by: Vitaly Chikunov --- tools/include/nolibc/arch-x86_64.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/include/nolibc/arch-x86_64.h b/tools/include/nolibc/arch-x86_64.h index 6fc4d8392742..a6be44b333ce 100644 --- a/tools/include/nolibc/arch-x86_64.h +++ b/tools/include/nolibc/arch-x86_64.h @@ -199,14 +199,14 @@ void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) __no_stack_pr "pop %rdi\n" /* argc (first arg, %rdi) */ "mov %rsp, %rsi\n" /* argv[] (second arg, %rsi) */ "lea 8(%rsi,%rdi,8),%rdx\n" /* then a NULL then envp (third arg, %rdx) */ - "mov %rdx, environ\n" /* save environ */ + "mov %rdx, environ(%rip)\n" /* save environ */ "xor %ebp, %ebp\n" /* zero the stack frame */ "mov %rdx, %rax\n" /* search for auxv (follows NULL after last env) */ "0:\n" "add $8, %rax\n" /* search for auxv using rax, it follows the */ "cmp -8(%rax), %rbp\n" /* ... NULL after last env (rbp is zero here) */ "jnz 0b\n" - "mov %rax, _auxv\n" /* save it into _auxv */ + "mov %rax, _auxv(%rip)\n" /* save it into _auxv */ "and $-16, %rsp\n" /* x86 ABI : esp must be 16-byte aligned before call */ "call main\n" /* main() returns the status code, we'll exit with it. */ "mov %eax, %edi\n" /* retrieve exit code (32 bit) */