From patchwork Thu Jul 27 14:59:48 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Zhangjin Wu X-Patchwork-Id: 13330232 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 C49E4C0015E for ; Thu, 27 Jul 2023 15:00:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233033AbjG0PAE (ORCPT ); Thu, 27 Jul 2023 11:00:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45682 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231882AbjG0PAD (ORCPT ); Thu, 27 Jul 2023 11:00:03 -0400 Received: from bg4.exmail.qq.com (bg4.exmail.qq.com [43.155.65.254]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 181F7A0; Thu, 27 Jul 2023 08:00:00 -0700 (PDT) X-QQ-mid: bizesmtp79t1690469990tez9w7ke Received: from linux-lab-host.localdomain ( [61.141.78.189]) by bizesmtp.qq.com (ESMTP) with id ; Thu, 27 Jul 2023 22:59:49 +0800 (CST) X-QQ-SSF: 01200000002000D0X000B00A0000000 X-QQ-FEAT: o+V1LJLjbvzV3UWkDlfl9YJBiuBSM8q6mhAUqw4CiQqpVl10jabxOV5BRj1oV HbzdwK1dZfSy9Si9hrkpLKYGVHNSIqbKzaZuKQe0ENfUC4t4+J1jtY56QV01f9qWUs0MEBj xO1n0TCs6dg3AKUkFjGSUtxXn69Rph8EuhFVPTY26qAGIheptJzjtSC1r3+VpRV/HhkyebM iI9K6GKuhdpCBcIDmqBkRLwdORKtzZ1BqMbxCkPVwRRWDkhK9ySSfydZTf4TOlPBHX5PdLP 0q8FSIGPts2qoYrcuIVfWnEgXfn7z8ArlmsXarZzdscmHKYjVFNQber2igt7jVoK0H6jh1U 1aavyKkizfApndAaRzKENcdMgenrKR2qf0teNAv24lwMMp8xcUj5+irv7XUDTM1+aL6M8Fp FxvKqiFczpw= X-QQ-GoodBg: 0 X-BIZMAIL-ID: 13764612502148830925 From: Zhangjin Wu To: w@1wt.eu Cc: falcon@tinylab.org, arnd@arndb.de, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, thomas@t-8ch.de, =?utf-8?q?Thomas_Wei?= =?utf-8?q?=C3=9Fschuh?= Subject: [PATCH v3 1/7] tools/nolibc: add support for powerpc Date: Thu, 27 Jul 2023 22:59:48 +0800 Message-Id: X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 X-QQ-SENDSIZE: 520 Feedback-ID: bizesmtp:tinylab.org:qybglogicsvrgz:qybglogicsvrgz5a-1 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Both syscall declarations and _start code definition are added for powerpc to nolibc. Like mips, powerpc uses a register (exactly, the summary overflow bit) to record the error occurred, and uses another register to return the value [1]. So, the return value of every syscall declaration must be normalized to match the __sysret() helper, return -value when there is an error, otheriwse, return value directly. Glibc and musl use different methods to check the summary overflow bit, glibc (sysdeps/unix/sysv/linux/powerpc/sysdep.h) saves the cr register to r0 at first, and then check the summary overflow bit in cr0: mfcr r0 r0 & (1 << 28) ? -r3 : r3 --> 10003c14: 7c 00 00 26 mfcr r0 10003c18: 74 09 10 00 andis. r9,r0,4096 10003c1c: 41 82 00 08 beq 0x10003c24 10003c20: 7c 63 00 d0 neg r3,r3 Musl (arch/powerpc/syscall_arch.h) directly checks the summary overflow bit with the 'bns' instruction, it is smaller: /* no summary overflow bit means no error, return value directly */ bns+ 1f /* otherwise, return negated value */ neg r3, r3 1: --> 10000418: 40 a3 00 08 bns 0x10000420 1000041c: 7c 63 00 d0 neg r3,r3 Like musl, Linux (arch/powerpc/include/asm/vdso/gettimeofday.h) uses the same method for do_syscall_2() too. Here applies the second method to get smaller size. [1]: https://man7.org/linux/man-pages/man2/syscall.2.html Reviewed-by: Thomas Weißschuh Signed-off-by: Zhangjin Wu --- tools/include/nolibc/arch-powerpc.h | 188 ++++++++++++++++++++++++++++ tools/include/nolibc/arch.h | 2 + 2 files changed, 190 insertions(+) create mode 100644 tools/include/nolibc/arch-powerpc.h diff --git a/tools/include/nolibc/arch-powerpc.h b/tools/include/nolibc/arch-powerpc.h new file mode 100644 index 000000000000..caa943e1521a --- /dev/null +++ b/tools/include/nolibc/arch-powerpc.h @@ -0,0 +1,188 @@ +/* SPDX-License-Identifier: LGPL-2.1 OR MIT */ +/* + * PowerPC specific definitions for NOLIBC + * Copyright (C) 2023 Zhangjin Wu + */ + +#ifndef _NOLIBC_ARCH_POWERPC_H +#define _NOLIBC_ARCH_POWERPC_H + +#include "compiler.h" +#include "crt.h" + +/* Syscalls for PowerPC : + * - stack is 16-byte aligned + * - syscall number is passed in r0 + * - arguments are in r3, r4, r5, r6, r7, r8, r9 + * - the system call is performed by calling "sc" + * - syscall return comes in r3, and the summary overflow bit is checked + * to know if an error occurred, in which case errno is in r3. + * - the arguments are cast to long and assigned into the target + * registers which are then simply passed as registers to the asm code, + * so that we don't have to experience issues with register constraints. + */ + +#define _NOLIBC_SYSCALL_CLOBBERLIST \ + "memory", "cr0", "r12", "r11", "r10", "r9" + +#define my_syscall0(num) \ +({ \ + register long _ret __asm__ ("r3"); \ + register long _num __asm__ ("r0") = (num); \ + \ + __asm__ volatile ( \ + " sc\n" \ + " bns+ 1f\n" \ + " neg %0, %0\n" \ + "1:\n" \ + : "=r"(_ret), "+r"(_num) \ + : \ + : _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6", "r5", "r4" \ + ); \ + _ret; \ +}) + +#define my_syscall1(num, arg1) \ +({ \ + register long _ret __asm__ ("r3"); \ + register long _num __asm__ ("r0") = (num); \ + register long _arg1 __asm__ ("r3") = (long)(arg1); \ + \ + __asm__ volatile ( \ + " sc\n" \ + " bns+ 1f\n" \ + " neg %0, %0\n" \ + "1:\n" \ + : "=r"(_ret), "+r"(_num) \ + : "0"(_arg1) \ + : _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6", "r5", "r4" \ + ); \ + _ret; \ +}) + + +#define my_syscall2(num, arg1, arg2) \ +({ \ + register long _ret __asm__ ("r3"); \ + register long _num __asm__ ("r0") = (num); \ + register long _arg1 __asm__ ("r3") = (long)(arg1); \ + register long _arg2 __asm__ ("r4") = (long)(arg2); \ + \ + __asm__ volatile ( \ + " sc\n" \ + " bns+ 1f\n" \ + " neg %0, %0\n" \ + "1:\n" \ + : "=r"(_ret), "+r"(_num), "+r"(_arg2) \ + : "0"(_arg1) \ + : _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6", "r5" \ + ); \ + _ret; \ +}) + + +#define my_syscall3(num, arg1, arg2, arg3) \ +({ \ + register long _ret __asm__ ("r3"); \ + register long _num __asm__ ("r0") = (num); \ + register long _arg1 __asm__ ("r3") = (long)(arg1); \ + register long _arg2 __asm__ ("r4") = (long)(arg2); \ + register long _arg3 __asm__ ("r5") = (long)(arg3); \ + \ + __asm__ volatile ( \ + " sc\n" \ + " bns+ 1f\n" \ + " neg %0, %0\n" \ + "1:\n" \ + : "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3) \ + : "0"(_arg1) \ + : _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6" \ + ); \ + _ret; \ +}) + + +#define my_syscall4(num, arg1, arg2, arg3, arg4) \ +({ \ + register long _ret __asm__ ("r3"); \ + register long _num __asm__ ("r0") = (num); \ + register long _arg1 __asm__ ("r3") = (long)(arg1); \ + register long _arg2 __asm__ ("r4") = (long)(arg2); \ + register long _arg3 __asm__ ("r5") = (long)(arg3); \ + register long _arg4 __asm__ ("r6") = (long)(arg4); \ + \ + __asm__ volatile ( \ + " sc\n" \ + " bns+ 1f\n" \ + " neg %0, %0\n" \ + "1:\n" \ + : "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3), \ + "+r"(_arg4) \ + : "0"(_arg1) \ + : _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7" \ + ); \ + _ret; \ +}) + + +#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \ +({ \ + register long _ret __asm__ ("r3"); \ + register long _num __asm__ ("r0") = (num); \ + register long _arg1 __asm__ ("r3") = (long)(arg1); \ + register long _arg2 __asm__ ("r4") = (long)(arg2); \ + register long _arg3 __asm__ ("r5") = (long)(arg3); \ + register long _arg4 __asm__ ("r6") = (long)(arg4); \ + register long _arg5 __asm__ ("r7") = (long)(arg5); \ + \ + __asm__ volatile ( \ + " sc\n" \ + " bns+ 1f\n" \ + " neg %0, %0\n" \ + "1:\n" \ + : "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3), \ + "+r"(_arg4), "+r"(_arg5) \ + : "0"(_arg1) \ + : _NOLIBC_SYSCALL_CLOBBERLIST, "r8" \ + ); \ + _ret; \ +}) + +#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \ +({ \ + register long _ret __asm__ ("r3"); \ + register long _num __asm__ ("r0") = (num); \ + register long _arg1 __asm__ ("r3") = (long)(arg1); \ + register long _arg2 __asm__ ("r4") = (long)(arg2); \ + register long _arg3 __asm__ ("r5") = (long)(arg3); \ + register long _arg4 __asm__ ("r6") = (long)(arg4); \ + register long _arg5 __asm__ ("r7") = (long)(arg5); \ + register long _arg6 __asm__ ("r8") = (long)(arg6); \ + \ + __asm__ volatile ( \ + " sc\n" \ + " bns+ 1f\n" \ + " neg %0, %0\n" \ + "1:\n" \ + : "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3), \ + "+r"(_arg4), "+r"(_arg5), "+r"(_arg6) \ + : "0"(_arg1) \ + : _NOLIBC_SYSCALL_CLOBBERLIST \ + ); \ + _ret; \ +}) + +/* startup code */ +void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void) +{ + __asm__ volatile ( + "mr 3, 1\n" /* save stack pointer to r3, as arg1 of _start_c */ + "clrrwi 1, 1, 4\n" /* align the stack to 16 bytes */ + "li 0, 0\n" /* zero the frame pointer */ + "stwu 1, -16(1)\n" /* the initial stack frame */ + "bl _start_c\n" /* transfer to c runtime */ + ); + __builtin_unreachable(); +} + +#endif /* _NOLIBC_ARCH_POWERPC_H */ diff --git a/tools/include/nolibc/arch.h b/tools/include/nolibc/arch.h index 82b43935650f..e276fb0680af 100644 --- a/tools/include/nolibc/arch.h +++ b/tools/include/nolibc/arch.h @@ -25,6 +25,8 @@ #include "arch-aarch64.h" #elif defined(__mips__) && defined(_ABIO32) #include "arch-mips.h" +#elif defined(__powerpc__) +#include "arch-powerpc.h" #elif defined(__riscv) #include "arch-riscv.h" #elif defined(__s390x__)