From nobody Tue Sep 16 14:09:21 2025 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 92C41C3DA7D for ; Tue, 3 Jan 2023 17:03:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238212AbjACRDC (ORCPT ); Tue, 3 Jan 2023 12:03:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41214 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238192AbjACRAZ (ORCPT ); Tue, 3 Jan 2023 12:00:25 -0500 Received: from fx409.security-mail.net (smtpout253.security-mail.net [46.30.205.253]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 13CFD12AE8 for ; Tue, 3 Jan 2023 09:00:24 -0800 (PST) Received: from localhost (fx409.security-mail.net [127.0.0.1]) by fx409.security-mail.net (Postfix) with ESMTP id 774DA34989A for ; Tue, 3 Jan 2023 17:44:33 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kalray.eu; s=sec-sig-email; t=1672764273; bh=lZWIdX21UTX9ve9MLDXTAEbB6rTrwd/xi58TRbDRty8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=YA4weplVyhPfdwYdh3Jd79OilH7Fa4CCr3ePlNa/ug/hFD/FZU4wgQorySMTeG583 oH/EP7Y/MRIfP5ofPd6341NN4lJ0yAQOj9AkAZkXKv0xhggh8CMQ7tw5142vxbZS32 t7MXnzBd/iOYtYd7GHqOC2KP7oLcMh4OSTssKNpg= Received: from fx409 (fx409.security-mail.net [127.0.0.1]) by fx409.security-mail.net (Postfix) with ESMTP id 528FB349898; Tue, 3 Jan 2023 17:44:33 +0100 (CET) Received: from zimbra2.kalray.eu (unknown [217.181.231.53]) by fx409.security-mail.net (Postfix) with ESMTPS id A90D434984A; Tue, 3 Jan 2023 17:44:32 +0100 (CET) Received: from zimbra2.kalray.eu (localhost [127.0.0.1]) by zimbra2.kalray.eu (Postfix) with ESMTPS id 5290E27E0407; Tue, 3 Jan 2023 17:44:32 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by zimbra2.kalray.eu (Postfix) with ESMTP id 3571727E0405; Tue, 3 Jan 2023 17:44:32 +0100 (CET) Received: from zimbra2.kalray.eu ([127.0.0.1]) by localhost (zimbra2.kalray.eu [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id 7J7bVzNCgGc6; Tue, 3 Jan 2023 17:44:32 +0100 (CET) Received: from junon.lin.mbt.kalray.eu (unknown [192.168.37.161]) by zimbra2.kalray.eu (Postfix) with ESMTPSA id 16FCD27E03FB; Tue, 3 Jan 2023 17:44:32 +0100 (CET) X-Virus-Scanned: E-securemail Secumail-id: DKIM-Filter: OpenDKIM Filter v2.10.3 zimbra2.kalray.eu 3571727E0405 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kalray.eu; s=32AE1B44-9502-11E5-BA35-3734643DEF29; t=1672764272; bh=Zhuy2u38jJYcNgi+ZHVG5mM0Gbmiag1TvE1upEGHYsY=; h=From:To:Date:Message-Id:MIME-Version; b=MWe0W+bIkprO7q3UjO/nm47iAEKp1g4pFI3+dxxnA1eoK9cgTdLbT0XZFOocAolCv jT/l5/tKbcaZouET1sHUZ6b63+lcaISIljDntfb7OiRQHHhcp8P55EvxvpOATUEfts y2LE0NtBKiwsJcjKPR7cCcuzwUOCWj05dUbsuErU= From: Yann Sionneau Cc: Yann Sionneau , linux-kernel@vger.kernel.org, Clement Leger , Jules Maselbas , Julian Vetter Subject: [RFC PATCH 13/25] kvx: Add signal handling support Date: Tue, 3 Jan 2023 17:43:47 +0100 Message-ID: <20230103164359.24347-14-ysionneau@kalray.eu> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20230103164359.24347-1-ysionneau@kalray.eu> References: <20230103164359.24347-1-ysionneau@kalray.eu> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ALTERMIMEV2_out: done To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Add sigcontext definition and signal handling support for kvx. CC: linux-kernel@vger.kernel.org Co-developed-by: Clement Leger Signed-off-by: Clement Leger Co-developed-by: Jules Maselbas Signed-off-by: Jules Maselbas Co-developed-by: Julian Vetter Signed-off-by: Julian Vetter Co-developed-by: Yann Sionneau Signed-off-by: Yann Sionneau --- arch/kvx/include/uapi/asm/sigcontext.h | 16 ++ arch/kvx/kernel/signal.c | 266 +++++++++++++++++++++++++ arch/kvx/kernel/vdso.c | 87 ++++++++ 3 files changed, 369 insertions(+) create mode 100644 arch/kvx/include/uapi/asm/sigcontext.h create mode 100644 arch/kvx/kernel/signal.c create mode 100644 arch/kvx/kernel/vdso.c diff --git a/arch/kvx/include/uapi/asm/sigcontext.h b/arch/kvx/include/uapi= /asm/sigcontext.h new file mode 100644 index 000000000000..97ab4f78152a --- /dev/null +++ b/arch/kvx/include/uapi/asm/sigcontext.h @@ -0,0 +1,16 @@ +/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */ +/* + * Copyright (C) 2017-2023 Kalray Inc. + * Author(s): Clement Leger + */ + +#ifndef _UAPI_ASM_KVX_SIGCONTEXT_H +#define _UAPI_ASM_KVX_SIGCONTEXT_H + +#include + +struct sigcontext { + struct user_pt_regs sc_regs; +}; + +#endif /* _UAPI_ASM_KVX_SIGCONTEXT_H */ diff --git a/arch/kvx/kernel/signal.c b/arch/kvx/kernel/signal.c new file mode 100644 index 000000000000..e52bbb30c336 --- /dev/null +++ b/arch/kvx/kernel/signal.c @@ -0,0 +1,266 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2017-2023 Kalray Inc. + * Author(s): Clement Leger + */ + +#include +#include + +#include +#include +#include +#include + +struct rt_sigframe { + struct siginfo info; + struct ucontext uc; +}; + +int __init setup_syscall_sigreturn_page(void *sigpage_addr) +{ + unsigned int frame_size =3D (uintptr_t) &user_scall_rt_sigreturn_end - + (uintptr_t) &user_scall_rt_sigreturn; + + /* Copy the sigreturn scall implementation */ + memcpy(sigpage_addr, &user_scall_rt_sigreturn, frame_size); + + flush_icache_range((unsigned long) sigpage_addr, + (unsigned long) sigpage_addr + frame_size); + + return 0; +} + +static long restore_sigcontext(struct pt_regs *regs, + struct sigcontext __user *sc) +{ + long err; + + /* sc_regs is structured the same as the start of pt_regs */ + err =3D __copy_from_user(regs, &sc->sc_regs, sizeof(sc->sc_regs)); + + return err; +} + +long _sys_rt_sigreturn(void) +{ + struct pt_regs *regs =3D current_pt_regs(); + struct rt_sigframe __user *frame; + struct task_struct *task; + sigset_t set; + + current->restart_block.fn =3D do_no_restart_syscall; + + frame =3D (struct rt_sigframe __user *) user_stack_pointer(regs); + + /* + * Stack is not aligned but should be ! + * User probably did some malicious things. + */ + if (user_stack_pointer(regs) & STACK_ALIGN_MASK) + goto badframe; + + if (!access_ok(frame, sizeof(*frame))) + goto badframe; + + /* Restore sigmask */ + if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) + goto badframe; + + set_current_blocked(&set); + + if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) + goto badframe; + + if (restore_altstack(&frame->uc.uc_stack)) + goto badframe; + + return regs->r0; + +badframe: + task =3D current; + if (show_unhandled_signals) { + pr_info_ratelimited( + "%s[%d]: bad frame in %s: frame=3D%p pc=3D%p sp=3D%p\n", + task->comm, task_pid_nr(task), __func__, + frame, (void *) instruction_pointer(regs), + (void *) user_stack_pointer(regs)); + } + force_sig(SIGSEGV); + return 0; +} + + +static long setup_sigcontext(struct rt_sigframe __user *frame, + struct pt_regs *regs) +{ + struct sigcontext __user *sc =3D &frame->uc.uc_mcontext; + long err; + + /* sc_regs is structured the same as the start of pt_regs */ + err =3D __copy_to_user(&sc->sc_regs, regs, sizeof(sc->sc_regs)); + + return err; +} + +static inline void __user *get_sigframe(struct ksignal *ksig, + struct pt_regs *regs, size_t framesize) +{ + unsigned long sp; + /* Default to using normal stack */ + sp =3D regs->sp; + + /* + * If we are on the alternate signal stack and would overflow it, don't. + * Return an always-bogus address instead so we will die with SIGSEGV. + */ + if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize))) + return (void __user __force *)(-1UL); + + /* This is the X/Open sanctioned signal stack switching. */ + sp =3D sigsp(sp, ksig) - framesize; + + /* Align the stack frame on 16bytes */ + sp &=3D ~STACK_ALIGN_MASK; + + return (void __user *)sp; +} + +/* TODO: Use VDSO when ready ! */ +static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, + struct pt_regs *regs) +{ + unsigned long sigpage =3D current->mm->context.sigpage; + struct rt_sigframe __user *frame; + long err =3D 0; + + frame =3D get_sigframe(ksig, regs, sizeof(*frame)); + if (!access_ok(frame, sizeof(*frame))) + return -EFAULT; + + err |=3D copy_siginfo_to_user(&frame->info, &ksig->info); + + /* Create the ucontext. */ + err |=3D __put_user(0, &frame->uc.uc_flags); + err |=3D __put_user(NULL, &frame->uc.uc_link); + err |=3D __save_altstack(&frame->uc.uc_stack, user_stack_pointer(regs)); + err |=3D setup_sigcontext(frame, regs); + err |=3D __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); + if (err) + return -EFAULT; + + /* + * When returning from the handler, we want to jump to the + * sigpage which will execute the sigreturn scall. + */ + regs->ra =3D sigpage; + /* Return to signal handler */ + regs->spc =3D (unsigned long)ksig->ka.sa.sa_handler; + regs->sp =3D (unsigned long) frame; + + /* Parameters for signal handler */ + regs->r0 =3D ksig->sig; /* r0: signal number */ + regs->r1 =3D (unsigned long)(&frame->info); /* r1: siginfo pointer */ + regs->r2 =3D (unsigned long)(&frame->uc); /* r2: ucontext pointer */ + + return 0; +} + +static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) +{ + sigset_t *oldset =3D sigmask_to_save(); + int ret; + + /* Are we from a system call? */ + if (in_syscall(regs)) { + /* If so, check system call restarting.. */ + switch (regs->r0) { + case -ERESTART_RESTARTBLOCK: + case -ERESTARTNOHAND: + regs->r0 =3D -EINTR; + break; + case -ERESTARTSYS: + if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { + regs->r0 =3D -EINTR; + break; + } + fallthrough; + case -ERESTARTNOINTR: + regs->r0 =3D regs->orig_r0; + regs->spc -=3D 0x4; + break; + } + } + + ret =3D setup_rt_frame(ksig, oldset, regs); + + signal_setup_done(ret, ksig, 0); +} + +asmlinkage void do_signal(struct pt_regs *regs) +{ + struct ksignal ksig; + + if (get_signal(&ksig)) { + handle_signal(&ksig, regs); + return; + } + + /* Are we from a system call? */ + if (in_syscall(regs)) { + /* + * If we are here, this means there is no handler + * present and we must restart the syscall. + */ + switch (regs->r0) { + case -ERESTART_RESTARTBLOCK: + /* Modify the syscall number in order to restart it */ + regs->r6 =3D __NR_restart_syscall; + fallthrough; + case -ERESTARTNOHAND: + case -ERESTARTSYS: + case -ERESTARTNOINTR: + /* We are restarting the syscall */ + regs->r0 =3D regs->orig_r0; + /* + * scall instruction isn't bundled with anything else, + * so we can just revert the spc to restart the syscall. + */ + regs->spc -=3D 0x4; + break; + } + } + + /* + * If there's no signal to deliver, we just put the saved sigmask + * back. + */ + restore_saved_sigmask(); +} + + +asmlinkage void do_work_pending(struct pt_regs *regs, + unsigned long thread_flags) +{ + /* We are called with IRQs disabled */ + trace_hardirqs_off(); + + do { + if (thread_flags & _TIF_NEED_RESCHED) { + schedule(); + } else { + local_irq_enable(); + if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) + do_signal(regs); + + if (thread_flags & _TIF_NOTIFY_RESUME) { + clear_thread_flag(TIF_NOTIFY_RESUME); + resume_user_mode_work(regs); + } + } + /* Guarantee task flag atomic read */ + local_irq_disable(); + thread_flags =3D READ_ONCE(current_thread_info()->flags); + } while (thread_flags & _TIF_WORK_MASK); +} + diff --git a/arch/kvx/kernel/vdso.c b/arch/kvx/kernel/vdso.c new file mode 100644 index 000000000000..1515de15eb31 --- /dev/null +++ b/arch/kvx/kernel/vdso.c @@ -0,0 +1,87 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2017-2023 Kalray Inc. + * Author(s): Clement Leger + */ + +#include +#include +#include + +#include + +static struct page *signal_page; + +static int __init init_sigreturn(void) +{ + struct page *sigpage; + void *mapped_sigpage; + int err; + + sigpage =3D alloc_page(GFP_KERNEL); + if (!sigpage) + panic("Cannot allocate sigreturn page"); + + mapped_sigpage =3D vmap(&sigpage, 1, 0, PAGE_KERNEL); + if (!mapped_sigpage) + panic("Cannot map sigreturn page"); + + clear_page(mapped_sigpage); + + err =3D setup_syscall_sigreturn_page(mapped_sigpage); + if (err) + panic("Cannot set signal return syscall, err: %x.", err); + + vunmap(mapped_sigpage); + + signal_page =3D sigpage; + + return 0; +} +arch_initcall(init_sigreturn); + +static int sigpage_mremap(const struct vm_special_mapping *sm, + struct vm_area_struct *new_vma) +{ + current->mm->context.sigpage =3D new_vma->vm_start; + return 0; +} + +static const struct vm_special_mapping sigpage_mapping =3D { + .name =3D "[sigpage]", + .pages =3D &signal_page, + .mremap =3D sigpage_mremap, +}; + +int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) +{ + int ret =3D 0; + unsigned long addr; + struct mm_struct *mm =3D current->mm; + struct vm_area_struct *vma; + + mmap_write_lock(mm); + + addr =3D get_unmapped_area(NULL, STACK_TOP, PAGE_SIZE, 0, 0); + if (IS_ERR_VALUE(addr)) { + ret =3D addr; + goto up_fail; + } + + vma =3D _install_special_mapping( + mm, + addr, + PAGE_SIZE, + VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC, + &sigpage_mapping); + if (IS_ERR(vma)) { + ret =3D PTR_ERR(vma); + goto up_fail; + } + + mm->context.sigpage =3D addr; + +up_fail: + mmap_write_unlock(mm); + return ret; +} --=20 2.37.2