From mboxrd@z Thu Jan 1 00:00:00 1970 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5D571C433F5 for ; Sun, 17 Oct 2021 13:21:15 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1E97861260 for ; Sun, 17 Oct 2021 13:21:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 1E97861260 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ZPYZikuy1hfHlaNpxqyEZiWsdwF/vrfyJktFbv3FFFo=; b=DZWTggIRQO8+iB N0badOPlUvcOCBYVSPiplYaLkfloF9fcCjmjrU5M0ybgz+SoETg2erlFhUBtLsVVLVppT+UXf5R/w CIO70l/jxy2kv6qIrM3DmGbbaYclc658fS0Q1T7mW1dDM3dmeetkZ0gHg9YR2r5Qqog1ooHEyZaSP O1/8BqJ8TU98Dp5kT2oFAIPOt/t0vqQwrQU3XjNDQMANA1Lt+5fBayNKFHZWlp7OzSu8Ji4d/a0mL Y9YWH7byoxbAZDZ0vz/ENsKceqKhDUq1vRj+z6RltZKt7jQgqLb4p0zipW8zBLsAgYu5VKNwuleid 5xB3GkouRG4XTjZA8mJw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mc64j-00CbP8-SI; Sun, 17 Oct 2021 13:19:42 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mc62y-00Cae3-Uq for linux-arm-kernel@lists.infradead.org; Sun, 17 Oct 2021 13:17:54 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7A69A60F9E; Sun, 17 Oct 2021 13:17:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1634476672; bh=Jh31lop36U9UoBRVUxxn06wC8IwH6k1aGBTjDOR+3bs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IIGL097Wx3hgcfXKUrf7gdbSWwy+7Ml9DQ4Ycw1m99Sn3tey4NclpjeDFUz3XcDB9 BGYDaSArZ5mqhyA+HkYGJHuiizKjlAn8UuqDFN8102ADi53b7f5oYVoXezjKDgpyof 2IQgtsMjX9IL+spGHQjaeEftEU+SkdZ9E2PtMK4hqV0CcY3/JWiq/HpDNtXj6y2vGn Ob3ZZ14cro624EEl7mr50XAdd7YoJgGOZNbcrzI5o1+j05iFM4qQHQ0BeUxwD4DW4w 3rX/GKsxEbJobg2EQ75rJHpwOx40a1KQ/VDv16hnFc/LKC5Yxj/pccc6PLFs5bqX4Q VKtbLGfOj1RNA== From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org Cc: Ard Biesheuvel , Russell King , Arnd Bergmann , Kees Cook , Keith Packard , Linus Walleij , Nick Desaulniers , Nicolas Pitre Subject: [PATCH v3 08/10] ARM: implement IRQ stacks Date: Sun, 17 Oct 2021 15:17:21 +0200 Message-Id: <20211017131723.4034662-9-ardb@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211017131723.4034662-1-ardb@kernel.org> References: <20211017131723.4034662-1-ardb@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=7684; h=from:subject; bh=Jh31lop36U9UoBRVUxxn06wC8IwH6k1aGBTjDOR+3bs=; b=owEB7QES/pANAwAKAcNPIjmS2Y8kAcsmYgBhbCJe0RiC9X+C/WWF9cKRjFuQV3vOt0qYPNR93J1E kdbYM6eJAbMEAAEKAB0WIQT72WJ8QGnJQhU3VynDTyI5ktmPJAUCYWwiXgAKCRDDTyI5ktmPJFTIDA CqCEJZJaPBJ49T16Gh1LXzU38sbQ8/2jTxgy1D1R3zBb54mgwWsa3rPPPIJVTCa9zwBYnW2Fq/t0co JQliJ7l2GpC6QrBWTR1uhZOFiywSJbRoiyNfgGegPNXNVvUelxiJ0w1koY0Nk4U5tQjCbiF21AqrzE l8QhmMk/xwFYE7VAugt1OJahF+Rt5J7UPbg9iLhmNqppJBzEpFoR73pPsVGj9JZPo6+DyH0bv2fkDB fesWtqlMWhYF/R1Udj10EiB5YWq7iGvg8sJkj3yXh6e/r8bkYzDZzFWOuvCaczq0shImpvU3co/eRX gpH0izQc0sqsj4j9Na2VUBEgZKaDbIP5dU3yeOGJrBsYMcW6QksFwIKE1jNFC3cmnoU2MIegqnaeMg yeylMJnXBAawRmjlesAaUVVKudLVzbAxKyuUD/3amFLXWUw3XLhMS/EXq3rUUz+Ctbh8oydDqXlWx8 Q4fWB85g3lJvNoDOOfrUBeFWeX65c3VQ1BeaO6MeSwpYU= X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211017_061753_063427_127FCD30 X-CRM114-Status: GOOD ( 23.97 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Now that we no longer rely on the stack pointer to access the current task struct or thread info, we can implement support for IRQ stacks cleanly as well. Define a per-CPU IRQ stack and switch to this stack when taking an IRQ, provided that we were not already using that stack in the interrupted context. This is never the case for IRQs taken from user space, but ones taken while running in the kernel could fire while one taken from user space has not completed yet. Signed-off-by: Ard Biesheuvel Acked-by: Linus Walleij Tested-by: Keith Packard --- arch/arm/Kconfig | 4 ++ arch/arm/include/asm/assembler.h | 4 ++ arch/arm/kernel/entry-armv.S | 54 ++++++++++++++++++-- arch/arm/kernel/irq.c | 23 +++++++++ arch/arm/kernel/traps.c | 15 +++++- arch/arm/lib/backtrace-clang.S | 8 +++ arch/arm/lib/backtrace.S | 8 +++ 7 files changed, 112 insertions(+), 4 deletions(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 4f61c9789e7f..a8c1db0736f3 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1163,6 +1163,10 @@ config CURRENT_POINTER_IN_TPIDRURO def_bool y depends on SMP && CPU_32v6K && !CPU_V6 +config IRQSTACKS + def_bool y + depends on GENERIC_IRQ_MULTI_HANDLER && THREAD_INFO_IN_TASK + config ARM_CPU_TOPOLOGY bool "Support cpu topology definition" depends on SMP && CPU_V7 diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h index abb8202ef0da..405950494208 100644 --- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -86,6 +86,10 @@ #define IMM12_MASK 0xfff +/* the frame pointer used for stack unwinding */ +ARM( fpreg .req r11 ) +THUMB( fpreg .req r7 ) + /* * Enable and disable interrupts */ diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S index 21896f702447..2a426bd27a69 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -36,11 +36,59 @@ /* * Interrupt handling. */ - .macro irq_handler + .macro irq_handler, from_user:req #ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER mov_l r1, handle_arch_irq mov r0, sp +#ifdef CONFIG_IRQSTACKS + mov_l r2, irq_stack_ptr @ Take base address + mrc p15, 0, r3, c13, c0, 4 @ Get CPU offset +#ifdef CONFIG_UNWINDER_ARM + mov fpreg, sp @ Preserve original SP +#else + mov r8, fp @ Preserve original FP + mov r9, sp @ Preserve original SP +#endif + ldr sp, [r2, r3] @ Load SP from per-CPU var + .if \from_user == 0 +UNWIND( .setfp fpreg, sp ) + @ + @ If we took the interrupt while running in the kernel, we may already + @ be using the IRQ stack, so revert to the original value in that case. + @ + subs r2, sp, r0 @ SP above bottom of IRQ stack? + rsbscs r2, r2, #THREAD_SIZE @ ... and below the top? + movcs sp, r0 @ If so, revert to incoming SP + +#ifndef CONFIG_UNWINDER_ARM + @ + @ Inform the frame pointer unwinder where the next frame lives + @ + movcc lr, pc @ Make LR point into .entry.text so + @ that we will get a dump of the + @ exception stack for this frame. +#ifdef CONFIG_CC_IS_GCC + movcc ip, r0 @ Store the old SP in the frame record. + stmdbcc sp!, {fp, ip, lr, pc} @ Push frame record + addcc fp, sp, #12 +#else + stmdbcc sp!, {fp, lr} @ Push frame record + movcc fp, sp +#endif // CONFIG_CC_IS_GCC +#endif // CONFIG_UNWINDER_ARM + .endif +#endif // CONFIG_IRQSTACKS + bl_m [r1] + +#ifdef CONFIG_IRQSTACKS +#ifdef CONFIG_UNWINDER_ARM + mov sp, fpreg @ Restore original SP +#else + mov fp, r8 @ Restore original FP + mov sp, r9 @ Restore original SP +#endif // CONFIG_UNWINDER_ARM +#endif // CONFIG_IRQSTACKS #else arch_irq_handler_default #endif @@ -200,7 +248,7 @@ ENDPROC(__dabt_svc) .align 5 __irq_svc: svc_entry - irq_handler + irq_handler from_user=0 #ifdef CONFIG_PREEMPTION ldr r8, [tsk, #TI_PREEMPT] @ get preempt count @@ -427,7 +475,7 @@ ENDPROC(__dabt_usr) __irq_usr: usr_entry kuser_cmpxchg_check - irq_handler + irq_handler from_user=1 get_thread_info tsk mov why, #0 b ret_to_user_from_irq diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c index 20ab1e607522..58af2adb1583 100644 --- a/arch/arm/kernel/irq.c +++ b/arch/arm/kernel/irq.c @@ -43,6 +43,25 @@ unsigned long irq_err_count; +#ifdef CONFIG_IRQSTACKS + +asmlinkage DEFINE_PER_CPU_READ_MOSTLY(u8 *, irq_stack_ptr); + +static void __init init_irq_stacks(void) +{ + u8 *stack; + int cpu; + + for_each_possible_cpu(cpu) { + stack = (u8 *)__get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER); + if (WARN_ON(!stack)) + break; + per_cpu(irq_stack_ptr, cpu) = &stack[THREAD_SIZE]; + } +} + +#endif + int arch_show_interrupts(struct seq_file *p, int prec) { #ifdef CONFIG_FIQ @@ -99,6 +118,10 @@ void __init init_IRQ(void) { int ret; +#ifdef CONFIG_IRQSTACKS + init_irq_stacks(); +#endif + if (IS_ENABLED(CONFIG_OF) && !machine_desc->init_irq) irqchip_init(); else diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index cda32385552b..1ba9fc2eb564 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -66,6 +66,19 @@ void dump_backtrace_entry(unsigned long where, unsigned long from, { unsigned long end = frame + 4 + sizeof(struct pt_regs); + if (IS_ENABLED(CONFIG_UNWINDER_FRAME_POINTER) && + IS_ENABLED(CONFIG_CC_IS_GCC) && + end > ALIGN(frame, THREAD_SIZE)) { + /* + * If we are walking past the end of the stack, it may be due + * to the fact that we are on an IRQ or overflow stack. In this + * case, we can load the address of the other stack from the + * frame record. + */ + frame = ((unsigned long *)frame)[-2] - 4; + end = frame + 4 + sizeof(struct pt_regs); + } + #ifdef CONFIG_KALLSYMS printk("%s[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", loglvl, where, (void *)where, from, (void *)from); @@ -278,7 +291,7 @@ static int __die(const char *str, int err, struct pt_regs *regs) if (!user_mode(regs) || in_interrupt()) { dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp, - THREAD_SIZE + (unsigned long)task_stack_page(tsk)); + ALIGN(regs->ARM_sp, THREAD_SIZE)); dump_backtrace(regs, tsk, KERN_EMERG); dump_instr(KERN_EMERG, regs); } diff --git a/arch/arm/lib/backtrace-clang.S b/arch/arm/lib/backtrace-clang.S index 5b4bca85d06d..290c52a60fc6 100644 --- a/arch/arm/lib/backtrace-clang.S +++ b/arch/arm/lib/backtrace-clang.S @@ -197,6 +197,14 @@ finished_setup: cmp sv_fp, frame @ next frame must be mov frame, sv_fp @ above the current frame +#ifdef CONFIG_IRQSTACKS + @ + @ Kernel stacks may be discontiguous in memory. If the next + @ frame is below the previous frame, accept it as long as it + @ lives in kernel memory. + @ + cmpls sv_fp, #PAGE_OFFSET +#endif bhi for_each_frame 1006: adr r0, .Lbad diff --git a/arch/arm/lib/backtrace.S b/arch/arm/lib/backtrace.S index e8408f22d4dc..293a2716bd20 100644 --- a/arch/arm/lib/backtrace.S +++ b/arch/arm/lib/backtrace.S @@ -98,6 +98,14 @@ for_each_frame: tst frame, mask @ Check for address exceptions cmp sv_fp, frame @ next frame must be mov frame, sv_fp @ above the current frame +#ifdef CONFIG_IRQSTACKS + @ + @ Kernel stacks may be discontiguous in memory. If the next + @ frame is below the previous frame, accept it as long as it + @ lives in kernel memory. + @ + cmpls sv_fp, #PAGE_OFFSET +#endif bhi for_each_frame 1006: adr r0, .Lbad -- 2.30.2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel