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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3B4B6C38145 for ; Thu, 8 Sep 2022 02:26:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230349AbiIHC0m (ORCPT ); Wed, 7 Sep 2022 22:26:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50666 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230284AbiIHC0K (ORCPT ); Wed, 7 Sep 2022 22:26:10 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 41B2FB958C; Wed, 7 Sep 2022 19:26:01 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 04698618C5; Thu, 8 Sep 2022 02:26:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 91DC2C4347C; Thu, 8 Sep 2022 02:25:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1662603959; bh=wxpJF7SaNhramyz16YL9eDK4i1yP+AOeg8NpfTS4U7Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JShYUUR7Kp0uWIkEZaMiUclAshLg878yFoife0D5Bt6Z54eeOYUsUIJzlFuNZ86zW t+6P9sKl6cj6rzjNCfGccefdKyrKtAjZuQObCWdoSvprkAB4zYf0cgupoUyWApgUsl wMwMuhKWIwD2bvWVMDimQxaAEGLAISqRXbtPPyxwrLirfaw72LdDCgqb5D110C8QNO clc1PHOFAWsIxkoDTGRDzm6yYAeO4uo7bDKvOgRNaz8HmuW8EB/EBSybMLDuiuJqAF yCMBP5og8xfaAtmPErvtSbKfXUvt62aNDeA4mQDM5iIK4PKoLJpqdvPvM9Lx5MH9YX 6IZ64ajTt3NCA== From: guoren@kernel.org To: arnd@arndb.de, guoren@kernel.org, palmer@rivosinc.com, tglx@linutronix.de, peterz@infradead.org, luto@kernel.org, conor.dooley@microchip.com, heiko@sntech.de, jszhang@kernel.org, lazyparser@gmail.com, falcon@tinylab.org, chenhuacai@kernel.org, apatel@ventanamicro.com, atishp@atishpatra.org, palmer@dabbelt.com, paul.walmsley@sifive.com, bigeasy@linutronix.de Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Guo Ren Subject: [PATCH V4 6/8] riscv: Support HAVE_IRQ_EXIT_ON_IRQ_STACK Date: Wed, 7 Sep 2022 22:25:04 -0400 Message-Id: <20220908022506.1275799-7-guoren@kernel.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220908022506.1275799-1-guoren@kernel.org> References: <20220908022506.1275799-1-guoren@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org From: Guo Ren Add independent irq stacks for percpu to prevent kernel stack overflows. It is also compatible with VMAP_STACK by implementing arch_alloc_vmap_stack. Many architectures have supported HAVE_IRQ_EXIT_ON_IRQ_STACK, riscv should follow up. Signed-off-by: Guo Ren Signed-off-by: Guo Ren --- arch/riscv/Kconfig | 8 +++++ arch/riscv/include/asm/irq.h | 3 ++ arch/riscv/include/asm/thread_info.h | 2 ++ arch/riscv/include/asm/vmap_stack.h | 28 ++++++++++++++++ arch/riscv/kernel/entry.S | 27 ++++++++++++++++ arch/riscv/kernel/irq.c | 48 ++++++++++++++++++++++++++-- 6 files changed, 114 insertions(+), 2 deletions(-) create mode 100644 arch/riscv/include/asm/vmap_stack.h diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index a07bb3b73b5b..a8a12b4ba1a9 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -433,6 +433,14 @@ config FPU If you don't know what to do here, say Y. +config IRQ_STACKS + bool "Independent irq stacks" + default y + select HAVE_IRQ_EXIT_ON_IRQ_STACK + help + Add independent irq stacks for percpu to prevent kernel stack overflows. + We may save some memory footprint by disabling IRQ_STACKS. + endmenu # "Platform type" menu "Kernel features" diff --git a/arch/riscv/include/asm/irq.h b/arch/riscv/include/asm/irq.h index e4c435509983..205e1c693dfd 100644 --- a/arch/riscv/include/asm/irq.h +++ b/arch/riscv/include/asm/irq.h @@ -13,5 +13,8 @@ #include extern void __init init_IRQ(void); +asmlinkage void call_on_stack(struct pt_regs *regs, ulong *sp, + void (*fn)(struct pt_regs *), ulong tmp); +asmlinkage void noinstr do_riscv_irq(struct pt_regs *regs); #endif /* _ASM_RISCV_IRQ_H */ diff --git a/arch/riscv/include/asm/thread_info.h b/arch/riscv/include/asm/thread_info.h index 7de4fb96f0b5..043da8ccc7e6 100644 --- a/arch/riscv/include/asm/thread_info.h +++ b/arch/riscv/include/asm/thread_info.h @@ -40,6 +40,8 @@ #define OVERFLOW_STACK_SIZE SZ_4K #define SHADOW_OVERFLOW_STACK_SIZE (1024) +#define IRQ_STACK_SIZE THREAD_SIZE + #ifndef __ASSEMBLY__ extern long shadow_stack[SHADOW_OVERFLOW_STACK_SIZE / sizeof(long)]; diff --git a/arch/riscv/include/asm/vmap_stack.h b/arch/riscv/include/asm/vmap_stack.h new file mode 100644 index 000000000000..3fbf481abf4f --- /dev/null +++ b/arch/riscv/include/asm/vmap_stack.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +// Copied from arch/arm64/include/asm/vmap_stack.h. +#ifndef _ASM_RISCV_VMAP_STACK_H +#define _ASM_RISCV_VMAP_STACK_H + +#include +#include +#include +#include +#include +#include + +/* + * To ensure that VMAP'd stack overflow detection works correctly, all VMAP'd + * stacks need to have the same alignment. + */ +static inline unsigned long *arch_alloc_vmap_stack(size_t stack_size, int node) +{ + void *p; + + BUILD_BUG_ON(!IS_ENABLED(CONFIG_VMAP_STACK)); + + p = __vmalloc_node(stack_size, THREAD_ALIGN, THREADINFO_GFP, node, + __builtin_return_address(0)); + return kasan_reset_tag(p); +} + +#endif /* _ASM_RISCV_VMAP_STACK_H */ diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S index 5f49517cd3a2..426529b84db0 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -332,6 +332,33 @@ ENTRY(ret_from_kernel_thread) tail syscall_exit_to_user_mode ENDPROC(ret_from_kernel_thread) +#ifdef CONFIG_IRQ_STACKS +ENTRY(call_on_stack) + /* Create a frame record to save our ra and fp */ + addi sp, sp, -RISCV_SZPTR + REG_S ra, (sp) + addi sp, sp, -RISCV_SZPTR + REG_S fp, (sp) + + /* Save sp in fp */ + move fp, sp + + /* Move to the new stack and call the function there */ + li a3, IRQ_STACK_SIZE + add sp, a1, a3 + jalr a2 + + /* + * Restore sp from prev fp, and fp, ra from the frame + */ + move sp, fp + REG_L fp, (sp) + addi sp, sp, RISCV_SZPTR + REG_L ra, (sp) + addi sp, sp, RISCV_SZPTR + ret +ENDPROC(call_on_stack) +#endif /* * Integer register context switch diff --git a/arch/riscv/kernel/irq.c b/arch/riscv/kernel/irq.c index 24c2e1bd756a..5ad4952203c5 100644 --- a/arch/riscv/kernel/irq.c +++ b/arch/riscv/kernel/irq.c @@ -10,6 +10,37 @@ #include #include #include +#include + +#ifdef CONFIG_IRQ_STACKS +static DEFINE_PER_CPU(ulong *, irq_stack_ptr); + +#ifdef CONFIG_VMAP_STACK +static void init_irq_stacks(void) +{ + int cpu; + ulong *p; + + for_each_possible_cpu(cpu) { + p = arch_alloc_vmap_stack(IRQ_STACK_SIZE, cpu_to_node(cpu)); + per_cpu(irq_stack_ptr, cpu) = p; + } +} +#else +/* irq stack only needs to be 16 byte aligned - not IRQ_STACK_SIZE aligned. */ +DEFINE_PER_CPU_ALIGNED(ulong [IRQ_STACK_SIZE/sizeof(ulong)], irq_stack); + +static void init_irq_stacks(void) +{ + int cpu; + + for_each_possible_cpu(cpu) + per_cpu(irq_stack_ptr, cpu) = per_cpu(irq_stack, cpu); +} +#endif /* CONFIG_VMAP_STACK */ +#else +static void init_irq_stacks(void) {} +#endif /* CONFIG_IRQ_STACKS */ int arch_show_interrupts(struct seq_file *p, int prec) { @@ -19,21 +50,34 @@ int arch_show_interrupts(struct seq_file *p, int prec) void __init init_IRQ(void) { + init_irq_stacks(); irqchip_init(); if (!handle_arch_irq) panic("No interrupt controller found."); } -asmlinkage void noinstr do_riscv_irq(struct pt_regs *regs) +static void noinstr handle_riscv_irq(struct pt_regs *regs) { struct pt_regs *old_regs; - irqentry_state_t state = irqentry_enter(regs); irq_enter_rcu(); old_regs = set_irq_regs(regs); handle_arch_irq(regs); set_irq_regs(old_regs); irq_exit_rcu(); +} + +asmlinkage void noinstr do_riscv_irq(struct pt_regs *regs) +{ + irqentry_state_t state = irqentry_enter(regs); +#ifdef CONFIG_IRQ_STACKS + ulong *sp = per_cpu(irq_stack_ptr, smp_processor_id()); + + if (on_thread_stack()) + call_on_stack(regs, sp, handle_riscv_irq, 0); + else +#endif + handle_riscv_irq(regs); irqentry_exit(regs, state); } -- 2.36.1