From patchwork Tue Oct 9 04:49:00 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 981024 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 42TlQH2Mhlz9s8T for ; Tue, 9 Oct 2018 15:59:35 +1100 (AEDT) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=c-s.fr Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 42TlQH14szzF3N5 for ; Tue, 9 Oct 2018 15:59:35 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=c-s.fr X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=c-s.fr (client-ip=93.17.236.30; helo=pegase1.c-s.fr; envelope-from=christophe.leroy@c-s.fr; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=c-s.fr Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 42TlBD0FMJzF3M5 for ; Tue, 9 Oct 2018 15:49:08 +1100 (AEDT) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 42Tl9x6wD5z9ttC8; Tue, 9 Oct 2018 06:48:53 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id jBCSQ_Xw8vHm; Tue, 9 Oct 2018 06:48:53 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 42Tl9x6KwZz9ttBR; Tue, 9 Oct 2018 06:48:53 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 8C2CB8B7BD; Tue, 9 Oct 2018 06:49:01 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id 5f17e0xLKfh3; Tue, 9 Oct 2018 06:49:01 +0200 (CEST) Received: from pc16082vm.idsi0.si.c-s.fr (unknown [192.168.232.3]) by messagerie.si.c-s.fr (Postfix) with ESMTP id B1F9B8B775; Tue, 9 Oct 2018 06:49:00 +0200 (CEST) Received: by pc16082vm.idsi0.si.c-s.fr (Postfix, from userid 0) id 6AE006F2C5; Tue, 9 Oct 2018 04:49:00 +0000 (UTC) Message-Id: In-Reply-To: References: From: Christophe Leroy Subject: [PATCH v7 5/9] powerpc: regain entire stack space To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman Date: Tue, 9 Oct 2018 04:49:00 +0000 (UTC) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" thread_info is not anymore in the stack, so the entire stack can now be used. There is also no risk anymore of corrupting task_cpu(p) with a stack overflow so the patch removes the test. When doing this, an explicit test for NULL stack pointer is needed in validate_sp() as it is not anymore implicitely covered by the sizeof(thread_info) gap. In the meantime, with the previous patch all pointers to the stacks are not anymore pointers to thread_info so this patch changes them to void* Signed-off-by: Christophe Leroy --- arch/powerpc/include/asm/irq.h | 10 +++++----- arch/powerpc/include/asm/processor.h | 3 +-- arch/powerpc/kernel/asm-offsets.c | 1 - arch/powerpc/kernel/entry_32.S | 14 ++++---------- arch/powerpc/kernel/irq.c | 19 +++++++++---------- arch/powerpc/kernel/misc_32.S | 6 ++---- arch/powerpc/kernel/process.c | 32 +++++++++++++------------------- arch/powerpc/kernel/setup_64.c | 8 ++++---- 8 files changed, 38 insertions(+), 55 deletions(-) diff --git a/arch/powerpc/include/asm/irq.h b/arch/powerpc/include/asm/irq.h index 2efbae8d93be..966ddd4d2414 100644 --- a/arch/powerpc/include/asm/irq.h +++ b/arch/powerpc/include/asm/irq.h @@ -48,9 +48,9 @@ struct pt_regs; * Per-cpu stacks for handling critical, debug and machine check * level interrupts. */ -extern struct thread_info *critirq_ctx[NR_CPUS]; -extern struct thread_info *dbgirq_ctx[NR_CPUS]; -extern struct thread_info *mcheckirq_ctx[NR_CPUS]; +extern void *critirq_ctx[NR_CPUS]; +extern void *dbgirq_ctx[NR_CPUS]; +extern void *mcheckirq_ctx[NR_CPUS]; extern void exc_lvl_ctx_init(void); #else #define exc_lvl_ctx_init() @@ -59,8 +59,8 @@ extern void exc_lvl_ctx_init(void); /* * Per-cpu stacks for handling hard and soft interrupts. */ -extern struct thread_info *hardirq_ctx[NR_CPUS]; -extern struct thread_info *softirq_ctx[NR_CPUS]; +extern void *hardirq_ctx[NR_CPUS]; +extern void *softirq_ctx[NR_CPUS]; extern void irq_ctx_init(void); void call_do_softirq(void *sp); diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h index b225c7f7c5a4..e763342265a2 100644 --- a/arch/powerpc/include/asm/processor.h +++ b/arch/powerpc/include/asm/processor.h @@ -331,8 +331,7 @@ struct thread_struct { #define ARCH_MIN_TASKALIGN 16 #define INIT_SP (sizeof(init_stack) + (unsigned long) &init_stack) -#define INIT_SP_LIMIT \ - (_ALIGN_UP(sizeof(struct thread_info), 16) + (unsigned long)&init_stack) +#define INIT_SP_LIMIT ((unsigned long)&init_stack) #ifdef CONFIG_SPE #define SPEFSCR_INIT \ diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 833d189df04c..768ce602d624 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -93,7 +93,6 @@ int main(void) DEFINE(NMI_MASK, NMI_MASK); OFFSET(TASKTHREADPPR, task_struct, thread.ppr); #else - DEFINE(THREAD_INFO_GAP, _ALIGN_UP(sizeof(struct thread_info), 16)); OFFSET(KSP_LIMIT, thread_struct, ksp_limit); #endif /* CONFIG_PPC64 */ OFFSET(TASK_STACK, task_struct, stack); diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index fa7a69ffb37a..bd3b146e18a3 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -97,14 +97,11 @@ crit_transfer_to_handler: mfspr r0,SPRN_SRR1 stw r0,_SRR1(r11) - /* set the stack limit to the current stack - * and set the limit to protect the thread_info - * struct - */ + /* set the stack limit to the current stack */ mfspr r8,SPRN_SPRG_THREAD lwz r0,KSP_LIMIT(r8) stw r0,SAVED_KSP_LIMIT(r11) - rlwimi r0,r1,0,0,(31-THREAD_SHIFT) + rlwinm r0,r1,0,0,(31 - THREAD_SHIFT) stw r0,KSP_LIMIT(r8) /* fall through */ #endif @@ -121,14 +118,11 @@ crit_transfer_to_handler: mfspr r0,SPRN_SRR1 stw r0,crit_srr1@l(0) - /* set the stack limit to the current stack - * and set the limit to protect the thread_info - * struct - */ + /* set the stack limit to the current stack */ mfspr r8,SPRN_SPRG_THREAD lwz r0,KSP_LIMIT(r8) stw r0,saved_ksp_limit@l(0) - rlwimi r0,r1,0,0,(31-THREAD_SHIFT) + rlwinm r0,r1,0,0,(31 - THREAD_SHIFT) stw r0,KSP_LIMIT(r8) /* fall through */ #endif diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c index 3fdb6b6973cf..62cfccf4af89 100644 --- a/arch/powerpc/kernel/irq.c +++ b/arch/powerpc/kernel/irq.c @@ -618,9 +618,8 @@ static inline void check_stack_overflow(void) sp = current_stack_pointer() & (THREAD_SIZE-1); /* check for stack overflow: is there less than 2KB free? */ - if (unlikely(sp < (sizeof(struct thread_info) + 2048))) { - pr_err("do_IRQ: stack overflow: %ld\n", - sp - sizeof(struct thread_info)); + if (unlikely(sp < 2048)) { + pr_err("do_IRQ: stack overflow: %ld\n", sp); dump_stack(); } #endif @@ -660,7 +659,7 @@ void __do_irq(struct pt_regs *regs) void do_IRQ(struct pt_regs *regs) { struct pt_regs *old_regs = set_irq_regs(regs); - struct thread_info *curtp, *irqtp, *sirqtp; + void *curtp, *irqtp, *sirqtp; /* Switch to the irq stack to handle this */ curtp = (void *)(current_stack_pointer() & ~(THREAD_SIZE - 1)); @@ -690,9 +689,9 @@ void __init init_IRQ(void) } #if defined(CONFIG_BOOKE) || defined(CONFIG_40x) -struct thread_info *critirq_ctx[NR_CPUS] __read_mostly; -struct thread_info *dbgirq_ctx[NR_CPUS] __read_mostly; -struct thread_info *mcheckirq_ctx[NR_CPUS] __read_mostly; +void *critirq_ctx[NR_CPUS] __read_mostly; +void *dbgirq_ctx[NR_CPUS] __read_mostly; +void *mcheckirq_ctx[NR_CPUS] __read_mostly; void exc_lvl_ctx_init(void) { @@ -718,8 +717,8 @@ void exc_lvl_ctx_init(void) } #endif -struct thread_info *softirq_ctx[NR_CPUS] __read_mostly; -struct thread_info *hardirq_ctx[NR_CPUS] __read_mostly; +void *softirq_ctx[NR_CPUS] __read_mostly; +void *hardirq_ctx[NR_CPUS] __read_mostly; void irq_ctx_init(void) { @@ -733,7 +732,7 @@ void irq_ctx_init(void) void do_softirq_own_stack(void) { - struct thread_info *irqtp; + void *irqtp; irqtp = softirq_ctx[smp_processor_id()]; call_do_softirq(irqtp); diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S index 32762f4c3458..a3663ad62f16 100644 --- a/arch/powerpc/kernel/misc_32.S +++ b/arch/powerpc/kernel/misc_32.S @@ -46,11 +46,10 @@ _GLOBAL(call_do_softirq) mflr r0 stw r0,4(r1) lwz r10,THREAD+KSP_LIMIT(r2) - addi r11,r3,THREAD_INFO_GAP + stw r3, THREAD+KSP_LIMIT(r2) stwu r1,THREAD_SIZE-STACK_FRAME_OVERHEAD(r3) mr r1,r3 stw r10,8(r1) - stw r11,THREAD+KSP_LIMIT(r2) bl __do_softirq lwz r10,8(r1) lwz r1,0(r1) @@ -66,11 +65,10 @@ _GLOBAL(call_do_irq) mflr r0 stw r0,4(r1) lwz r10,THREAD+KSP_LIMIT(r2) - addi r11,r4,THREAD_INFO_GAP + stw r4, THREAD+KSP_LIMIT(r2) stwu r1,THREAD_SIZE-STACK_FRAME_OVERHEAD(r4) mr r1,r4 stw r10,8(r1) - stw r11,THREAD+KSP_LIMIT(r2) bl __do_irq lwz r10,8(r1) lwz r1,0(r1) diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index a12307ebb7ef..23657b00e161 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -1689,8 +1689,7 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, sp -= STACK_FRAME_OVERHEAD; p->thread.ksp = sp; #ifdef CONFIG_PPC32 - p->thread.ksp_limit = (unsigned long)task_stack_page(p) + - _ALIGN_UP(sizeof(struct thread_info), 16); + p->thread.ksp_limit = (unsigned long)end_of_stack(p); #endif #ifdef CONFIG_HAVE_HW_BREAKPOINT p->thread.ptrace_bps[0] = NULL; @@ -1986,21 +1985,14 @@ static inline int valid_irq_stack(unsigned long sp, struct task_struct *p, unsigned long stack_page; unsigned long cpu = task_cpu(p); - /* - * Avoid crashing if the stack has overflowed and corrupted - * task_cpu(p), which is in the thread_info struct. - */ - if (cpu < NR_CPUS && cpu_possible(cpu)) { - stack_page = (unsigned long) hardirq_ctx[cpu]; - if (sp >= stack_page + sizeof(struct thread_struct) - && sp <= stack_page + THREAD_SIZE - nbytes) - return 1; - - stack_page = (unsigned long) softirq_ctx[cpu]; - if (sp >= stack_page + sizeof(struct thread_struct) - && sp <= stack_page + THREAD_SIZE - nbytes) - return 1; - } + stack_page = (unsigned long)hardirq_ctx[cpu]; + if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes) + return 1; + + stack_page = (unsigned long)softirq_ctx[cpu]; + if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes) + return 1; + return 0; } @@ -2009,8 +2001,10 @@ int validate_sp(unsigned long sp, struct task_struct *p, { unsigned long stack_page = (unsigned long)task_stack_page(p); - if (sp >= stack_page + sizeof(struct thread_struct) - && sp <= stack_page + THREAD_SIZE - nbytes) + if (sp < THREAD_SIZE) + return 0; + + if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes) return 1; return valid_irq_stack(sp, p, nbytes); diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index 2d682f3e31c6..6792e9c90689 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -717,22 +717,22 @@ void __init emergency_stack_init(void) limit = min(ppc64_bolted_size(), ppc64_rma_size); for_each_possible_cpu(i) { - struct thread_info *ti; + void *ti; ti = alloc_stack(limit, i); memset(ti, 0, THREAD_SIZE); - paca_ptrs[i]->emergency_sp = (void *)ti + THREAD_SIZE; + paca_ptrs[i]->emergency_sp = ti + THREAD_SIZE; #ifdef CONFIG_PPC_BOOK3S_64 /* emergency stack for NMI exception handling. */ ti = alloc_stack(limit, i); memset(ti, 0, THREAD_SIZE); - paca_ptrs[i]->nmi_emergency_sp = (void *)ti + THREAD_SIZE; + paca_ptrs[i]->nmi_emergency_sp = ti + THREAD_SIZE; /* emergency stack for machine check exception handling. */ ti = alloc_stack(limit, i); memset(ti, 0, THREAD_SIZE); - paca_ptrs[i]->mc_emergency_sp = (void *)ti + THREAD_SIZE; + paca_ptrs[i]->mc_emergency_sp = ti + THREAD_SIZE; #endif } }