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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=dz7r1q013n6NcVaMMRs0TXOzsYswHRkIsJwZpxS1u88=; b=uQaUZZ94Ocw1OBEXgsPdnAziUZTt9cCsY15lCAfrCEBEBfOsZfvTNimivnuQNrIUD4 IsgIQNXYGXlE63x/mQlDR0r6SsplDdO7dvJgzldfgUc66X4+1tu/h2EM+S+zSLW9CU/P Lwl3U/Gsj8YysKWEb6wAyiiH2mxkCFxvrrJOXwRKCKwpT3DWFCfN6RYwpknWBK074amZ 0Pnmk3Y7QVnErszEJ9k+gEubtPFsSE18esXis+axmvC8GWxyWUJ3AUFoJD0rrgCGjdEw X+lep1C/Ew5Qntl3H+cxJfExkvuzW9f9z50CSR2XbWd9FAyLr4ZDmLCaRG+KwtZEtZsr 4RjA== X-Gm-Message-State: APjAAAVxbcQcaxSVLvg+kRTqud8qre4X7vcSEzo4JTVHigO52W7Qp4HV uyCxShKwG9fDfDpSzXtNMBWJJU248N2BgRr0+wU= X-Google-Smtp-Source: APXvYqxdy6rSOfurv0NH1mFMEAFvcqncWUlmBGdVDIxGZO12j+zNLVCFjC+X3DonlD/4S+Eforr6Y8tqp95Uin4nxVE= X-Received: by 2002:ad4:4e24:: with SMTP id dm4mr49827392qvb.170.1582652417166; Tue, 25 Feb 2020 09:40:17 -0800 (PST) Date: Tue, 25 Feb 2020 09:39:32 -0800 In-Reply-To: <20200225173933.74818-1-samitolvanen@google.com> Message-Id: <20200225173933.74818-12-samitolvanen@google.com> Mime-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20200225173933.74818-1-samitolvanen@google.com> X-Mailer: git-send-email 2.25.0.265.gbab2e86ba0-goog Subject: [PATCH v9 11/12] arm64: scs: add shadow stacks for SDEI From: Sami Tolvanen To: Will Deacon , Catalin Marinas , James Morse , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Mark Rutland X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200225_094020_718656_D71B6D50 X-CRM114-Status: GOOD ( 16.12 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kees Cook , Jann Horn , Masahiro Yamada , Marc Zyngier , kernel-hardening@lists.openwall.com, Nick Desaulniers , linux-kernel@vger.kernel.org, Miguel Ojeda , clang-built-linux@googlegroups.com, Sami Tolvanen , Laura Abbott , Dave Martin , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org This change adds per-CPU shadow call stacks for the SDEI handler. Similarly to how the kernel stacks are handled, we add separate shadow stacks for normal and critical events. Signed-off-by: Sami Tolvanen Reviewed-by: James Morse Tested-by: James Morse --- arch/arm64/include/asm/scs.h | 2 + arch/arm64/kernel/entry.S | 14 ++++- arch/arm64/kernel/scs.c | 106 +++++++++++++++++++++++++++++------ arch/arm64/kernel/sdei.c | 7 +++ 4 files changed, 112 insertions(+), 17 deletions(-) diff --git a/arch/arm64/include/asm/scs.h b/arch/arm64/include/asm/scs.h index c50d2b0c6c5f..8e327e14bc15 100644 --- a/arch/arm64/include/asm/scs.h +++ b/arch/arm64/include/asm/scs.h @@ -9,6 +9,7 @@ #ifdef CONFIG_SHADOW_CALL_STACK extern void scs_init_irq(void); +extern int scs_init_sdei(void); static __always_inline void scs_save(struct task_struct *tsk) { @@ -27,6 +28,7 @@ static inline void scs_overflow_check(struct task_struct *tsk) #else /* CONFIG_SHADOW_CALL_STACK */ static inline void scs_init_irq(void) {} +static inline int scs_init_sdei(void) { return 0; } static inline void scs_save(struct task_struct *tsk) {} static inline void scs_overflow_check(struct task_struct *tsk) {} diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 4b18c3bbdea5..2e2ce1b9ebf5 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -1050,13 +1050,16 @@ ENTRY(__sdei_asm_handler) mov x19, x1 +#if defined(CONFIG_VMAP_STACK) || defined(CONFIG_SHADOW_CALL_STACK) + ldrb w4, [x19, #SDEI_EVENT_PRIORITY] +#endif + #ifdef CONFIG_VMAP_STACK /* * entry.S may have been using sp as a scratch register, find whether * this is a normal or critical event and switch to the appropriate * stack for this CPU. */ - ldrb w4, [x19, #SDEI_EVENT_PRIORITY] cbnz w4, 1f ldr_this_cpu dst=x5, sym=sdei_stack_normal_ptr, tmp=x6 b 2f @@ -1066,6 +1069,15 @@ ENTRY(__sdei_asm_handler) mov sp, x5 #endif +#ifdef CONFIG_SHADOW_CALL_STACK + /* Use a separate shadow call stack for normal and critical events */ + cbnz w4, 3f + ldr_this_cpu dst=x18, sym=sdei_shadow_call_stack_normal_ptr, tmp=x6 + b 4f +3: ldr_this_cpu dst=x18, sym=sdei_shadow_call_stack_critical_ptr, tmp=x6 +4: +#endif + /* * We may have interrupted userspace, or a guest, or exit-from or * return-to either of these. We can't trust sp_el0, restore it. diff --git a/arch/arm64/kernel/scs.c b/arch/arm64/kernel/scs.c index eaadf5430baa..dddb7c56518b 100644 --- a/arch/arm64/kernel/scs.c +++ b/arch/arm64/kernel/scs.c @@ -10,31 +10,105 @@ #include #include -DEFINE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr); +#define DECLARE_SCS(name) \ + DECLARE_PER_CPU(unsigned long *, name ## _ptr); \ + DECLARE_PER_CPU(unsigned long [SCS_SIZE/sizeof(long)], name) -#ifndef CONFIG_SHADOW_CALL_STACK_VMAP -DEFINE_PER_CPU(unsigned long [SCS_SIZE/sizeof(long)], irq_shadow_call_stack) - __aligned(SCS_SIZE); +#ifdef CONFIG_SHADOW_CALL_STACK_VMAP +#define DEFINE_SCS(name) \ + DEFINE_PER_CPU(unsigned long *, name ## _ptr) +#else +/* Allocate a static per-CPU shadow stack */ +#define DEFINE_SCS(name) \ + DEFINE_PER_CPU(unsigned long *, name ## _ptr); \ + DEFINE_PER_CPU(unsigned long [SCS_SIZE/sizeof(long)], name) \ + __aligned(SCS_SIZE) +#endif /* CONFIG_SHADOW_CALL_STACK_VMAP */ + +DECLARE_SCS(irq_shadow_call_stack); +DECLARE_SCS(sdei_shadow_call_stack_normal); +DECLARE_SCS(sdei_shadow_call_stack_critical); + +DEFINE_SCS(irq_shadow_call_stack); +#ifdef CONFIG_ARM_SDE_INTERFACE +DEFINE_SCS(sdei_shadow_call_stack_normal); +DEFINE_SCS(sdei_shadow_call_stack_critical); #endif +static int scs_alloc_percpu(unsigned long * __percpu *ptr, int cpu) +{ + unsigned long *p; + + p = __vmalloc_node_range(PAGE_SIZE, SCS_SIZE, + VMALLOC_START, VMALLOC_END, + GFP_SCS, PAGE_KERNEL, + 0, cpu_to_node(cpu), + __builtin_return_address(0)); + + if (!p) + return -ENOMEM; + per_cpu(*ptr, cpu) = p; + + return 0; +} + +static void scs_free_percpu(unsigned long * __percpu *ptr, int cpu) +{ + unsigned long *p = per_cpu(*ptr, cpu); + + if (p) { + per_cpu(*ptr, cpu) = NULL; + vfree(p); + } +} + +static void scs_free_sdei(void) +{ + int cpu; + + for_each_possible_cpu(cpu) { + scs_free_percpu(&sdei_shadow_call_stack_normal_ptr, cpu); + scs_free_percpu(&sdei_shadow_call_stack_critical_ptr, cpu); + } +} + void scs_init_irq(void) { int cpu; for_each_possible_cpu(cpu) { -#ifdef CONFIG_SHADOW_CALL_STACK_VMAP - unsigned long *p; + if (IS_ENABLED(CONFIG_SHADOW_CALL_STACK_VMAP)) + WARN_ON(scs_alloc_percpu(&irq_shadow_call_stack_ptr, + cpu)); + else + per_cpu(irq_shadow_call_stack_ptr, cpu) = + per_cpu(irq_shadow_call_stack, cpu); + } +} - p = __vmalloc_node_range(PAGE_SIZE, SCS_SIZE, - VMALLOC_START, VMALLOC_END, - GFP_SCS, PAGE_KERNEL, - 0, cpu_to_node(cpu), - __builtin_return_address(0)); +int scs_init_sdei(void) +{ + int cpu; - per_cpu(irq_shadow_call_stack_ptr, cpu) = p; -#else - per_cpu(irq_shadow_call_stack_ptr, cpu) = - per_cpu(irq_shadow_call_stack, cpu); -#endif /* CONFIG_SHADOW_CALL_STACK_VMAP */ + if (!IS_ENABLED(CONFIG_ARM_SDE_INTERFACE)) + return 0; + + for_each_possible_cpu(cpu) { + if (IS_ENABLED(CONFIG_SHADOW_CALL_STACK_VMAP)) { + if (scs_alloc_percpu( + &sdei_shadow_call_stack_normal_ptr, cpu) || + scs_alloc_percpu( + &sdei_shadow_call_stack_critical_ptr, cpu)) { + scs_free_sdei(); + return -ENOMEM; + } + } else { + per_cpu(sdei_shadow_call_stack_normal_ptr, cpu) = + per_cpu(sdei_shadow_call_stack_normal, cpu); + per_cpu(sdei_shadow_call_stack_critical_ptr, cpu) = + per_cpu(sdei_shadow_call_stack_critical, cpu); + } } + + return 0; } diff --git a/arch/arm64/kernel/sdei.c b/arch/arm64/kernel/sdei.c index d6259dac62b6..2854b9f7760a 100644 --- a/arch/arm64/kernel/sdei.c +++ b/arch/arm64/kernel/sdei.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include @@ -162,6 +163,12 @@ unsigned long sdei_arch_get_entry_point(int conduit) return 0; } + if (scs_init_sdei()) { + if (IS_ENABLED(CONFIG_VMAP_STACK)) + free_sdei_stacks(); + return 0; + } + sdei_exit_mode = (conduit == SMCCC_CONDUIT_HVC) ? SDEI_EXIT_HVC : SDEI_EXIT_SMC; #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 -- 2.25.0.265.gbab2e86ba0-goog _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel