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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=RFQeZBUfRbHmuBkixdwdHyK03/i2WwDYL6zKZ0PVNPE=; b=ggRQHFNdgF6ze/4Qb88BnJI1fNY0dsGi0RKUnvZ2X8s4qBJ5iit2ye7vIe0BDEq+NK ynDJ+KeQ7ZbH5ABtygybSvT6wsVgCBISInM3NoJREw22/aM7NeqykMu/8fbtUZry06yp 1jR7SC6MaUlLyfcASlEHZcCtPaFcn3LdvkkM8H85AYCzLTET0hH4j78FMW8AXfI98qzb 8gGzM/i/aQxDuMk6Gb05MnnLAvrvez/54ryTeWg8Nk/cg1x/A5ltfhVdzsiEzuz03bSA 3y/UKJgdWpbZUBUWi/RZ35ozi1HMLKliec/ZYnRfBkMh23vqv7WZ8GYkPAs20iLZWkPn wbHA== X-Gm-Message-State: APjAAAW4gBwX+ylREXQUWcii5wW3SYZMvpnYfQv14Wc6hyc7/BdE/inI DCyZRk3h7e67dl/Bplxil8R4AUN5N2SoG2okTDs= X-Google-Smtp-Source: APXvYqxpGanN1bCoq5Nmn3aCH0YBZJAgBLdmk2cjRtHg7acgtGNdUOb0ffYjmscMm2O9CKp+3KwgpjzPR+bJF894TjI= X-Received: by 2002:a63:3484:: with SMTP id b126mr5874359pga.17.1575670473753; Fri, 06 Dec 2019 14:14:33 -0800 (PST) Date: Fri, 6 Dec 2019 14:13:51 -0800 In-Reply-To: <20191206221351.38241-1-samitolvanen@google.com> Message-Id: <20191206221351.38241-16-samitolvanen@google.com> Mime-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191206221351.38241-1-samitolvanen@google.com> X-Mailer: git-send-email 2.24.0.393.g34dc348eaf-goog Subject: [PATCH v6 15/15] arm64: scs: add shadow stacks for SDEI From: Sami Tolvanen To: Will Deacon , Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Mark Rutland X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191206_141435_994374_D154A265 X-CRM114-Status: GOOD ( 15.54 ) X-Spam-Score: -7.7 (-------) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-7.7 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [2607:f8b0:4864:20:0:0:0:549 listed in] [list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -7.5 USER_IN_DEF_DKIM_WL From: address is in the default DKIM white-list -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.0 DKIMWL_WL_MED DKIMwl.org - Medium sender 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 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.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 --- 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 7aa2d366b2df..9327c3d21b64 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -1048,13 +1048,16 @@ 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 @@ -1064,6 +1067,15 @@ 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