diff options
author | Sami Tolvanen <samitolvanen@google.com> | 2020-12-01 00:34:42 +0100 |
---|---|---|
committer | Will Deacon <will@kernel.org> | 2020-12-01 12:23:34 +0100 |
commit | ac20ffbb0279aae7be48567fb734eae7d050769e (patch) | |
tree | 15c0a54aa692cf18d40cd21b48964f77f7d13ea2 | |
parent | scs: switch to vmapped shadow stacks (diff) | |
download | linux-ac20ffbb0279aae7be48567fb734eae7d050769e.tar.xz linux-ac20ffbb0279aae7be48567fb734eae7d050769e.zip |
arm64: scs: use vmapped IRQ and SDEI shadow stacks
Use scs_alloc() to allocate also IRQ and SDEI shadow stacks instead of
using statically allocated stacks.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201130233442.2562064-3-samitolvanen@google.com
[will: Move CONFIG_SHADOW_CALL_STACK check into init_irq_scs()]
Signed-off-by: Will Deacon <will@kernel.org>
-rw-r--r-- | arch/arm64/kernel/Makefile | 1 | ||||
-rw-r--r-- | arch/arm64/kernel/entry.S | 6 | ||||
-rw-r--r-- | arch/arm64/kernel/irq.c | 21 | ||||
-rw-r--r-- | arch/arm64/kernel/scs.c | 16 | ||||
-rw-r--r-- | arch/arm64/kernel/sdei.c | 70 | ||||
-rw-r--r-- | include/linux/scs.h | 4 |
6 files changed, 94 insertions, 24 deletions
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index bbaf0bc4ad60..86364ab6f13f 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -58,7 +58,6 @@ obj-$(CONFIG_CRASH_DUMP) += crash_dump.o obj-$(CONFIG_CRASH_CORE) += crash_core.o obj-$(CONFIG_ARM_SDE_INTERFACE) += sdei.o obj-$(CONFIG_ARM64_PTR_AUTH) += pointer_auth.o -obj-$(CONFIG_SHADOW_CALL_STACK) += scs.o obj-$(CONFIG_ARM64_MTE) += mte.o obj-y += vdso/ probes/ diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index b295fb912b12..5c2ac4b5b2da 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -441,7 +441,7 @@ SYM_CODE_END(__swpan_exit_el0) #ifdef CONFIG_SHADOW_CALL_STACK /* also switch to the irq shadow stack */ - adr_this_cpu scs_sp, irq_shadow_call_stack, x26 + ldr_this_cpu scs_sp, irq_shadow_call_stack_ptr, x26 #endif 9998: @@ -1097,9 +1097,9 @@ SYM_CODE_START(__sdei_asm_handler) #ifdef CONFIG_SHADOW_CALL_STACK /* Use a separate shadow call stack for normal and critical events */ cbnz w4, 3f - adr_this_cpu dst=scs_sp, sym=sdei_shadow_call_stack_normal, tmp=x6 + ldr_this_cpu dst=scs_sp, sym=sdei_shadow_call_stack_normal_ptr, tmp=x6 b 4f -3: adr_this_cpu dst=scs_sp, sym=sdei_shadow_call_stack_critical, tmp=x6 +3: ldr_this_cpu dst=scs_sp, sym=sdei_shadow_call_stack_critical_ptr, tmp=x6 4: #endif diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c index 9cf2fb87584a..ac54c21140d4 100644 --- a/arch/arm64/kernel/irq.c +++ b/arch/arm64/kernel/irq.c @@ -17,6 +17,7 @@ #include <linux/init.h> #include <linux/irqchip.h> #include <linux/kprobes.h> +#include <linux/scs.h> #include <linux/seq_file.h> #include <linux/vmalloc.h> #include <asm/daifflags.h> @@ -27,6 +28,25 @@ DEFINE_PER_CPU(struct nmi_ctx, nmi_contexts); DEFINE_PER_CPU(unsigned long *, irq_stack_ptr); + +DECLARE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr); + +#ifdef CONFIG_SHADOW_CALL_STACK +DEFINE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr); +#endif + +static void init_irq_scs(void) +{ + int cpu; + + if (!IS_ENABLED(CONFIG_SHADOW_CALL_STACK)) + return; + + for_each_possible_cpu(cpu) + per_cpu(irq_shadow_call_stack_ptr, cpu) = + scs_alloc(cpu_to_node(cpu)); +} + #ifdef CONFIG_VMAP_STACK static void init_irq_stacks(void) { @@ -54,6 +74,7 @@ static void init_irq_stacks(void) void __init init_IRQ(void) { init_irq_stacks(); + init_irq_scs(); irqchip_init(); if (!handle_arch_irq) panic("No interrupt controller found."); diff --git a/arch/arm64/kernel/scs.c b/arch/arm64/kernel/scs.c deleted file mode 100644 index e8f7ff45dd8f..000000000000 --- a/arch/arm64/kernel/scs.c +++ /dev/null @@ -1,16 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * Shadow Call Stack support. - * - * Copyright (C) 2019 Google LLC - */ - -#include <linux/percpu.h> -#include <linux/scs.h> - -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 diff --git a/arch/arm64/kernel/sdei.c b/arch/arm64/kernel/sdei.c index 7689f2031c0c..d12fd786b267 100644 --- a/arch/arm64/kernel/sdei.c +++ b/arch/arm64/kernel/sdei.c @@ -7,6 +7,7 @@ #include <linux/hardirq.h> #include <linux/irqflags.h> #include <linux/sched/task_stack.h> +#include <linux/scs.h> #include <linux/uaccess.h> #include <asm/alternative.h> @@ -37,6 +38,14 @@ DEFINE_PER_CPU(unsigned long *, sdei_stack_normal_ptr); DEFINE_PER_CPU(unsigned long *, sdei_stack_critical_ptr); #endif +DECLARE_PER_CPU(unsigned long *, sdei_shadow_call_stack_normal_ptr); +DECLARE_PER_CPU(unsigned long *, sdei_shadow_call_stack_critical_ptr); + +#ifdef CONFIG_SHADOW_CALL_STACK +DEFINE_PER_CPU(unsigned long *, sdei_shadow_call_stack_normal_ptr); +DEFINE_PER_CPU(unsigned long *, sdei_shadow_call_stack_critical_ptr); +#endif + static void _free_sdei_stack(unsigned long * __percpu *ptr, int cpu) { unsigned long *p; @@ -90,6 +99,59 @@ static int init_sdei_stacks(void) return err; } +static void _free_sdei_scs(unsigned long * __percpu *ptr, int cpu) +{ + void *s; + + s = per_cpu(*ptr, cpu); + if (s) { + per_cpu(*ptr, cpu) = NULL; + scs_free(s); + } +} + +static void free_sdei_scs(void) +{ + int cpu; + + for_each_possible_cpu(cpu) { + _free_sdei_scs(&sdei_shadow_call_stack_normal_ptr, cpu); + _free_sdei_scs(&sdei_shadow_call_stack_critical_ptr, cpu); + } +} + +static int _init_sdei_scs(unsigned long * __percpu *ptr, int cpu) +{ + void *s; + + s = scs_alloc(cpu_to_node(cpu)); + if (!s) + return -ENOMEM; + per_cpu(*ptr, cpu) = s; + + return 0; +} + +static int init_sdei_scs(void) +{ + int cpu; + int err = 0; + + for_each_possible_cpu(cpu) { + err = _init_sdei_scs(&sdei_shadow_call_stack_normal_ptr, cpu); + if (err) + break; + err = _init_sdei_scs(&sdei_shadow_call_stack_critical_ptr, cpu); + if (err) + break; + } + + if (err) + free_sdei_scs(); + + return err; +} + static bool on_sdei_normal_stack(unsigned long sp, struct stack_info *info) { unsigned long low = (unsigned long)raw_cpu_read(sdei_stack_normal_ptr); @@ -138,6 +200,14 @@ unsigned long sdei_arch_get_entry_point(int conduit) return 0; } + if (IS_ENABLED(CONFIG_SHADOW_CALL_STACK)) { + if (init_sdei_scs()) { + 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 diff --git a/include/linux/scs.h b/include/linux/scs.h index 2a506c2a16f4..18122d9e17ff 100644 --- a/include/linux/scs.h +++ b/include/linux/scs.h @@ -22,10 +22,6 @@ /* An illegal pointer value to mark the end of the shadow stack. */ #define SCS_END_MAGIC (0x5f6UL + POISON_POINTER_DELTA) -/* Allocate a static per-CPU shadow stack */ -#define DEFINE_SCS(name) \ - DEFINE_PER_CPU(unsigned long [SCS_SIZE/sizeof(long)], name) \ - #define task_scs(tsk) (task_thread_info(tsk)->scs_base) #define task_scs_sp(tsk) (task_thread_info(tsk)->scs_sp) |