diff options
| -rw-r--r-- | arch/riscv/Kconfig | 1 | ||||
| -rw-r--r-- | arch/riscv/include/asm/asm-prototypes.h | 3 | ||||
| -rw-r--r-- | arch/riscv/include/asm/thread_info.h | 15 | ||||
| -rw-r--r-- | arch/riscv/kernel/entry.S | 108 | ||||
| -rw-r--r-- | arch/riscv/kernel/traps.c | 35 | ||||
| -rw-r--r-- | arch/riscv/kernel/vmlinux.lds.S | 2 |
6 files changed, 163 insertions, 1 deletions
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 1e8dde174946..3590eb76000e 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -70,6 +70,7 @@ config RISCV select HAVE_ARCH_MMAP_RND_BITS if MMU select HAVE_ARCH_SECCOMP_FILTER select HAVE_ARCH_TRACEHOOK + select HAVE_ARCH_VMAP_STACK if MMU && 64BIT select HAVE_ASM_MODVERSIONS select HAVE_CONTEXT_TRACKING select HAVE_DEBUG_KMEMLEAK diff --git a/arch/riscv/include/asm/asm-prototypes.h b/arch/riscv/include/asm/asm-prototypes.h index 2a652b0c987d..ef386fcf3939 100644 --- a/arch/riscv/include/asm/asm-prototypes.h +++ b/arch/riscv/include/asm/asm-prototypes.h @@ -25,4 +25,7 @@ DECLARE_DO_ERROR_INFO(do_trap_ecall_s); DECLARE_DO_ERROR_INFO(do_trap_ecall_m); DECLARE_DO_ERROR_INFO(do_trap_break); +asmlinkage unsigned long get_overflow_stack(void); +asmlinkage void handle_bad_stack(struct pt_regs *regs); + #endif /* _ASM_RISCV_PROTOTYPES_H */ diff --git a/arch/riscv/include/asm/thread_info.h b/arch/riscv/include/asm/thread_info.h index 0e549a3089b3..60da0dcacf14 100644 --- a/arch/riscv/include/asm/thread_info.h +++ b/arch/riscv/include/asm/thread_info.h @@ -19,6 +19,21 @@ #endif #define THREAD_SIZE (PAGE_SIZE << THREAD_SIZE_ORDER) +/* + * By aligning VMAP'd stacks to 2 * THREAD_SIZE, we can detect overflow by + * checking sp & (1 << THREAD_SHIFT), which we can do cheaply in the entry + * assembly. + */ +#ifdef CONFIG_VMAP_STACK +#define THREAD_ALIGN (2 * THREAD_SIZE) +#else +#define THREAD_ALIGN THREAD_SIZE +#endif + +#define THREAD_SHIFT (PAGE_SHIFT + THREAD_SIZE_ORDER) +#define OVERFLOW_STACK_SIZE SZ_4K +#define SHADOW_OVERFLOW_STACK_SIZE (1024) + #ifndef __ASSEMBLY__ #include <asm/processor.h> diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S index 80d5a9e017b0..98f502654edd 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -30,6 +30,15 @@ ENTRY(handle_exception) _restore_kernel_tpsp: csrr tp, CSR_SCRATCH REG_S sp, TASK_TI_KERNEL_SP(tp) + +#ifdef CONFIG_VMAP_STACK + addi sp, sp, -(PT_SIZE_ON_STACK) + srli sp, sp, THREAD_SHIFT + andi sp, sp, 0x1 + bnez sp, handle_kernel_stack_overflow + REG_L sp, TASK_TI_KERNEL_SP(tp) +#endif + _save_context: REG_S sp, TASK_TI_USER_SP(tp) REG_L sp, TASK_TI_KERNEL_SP(tp) @@ -376,6 +385,105 @@ handle_syscall_trace_exit: call do_syscall_trace_exit j ret_from_exception +#ifdef CONFIG_VMAP_STACK +handle_kernel_stack_overflow: + la sp, shadow_stack + addi sp, sp, SHADOW_OVERFLOW_STACK_SIZE + + //save caller register to shadow stack + addi sp, sp, -(PT_SIZE_ON_STACK) + REG_S x1, PT_RA(sp) + REG_S x5, PT_T0(sp) + REG_S x6, PT_T1(sp) + REG_S x7, PT_T2(sp) + REG_S x10, PT_A0(sp) + REG_S x11, PT_A1(sp) + REG_S x12, PT_A2(sp) + REG_S x13, PT_A3(sp) + REG_S x14, PT_A4(sp) + REG_S x15, PT_A5(sp) + REG_S x16, PT_A6(sp) + REG_S x17, PT_A7(sp) + REG_S x28, PT_T3(sp) + REG_S x29, PT_T4(sp) + REG_S x30, PT_T5(sp) + REG_S x31, PT_T6(sp) + + la ra, restore_caller_reg + tail get_overflow_stack + +restore_caller_reg: + //save per-cpu overflow stack + REG_S a0, -8(sp) + //restore caller register from shadow_stack + REG_L x1, PT_RA(sp) + REG_L x5, PT_T0(sp) + REG_L x6, PT_T1(sp) + REG_L x7, PT_T2(sp) + REG_L x10, PT_A0(sp) + REG_L x11, PT_A1(sp) + REG_L x12, PT_A2(sp) + REG_L x13, PT_A3(sp) + REG_L x14, PT_A4(sp) + REG_L x15, PT_A5(sp) + REG_L x16, PT_A6(sp) + REG_L x17, PT_A7(sp) + REG_L x28, PT_T3(sp) + REG_L x29, PT_T4(sp) + REG_L x30, PT_T5(sp) + REG_L x31, PT_T6(sp) + + //load per-cpu overflow stack + REG_L sp, -8(sp) + addi sp, sp, -(PT_SIZE_ON_STACK) + + //save context to overflow stack + REG_S x1, PT_RA(sp) + REG_S x3, PT_GP(sp) + REG_S x5, PT_T0(sp) + REG_S x6, PT_T1(sp) + REG_S x7, PT_T2(sp) + REG_S x8, PT_S0(sp) + REG_S x9, PT_S1(sp) + REG_S x10, PT_A0(sp) + REG_S x11, PT_A1(sp) + REG_S x12, PT_A2(sp) + REG_S x13, PT_A3(sp) + REG_S x14, PT_A4(sp) + REG_S x15, PT_A5(sp) + REG_S x16, PT_A6(sp) + REG_S x17, PT_A7(sp) + REG_S x18, PT_S2(sp) + REG_S x19, PT_S3(sp) + REG_S x20, PT_S4(sp) + REG_S x21, PT_S5(sp) + REG_S x22, PT_S6(sp) + REG_S x23, PT_S7(sp) + REG_S x24, PT_S8(sp) + REG_S x25, PT_S9(sp) + REG_S x26, PT_S10(sp) + REG_S x27, PT_S11(sp) + REG_S x28, PT_T3(sp) + REG_S x29, PT_T4(sp) + REG_S x30, PT_T5(sp) + REG_S x31, PT_T6(sp) + + REG_L s0, TASK_TI_KERNEL_SP(tp) + csrr s1, CSR_STATUS + csrr s2, CSR_EPC + csrr s3, CSR_TVAL + csrr s4, CSR_CAUSE + csrr s5, CSR_SCRATCH + REG_S s0, PT_SP(sp) + REG_S s1, PT_STATUS(sp) + REG_S s2, PT_EPC(sp) + REG_S s3, PT_BADADDR(sp) + REG_S s4, PT_CAUSE(sp) + REG_S s5, PT_TP(sp) + move a0, sp + tail handle_bad_stack +#endif + END(handle_exception) ENTRY(ret_from_fork) diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c index 0721b9798595..bb6a450f0ecc 100644 --- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -198,3 +198,38 @@ int is_valid_bugaddr(unsigned long pc) void __init trap_init(void) { } + +#ifdef CONFIG_VMAP_STACK +static DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], + overflow_stack)__aligned(16); +/* + * shadow stack, handled_ kernel_ stack_ overflow(in kernel/entry.S) is used + * to get per-cpu overflow stack(get_overflow_stack). + */ +long shadow_stack[SHADOW_OVERFLOW_STACK_SIZE/sizeof(long)]; +asmlinkage unsigned long get_overflow_stack(void) +{ + return (unsigned long)this_cpu_ptr(overflow_stack) + + OVERFLOW_STACK_SIZE; +} + +asmlinkage void handle_bad_stack(struct pt_regs *regs) +{ + unsigned long tsk_stk = (unsigned long)current->stack; + unsigned long ovf_stk = (unsigned long)this_cpu_ptr(overflow_stack); + + console_verbose(); + + pr_emerg("Insufficient stack space to handle exception!\n"); + pr_emerg("Task stack: [0x%016lx..0x%016lx]\n", + tsk_stk, tsk_stk + THREAD_SIZE); + pr_emerg("Overflow stack: [0x%016lx..0x%016lx]\n", + ovf_stk, ovf_stk + OVERFLOW_STACK_SIZE); + + __show_regs(regs); + panic("Kernel stack overflow"); + + for (;;) + wait_for_interrupt(); +} +#endif diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S index 891742ff75a7..502d0826ecb1 100644 --- a/arch/riscv/kernel/vmlinux.lds.S +++ b/arch/riscv/kernel/vmlinux.lds.S @@ -117,7 +117,7 @@ SECTIONS . = ALIGN(SECTION_ALIGN); _data = .; - RW_DATA(L1_CACHE_BYTES, PAGE_SIZE, THREAD_SIZE) + RW_DATA(L1_CACHE_BYTES, PAGE_SIZE, THREAD_ALIGN) .sdata : { __global_pointer$ = . + 0x800; *(.sdata*) |