diff options
| -rw-r--r-- | arch/mips/include/asm/irq.h | 15 | ||||
| -rw-r--r-- | arch/mips/kernel/asm-offsets.c | 1 | ||||
| -rw-r--r-- | arch/mips/kernel/genex.S | 8 | ||||
| -rw-r--r-- | arch/mips/kernel/process.c | 56 |
4 files changed, 60 insertions, 20 deletions
diff --git a/arch/mips/include/asm/irq.h b/arch/mips/include/asm/irq.h index 956db6e201d1..ddd1c918103b 100644 --- a/arch/mips/include/asm/irq.h +++ b/arch/mips/include/asm/irq.h @@ -18,9 +18,24 @@ #include <irq.h> #define IRQ_STACK_SIZE THREAD_SIZE +#define IRQ_STACK_START (IRQ_STACK_SIZE - sizeof(unsigned long)) extern void *irq_stack[NR_CPUS]; +/* + * The highest address on the IRQ stack contains a dummy frame put down in + * genex.S (handle_int & except_vec_vi_handler) which is structured as follows: + * + * top ------------ + * | task sp | <- irq_stack[cpu] + IRQ_STACK_START + * ------------ + * | | <- First frame of IRQ context + * ------------ + * + * task sp holds a copy of the task stack pointer where the struct pt_regs + * from exception entry can be found. + */ + static inline bool on_irq_stack(int cpu, unsigned long sp) { unsigned long low = (unsigned long)irq_stack[cpu]; diff --git a/arch/mips/kernel/asm-offsets.c b/arch/mips/kernel/asm-offsets.c index bb5c5d34ba81..a670c0c11875 100644 --- a/arch/mips/kernel/asm-offsets.c +++ b/arch/mips/kernel/asm-offsets.c @@ -102,6 +102,7 @@ void output_thread_info_defines(void) DEFINE(_THREAD_SIZE, THREAD_SIZE); DEFINE(_THREAD_MASK, THREAD_MASK); DEFINE(_IRQ_STACK_SIZE, IRQ_STACK_SIZE); + DEFINE(_IRQ_STACK_START, IRQ_STACK_START); BLANK(); } diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S index 2ac6c2625c13..ae810da4d499 100644 --- a/arch/mips/kernel/genex.S +++ b/arch/mips/kernel/genex.S @@ -215,9 +215,11 @@ NESTED(handle_int, PT_SIZE, sp) beq t0, t1, 2f /* Switch to IRQ stack */ - li t1, _IRQ_STACK_SIZE + li t1, _IRQ_STACK_START PTR_ADD sp, t0, t1 + /* Save task's sp on IRQ stack so that unwinding can follow it */ + LONG_S s1, 0(sp) 2: jal plat_irq_dispatch @@ -325,9 +327,11 @@ NESTED(except_vec_vi_handler, 0, sp) beq t0, t1, 2f /* Switch to IRQ stack */ - li t1, _IRQ_STACK_SIZE + li t1, _IRQ_STACK_START PTR_ADD sp, t0, t1 + /* Save task's sp on IRQ stack so that unwinding can follow it */ + LONG_S s1, 0(sp) 2: jalr v0 diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c index fb6b6b650719..b68e10fc453d 100644 --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -488,31 +488,52 @@ unsigned long notrace unwind_stack_by_address(unsigned long stack_page, unsigned long pc, unsigned long *ra) { + unsigned long low, high, irq_stack_high; struct mips_frame_info info; unsigned long size, ofs; + struct pt_regs *regs; int leaf; - extern void ret_from_irq(void); - extern void ret_from_exception(void); if (!stack_page) return 0; /* - * If we reached the bottom of interrupt context, - * return saved pc in pt_regs. + * IRQ stacks start at IRQ_STACK_START + * task stacks at THREAD_SIZE - 32 */ - if (pc == (unsigned long)ret_from_irq || - pc == (unsigned long)ret_from_exception) { - struct pt_regs *regs; - if (*sp >= stack_page && - *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) { - regs = (struct pt_regs *)*sp; - pc = regs->cp0_epc; - if (!user_mode(regs) && __kernel_text_address(pc)) { - *sp = regs->regs[29]; - *ra = regs->regs[31]; - return pc; - } + low = stack_page; + if (!preemptible() && on_irq_stack(raw_smp_processor_id(), *sp)) { + high = stack_page + IRQ_STACK_START; + irq_stack_high = high; + } else { + high = stack_page + THREAD_SIZE - 32; + irq_stack_high = 0; + } + + /* + * If we reached the top of the interrupt stack, start unwinding + * the interrupted task stack. + */ + if (unlikely(*sp == irq_stack_high)) { + unsigned long task_sp = *(unsigned long *)*sp; + + /* + * Check that the pointer saved in the IRQ stack head points to + * something within the stack of the current task + */ + if (!object_is_on_stack((void *)task_sp)) + return 0; + + /* + * Follow pointer to tasks kernel stack frame where interrupted + * state was saved. + */ + regs = (struct pt_regs *)task_sp; + pc = regs->cp0_epc; + if (!user_mode(regs) && __kernel_text_address(pc)) { + *sp = regs->regs[29]; + *ra = regs->regs[31]; + return pc; } return 0; } @@ -533,8 +554,7 @@ unsigned long notrace unwind_stack_by_address(unsigned long stack_page, if (leaf < 0) return 0; - if (*sp < stack_page || - *sp + info.frame_size > stack_page + THREAD_SIZE - 32) + if (*sp < low || *sp + info.frame_size > high) return 0; if (leaf) |