| .. | .. |
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| 16 | 16 | #include <linux/bug.h> |
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| 17 | 17 | #include <linux/nmi.h> |
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| 18 | 18 | |
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| 19 | +#include <asm/cpu_entry_area.h> |
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| 19 | 20 | #include <asm/stacktrace.h> |
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| 20 | 21 | |
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| 21 | | -static char *exception_stack_names[N_EXCEPTION_STACKS] = { |
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| 22 | | - [ DOUBLEFAULT_STACK-1 ] = "#DF", |
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| 23 | | - [ NMI_STACK-1 ] = "NMI", |
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| 24 | | - [ DEBUG_STACK-1 ] = "#DB", |
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| 25 | | - [ MCE_STACK-1 ] = "#MC", |
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| 26 | | -}; |
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| 27 | | - |
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| 28 | | -static unsigned long exception_stack_sizes[N_EXCEPTION_STACKS] = { |
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| 29 | | - [0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STKSZ, |
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| 30 | | - [DEBUG_STACK - 1] = DEBUG_STKSZ |
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| 22 | +static const char * const exception_stack_names[] = { |
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| 23 | + [ ESTACK_DF ] = "#DF", |
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| 24 | + [ ESTACK_NMI ] = "NMI", |
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| 25 | + [ ESTACK_DB ] = "#DB", |
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| 26 | + [ ESTACK_MCE ] = "#MC", |
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| 27 | + [ ESTACK_VC ] = "#VC", |
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| 28 | + [ ESTACK_VC2 ] = "#VC2", |
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| 31 | 29 | }; |
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| 32 | 30 | |
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| 33 | 31 | const char *stack_type_name(enum stack_type type) |
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| 34 | 32 | { |
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| 35 | | - BUILD_BUG_ON(N_EXCEPTION_STACKS != 4); |
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| 33 | + BUILD_BUG_ON(N_EXCEPTION_STACKS != 6); |
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| 36 | 34 | |
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| 37 | 35 | if (type == STACK_TYPE_IRQ) |
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| 38 | 36 | return "IRQ"; |
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| .. | .. |
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| 52 | 50 | return NULL; |
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| 53 | 51 | } |
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| 54 | 52 | |
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| 55 | | -static bool in_exception_stack(unsigned long *stack, struct stack_info *info) |
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| 53 | +/** |
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| 54 | + * struct estack_pages - Page descriptor for exception stacks |
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| 55 | + * @offs: Offset from the start of the exception stack area |
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| 56 | + * @size: Size of the exception stack |
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| 57 | + * @type: Type to store in the stack_info struct |
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| 58 | + */ |
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| 59 | +struct estack_pages { |
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| 60 | + u32 offs; |
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| 61 | + u16 size; |
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| 62 | + u16 type; |
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| 63 | +}; |
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| 64 | + |
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| 65 | +#define EPAGERANGE(st) \ |
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| 66 | + [PFN_DOWN(CEA_ESTACK_OFFS(st)) ... \ |
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| 67 | + PFN_DOWN(CEA_ESTACK_OFFS(st) + CEA_ESTACK_SIZE(st) - 1)] = { \ |
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| 68 | + .offs = CEA_ESTACK_OFFS(st), \ |
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| 69 | + .size = CEA_ESTACK_SIZE(st), \ |
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| 70 | + .type = STACK_TYPE_EXCEPTION + ESTACK_ ##st, } |
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| 71 | + |
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| 72 | +/* |
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| 73 | + * Array of exception stack page descriptors. If the stack is larger than |
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| 74 | + * PAGE_SIZE, all pages covering a particular stack will have the same |
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| 75 | + * info. The guard pages including the not mapped DB2 stack are zeroed |
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| 76 | + * out. |
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| 77 | + */ |
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| 78 | +static const |
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| 79 | +struct estack_pages estack_pages[CEA_ESTACK_PAGES] ____cacheline_aligned = { |
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| 80 | + EPAGERANGE(DF), |
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| 81 | + EPAGERANGE(NMI), |
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| 82 | + EPAGERANGE(DB), |
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| 83 | + EPAGERANGE(MCE), |
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| 84 | + EPAGERANGE(VC), |
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| 85 | + EPAGERANGE(VC2), |
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| 86 | +}; |
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| 87 | + |
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| 88 | +static __always_inline bool in_exception_stack(unsigned long *stack, struct stack_info *info) |
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| 56 | 89 | { |
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| 57 | | - unsigned long *begin, *end; |
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| 90 | + unsigned long begin, end, stk = (unsigned long)stack; |
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| 91 | + const struct estack_pages *ep; |
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| 58 | 92 | struct pt_regs *regs; |
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| 59 | | - unsigned k; |
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| 93 | + unsigned int k; |
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| 60 | 94 | |
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| 61 | | - BUILD_BUG_ON(N_EXCEPTION_STACKS != 4); |
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| 95 | + BUILD_BUG_ON(N_EXCEPTION_STACKS != 6); |
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| 62 | 96 | |
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| 63 | | - for (k = 0; k < N_EXCEPTION_STACKS; k++) { |
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| 64 | | - end = (unsigned long *)raw_cpu_ptr(&orig_ist)->ist[k]; |
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| 65 | | - begin = end - (exception_stack_sizes[k] / sizeof(long)); |
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| 66 | | - regs = (struct pt_regs *)end - 1; |
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| 97 | + begin = (unsigned long)__this_cpu_read(cea_exception_stacks); |
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| 98 | + /* |
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| 99 | + * Handle the case where stack trace is collected _before_ |
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| 100 | + * cea_exception_stacks had been initialized. |
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| 101 | + */ |
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| 102 | + if (!begin) |
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| 103 | + return false; |
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| 67 | 104 | |
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| 68 | | - if (stack <= begin || stack >= end) |
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| 69 | | - continue; |
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| 105 | + end = begin + sizeof(struct cea_exception_stacks); |
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| 106 | + /* Bail if @stack is outside the exception stack area. */ |
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| 107 | + if (stk < begin || stk >= end) |
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| 108 | + return false; |
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| 70 | 109 | |
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| 71 | | - info->type = STACK_TYPE_EXCEPTION + k; |
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| 72 | | - info->begin = begin; |
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| 73 | | - info->end = end; |
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| 74 | | - info->next_sp = (unsigned long *)regs->sp; |
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| 110 | + /* Calc page offset from start of exception stacks */ |
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| 111 | + k = (stk - begin) >> PAGE_SHIFT; |
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| 112 | + /* Lookup the page descriptor */ |
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| 113 | + ep = &estack_pages[k]; |
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| 114 | + /* Guard page? */ |
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| 115 | + if (!ep->size) |
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| 116 | + return false; |
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| 75 | 117 | |
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| 76 | | - return true; |
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| 77 | | - } |
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| 118 | + begin += (unsigned long)ep->offs; |
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| 119 | + end = begin + (unsigned long)ep->size; |
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| 120 | + regs = (struct pt_regs *)end - 1; |
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| 78 | 121 | |
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| 79 | | - return false; |
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| 122 | + info->type = ep->type; |
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| 123 | + info->begin = (unsigned long *)begin; |
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| 124 | + info->end = (unsigned long *)end; |
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| 125 | + info->next_sp = (unsigned long *)regs->sp; |
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| 126 | + return true; |
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| 80 | 127 | } |
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| 81 | 128 | |
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| 82 | | -static bool in_irq_stack(unsigned long *stack, struct stack_info *info) |
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| 129 | +static __always_inline bool in_irq_stack(unsigned long *stack, struct stack_info *info) |
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| 83 | 130 | { |
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| 84 | | - unsigned long *end = (unsigned long *)this_cpu_read(irq_stack_ptr); |
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| 131 | + unsigned long *end = (unsigned long *)this_cpu_read(hardirq_stack_ptr); |
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| 85 | 132 | unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long)); |
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| 86 | 133 | |
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| 87 | 134 | /* |
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| 88 | 135 | * This is a software stack, so 'end' can be a valid stack pointer. |
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| 89 | 136 | * It just means the stack is empty. |
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| 90 | 137 | */ |
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| 91 | | - if (stack <= begin || stack > end) |
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| 138 | + if (stack < begin || stack >= end) |
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| 92 | 139 | return false; |
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| 93 | 140 | |
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| 94 | 141 | info->type = STACK_TYPE_IRQ; |
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| .. | .. |
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| 104 | 151 | return true; |
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| 105 | 152 | } |
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| 106 | 153 | |
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| 154 | +bool noinstr get_stack_info_noinstr(unsigned long *stack, struct task_struct *task, |
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| 155 | + struct stack_info *info) |
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| 156 | +{ |
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| 157 | + if (in_task_stack(stack, task, info)) |
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| 158 | + return true; |
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| 159 | + |
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| 160 | + if (task != current) |
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| 161 | + return false; |
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| 162 | + |
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| 163 | + if (in_exception_stack(stack, info)) |
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| 164 | + return true; |
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| 165 | + |
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| 166 | + if (in_irq_stack(stack, info)) |
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| 167 | + return true; |
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| 168 | + |
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| 169 | + if (in_entry_stack(stack, info)) |
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| 170 | + return true; |
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| 171 | + |
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| 172 | + return false; |
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| 173 | +} |
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| 174 | + |
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| 107 | 175 | int get_stack_info(unsigned long *stack, struct task_struct *task, |
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| 108 | 176 | struct stack_info *info, unsigned long *visit_mask) |
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| 109 | 177 | { |
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| 178 | + task = task ? : current; |
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| 179 | + |
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| 110 | 180 | if (!stack) |
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| 111 | 181 | goto unknown; |
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| 112 | 182 | |
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| 113 | | - task = task ? : current; |
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| 114 | | - |
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| 115 | | - if (in_task_stack(stack, task, info)) |
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| 116 | | - goto recursion_check; |
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| 117 | | - |
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| 118 | | - if (task != current) |
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| 183 | + if (!get_stack_info_noinstr(stack, task, info)) |
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| 119 | 184 | goto unknown; |
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| 120 | 185 | |
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| 121 | | - if (in_exception_stack(stack, info)) |
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| 122 | | - goto recursion_check; |
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| 123 | | - |
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| 124 | | - if (in_irq_stack(stack, info)) |
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| 125 | | - goto recursion_check; |
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| 126 | | - |
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| 127 | | - if (in_entry_stack(stack, info)) |
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| 128 | | - goto recursion_check; |
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| 129 | | - |
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| 130 | | - goto unknown; |
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| 131 | | - |
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| 132 | | -recursion_check: |
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| 133 | 186 | /* |
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| 134 | 187 | * Make sure we don't iterate through any given stack more than once. |
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| 135 | 188 | * If it comes up a second time then there's something wrong going on: |
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| .. | .. |
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| 137 | 190 | */ |
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| 138 | 191 | if (visit_mask) { |
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| 139 | 192 | if (*visit_mask & (1UL << info->type)) { |
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| 140 | | - printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type); |
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| 193 | + if (task == current) |
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| 194 | + printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type); |
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| 141 | 195 | goto unknown; |
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| 142 | 196 | } |
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| 143 | 197 | *visit_mask |= 1UL << info->type; |
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