1 // SPDX-License-Identifier: GPL-2.0+ 2 #include <linux/kernel.h> 3 #include <linux/uaccess.h> 4 #include <linux/sched.h> 5 #include <asm/hw_breakpoint.h> 6 #include <asm/sstep.h> 7 #include <asm/cache.h> 8 9 static bool dar_in_user_range(unsigned long dar, struct arch_hw_breakpoint *info) 10 { 11 return ((info->address <= dar) && (dar - info->address < info->len)); 12 } 13 14 static bool ea_user_range_overlaps(unsigned long ea, int size, 15 struct arch_hw_breakpoint *info) 16 { 17 return ((ea < info->address + info->len) && 18 (ea + size > info->address)); 19 } 20 21 static bool dar_in_hw_range(unsigned long dar, struct arch_hw_breakpoint *info) 22 { 23 unsigned long hw_start_addr, hw_end_addr; 24 25 hw_start_addr = ALIGN_DOWN(info->address, HW_BREAKPOINT_SIZE); 26 hw_end_addr = ALIGN(info->address + info->len, HW_BREAKPOINT_SIZE); 27 28 return ((hw_start_addr <= dar) && (hw_end_addr > dar)); 29 } 30 31 static bool ea_hw_range_overlaps(unsigned long ea, int size, 32 struct arch_hw_breakpoint *info) 33 { 34 unsigned long hw_start_addr, hw_end_addr; 35 unsigned long align_size = HW_BREAKPOINT_SIZE; 36 37 /* 38 * On p10 predecessors, quadword is handle differently then 39 * other instructions. 40 */ 41 if (!cpu_has_feature(CPU_FTR_ARCH_31) && size == 16) 42 align_size = HW_BREAKPOINT_SIZE_QUADWORD; 43 44 hw_start_addr = ALIGN_DOWN(info->address, align_size); 45 hw_end_addr = ALIGN(info->address + info->len, align_size); 46 47 return ((ea < hw_end_addr) && (ea + size > hw_start_addr)); 48 } 49 50 /* 51 * If hw has multiple DAWR registers, we also need to check all 52 * dawrx constraint bits to confirm this is _really_ a valid event. 53 * If type is UNKNOWN, but privilege level matches, consider it as 54 * a positive match. 55 */ 56 static bool check_dawrx_constraints(struct pt_regs *regs, int type, 57 struct arch_hw_breakpoint *info) 58 { 59 if (OP_IS_LOAD(type) && !(info->type & HW_BRK_TYPE_READ)) 60 return false; 61 62 /* 63 * The Cache Management instructions other than dcbz never 64 * cause a match. i.e. if type is CACHEOP, the instruction 65 * is dcbz, and dcbz is treated as Store. 66 */ 67 if ((OP_IS_STORE(type) || type == CACHEOP) && !(info->type & HW_BRK_TYPE_WRITE)) 68 return false; 69 70 if (is_kernel_addr(regs->nip) && !(info->type & HW_BRK_TYPE_KERNEL)) 71 return false; 72 73 if (user_mode(regs) && !(info->type & HW_BRK_TYPE_USER)) 74 return false; 75 76 return true; 77 } 78 79 /* 80 * Return true if the event is valid wrt dawr configuration, 81 * including extraneous exception. Otherwise return false. 82 */ 83 bool wp_check_constraints(struct pt_regs *regs, ppc_inst_t instr, 84 unsigned long ea, int type, int size, 85 struct arch_hw_breakpoint *info) 86 { 87 bool in_user_range = dar_in_user_range(regs->dar, info); 88 bool dawrx_constraints; 89 90 /* 91 * 8xx supports only one breakpoint and thus we can 92 * unconditionally return true. 93 */ 94 if (IS_ENABLED(CONFIG_PPC_8xx)) { 95 if (!in_user_range) 96 info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ; 97 return true; 98 } 99 100 if (unlikely(ppc_inst_equal(instr, ppc_inst(0)))) { 101 if (cpu_has_feature(CPU_FTR_ARCH_31) && 102 !dar_in_hw_range(regs->dar, info)) 103 return false; 104 105 return true; 106 } 107 108 dawrx_constraints = check_dawrx_constraints(regs, type, info); 109 110 if (type == UNKNOWN) { 111 if (cpu_has_feature(CPU_FTR_ARCH_31) && 112 !dar_in_hw_range(regs->dar, info)) 113 return false; 114 115 return dawrx_constraints; 116 } 117 118 if (ea_user_range_overlaps(ea, size, info)) 119 return dawrx_constraints; 120 121 if (ea_hw_range_overlaps(ea, size, info)) { 122 if (dawrx_constraints) { 123 info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ; 124 return true; 125 } 126 } 127 return false; 128 } 129 130 void wp_get_instr_detail(struct pt_regs *regs, ppc_inst_t *instr, 131 int *type, int *size, unsigned long *ea) 132 { 133 struct instruction_op op; 134 int err; 135 136 pagefault_disable(); 137 err = __get_user_instr(*instr, (void __user *)regs->nip); 138 pagefault_enable(); 139 140 if (err) 141 return; 142 143 analyse_instr(&op, regs, *instr); 144 *type = GETTYPE(op.type); 145 *ea = op.ea; 146 147 if (!(regs->msr & MSR_64BIT)) 148 *ea &= 0xffffffffUL; 149 150 151 *size = GETSIZE(op.type); 152 if (*type == CACHEOP) { 153 *size = l1_dcache_bytes(); 154 *ea &= ~(*size - 1); 155 } else if (*type == LOAD_VMX || *type == STORE_VMX) { 156 *ea &= ~(*size - 1); 157 } 158 } 159