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
dar_in_user_range(unsigned long dar,struct arch_hw_breakpoint * info)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
ea_user_range_overlaps(unsigned long ea,int size,struct arch_hw_breakpoint * info)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
dar_in_hw_range(unsigned long dar,struct arch_hw_breakpoint * info)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
ea_hw_range_overlaps(unsigned long ea,int size,struct arch_hw_breakpoint * info)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 */
check_dawrx_constraints(struct pt_regs * regs,int type,struct arch_hw_breakpoint * info)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 */
wp_check_constraints(struct pt_regs * regs,ppc_inst_t instr,unsigned long ea,int type,int size,struct arch_hw_breakpoint * info)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
wp_get_instr_detail(struct pt_regs * regs,ppc_inst_t * instr,int * type,int * size,unsigned long * ea)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