1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_KCOV_H 3 #define _LINUX_KCOV_H 4 5 #include <linux/sched.h> 6 #include <uapi/linux/kcov.h> 7 8 struct task_struct; 9 10 #ifdef CONFIG_KCOV 11 12 enum kcov_mode { 13 /* Coverage collection is not enabled yet. */ 14 KCOV_MODE_DISABLED = 0, 15 /* KCOV was initialized, but tracing mode hasn't been chosen yet. */ 16 KCOV_MODE_INIT = 1, 17 /* 18 * Tracing coverage collection mode. 19 * Covered PCs are collected in a per-task buffer. 20 */ 21 KCOV_MODE_TRACE_PC = 2, 22 /* Collecting comparison operands mode. */ 23 KCOV_MODE_TRACE_CMP = 3, 24 /* The process owns a KCOV remote reference. */ 25 KCOV_MODE_REMOTE = 4, 26 }; 27 28 #define KCOV_IN_CTXSW (1 << 30) 29 30 void kcov_task_init(struct task_struct *t); 31 void kcov_task_exit(struct task_struct *t); 32 33 #define kcov_prepare_switch(t) \ 34 do { \ 35 (t)->kcov_mode |= KCOV_IN_CTXSW; \ 36 } while (0) 37 38 #define kcov_finish_switch(t) \ 39 do { \ 40 (t)->kcov_mode &= ~KCOV_IN_CTXSW; \ 41 } while (0) 42 43 /* See Documentation/dev-tools/kcov.rst for usage details. */ 44 void kcov_remote_start(u64 handle); 45 void kcov_remote_stop(void); 46 u64 kcov_common_handle(void); 47 48 static inline void kcov_remote_start_common(u64 id) 49 { 50 kcov_remote_start(kcov_remote_handle(KCOV_SUBSYSTEM_COMMON, id)); 51 } 52 53 static inline void kcov_remote_start_usb(u64 id) 54 { 55 kcov_remote_start(kcov_remote_handle(KCOV_SUBSYSTEM_USB, id)); 56 } 57 58 /* 59 * The softirq flavor of kcov_remote_*() functions is introduced as a temporary 60 * workaround for KCOV's lack of nested remote coverage sections support. 61 * 62 * Adding support is tracked in https://bugzilla.kernel.org/show_bug.cgi?id=210337. 63 * 64 * kcov_remote_start_usb_softirq(): 65 * 66 * 1. Only collects coverage when called in the softirq context. This allows 67 * avoiding nested remote coverage collection sections in the task context. 68 * For example, USB/IP calls usb_hcd_giveback_urb() in the task context 69 * within an existing remote coverage collection section. Thus, KCOV should 70 * not attempt to start collecting coverage within the coverage collection 71 * section in __usb_hcd_giveback_urb() in this case. 72 * 73 * 2. Disables interrupts for the duration of the coverage collection section. 74 * This allows avoiding nested remote coverage collection sections in the 75 * softirq context (a softirq might occur during the execution of a work in 76 * the BH workqueue, which runs with in_serving_softirq() > 0). 77 * For example, usb_giveback_urb_bh() runs in the BH workqueue with 78 * interrupts enabled, so __usb_hcd_giveback_urb() might be interrupted in 79 * the middle of its remote coverage collection section, and the interrupt 80 * handler might invoke __usb_hcd_giveback_urb() again. 81 */ 82 83 static inline unsigned long kcov_remote_start_usb_softirq(u64 id) 84 { 85 unsigned long flags = 0; 86 87 if (in_serving_softirq()) { 88 local_irq_save(flags); 89 kcov_remote_start_usb(id); 90 } 91 92 return flags; 93 } 94 95 static inline void kcov_remote_stop_softirq(unsigned long flags) 96 { 97 if (in_serving_softirq()) { 98 kcov_remote_stop(); 99 local_irq_restore(flags); 100 } 101 } 102 103 #ifdef CONFIG_64BIT 104 typedef unsigned long kcov_u64; 105 #else 106 typedef unsigned long long kcov_u64; 107 #endif 108 109 void __sanitizer_cov_trace_pc(void); 110 void __sanitizer_cov_trace_cmp1(u8 arg1, u8 arg2); 111 void __sanitizer_cov_trace_cmp2(u16 arg1, u16 arg2); 112 void __sanitizer_cov_trace_cmp4(u32 arg1, u32 arg2); 113 void __sanitizer_cov_trace_cmp8(kcov_u64 arg1, kcov_u64 arg2); 114 void __sanitizer_cov_trace_const_cmp1(u8 arg1, u8 arg2); 115 void __sanitizer_cov_trace_const_cmp2(u16 arg1, u16 arg2); 116 void __sanitizer_cov_trace_const_cmp4(u32 arg1, u32 arg2); 117 void __sanitizer_cov_trace_const_cmp8(kcov_u64 arg1, kcov_u64 arg2); 118 void __sanitizer_cov_trace_switch(kcov_u64 val, void *cases); 119 120 #else 121 122 static inline void kcov_task_init(struct task_struct *t) {} 123 static inline void kcov_task_exit(struct task_struct *t) {} 124 static inline void kcov_prepare_switch(struct task_struct *t) {} 125 static inline void kcov_finish_switch(struct task_struct *t) {} 126 static inline void kcov_remote_start(u64 handle) {} 127 static inline void kcov_remote_stop(void) {} 128 static inline u64 kcov_common_handle(void) 129 { 130 return 0; 131 } 132 static inline void kcov_remote_start_common(u64 id) {} 133 static inline void kcov_remote_start_usb(u64 id) {} 134 static inline unsigned long kcov_remote_start_usb_softirq(u64 id) 135 { 136 return 0; 137 } 138 static inline void kcov_remote_stop_softirq(unsigned long flags) {} 139 140 #endif /* CONFIG_KCOV */ 141 #endif /* _LINUX_KCOV_H */ 142