cc6eed90a4
Allow up to two attachments to restricted vendor hooks to enable OEM and vendor coexistence. Priorities are not exposed to callers on purpose. Life's too short to re-order the callback array with concurrent readers. Bug: 183720636 Signed-off-by: Quentin Perret <qperret@google.com> Change-Id: I5c7aca7f69e581b4197388478d47e0da6d2893e6
115 lines
3.7 KiB
C
115 lines
3.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Note: we intentionally omit include file ifdef protection
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* This is due to the way trace events work. If a file includes two
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* trace event headers under one "CREATE_TRACE_POINTS" the first include
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* will override the DECLARE_RESTRICTED_HOOK and break the second include.
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*/
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#include <linux/tracepoint.h>
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#if defined(CONFIG_TRACEPOINTS) && defined(CONFIG_ANDROID_VENDOR_HOOKS)
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#define DECLARE_HOOK DECLARE_TRACE
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int android_rvh_probe_register(struct tracepoint *tp, void *probe, void *data);
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#ifdef TRACE_HEADER_MULTI_READ
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#define DEFINE_HOOK_FN(_name, _reg, _unreg, proto, args) \
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static const char __tpstrtab_##_name[] \
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__section("__tracepoints_strings") = #_name; \
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extern struct static_call_key STATIC_CALL_KEY(tp_func_##_name); \
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int __traceiter_##_name(void *__data, proto); \
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struct tracepoint __tracepoint_##_name __used \
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__section("__tracepoints") = { \
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.name = __tpstrtab_##_name, \
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.key = STATIC_KEY_INIT_FALSE, \
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.static_call_key = &STATIC_CALL_KEY(tp_func_##_name), \
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.static_call_tramp = STATIC_CALL_TRAMP_ADDR(tp_func_##_name), \
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.iterator = &__traceiter_##_name, \
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.regfunc = _reg, \
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.unregfunc = _unreg, \
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.funcs = NULL }; \
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__TRACEPOINT_ENTRY(_name); \
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int __traceiter_##_name(void *__data, proto) \
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{ \
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struct tracepoint_func *it_func_ptr; \
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void *it_func; \
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\
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it_func_ptr = (&__tracepoint_##_name)->funcs; \
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it_func = (it_func_ptr)->func; \
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do { \
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__data = (it_func_ptr)->data; \
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((void(*)(void *, proto))(it_func))(__data, args); \
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it_func = READ_ONCE((++it_func_ptr)->func); \
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} while (it_func); \
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return 0; \
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} \
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DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name);
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#undef DECLARE_RESTRICTED_HOOK
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#define DECLARE_RESTRICTED_HOOK(name, proto, args, cond) \
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DEFINE_HOOK_FN(name, NULL, NULL, PARAMS(proto), PARAMS(args))
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/* prevent additional recursion */
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#undef TRACE_HEADER_MULTI_READ
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#else /* TRACE_HEADER_MULTI_READ */
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#define DO_HOOK(name, proto, args, cond) \
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do { \
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struct tracepoint_func *it_func_ptr; \
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void *__data; \
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\
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if (!(cond)) \
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return; \
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\
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it_func_ptr = (&__tracepoint_##name)->funcs; \
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if (it_func_ptr) { \
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__data = (it_func_ptr)->data; \
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__DO_TRACE_CALL(name)(args); \
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} \
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} while (0)
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#define __DECLARE_HOOK(name, proto, args, cond, data_proto, data_args) \
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extern int __traceiter_##name(data_proto); \
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DECLARE_STATIC_CALL(tp_func_##name, __traceiter_##name); \
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extern struct tracepoint __tracepoint_##name; \
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static inline void __nocfi trace_##name(proto) \
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{ \
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if (static_key_false(&__tracepoint_##name.key)) \
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DO_HOOK(name, \
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TP_PROTO(data_proto), \
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TP_ARGS(data_args), \
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TP_CONDITION(cond)); \
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} \
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static inline bool \
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trace_##name##_enabled(void) \
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{ \
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return static_key_false(&__tracepoint_##name.key); \
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} \
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static inline int \
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register_trace_##name(void (*probe)(data_proto), void *data) \
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{ \
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return android_rvh_probe_register(&__tracepoint_##name, \
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(void *)probe, data); \
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} \
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/* vendor hooks cannot be unregistered */ \
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#undef DECLARE_RESTRICTED_HOOK
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#define DECLARE_RESTRICTED_HOOK(name, proto, args, cond) \
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__DECLARE_HOOK(name, PARAMS(proto), PARAMS(args), \
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cond, \
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PARAMS(void *__data, proto), \
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PARAMS(__data, args))
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#endif /* TRACE_HEADER_MULTI_READ */
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#else /* !CONFIG_TRACEPOINTS || !CONFIG_ANDROID_VENDOR_HOOKS */
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/* suppress trace hooks */
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#define DECLARE_HOOK DECLARE_EVENT_NOP
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#define DECLARE_RESTRICTED_HOOK(name, proto, args, cond) \
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DECLARE_EVENT_NOP(name, PARAMS(proto), PARAMS(args))
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#endif
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