tracing: Automatic syscall tracing
When generating syscall wrappers, call a tracing macro with the id, name, and all parameters of the syscall as params when entering and leaving the syscall. This can be disabled in certain call sites by defining DISABLE_SYSCALL_TRACING which is useful for certain tracing implementations which require syscalls themselves to work. Notably some syscalls *cannot* be automatically traced this way and headers where exclusions are set are in the gen_syscall.py as notracing. Includes a systemview and test format implementation. Tested with systemview, usb, and uart backends with the string formatter using the tracing sample app. Debugging the trace wrapper can be aided by setting the TRACE_DIAGNOSTIC env var and rebuilding from scratch, a warning is issued for every instance a syscall is traced. Automatically generating a name mapping for SYSVIEW_Zephyr.txt is a future item as is documenting how to capture and use the tracing data generated. Signed-off-by: Tom Burdick <thomas.burdick@intel.com>
This commit is contained in:
Tom Burdick
Anas Nashif
parent
43fa7ce53f
commit
97dc88bb6d
15 changed files with 533 additions and 172 deletions
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@ -29,6 +29,12 @@ import argparse
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import os
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import json
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# Some kernel headers cannot include automated tracing without causing unintended recursion or
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# other serious issues.
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# These headers typically already have very specific tracing hooks for all relevant things
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# written by hand so are excluded.
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notracing = ["kernel.h", "errno_private.h"]
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types64 = ["int64_t", "uint64_t"]
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# The kernel linkage is complicated. These functions from
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@ -73,7 +79,9 @@ list_template = """
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syscall_template = """
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/* auto-generated by gen_syscalls.py, don't edit */
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%s
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{include_guard}
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{tracing_include}
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#ifndef _ASMLANGUAGE
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@ -82,6 +90,7 @@ syscall_template = """
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#include <linker/sections.h>
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#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
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#pragma GCC diagnostic push
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#endif
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@ -94,13 +103,13 @@ syscall_template = """
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#endif
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#ifdef __cplusplus
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extern "C" {
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extern "C" {{
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#endif
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%s
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{invocations}
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#ifdef __cplusplus
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}
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}}
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#endif
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#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
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@ -122,6 +131,36 @@ uintptr_t %s(uintptr_t arg1, uintptr_t arg2, uintptr_t arg3,
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uintptr_t arg4, uintptr_t arg5, uintptr_t arg6, void *ssf);
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"""
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# defines a macro wrapper which supercedes the syscall when used
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# and provides tracing enter/exit hooks while allowing per compilation unit
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# enable/disable of syscall tracing. Used for returning functions
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# Note that the last argument to the exit macro is the return value.
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syscall_tracer_with_return_template = """
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#ifndef DISABLE_SYSCALL_TRACING
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{trace_diagnostic}
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#define {func_name}({argnames}) ({{ \
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{func_type} retval; \
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sys_port_trace_syscall_enter({syscall_id}, {func_name}{trace_argnames}); \
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retval = {func_name}({argnames}); \
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sys_port_trace_syscall_exit({syscall_id}, {func_name}{trace_argnames}, retval); \
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retval; \
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}})
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#endif
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"""
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# defines a macro wrapper which supercedes the syscall when used
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# and provides tracing enter/exit hooks while allowing per compilation unit
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# enable/disable of syscall tracing. Used for non-returning (void) functions
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syscall_tracer_void_template = """
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#ifndef DISABLE_SYSCALL_TRACING
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{trace_diagnostic}
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#define {func_name}({argnames}) do {{ \
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sys_port_trace_syscall_enter({syscall_id}, {func_name}{trace_argnames}); \
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{func_name}({argnames}); \
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sys_port_trace_syscall_exit({syscall_id}, {func_name}{trace_argnames}); \
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}} while(false)
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#endif
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"""
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typename_regex = re.compile(r'(.*?)([A-Za-z0-9_]+)$')
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@ -156,7 +195,7 @@ def need_split(argtype):
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def union_decl(type):
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return "union { struct { uintptr_t lo, hi; } split; %s val; }" % type
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def wrapper_defs(func_name, func_type, args):
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def wrapper_defs(func_name, func_type, args, fn):
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ret64 = need_split(func_type)
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mrsh_args = [] # List of rvalue expressions for the marshalled invocation
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split_args = []
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@ -174,6 +213,7 @@ def wrapper_defs(func_name, func_type, args):
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mrsh_args.append("(uintptr_t)&ret64")
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decl_arglist = ", ".join([" ".join(argrec) for argrec in args]) or "void"
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syscall_id = "K_SYSCALL_" + func_name.upper()
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wrap = "extern %s z_impl_%s(%s);\n" % (func_type, func_name, decl_arglist)
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wrap += "\n"
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@ -195,7 +235,6 @@ def wrapper_defs(func_name, func_type, args):
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wrap += "\t\t" + "};\n"
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mrsh_args[5:] = ["(uintptr_t) &more"]
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syscall_id = "K_SYSCALL_" + func_name.upper()
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invoke = ("arch_syscall_invoke%d(%s)"
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% (len(mrsh_args),
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", ".join(mrsh_args + [syscall_id])))
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@ -230,6 +269,23 @@ def wrapper_defs(func_name, func_type, args):
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wrap += "}\n"
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if fn not in notracing:
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argnames = ", ".join([f"{argname}" for _, argname in args])
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trace_argnames = ""
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if len(args) > 0:
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trace_argnames = ", " + argnames
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trace_diagnostic = ""
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if os.getenv('TRACE_DIAGNOSTICS'):
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trace_diagnostic = f"#warning Tracing {func_name}"
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if func_type != "void":
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wrap += syscall_tracer_with_return_template.format(func_type=func_type, func_name=func_name,
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argnames=argnames, trace_argnames=trace_argnames,
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syscall_id=syscall_id, trace_diagnostic=trace_diagnostic)
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else:
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wrap += syscall_tracer_void_template.format(func_type=func_type, func_name=func_name,
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argnames=argnames, trace_argnames=trace_argnames,
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syscall_id=syscall_id, trace_diagnostic=trace_diagnostic)
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return wrap
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# Returns an expression for the specified (zero-indexed!) marshalled
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@ -316,7 +372,7 @@ def marshall_defs(func_name, func_type, args):
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return mrsh, mrsh_name
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def analyze_fn(match_group):
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def analyze_fn(match_group, fn):
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func, args = match_group
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try:
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@ -334,7 +390,7 @@ def analyze_fn(match_group):
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marshaller = None
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marshaller, handler = marshall_defs(func_name, func_type, args)
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invocation = wrapper_defs(func_name, func_type, args)
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invocation = wrapper_defs(func_name, func_type, args, fn)
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# Entry in _k_syscall_table
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table_entry = "[%s] = %s" % (sys_id, handler)
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@ -380,7 +436,7 @@ def main():
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handlers = []
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for match_group, fn in syscalls:
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handler, inv, mrsh, sys_id, entry = analyze_fn(match_group)
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handler, inv, mrsh, sys_id, entry = analyze_fn(match_group, fn)
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if fn not in invocations:
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invocations[fn] = []
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@ -426,7 +482,10 @@ def main():
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ig = re.sub("[^a-zA-Z0-9]", "_", "Z_INCLUDE_SYSCALLS_" + fn).upper()
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include_guard = "#ifndef %s\n#define %s\n" % (ig, ig)
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header = syscall_template % (include_guard, "\n\n".join(invo_list))
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tracing_include = ""
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if fn not in notracing:
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tracing_include = "#include <tracing/tracing_syscall.h>"
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header = syscall_template.format(include_guard=include_guard, tracing_include=tracing_include, invocations="\n\n".join(invo_list))
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with open(out_fn, "w") as fp:
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fp.write(header)
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