| #!/usr/bin/env python3 |
| # |
| # Copyright (c) 2017 Intel Corporation |
| # |
| # SPDX-License-Identifier: Apache-2.0 |
| |
| """ |
| Script to generate system call invocation macros |
| |
| This script parses the system call metadata JSON file emitted by |
| parse_syscalls.py to create several files: |
| |
| - A file containing weak aliases of any potentially unimplemented system calls, |
| as well as the system call dispatch table, which maps system call type IDs |
| to their handler functions. |
| |
| - A header file defining the system call type IDs, as well as function |
| prototypes for all system call handler functions. |
| |
| - A directory containing header files. Each header corresponds to a header |
| that was identified as containing system call declarations. These |
| generated headers contain the inline invocation functions for each system |
| call in that header. |
| """ |
| |
| import sys |
| import re |
| import argparse |
| import os |
| import json |
| |
| types64 = ["int64_t", "uint64_t"] |
| |
| # The kernel linkage is complicated. These functions from |
| # userspace_handlers.c are present in the kernel .a library after |
| # userspace.c, which contains the weak fallbacks defined here. So the |
| # linker finds the weak one first and stops searching, and thus won't |
| # see the real implementation which should override. Yet changing the |
| # order runs afoul of a comment in CMakeLists.txt that the order is |
| # critical. These are core syscalls that won't ever be unconfigured, |
| # just disable the fallback mechanism as a simple workaround. |
| noweak = ["z_mrsh_k_object_release", |
| "z_mrsh_k_object_access_grant", |
| "z_mrsh_k_object_alloc"] |
| |
| table_template = """/* auto-generated by gen_syscalls.py, don't edit */ |
| |
| /* Weak handler functions that get replaced by the real ones unless a system |
| * call is not implemented due to kernel configuration. |
| */ |
| %s |
| |
| const _k_syscall_handler_t _k_syscall_table[K_SYSCALL_LIMIT] = { |
| \t%s |
| }; |
| """ |
| |
| list_template = """ |
| /* auto-generated by gen_syscalls.py, don't edit */ |
| #ifndef ZEPHYR_SYSCALL_LIST_H |
| #define ZEPHYR_SYSCALL_LIST_H |
| |
| %s |
| |
| #ifndef _ASMLANGUAGE |
| |
| #include <stdint.h> |
| |
| #endif /* _ASMLANGUAGE */ |
| |
| #endif /* ZEPHYR_SYSCALL_LIST_H */ |
| """ |
| |
| syscall_template = """ |
| /* auto-generated by gen_syscalls.py, don't edit */ |
| %s |
| |
| #ifndef _ASMLANGUAGE |
| |
| #include <syscall_list.h> |
| #include <syscall.h> |
| |
| #include <linker/sections.h> |
| |
| #if (__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 6)) |
| #pragma GCC diagnostic push |
| #endif |
| |
| #ifdef __GNUC__ |
| #pragma GCC diagnostic ignored "-Wstrict-aliasing" |
| #if !defined(__XCC__) |
| #pragma GCC diagnostic ignored "-Warray-bounds" |
| #endif |
| #endif |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| %s |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #if (__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 6)) |
| #pragma GCC diagnostic pop |
| #endif |
| |
| #endif |
| #endif /* include guard */ |
| """ |
| |
| handler_template = """ |
| extern uintptr_t z_hdlr_%s(uintptr_t arg1, uintptr_t arg2, uintptr_t arg3, |
| uintptr_t arg4, uintptr_t arg5, uintptr_t %s, void *ssf); |
| """ |
| |
| weak_template = """ |
| __weak ALIAS_OF(handler_no_syscall) |
| uintptr_t %s(uintptr_t arg1, uintptr_t arg2, uintptr_t arg3, |
| uintptr_t arg4, uintptr_t arg5, uintptr_t %s, void *ssf); |
| """ |
| |
| |
| typename_regex = re.compile(r'(.*?)([A-Za-z0-9_]+)$') |
| |
| |
| class SyscallParseException(Exception): |
| pass |
| |
| |
| def typename_split(item): |
| if "[" in item: |
| raise SyscallParseException( |
| "Please pass arrays to syscalls as pointers, unable to process '%s'" % |
| item) |
| |
| if "(" in item: |
| raise SyscallParseException( |
| "Please use typedefs for function pointers") |
| |
| mo = typename_regex.match(item) |
| if not mo: |
| raise SyscallParseException("Malformed system call invocation") |
| |
| m = mo.groups() |
| return (m[0].strip(), m[1]) |
| |
| def need_split(argtype): |
| return (not args.long_registers) and (argtype in types64) |
| |
| # Note: "lo" and "hi" are named in little endian conventions, |
| # but it doesn't matter as long as they are consistently |
| # generated. |
| def union_decl(type): |
| return "union { struct { uintptr_t lo, hi; } split; %s val; }" % type |
| |
| def wrapper_defs(func_name, func_type, args): |
| ret64 = need_split(func_type) |
| mrsh_args = [] # List of rvalue expressions for the marshalled invocation |
| split_args = [] |
| nsplit = 0 |
| for argtype, argname in args: |
| if need_split(argtype): |
| split_args.append((argtype, argname)) |
| mrsh_args.append("parm%d.split.lo" % nsplit) |
| mrsh_args.append("parm%d.split.hi" % nsplit) |
| nsplit += 1 |
| else: |
| mrsh_args.append("*(const uintptr_t *)&" + argname) |
| |
| if ret64: |
| mrsh_args.append("(uintptr_t)&ret64") |
| |
| decl_arglist = ", ".join([" ".join(argrec) for argrec in args]) or "void" |
| |
| wrap = "extern %s z_impl_%s(%s);\n" % (func_type, func_name, decl_arglist) |
| wrap += "\n" |
| wrap += "__pinned_func\n" |
| wrap += "static inline %s %s(%s)\n" % (func_type, func_name, decl_arglist) |
| wrap += "{\n" |
| wrap += "#ifdef CONFIG_USERSPACE\n" |
| wrap += ("\t" + "uint64_t ret64;\n") if ret64 else "" |
| wrap += "\t" + "if (z_syscall_trap()) {\n" |
| |
| for parmnum, rec in enumerate(split_args): |
| (argtype, argname) = rec |
| wrap += "\t\t%s parm%d;\n" % (union_decl(argtype), parmnum) |
| wrap += "\t\t" + "parm%d.val = %s;\n" % (parmnum, argname) |
| |
| if len(mrsh_args) > 6: |
| wrap += "\t\t" + "uintptr_t more[] = {\n" |
| wrap += "\t\t\t" + (",\n\t\t\t".join(mrsh_args[5:])) + "\n" |
| wrap += "\t\t" + "};\n" |
| mrsh_args[5:] = ["(uintptr_t) &more"] |
| |
| syscall_id = "K_SYSCALL_" + func_name.upper() |
| invoke = ("arch_syscall_invoke%d(%s)" |
| % (len(mrsh_args), |
| ", ".join(mrsh_args + [syscall_id]))) |
| |
| # Coverity does not understand syscall mechanism |
| # and will already complain when any function argument |
| # is not of exact size as uintptr_t. So tell Coverity |
| # to ignore this particular rule here. |
| wrap += "\t\t/* coverity[OVERRUN] */\n" |
| |
| if ret64: |
| wrap += "\t\t" + "(void)%s;\n" % invoke |
| wrap += "\t\t" + "return (%s)ret64;\n" % func_type |
| elif func_type == "void": |
| wrap += "\t\t" + "(void)%s;\n" % invoke |
| wrap += "\t\t" + "return;\n" |
| elif func_type == "bool": |
| wrap += "\t\t" + "return %s != 0U;\n" % (invoke) |
| else: |
| wrap += "\t\t" + "return (%s) %s;\n" % (func_type, invoke) |
| |
| wrap += "\t" + "}\n" |
| wrap += "#endif\n" |
| |
| # Otherwise fall through to direct invocation of the impl func. |
| # Note the compiler barrier: that is required to prevent code from |
| # the impl call from being hoisted above the check for user |
| # context. |
| impl_arglist = ", ".join([argrec[1] for argrec in args]) |
| impl_call = "z_impl_%s(%s)" % (func_name, impl_arglist) |
| wrap += "\t" + "compiler_barrier();\n" |
| wrap += "\t" + "%s%s;\n" % ("return " if func_type != "void" else "", |
| impl_call) |
| |
| wrap += "}\n" |
| |
| return wrap |
| |
| # Returns an expression for the specified marshalled parameter |
| # to a syscall, with handling for a final "more" parameter. |
| def mrsh_rval(mrsh_num, total): |
| if mrsh_num < 6 or total <= 6: |
| return "arg%d" % mrsh_num |
| else: |
| return "(((const uintptr_t *)more)[%d])" % (mrsh_num - 6) |
| |
| def marshall_defs(func_name, func_type, args): |
| mrsh_name = "z_mrsh_" + func_name |
| |
| nmrsh = 0 # number of marshalled uintptr_t parameter |
| vrfy_parms = [] # list of (arg_num, mrsh_or_parm_num, bool_is_split) |
| split_parms = [] # list of a (arg_num, mrsh_num) for each split |
| for i, (argtype, _) in enumerate(args): |
| if need_split(argtype): |
| vrfy_parms.append((i, len(split_parms) + 1, True)) |
| split_parms.append((i, nmrsh + 1)) |
| nmrsh += 2 |
| else: |
| vrfy_parms.append((i, nmrsh + 1, False)) |
| nmrsh += 1 |
| |
| # Final argument for a 64 bit return value? |
| if need_split(func_type): |
| nmrsh += 1 |
| |
| decl_arglist = ", ".join([" ".join(argrec) for argrec in args]) |
| mrsh = "extern %s z_vrfy_%s(%s);\n" % (func_type, func_name, decl_arglist) |
| |
| mrsh += "uintptr_t %s(uintptr_t arg1, uintptr_t arg2, uintptr_t arg3,\n" % mrsh_name |
| if nmrsh <= 6: |
| mrsh += "\t\t" + "uintptr_t arg4, uintptr_t arg5, uintptr_t arg6, void *ssf)\n" |
| else: |
| mrsh += "\t\t" + "uintptr_t arg4, uintptr_t arg5, uintptr_t more, void *ssf)\n" |
| mrsh += "{\n" |
| mrsh += "\t" + "_current->syscall_frame = ssf;\n" |
| |
| for unused_arg in range(nmrsh + 1, 7): |
| mrsh += "\t(void) arg%d;\t/* unused */\n" % unused_arg |
| |
| if nmrsh > 6: |
| mrsh += ("\tZ_OOPS(Z_SYSCALL_MEMORY_READ((const uintptr_t *)more, " |
| + str(nmrsh - 6) + " * sizeof(uintptr_t)));\n") |
| |
| for i, split_rec in enumerate(split_parms): |
| arg_num, mrsh_num = split_rec |
| arg_type = args[arg_num][0] |
| mrsh += "\t%s parm%d;\n" % (union_decl(arg_type), i + 1) |
| mrsh += "\t" + "parm%d.split.lo = %s;\n" % (i + 1, mrsh_rval(mrsh_num, |
| nmrsh)) |
| mrsh += "\t" + "parm%d.split.hi = %s;\n" % (i + 1, mrsh_rval(mrsh_num + 1, |
| nmrsh)) |
| # Finally, invoke the verify function |
| out_args = [] |
| for i, argn, is_split in vrfy_parms: |
| if is_split: |
| out_args.append("parm%d.val" % argn) |
| else: |
| out_args.append("*(%s*)&%s" % (args[i][0], mrsh_rval(argn, nmrsh))) |
| |
| vrfy_call = "z_vrfy_%s(%s)\n" % (func_name, ", ".join(out_args)) |
| |
| if func_type == "void": |
| mrsh += "\t" + "%s;\n" % vrfy_call |
| mrsh += "\t" + "_current->syscall_frame = NULL;\n" |
| mrsh += "\t" + "return 0;\n" |
| else: |
| mrsh += "\t" + "%s ret = %s;\n" % (func_type, vrfy_call) |
| |
| if need_split(func_type): |
| ptr = "((uint64_t *)%s)" % mrsh_rval(nmrsh, nmrsh) |
| mrsh += "\t" + "Z_OOPS(Z_SYSCALL_MEMORY_WRITE(%s, 8));\n" % ptr |
| mrsh += "\t" + "*%s = ret;\n" % ptr |
| mrsh += "\t" + "_current->syscall_frame = NULL;\n" |
| mrsh += "\t" + "return 0;\n" |
| else: |
| mrsh += "\t" + "_current->syscall_frame = NULL;\n" |
| mrsh += "\t" + "return (uintptr_t) ret;\n" |
| |
| mrsh += "}\n" |
| |
| return mrsh, mrsh_name, nmrsh |
| |
| def analyze_fn(match_group): |
| func, args = match_group |
| |
| try: |
| if args == "void": |
| args = [] |
| else: |
| args = [typename_split(a.strip()) for a in args.split(",")] |
| |
| func_type, func_name = typename_split(func) |
| except SyscallParseException: |
| sys.stderr.write("In declaration of %s\n" % func) |
| raise |
| |
| sys_id = "K_SYSCALL_" + func_name.upper() |
| |
| marshaller = None |
| marshaller, handler, nmrsh = marshall_defs(func_name, func_type, args) |
| invocation = wrapper_defs(func_name, func_type, args) |
| |
| # Entry in _k_syscall_table |
| table_entry = "[%s] = %s" % (sys_id, handler) |
| |
| return (handler, invocation, marshaller, sys_id, table_entry, nmrsh) |
| |
| def parse_args(): |
| global args |
| parser = argparse.ArgumentParser( |
| description=__doc__, |
| formatter_class=argparse.RawDescriptionHelpFormatter) |
| |
| parser.add_argument("-i", "--json-file", required=True, |
| help="Read syscall information from json file") |
| parser.add_argument("-d", "--syscall-dispatch", required=True, |
| help="output C system call dispatch table file") |
| parser.add_argument("-l", "--syscall-list", required=True, |
| help="output C system call list header") |
| parser.add_argument("-o", "--base-output", required=True, |
| help="Base output directory for syscall macro headers") |
| parser.add_argument("-s", "--split-type", action="append", |
| help="A long type that must be split/marshalled on 32-bit systems") |
| parser.add_argument("-x", "--long-registers", action="store_true", |
| help="Indicates we are on system with 64-bit registers") |
| args = parser.parse_args() |
| |
| |
| def main(): |
| parse_args() |
| |
| if args.split_type is not None: |
| for t in args.split_type: |
| types64.append(t) |
| |
| with open(args.json_file, 'r') as fd: |
| syscalls = json.load(fd) |
| |
| invocations = {} |
| mrsh_defs = {} |
| mrsh_includes = {} |
| ids = [] |
| table_entries = [] |
| handlers = [] |
| arg_numbers = [] |
| |
| for match_group, fn in syscalls: |
| handler, inv, mrsh, sys_id, entry, nmrsh = analyze_fn(match_group) |
| |
| if fn not in invocations: |
| invocations[fn] = [] |
| |
| invocations[fn].append(inv) |
| ids.append(sys_id) |
| table_entries.append(entry) |
| handlers.append(handler) |
| arg_numbers.append(nmrsh) |
| |
| if mrsh: |
| syscall = typename_split(match_group[0])[1] |
| mrsh_defs[syscall] = mrsh |
| mrsh_includes[syscall] = "#include <syscalls/%s>" % fn |
| |
| with open(args.syscall_dispatch, "w") as fp: |
| table_entries.append("[K_SYSCALL_BAD] = handler_bad_syscall") |
| |
| weak_defines = "".join([weak_template % (name, |
| "arg6" if nmrsh <= 6 else "more") |
| for (name, nmrsh) in zip(handlers, arg_numbers) |
| if not name in noweak]) |
| |
| # The "noweak" ones just get a regular declaration |
| weak_defines += "\n".join(["extern uintptr_t %s(uintptr_t arg1, uintptr_t arg2, uintptr_t arg3, uintptr_t arg4, uintptr_t arg5, uintptr_t arg6, void *ssf);" |
| % s for s in noweak]) |
| |
| fp.write(table_template % (weak_defines, |
| ",\n\t".join(table_entries))) |
| |
| # Listing header emitted to stdout |
| ids.sort() |
| ids.extend(["K_SYSCALL_BAD", "K_SYSCALL_LIMIT"]) |
| |
| ids_as_defines = "" |
| for i, item in enumerate(ids): |
| ids_as_defines += "#define {} {}\n".format(item, i) |
| |
| with open(args.syscall_list, "w") as fp: |
| fp.write(list_template % ids_as_defines) |
| |
| os.makedirs(args.base_output, exist_ok=True) |
| for fn, invo_list in invocations.items(): |
| out_fn = os.path.join(args.base_output, fn) |
| |
| ig = re.sub("[^a-zA-Z0-9]", "_", "Z_INCLUDE_SYSCALLS_" + fn).upper() |
| include_guard = "#ifndef %s\n#define %s\n" % (ig, ig) |
| header = syscall_template % (include_guard, "\n\n".join(invo_list)) |
| |
| with open(out_fn, "w") as fp: |
| fp.write(header) |
| |
| # Likewise emit _mrsh.c files for syscall inclusion |
| for fn in mrsh_defs: |
| mrsh_fn = os.path.join(args.base_output, fn + "_mrsh.c") |
| |
| with open(mrsh_fn, "w") as fp: |
| fp.write("/* auto-generated by gen_syscalls.py, don't edit */\n") |
| fp.write("#if (__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 6))\n") |
| fp.write("#pragma GCC diagnostic push\n") |
| fp.write("#endif\n") |
| fp.write("#ifdef __GNUC__\n") |
| fp.write("#pragma GCC diagnostic ignored \"-Wstrict-aliasing\"\n") |
| fp.write("#endif\n") |
| fp.write(mrsh_includes[fn] + "\n") |
| fp.write("\n") |
| fp.write(mrsh_defs[fn] + "\n") |
| fp.write("#if (__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 6))\n") |
| fp.write("#pragma GCC diagnostic pop\n") |
| fp.write("#endif\n") |
| |
| if __name__ == "__main__": |
| main() |
