Add luacpu module

Kbuild

@@ -52,4 +52,5 @@ obj-$(CONFIG_LUNATIK_CRYPTO_SKCIPHER) += lib/luacrypto_skcipher.o
 obj-$(CONFIG_LUNATIK_CRYPTO_AEAD) += lib/luacrypto_aead.o
 obj-$(CONFIG_LUNATIK_CRYPTO_RNG) += lib/luacrypto_rng.o
 obj-$(CONFIG_LUNATIK_CRYPTO_COMP) += lib/luacrypto_comp.o
+obj-$(CONFIG_LUNATIK_CPU) += lib/luacpu.o
 

Makefile

@@ -30,7 +30,7 @@ all: lunatik_sym.h
 	CONFIG_LUNATIK_NETFILTER=m CONFIG_LUNATIK_COMPLETION=m \
 	CONFIG_LUNATIK_CRYPTO_SHASH=m CONFIG_LUNATIK_CRYPTO_SKCIPHER=m \
 	CONFIG_LUNATIK_CRYPTO_AEAD=m CONFIG_LUNATIK_CRYPTO_RNG=m \
-	CONFIG_LUNATIK_CRYPTO_COMP=m
+	CONFIG_LUNATIK_CRYPTO_COMP=m CONFIG_LUNATIK_CPU=m
 
 clean:
 	${MAKE} -C ${MODULES_BUILD_PATH} M=${PWD} clean

bin/lunatik

@@ -10,7 +10,7 @@ local lunatik = {
 	modules = {"lunatik", "luadevice", "lualinux", "luanotifier", "luasocket", "luarcu",
 		"luathread", "luafib", "luadata", "luaprobe", "luasyscall", "luaxdp", "luafifo", "luaxtable",
 		"luanetfilter", "luacompletion", "luacrypto_shash", "luacrypto_skcipher", "luacrypto_aead",
-		"luacrypto_rng", "luacrypto_comp", "lunatik_run"}
+		"luacrypto_rng", "luacrypto_comp", "luacpu", "lunatik_run"},
 }
 
 function lunatik.prompt()

lib/luacpu.c

@@ -0,0 +1,196 @@
+/*
+* SPDX-FileCopyrightText: (c) 2025 Enderson Maia <[email protected]
+* SPDX-License-Identifier: MIT OR GPL-2.0-only
+*/
+
+/***
+* Linux CPU Lua interface.
+*
+* This module provides access to Linux's CPU abstractions.
+*
+* @module cpu
+*/
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
+#include <linux/cpumask.h>
+#include <linux/kernel_stat.h>
+
+#include <lua.h>
+#include <lualib.h>
+#include <lauxlib.h>
+
+#include <lunatik.h>
+
+#define LUACPU_NUM(name)					\
+static int luacpu_num_##name(lua_State *L) {			\
+	lua_pushinteger(L, (lua_Integer)num_##name##_cpus());	\
+	return 1;						\
+}
+
+/***
+* Returns the possible CPUs in the system.
+*
+* @function num_possible
+* @treturn integer The number of possible CPUs in the system
+*/
+LUACPU_NUM(possible)
+
+/***
+* Returns the possible CPUs in the system.
+*
+* @function num_possible
+* @treturn integer The number of possible CPUs in the system
+*/
+LUACPU_NUM(present)
+
+/***
+* Returns the possible CPUs in the system.
+*
+* @function num_possible
+* @treturn integer The number of possible CPUs in the system
+*/
+LUACPU_NUM(online)
+
+/***
+ * Macro to set CPU statistics in Lua table.
+ * @param L Lua state
+ * @param idx Index of the table in the Lua stack
+ * @param kcs Kernel CPU statistics structure (kernel_cpustat)
+ * @param name Field name in the Lua table
+ * @param NAME Corresponding C enum name for CPU time
+ */
+#define luacpu_setstat(L, idx, kcs, name, NAME)				\
+do {									\
+	lua_pushinteger(L, (lua_Integer)kcs.cpustat[CPUTIME_##NAME]);	\
+	lua_setfield(L, idx - 1, #name);				\
+} while (0)
+
+/***
+* Gets CPU statistics for a specific CPU.
+* Fetches kernel CPU statistics including user, nice, system, idle, iowait,
+* irq, softirq, steal, guest, guest_nice and forceidle times.
+*
+* @function stats
+* @tparam integer cpu The CPU number (0-based) to query.
+* @treturn table A table containing CPU time statistics with the following fields:
+*   @tfield integer user Time spent in user mode
+*   @tfield integer nice Time spent in user mode with low priority (nice)
+*   @tfield integer system Time spent in system mode
+*   @tfield integer idle Time spent in idle task
+*   @tfield integer iowait Time waiting for I/O to complete
+*   @tfield integer irq Time servicing hardware interrupts
+*   @tfield integer softirq Time servicing software interrupts
+*   @tfield integer steal Time stolen by other operating systems (virtualized environment)
+*   @tfield integer guest Time spent running a virtual CPU for guest OS
+*   @tfield integer guest_nice Time spent running a niced guest
+*   @tfield integer forceidle Time spent in forced idle (if CONFIG_SCHED_CORE is enabled)
+* @raise Error if CPU is offline
+* @usage
+*   local cpu0 = cpu.stats(0)
+*   print("CPU 0 user time:", cpu0.user)
+*   print("CPU 0 idle time:", cpu0.idle)
+*/
+static int luacpu_stats(lua_State *L)
+{
+	unsigned int cpu = luaL_checkinteger(L, 1);
+	struct kernel_cpustat kcs;
+
+	luaL_argcheck(L, cpu_online(cpu), 1, "CPU is offline");
+
+	kcpustat_cpu_fetch(&kcs, cpu);
+
+	lua_createtable(L, 0, NR_STATS);
+
+	luacpu_setstat(L, -1, kcs, user, USER);
+	luacpu_setstat(L, -1, kcs, nice, NICE);
+	luacpu_setstat(L, -1, kcs, system, SYSTEM);
+	luacpu_setstat(L, -1, kcs, idle, IDLE);
+	luacpu_setstat(L, -1, kcs, iowait, IOWAIT);
+	luacpu_setstat(L, -1, kcs, irq, IRQ);
+	luacpu_setstat(L, -1, kcs, softirq, SOFTIRQ);
+	luacpu_setstat(L, -1, kcs, steal, STEAL);
+	luacpu_setstat(L, -1, kcs, guest, GUEST);
+	luacpu_setstat(L, -1, kcs, guest_nice, GUEST_NICE);
+#ifdef CONFIG_SCHED_CORE
+	luacpu_setstat(L, -1, kcs, forceidle, FORCEIDLE);
+#endif
+	return 1;
+}
+
+#define LUACPU_FOREACH(name)				\
+static int luacpu_foreach_##name(lua_State *L) {	\
+	unsigned int cpu;				\
+	luaL_checktype(L, 1, LUA_TFUNCTION);		\
+	for_each_##name##_cpu(cpu) {			\
+		lua_pushvalue(L, 1);			\
+		lua_pushinteger(L, cpu);		\
+		lua_call(L, 1, 0);			\
+	}						\
+	return 0;					\
+};
+
+/***
+* Iterates over all possible CPUs and calls a function for each.
+*
+* @function foreach_possible
+* @tparam function callback Function to call for each possible CPU
+* @usage
+*   cpu.foreach_possible(function(cpu_num)
+*       print("CPU", cpu.stats(cpu_num))
+*   end)
+*/
+LUACPU_FOREACH(possible)
+
+/***
+* Iterates over all present CPUs and calls a function for each.
+*
+* @function foreach_present
+* @tparam function callback Function to call for each present CPU
+* @usage
+*   cpu.foreach_present(function(cpu_num)
+*       print("CPU", cpu.stats(cpu_num))
+*   end)
+*/
+LUACPU_FOREACH(present)
+
+/***
+* Iterates over all online CPUs and calls a function for each.
+*
+* @function foreach_online
+* @tparam function callback Function to call for each online CPU
+* @usage
+*   cpu.foreach_online(function(cpu_num)
+*       print("CPU", cpu.stats(cpu_num))
+*   end)
+*/
+LUACPU_FOREACH(online)
+
+static const luaL_Reg luacpu_lib[] = {
+	{"num_possible", luacpu_num_possible},
+	{"num_present", luacpu_num_present},
+	{"num_online", luacpu_num_online},
+	{"stats", luacpu_stats},
+	{"foreach_possible", luacpu_foreach_possible},
+	{"foreach_present", luacpu_foreach_present},
+	{"foreach_online", luacpu_foreach_online},
+	{NULL, NULL}
+};
+
+LUNATIK_NEWLIB(cpu, luacpu_lib, NULL, NULL);
+
+static int __init luacpu_init(void)
+{
+	return 0;
+}
+
+static void __exit luacpu_exit(void)
+{
+}
+
+module_init(luacpu_init);
+module_exit(luacpu_exit);
+MODULE_LICENSE("Dual MIT/GPL");
+MODULE_AUTHOR("Enderson Maia <[email protected]");
+MODULE_DESCRIPTION("Lunatik interface to Linux's CPU abstractions.");
+