Add some information to /proc/cpuinfo

arch/lkl/include/uapi/asm/host_ops.h

@@ -107,6 +107,12 @@ struct ucontext;
  * the function that will eventually call longjmp here
  *
  * @jmp_buf_longjmp - perform a jump back to the saved jump buffer
+ *
+ * @cpuinfo_get - Returns the /proc/cpuinfo string. It needs to be provided a
+ * pointer to the destination buffer and its size, and it returns the total
+ * length of the string. As the string may be longer than the provided buffer,
+ * the returned value may be bigger than the buffer size. The string will be
+ * cropped in that case.
  */
 struct lkl_host_operations {
 	const char *virtio_devices;
@@ -159,6 +165,8 @@ struct lkl_host_operations {
 
 	void (*jmp_buf_set)(struct lkl_jmp_buf *jmpb, void (*f)(void));
 	void (*jmp_buf_longjmp)(struct lkl_jmp_buf *jmpb, int val);
+
+	unsigned int (*cpuinfo_get)(char *buffer, unsigned int buffer_len);
 };
 
 /**

arch/lkl/kernel/proc.c

@@ -1,69 +1,77 @@
 
+#include <asm/host_ops.h>
+#include <linux/printk.h>
 #include <linux/seq_file.h>
+#include <linux/slab.h>
 
 #ifdef CONFIG_PROC_FS
 
-/*
- * TODO: This currently just hard-codes some output for /proc/cpuinfo that is
- * plausible and can be parsed by an application. Note though that CPU features, 
- * the virtual CPU core count and socket count are wrong.
- */
+static char *cpuinfo_buf;
+static unsigned int cpuinfo_len;
+
 static int show_cpuinfo(struct seq_file *m, void *v)
 {
-    seq_printf(m, "processor       : 0\n"
-                "cpu family      : 6\n"
-                "model           : 158\n"
-                "model name      : Intel(R) Xeon(R) CPU E3-1280 v6 @ 3.90GHz\n"
-                "stepping        : 9\n"
-                "microcode       : 0xb4\n"
-                "cpu MHz         : 800.063\n"
-                "cache size      : 8192 KB\n"
-                "physical id     : 0\n"
-                "siblings        : 4\n"
-                "core id         : 0\n"
-                "cpu cores       : 4\n"
-                "apicid          : 0\n"
-                "initial apicid  : 0\n"
-                "fpu             : yes\n"
-                "fpu_exception   : yes\n"
-                "cpuid level     : 22\n"
-                "wp              : yes\n"
-                "flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb invpcid_single pti ssbd ibrs ibpb stibp tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm mpx rdseed adx smap clflushopt intel_pt xsaveopt xsavec xgetbv1 xsaves dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp md_clear flush_l1d\n"
-                "bugs            : cpu_meltdown spectre_v1 spectre_v2 spec_store_bypass l1tf mds swapgs\n"
-                "bogomips        : 7824.00\n"
-                "clflush size    : 64\n"
-                "cache_alignment : 64\n"
-                "address sizes   : 39 bits physical, 48 bits virtual\n"
-                "power management: \n");
-
-    seq_puts(m, "\n\n");
-
-    return 0;
-}
+	loff_t *spos = v;
+
+	if (*spos >= cpuinfo_len)
+		return 0;
+
+	seq_putc(m, cpuinfo_buf[*spos]);
 
-int __cpuinfo_accessed = 0;
+	return 0;
+}
 
 static void *c_start(struct seq_file *m, loff_t *pos)
 {
-  // TODO: missing correct implementation
-
-  // Only output information once
-  if (__cpuinfo_accessed)
-    return NULL;
-
-  __cpuinfo_accessed = 1;
-  return (void*)1;
+	unsigned int buf_size;
+	loff_t *spos;
+
+	if (cpuinfo_buf == NULL) {
+
+		/* How big is the buffer that we need? */
+		cpuinfo_len = lkl_ops->cpuinfo_get(NULL, 0);
+		buf_size = cpuinfo_len + 1;
+
+		cpuinfo_buf = kmalloc(buf_size, GFP_KERNEL);
+		if (cpuinfo_buf == NULL) {
+			printk("cpuinfo: Not enough memory (%u bytes needed)\n", buf_size);
+			return NULL;
+		}
+
+		/* Print cpuinfo to the buffer we have allocated */
+		cpuinfo_len = lkl_ops->cpuinfo_get(cpuinfo_buf, buf_size);
+	}
+
+	spos = kmalloc(sizeof(loff_t), GFP_KERNEL);
+	if (spos == NULL) {
+		printk("cpuinfo: Not enough memory (%lu bytes needed)\n",
+				sizeof(loff_t));
+		return NULL;
+	}
+
+	if (*pos >= cpuinfo_len)
+		return NULL;
+
+	*spos = *pos;
+	return spos;
 }
 
 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
 {
-  // TODO: missing implementation
-  return NULL;
+	loff_t *spos = v;
+
+	*spos = *spos + 1;
+	*pos = *spos;
+
+	if (*spos >= cpuinfo_len)
+		return NULL;
+
+	return spos;
 }
 
 static void c_stop(struct seq_file *m, void *v)
 {
-  // TODO: missing implementation
+	kfree(v);
 }
 
 const struct seq_operations cpuinfo_op = {
@@ -73,4 +81,4 @@ const struct seq_operations cpuinfo_op = {
 	.show	= show_cpuinfo,
 };
 
-#endif
+#endif

tools/lkl/Targets

@@ -22,6 +22,7 @@ LDLIBS_cptofs-y := -larchive
 LDLIBS_cptofs-$(LKL_HOST_CONFIG_NEEDS_LARGP) += -largp
 
 progs-y += tests/boot
+progs-y += tests/cpuinfo
 progs-y += tests/disk
 progs-y += tests/net-test
 

tools/lkl/lib/posix-host.c

@@ -6,6 +6,7 @@
 #include <assert.h>
 #include <unistd.h>
 #include <errno.h>
+#include <stdio.h>
 #include <string.h>
 #include <time.h>
 #include <stdint.h>
@@ -311,6 +312,42 @@ static long _gettid(void)
 #endif
 }
 
+static unsigned int cpuinfo_get(char *buffer, unsigned int buffer_len)
+{
+	/* TODO: The output of this function is hardcoded for now. */
+	int len;
+
+	len = snprintf(buffer, buffer_len,
+		"processor       : 0\n"
+		"cpu family      : 6\n"
+		"model           : 158\n"
+		"model name      : Intel(R) Xeon(R) CPU E3-1280 v6 @ 3.90GHz\n"
+		"stepping        : 9\n"
+		"microcode       : 0xb4\n"
+		"cpu MHz         : 800.063\n"
+		"cache size      : 8192 KB\n"
+		"physical id     : 0\n"
+		"siblings        : 1\n"
+		"core id         : 0\n"
+		"cpu cores       : 1\n"
+		"apicid          : 0\n"
+		"initial apicid  : 0\n"
+		"fpu             : yes\n"
+		"fpu_exception   : yes\n"
+		"cpuid level     : 22\n"
+		"wp              : yes\n"
+		"flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse3 clflush dts ac  pi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bt rep_good nopl x  topology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg   fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm aabm   3dnowprefetch cpuid_fault epb invpcid_single pti ssbd ibrs ibpb stibp tpr_shadow vnmi flexpriority ept vpid fsgsbase   tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm mpx rdseed adx smap clflushopt intel_pt xsaveopt xsavec xgetbv1   xsaves dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp md_clear flush_l1d\n"
+		"bugs            : cpu_meltdown spectre_v1 spectre_v2 spec_store_bypass l1tf mds swapgs\n"
+		"bogomips        : 7824.00\n"
+		"clflush size    : 64\n"
+		"cache_alignment : 64\n"
+		"address sizes   : 39 bits physical, 48 bits virtual\n"
+		"power management: \n"
+		"\n");
+
+	return len;
+}
+
 struct lkl_host_operations lkl_host_ops = {
 	.panic = panic,
 	.thread_create = thread_create,
@@ -344,6 +381,7 @@ struct lkl_host_operations lkl_host_ops = {
 	.gettid = _gettid,
 	.jmp_buf_set = jmp_buf_set,
 	.jmp_buf_longjmp = jmp_buf_longjmp,
+	.cpuinfo_get = cpuinfo_get,
 };
 
 static int fd_get_capacity(struct lkl_disk disk, unsigned long long *res)

tools/lkl/tests/Build

@@ -1,3 +1,4 @@
 boot-y += boot.o test.o
+cpuinfo-y += cpuinfo.o test.o
 disk-y += disk.o cla.o test.o
 net-test-y += net-test.o cla.o test.o

tools/lkl/tests/cpuinfo.c

@@ -0,0 +1,116 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <lkl.h>
+#include <lkl_host.h>
+
+#include "test.h"
+
+LKL_TEST_CALL(start_kernel, lkl_start_kernel, 0, &lkl_host_ops,
+	      "mem=16M loglevel=8");
+
+static int lkl_test_cpuinfo(void)
+{
+	/* The buffer size must be a multiple of the read sizes */
+#define BUF_SIZE (64 * 1024)
+#define READ_SIZE_1 16
+#define READ_SIZE_2 32
+
+	int ret;
+	int err;
+	int f1, f2;
+	static char buf1[BUF_SIZE], buf2[BUF_SIZE];
+	long read1, read2;
+	int done1, done2;
+	long totalread1, totalread2;
+
+	ret = TEST_FAILURE;
+
+	err = lkl_mount_fs("proc");
+	if (err < 0) {
+		lkl_test_logf("failed to mount /proc\n");
+		return TEST_FAILURE;
+	}
+
+	f1 = lkl_sys_open("/proc/cpuinfo", LKL_O_RDONLY, 0);
+	if (f1 < 0) {
+		lkl_test_logf("failed to open /proc/cpuinfo (f1): %s\n",
+			      lkl_strerror(f1));
+		return TEST_FAILURE;
+	}
+
+	f2 = lkl_sys_open("/proc/cpuinfo", LKL_O_RDONLY, 0);
+	if (f2 < 0) {
+		lkl_sys_close(f1);
+		lkl_test_logf("failed to open /proc/cpuinfo (f2): %s\n",
+			      lkl_strerror(f2));
+		return TEST_FAILURE;
+	}
+
+	totalread1 = 0;
+	totalread2 = 0;
+
+	done1 = 0;
+	done2 = 0;
+
+	while (!done1 || !done2) {
+		if (totalread1 >= (BUF_SIZE - READ_SIZE_1)) {
+			lkl_test_logf("file is too big\n");
+			totalread1 = 0;
+			break;
+		}
+
+		if (totalread2 >= (BUF_SIZE - READ_SIZE_2)) {
+			lkl_test_logf("file is too big\n");
+			totalread2 = 0;
+			break;
+		}
+
+		if (!done1) {
+			read1 = lkl_sys_read(f1, &(buf1[totalread1]),
+					     READ_SIZE_1);
+			if (read1 <= 0)
+				done1 = 1;
+			totalread1 += read1;
+		}
+
+		if (!done2) {
+			read2 = lkl_sys_read(f2, &(buf2[totalread2]),
+					     READ_SIZE_2);
+			if (read2 <= 0)
+				done2 = 1;
+			totalread2 += read2;
+		}
+	}
+
+	lkl_sys_close(f1);
+	lkl_sys_close(f2);
+
+	if (totalread1 == 0) {
+		lkl_test_logf("file is empty\n");
+	} else if (totalread1 != totalread2) {
+		lkl_test_logf("sizes don't match: %lu != %lu\n",
+			      totalread1, totalread2);
+	} else {
+		if (memcmp(buf1, buf2, totalread1) == 0)
+			ret = TEST_SUCCESS;
+		else
+			lkl_test_logf("read contents don't match");
+	}
+
+	return ret;
+}
+
+struct lkl_test tests[] = {
+	LKL_TEST(start_kernel),
+	LKL_TEST(cpuinfo),
+};
+
+int main(int argc, const char **argv)
+{
+	lkl_host_ops.print = lkl_test_log;
+
+	return lkl_test_run(tests, sizeof(tests)/sizeof(struct lkl_test),
+			    "cpuinfo");
+}

tools/lkl/tests/cpuinfo.sh

@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+
+script_dir=$(cd $(dirname ${BASH_SOURCE:-$0}); pwd)
+source $script_dir/test.sh
+
+lkl_test_plan 1 "cpuinfo"
+lkl_test_run 1
+lkl_test_exec $script_dir/cpuinfo

tools/lkl/tests/run.py

@@ -49,6 +49,7 @@ def end(self, obj):
 
 tests = [
     'boot.sh',
+    'cpuinfo.sh',
     'disk.sh -t ext4',
     'disk.sh -t btrfs',
     'disk.sh -t vfat',