obj-m += hello-1.o

all:
make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules

clean:
make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean

这是错误：

snehil@ubuntu:~/Desktop/measure$make
make -C /lib/modules/3.0.0-12-generic/build M=/home/snehil/Desktop/measure modules
make[1]: Entering directory `/usr/src/linux-headers-3.0.0-12-generic'
CC [M]  /home/snehil/Desktop/measure/measure1.o
/home/snehil/Desktop/measure/measure1.c: In function ‘hello_start’:
/home/snehil/Desktop/measure/measure1.c:108:2: error: implicit declaration of function
  ‘kmalloc’ [-Werror=implicit-function-declaration]
/home/snehil/Desktop/measure/measure1.c:108:8: warning: assignment makes pointer from  
 integer without a cast [enabled by default]
/home/snehil/Desktop/measure/measure1.c:115:11: warning: assignment makes pointer from
 integer without a cast [enabled by default]
/home/snehil/Desktop/measure/measure1.c:124:12: warning: assignment makes pointer from  
integer without a cast [enabled by default]
/home/snehil/Desktop/measure/measure1.c:130:13: warning: assignment makes pointer from
integer without a cast [enabled by default]
cc1: some warnings being treated as errors

make[2]: *** [/home/snehil/Desktop/measure/measure1.o] Error 1
make[1]: *** [_module_/home/snehil/Desktop/measure] Error 2
make[1]: Leaving directory `/usr/src/linux-headers-3.0.0-12-generic'
make: *** [all] Error 2
snehil@ubuntu:~/Desktop/measure$gcc measure1
gcc: error: measure1: No such file or directory
gcc: fatal error: no input files
compilation terminated.

这是内核模块代码：

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/hardirq.h>
#include <linux/preempt.h>
#include <linux/sched.h>

#define SIZE_OF_STAT 100000
#define BOUND_OF_LOOP 1000
#define UINT64_MAX (18446744073709551615ULL)

void inline Filltimes(uint64_t **times) {
unsigned long flags;
int i,j;
uint64_t start,end;
unsigned cycles_low,cycles_high,cycles_low1,cycles_high1;
volatile int variable = 0;

asm volatile ("cpuID\n\t"
"RDTSC\n\t"
"mov %%edx,%0\n\t"
"mov %%eax,%1\n\t": "=r" (cycles_high),"=r" (cycles_low)::"%rax","%rbx","%rcx","%rdx");
asm volatile ("cpuID\n\t"
"RDTSC\n\t"
"cpuID\n\t"
"RDTSC\n\t"
"mov %%edx,"=r" (cycles_low):: "%rax","%rdx");
asm volatile ("cpuID\n\t"
"RDTSC\n\t"::: "%rax","%rdx");


for (j=0; j<BOUND_OF_LOOP; j++) {
for (i =0; i<SIZE_OF_STAT; i++) { 

variable = 0;

preempt_disable();
raw_local_irq_save(flags);

asm volatile (
"cpuID\n\t"
"RDTSC\n\t"
"mov %%edx,"%rdx");
/*call the function to measure here*/
asm volatile(
"cpuID\n\t"
"RDTSC\n\t"
"mov %%edx,%0\n\t"
 "mov %%eax,%1\n\t": "=r" (cycles_high1),"=r" (cycles_low1):: "%rax","%rdx");

raw_local_irq_restore(flags);
preempt_enable();


start = ( ((uint64_t)cycles_high << 32) | cycles_low );

end = ( ((uint64_t)cycles_high1 << 32) | cycles_low1 );

if ( (end - start) < 0) {
printk(KERN_ERR "\n\n>>>>>>>>>>>>>>  CRITICAL ERROR IN TAKING THE TIME!!!!!!\n loop(%d)
 stat(%d) start = %llu,end = %llu,variable = %u\n",j,i,start,end,variable);
times[j][i] = 0;
}
else 
{
times[j][i] = end - start;
}
}
}   
return;
}
uint64_t var_calc(uint64_t *inputs,int size)
{
 int i;
uint64_t acc = 0,prevIoUs = 0,temp_var = 0;
for (i=0; i< size; i++) {
if (acc < prevIoUs) goto overflow;
prevIoUs = acc;
acc += inputs[i];
}
acc = acc * acc;
if (acc < prevIoUs) goto overflow;
prevIoUs = 0;
for (i=0; i< size; i++){
if (temp_var < prevIoUs) goto overflow;
prevIoUs = temp_var;
temp_var+= (inputs[i]*inputs[i]);
}
 temp_var = temp_var * size;
if (temp_var < prevIoUs) goto overflow;
temp_var =(temp_var - acc)/(((uint64_t)(size))*((uint64_t)(size)));
 return (temp_var);
overflow:
printk(KERN_ERR "\n\n>>>>>>>>>>>>>> CRITICAL OVERFLOW ERROR IN var_calc!!!!!!\n\n");
return -EINVAL;
}
static int __init hello_start(void)
{
int i = 0,j = 0,spurIoUs = 0,k =0;
uint64_t **times;
uint64_t *variances;
uint64_t *min_values;
uint64_t max_dev = 0,min_time = 0,max_time = 0,prev_min =0,tot_var=0,max_dev_all=0,var_of_vars=0,var_of_mins=0;

printk(KERN_INFO "Loading hello module...\n");

times = kmalloc(BOUND_OF_LOOP*sizeof(uint64_t*),GFP_KERNEL);
if (!times) {
printk(KERN_ERR "unable to allocate memory for times\n");
return 0;
}

for (j=0; j<BOUND_OF_LOOP; j++) {
times[j] = kmalloc(SIZE_OF_STAT*sizeof(uint64_t),GFP_KERNEL);
if (!times[j]) {
printk(KERN_ERR "unable to allocate memory for times[%d]\n",j);
for (k=0; k<j; k++)
kfree(times[k]);
return 0;
}
}

variances = kmalloc(BOUND_OF_LOOP*sizeof(uint64_t),GFP_KERNEL);
if (!variances) {
printk(KERN_ERR "unable to allocate memory for variances\n");
return 0;
}

min_values = kmalloc(BOUND_OF_LOOP*sizeof(uint64_t),GFP_KERNEL);
if (!min_values) {
printk(KERN_ERR "unable to allocate memory for min_values\n");
return 0;
}


Filltimes(times);

for (j=0; j<BOUND_OF_LOOP; j++) {

max_dev = 0;
min_time = 0;
max_time = 0;

for (i =0; i<SIZE_OF_STAT; i++) {
if ((min_time == 0)||(min_time > times[j][i]))
min_time = times[j][i];
if (max_time < times[j][i])
max_time = times[j][i];
}

max_dev = max_time - min_time;
min_values[j] = min_time;

if ((prev_min != 0) && (prev_min > min_time))
spurIoUs++;
if (max_dev > max_dev_all)
max_dev_all = max_dev;

variances[j] = var_calc(times[j],SIZE_OF_STAT);
tot_var += variances[j];

printk(KERN_ERR "loop_size:%d >>>> variance(cycles): %llu; max_deviation: %llu ;min 
 time: %llu",variances[j],max_dev,min_time);

prev_min = min_time;
}

var_of_vars = var_calc(variances,BOUND_OF_LOOP);
var_of_mins = var_calc(min_values,BOUND_OF_LOOP);
printk(KERN_ERR "\n total number of spurIoUs min values = %d",spurIoUs);
printk(KERN_ERR "\n total variance = %llu",(tot_var/BOUND_OF_LOOP));
printk(KERN_ERR "\n absolute max deviation = %llu",max_dev_all);
printk(KERN_ERR "\n variance of variances = %llu",var_of_vars);
printk(KERN_ERR "\n variance of minimum values = %llu",var_of_mins);

for (j=0; j<BOUND_OF_LOOP; j++) {
kfree(times[j]);
}
kfree(times);
kfree(variances);
kfree(min_values);
return 0;
}

static void __exit hello_end(void)
{
printk(KERN_INFO "Goodbye Mr.\n");
}

module_init(hello_start);
module_exit(hello_end);