Hi, Please ignore the email below. I am sorry I made a very silly mistake. Thanks Vaibhav Jain On Wed, Oct 19, 2011 at 10:12 AM, Vaibhav Jain <vjoss197@gmail.com> wrote:

On Fri, Oct 14, 2011 at 9:10 PM, Mulyadi Santosa < mulyadi.santosa@gmail.com> wrote:

...

hi...

On Sat, Oct 15, 2011 at 07:22, Vaibhav Jain <vjoss197@gmail.com> wrote:

...

Hi,

I am trying to map local APIC on an intel system (physical address 0xfee00000) in a user level program using mmap but my mmap is failing saying "Bad file descriptor". I am not sure if this problem is related to apic or mmap. I am running the program as root. Please help me figure this out.

could you post the code?

anyway, check "man mmap" in "errors" section....the hint could be found there.....

-- regards,

Mulyadi Santosa Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com

Hi,

Here's the code

typedef unsigned int u32;

#define MAP_LEN 0x1000 //4 KB page #define BUFLEN 100 *#define APIC_BASE 0xfee00000* #define APIC_ICR_low 0xfee00300 #define APIC_ICR_high 0xfee00310 #define APIC_ICR_init 0x00000500 #define APIC_ICR_start 0x00000600 #define APIC_ICR_ASSERT_LVL_TRG 0x0000c000 #define BOUNCE_CODE 0x2000

int apic_reset_cpu(cpu); int cpu = 2;

int main(){ if ((apic_reset_cpu(cpu)) != 0) printf("INIT & Startup failed!\n"); }

int apic_reset_cpu(int cpu) { unsigned long tmpaddress, apic_icr, *apic_phy_addr; int fd, sleep_now=0;

printf("Assuming APIC physical base: %lx \n", APIC_BASE); tmpaddress = (unsigned long) mmap(NULL, MAP_LEN, PROT_READ|PROT_WRITE, MAP_SHARED, fd, (off_t)APIC_BASE);

* if(tmpaddress == (unsigned long)MAP_FAILED) //check if it worked { perror("Mapping memory for absolute memory access failed.\n"); return -3; }*

//prep ICR high apic_icr = tmpaddress; apic_icr |= APIC_ICR_high; apic_phy_addr = (unsigned long *) apic_icr; *apic_phy_addr = cpu << 24;

//prep ICR low Send INIT and wait apic_icr = tmpaddress; apic_icr |= APIC_ICR_low; apic_phy_addr = (unsigned long *) apic_icr; *apic_phy_addr = APIC_ICR_init | APIC_ICR_ASSERT_LVL_TRG; sleep_now = usleep( 10000 ); //sleep 10 ms

//prep for SIPI apic_icr = tmpaddress; apic_icr |= APIC_ICR_low; apic_phy_addr = (unsigned long *) apic_icr; *apic_phy_addr = APIC_ICR_start | (BOUNCE_CODE >> 12); sleep_now = usleep( 500 ); //sleep 500 usec

printf("Unmapping APIC Base page\n"); tmpaddress &= 0xfffff000; munmap(tmpaddress, MAP_LEN);

return 0; }

Thanks Vaibhav Jain