Re: Problem with a UDP server implements
Hi! On Die, 2011-10-18 at 22:48 +0800, tao jiang wrote: [...] Thanks for your guide. But there is still a question if recvfrom() used, how to figure out the client's dest ip for reply ? i.e. on which ip the server receieved the request when construct the IP header, i don't know which saddr to fill in Ooops, forgot that we need the destination address of the received packet too to construct the answer for it. Then yes, it seems that you would need the raw packet on the receiving side too. [ Full quote deelted ] Bernd -- Bernd Petrovitsch Email : be...@petrovitsch.priv.at LUGA : http://www.luga.at ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
print contents of runqueue
Hi, I want to print contents of runqueue of my current processor. I got the pointer to current task_struct. To get runqueue, I called task_rq(). When compiled the module, it gave an error. Actually struct runqueue and task_rq() is not in any header file. It is present in kernel/sched.c Is there any way to access this structure without making changes to kernel . -- Regards, Kashish ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Trouble removing character device
I can't seem to get my character device to remove itself from the /proc/devices list. I'm calling all of the following functions like so: alloc_chrdev_region(dev, 0, 5, my_char); cdev_init(my_cdev, my_ops); cdev_add(my_cdev, MKDEV(my_major, my_minor), 1); cdev_del(my_cdev); unregister_chrdev_region(my_major, 5); It seems like I'm missing something, but I can't find it. I'm referencing the Linux Device Drivers v3, chapter 3. In the example code, the scull_cleanup_module function calls cdev_dell and unregister_chrdev_region, just like I do. To be clear, after I unload my module (after calling cdev_del and unregister_chrdev_region), my my_char string still shows up in /proc/devices. -Kai Meyer ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: mmap local APIC address
On Fri, Oct 14, 2011 at 9:10 PM, Mulyadi Santosa
mulyadi.sant...@gmail.comwrote:
hi...
On Sat, Oct 15, 2011 at 07:22, Vaibhav Jain vjoss...@gmail.com wrote:
Hi,
I am trying to map local APIC on an intel system (physical address
0xfee0) 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 sectionthe 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 0xfee0*
#define APIC_ICR_low0xfee00300
#define APIC_ICR_high 0xfee00310
#define APIC_ICR_init 0x0500
#define APIC_ICR_start 0x0600
#define APIC_ICR_ASSERT_LVL_TRG 0xc000
#define BOUNCE_CODE0x2000
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( 1 ); //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 = 0xf000;
munmap(tmpaddress, MAP_LEN);
return 0;
}
Thanks
Vaibhav Jain
___
Kernelnewbies mailing list
Kernelnewbies@kernelnewbies.org
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: mmap local APIC address
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 vjoss...@gmail.com wrote:
On Fri, Oct 14, 2011 at 9:10 PM, Mulyadi Santosa
mulyadi.sant...@gmail.com wrote:
hi...
On Sat, Oct 15, 2011 at 07:22, Vaibhav Jain vjoss...@gmail.com wrote:
Hi,
I am trying to map local APIC on an intel system (physical address
0xfee0) 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 sectionthe 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 0xfee0*
#define APIC_ICR_low0xfee00300
#define APIC_ICR_high 0xfee00310
#define APIC_ICR_init 0x0500
#define APIC_ICR_start 0x0600
#define APIC_ICR_ASSERT_LVL_TRG 0xc000
#define BOUNCE_CODE0x2000
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( 1 ); //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 = 0xf000;
munmap(tmpaddress, MAP_LEN);
return 0;
}
Thanks
Vaibhav Jain
___
Kernelnewbies mailing list
Kernelnewbies@kernelnewbies.org
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: mmap local APIC address
On Wed, Oct 19, 2011 at 10:57 AM, bob ilikepie...@live.com wrote: It would be nice to share your solution in case someone else comes into the same problem. Hi, It was stupid mistake. I forgot to initialize the file descriptor which was passed to mmap and therefore it was throwing Bad file descriptor error.i realized it after looking the errors in man mmap. Thanks Vaibhav Jain ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Trouble removing character device
On Wed, Oct 19, 2011 at 7:04 PM, Kai Meyer k...@gnukai.com wrote: I can't seem to get my character device to remove itself from the /proc/devices list. I'm calling all of the following functions like so: alloc_chrdev_region(dev, 0, 5, my_char); cdev_init(my_cdev, my_ops); cdev_add(my_cdev, MKDEV(my_major, my_minor), 1); cdev_del(my_cdev); unregister_chrdev_region(my_major, 5); It seems like I'm missing something, but I can't find it. I'm referencing the Linux Device Drivers v3, chapter 3. In the example code, the scull_cleanup_module function calls cdev_dell and unregister_chrdev_region, just like I do. To be clear, after I unload my module (after calling cdev_del and unregister_chrdev_region), my my_char string still shows up in /proc/devices. Did you check return codes for all functions? Also, can you post a link to the code? thanks, Daniel. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Understanding memcpy
I'm trying to poke around an ext4 file system. I can submit a bio for
the correct block, and read in what seems to be the correct information,
but when I try to memcpy my char *buffer to a reference to a struct I've
made, it just doesn't seem to work. The relevant code looks like this:
typedef struct ext2_superblock {
/* 00-03 */ uint32_t e2sb_inode_count;
/* 04-07 */ uint32_t e2sb_block_count;
/* 08-11 */ uint32_t e2sb_blocks_reserved;
/* 12-15 */ uint32_t e2sb_unallocated_blocks;
/* 16-19 */ uint32_t e2sb_unallocated_inodes;
/* 20-23 */ uint32_t e2sb_sb_block;
/* 24-27 */ uint32_t e2sb_log_block_size;
/* 28-31 */ uint32_t e2sb_log_fragment_size;
/* 32-35 */ uint32_t e2sb_num_blocks_per_group;
/* 36-39 */ uint32_t e2sb_num_frag_per_group;
/* 40-43 */ uint32_t e2sb_num_inodes_per_group;
/* 44-47 */ uint32_t e2sb_last_mount_time;
/* 48-51 */ uint32_t e2sb_last_written_time;
/* 52-53 */ uint16_t e2sb_num_mounted;
/* 54-55 */ uint16_t e2sb_num_allowed_mounts;
/* 56-57 */ uint16_t e2sb_signature;
/* 58-59 */ uint16_t e2sb_fs_state;
/* 60-61 */ uint16_t e2sb_error_action;
/* 62-63 */ uint16_t e2sb_ver_minor;
/* 64-67 */ uint32_t e2sb_last_check;
/* 68-71 */ uint32_t e2sb_time_between_checks;
/* 72-75 */ uint32_t e2sb_os_id;
/* 76-79 */ uint32_t e2sb_ver_major;
/* 80-81 */ uint16_t e2sb_uid;
/* 82-83 */ uint16_t e2sb_gid;
} e2sb;
char *buffer;
uint32_t *pointer;
e2sb sb;
buffer = __bio_kmap_atomic(bio, 0, KM_USER0);
pointer = (uint32_t *)buffer;
printk(KERN_DEBUG sizeof pbd-sb %lu\n, sizeof(bpd-sb));
printk(KERN_DEBUG Inode Count: %u\n, pointer[0]); /* Works! */
printk(KERN_DEBUG Block Count: %u\n, pointer[1]); /* Works! */
printk(KERN_DEBUG Block Reserved: %u\n, pointer[2]); /* Works! */
printk(KERN_DEBUG Unallocated blocks: %u\n, pointer[3]); /* Works! */
printk(KERN_DEBUG Unallocated inodes: %u\n, pointer[4]); /* Works! */
memcpy(buffer, sb, sizeof(sb));
__bio_kunmap_atomic(bio, KM_USER0);
printk(KERN_DEBUG e2sb_debug: Total number of inodes in file system
%u\n, sb-e2sb_inode_count);/* Doesn't work! */
printk(KERN_DEBUG e2sb_debug: Total number of blocks in file
system%u\n, sb-e2sb_block_count); /* Doesn't work! */
My code is actually much more verbose. The values I get from indexing
into pointer are correct, and match what I get from dumpe2fs. The values
I get from the e2sb struct are not. They are usually 0. I would imagine
that memcpy is the fastest way to copy data from buffer instead of
casting the pointer to something else, and using array indexing to get
the values.
I struggled to find where ext4 actually does this, so I'm making this up
as I go along. Any thing that you see that I should be doing a different
way that isn't actually part of my question is welcome too.
___
Kernelnewbies mailing list
Kernelnewbies@kernelnewbies.org
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Trouble removing character device
On Thu, Oct 20, 2011 at 2:25 AM, Kai Meyer k...@gnukai.com wrote: Unfortunately I can't share the source code, it belongs to the company I work for. All of cdev_init, cdev_del, and unregister_chrdev_region are void functions, so they have no return value. I check the return value of alloc_chrdev_region and cdev_add and check for errors with BUG_ON (for now). -Kai Meyer On 10/19/2011 02:18 PM, Daniel Baluta wrote: On Wed, Oct 19, 2011 at 7:04 PM, Kai Meyerk...@gnukai.com wrote: I can't seem to get my character device to remove itself from the /proc/devices list. I'm calling all of the following functions like so: alloc_chrdev_region(dev, 0, 5, my_char); cdev_init(my_cdev,my_ops); cdev_add(my_cdev, MKDEV(my_major, my_minor), 1); cdev_del(my_cdev); unregister_chrdev_region(my_major, 5); It seems like I'm missing something, but I can't find it. I'm referencing the Linux Device Drivers v3, chapter 3. In the example code, the scull_cleanup_module function calls cdev_dell and unregister_chrdev_region, just like I do. To be clear, after I unload my module (after calling cdev_del and unregister_chrdev_region), my my_char string still shows up in /proc/devices. Did you check return codes for all functions? Also, can you post a link to the code? thanks, Daniel. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies During cleanup i think you need to call function unregister_chrdev_region(). Regards, Rohan Puri ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Understanding memcpy
On Thu, Oct 20, 2011 at 3:04 AM, Kai Meyer k...@gnukai.com wrote:
I'm trying to poke around an ext4 file system. I can submit a bio for
the correct block, and read in what seems to be the correct information,
but when I try to memcpy my char *buffer to a reference to a struct I've
made, it just doesn't seem to work. The relevant code looks like this:
typedef struct ext2_superblock {
/* 00-03 */ uint32_t e2sb_inode_count;
/* 04-07 */ uint32_t e2sb_block_count;
/* 08-11 */ uint32_t e2sb_blocks_reserved;
/* 12-15 */ uint32_t e2sb_unallocated_blocks;
/* 16-19 */ uint32_t e2sb_unallocated_inodes;
/* 20-23 */ uint32_t e2sb_sb_block;
/* 24-27 */ uint32_t e2sb_log_block_size;
/* 28-31 */ uint32_t e2sb_log_fragment_size;
/* 32-35 */ uint32_t e2sb_num_blocks_per_group;
/* 36-39 */ uint32_t e2sb_num_frag_per_group;
/* 40-43 */ uint32_t e2sb_num_inodes_per_group;
/* 44-47 */ uint32_t e2sb_last_mount_time;
/* 48-51 */ uint32_t e2sb_last_written_time;
/* 52-53 */ uint16_t e2sb_num_mounted;
/* 54-55 */ uint16_t e2sb_num_allowed_mounts;
/* 56-57 */ uint16_t e2sb_signature;
/* 58-59 */ uint16_t e2sb_fs_state;
/* 60-61 */ uint16_t e2sb_error_action;
/* 62-63 */ uint16_t e2sb_ver_minor;
/* 64-67 */ uint32_t e2sb_last_check;
/* 68-71 */ uint32_t e2sb_time_between_checks;
/* 72-75 */ uint32_t e2sb_os_id;
/* 76-79 */ uint32_t e2sb_ver_major;
/* 80-81 */ uint16_t e2sb_uid;
/* 82-83 */ uint16_t e2sb_gid;
} e2sb;
char *buffer;
uint32_t *pointer;
e2sb sb;
buffer = __bio_kmap_atomic(bio, 0, KM_USER0);
pointer = (uint32_t *)buffer;
printk(KERN_DEBUG sizeof pbd-sb %lu\n, sizeof(bpd-sb));
printk(KERN_DEBUG Inode Count: %u\n, pointer[0]); /* Works! */
printk(KERN_DEBUG Block Count: %u\n, pointer[1]); /* Works! */
printk(KERN_DEBUG Block Reserved: %u\n, pointer[2]); /* Works! */
printk(KERN_DEBUG Unallocated blocks: %u\n, pointer[3]); /* Works! */
printk(KERN_DEBUG Unallocated inodes: %u\n, pointer[4]); /* Works! */
memcpy(buffer, sb, sizeof(sb));
This should be : -
memcpy(sb, buffer, sizeof(sb));
__bio_kunmap_atomic(bio, KM_USER0);
printk(KERN_DEBUG e2sb_debug: Total number of inodes in file system
%u\n, sb-e2sb_inode_count);/* Doesn't work! */
printk(KERN_DEBUG e2sb_debug: Total number of blocks in file
system%u\n, sb-e2sb_block_count); /* Doesn't work! */
My code is actually much more verbose. The values I get from indexing
into pointer are correct, and match what I get from dumpe2fs. The values
I get from the e2sb struct are not. They are usually 0. I would imagine
that memcpy is the fastest way to copy data from buffer instead of
casting the pointer to something else, and using array indexing to get
the values.
I struggled to find where ext4 actually does this, so I'm making this up
as I go along. Any thing that you see that I should be doing a different
way that isn't actually part of my question is welcome too.
___
Kernelnewbies mailing list
Kernelnewbies@kernelnewbies.org
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Regards,
Rohan Puri
___
Kernelnewbies mailing list
Kernelnewbies@kernelnewbies.org
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Getting 'bad file number' error writing to device driver
Thanks for the link; but this bit has to be set on the original executable. Is there any way a program in user mode can get around this or set the bit himself? Ummm...now that would be a security violation, don't you think? If a program can elevate it's own privileges, then whats the point of having access control! :) I think a user-space program will always need _some_ help from a privileged user/program. Eg in the case of setuid, typically the root user will be setting this bit (on a executable) so that an unprivileged user can execute with temporarily elevated privileges. CMIIW. HTH, -mandeep Anil ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
