relocatable modules' symbols
hi: I have built vmlinux at the top dir of kernel source ,then I use objdump to look into its section information.I find the statup_32 which is the start routine of kernel , locats at 0xc0100000. I know the 0x100000 is the defined address for locating protect-mode code .But which I can not understand is the 0xc prefix .where does it come from? thanks!
On Sat, Feb 23, 2013 at 6:45 AM, horseriver <horserivers@gmail.com> wrote:
hi:
I have built vmlinux at the top dir of kernel source ,then I use objdump to look into its section information.I find the statup_32 which is the start routine of kernel , locats at 0xc0100000. I know the 0x100000 is the defined address for locating protect-mode code .But which I can not understand is the 0xc prefix .where does it come from?
If my guess is right, that's because kernel mode code start at 0xc000000 a.k.a a bit above 3 GiB on x86 32 bit machine -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com
On Sun, Feb 24, 2013 at 04:00:37PM +0700, Mulyadi Santosa wrote:
On Sat, Feb 23, 2013 at 6:45 AM, horseriver <horserivers@gmail.com> wrote:
hi:
I have built vmlinux at the top dir of kernel source ,then I use objdump to look into its section information.I find the statup_32 which is the start routine of kernel , locats at 0xc0100000. I know the 0x100000 is the defined address for locating protect-mode code .But which I can not understand is the 0xc prefix .where does it come from?
If my guess is right, that's because kernel mode code start at 0xc000000 a.k.a a bit above 3 GiB on x86 32 bit machine
I have find this answer . It is defined in lds script file . here is the code : SECTIONS { . = 0xC0000000 + 0x100000; /* read-only */ _text = .; /* Text and read-only data */ why use 0xC0000000 as its start ? why not just use 0x100000 only ? if use 0xC0000000,every linked symbole will be prefixed by 0xc , what is the purpose ? thanks! --
regards,
Mulyadi Santosa Freelance Linux trainer and consultant
blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com
Hi... On Sun, Feb 24, 2013 at 8:56 AM, horseriver <horserivers@gmail.com> wrote:
I have find this answer . It is defined in lds script file .
here is the code : SECTIONS { . = 0xC0000000 + 0x100000; /* read-only */ _text = .; /* Text and read-only data */
why use 0xC0000000 as its start ? why not just use 0x100000 only ? if use 0xC0000000,every linked symbole will be prefixed by 0xc , what is the purpose ?
maybe because some symbols are object of relocation, so their address don't need to be incremented with 0xc000 0000. Different situation with startup_32. AFAIK it's doing many thing during early protected mode initialization, so its address must be set to certain number. -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com
Hi Horseriver, On Sun, Feb 24, 2013 at 7:26 AM, horseriver <horserivers@gmail.com> wrote:
On Sun, Feb 24, 2013 at 04:00:37PM +0700, Mulyadi Santosa wrote:
On Sat, Feb 23, 2013 at 6:45 AM, horseriver <horserivers@gmail.com> wrote:
hi:
I have built vmlinux at the top dir of kernel source ,then I use objdump to look into its section information.I find the statup_32 which is the start routine of kernel , locats at 0xc0100000. I know the 0x100000 is the defined address for locating protect-mode code .But which I can not understand is the 0xc prefix .where does it come from?
If my guess is right, that's because kernel mode code start at 0xc000000 a.k.a a bit above 3 GiB on x86 32 bit machine
I have find this answer . It is defined in lds script file .
here is the code : SECTIONS { . = 0xC0000000 + 0x100000; /* read-only */ _text = .; /* Text and read-only data */
why use 0xC0000000 as its start ? why not just use 0x100000 only ? if use 0xC0000000,every linked symbole will be prefixed by 0xc , what is the purpose ?
Usually, user kernel space split is 3G:1G. ie 1G for kernel space. And this starts from 0xC000_0000 till 0xFFFF_FFFF All the address below 0xC000_0000(ie 3G from 0x0 to 0xBFFF_FFFF) is used for user space. Thanks, Arun
thanks!
--
regards,
Mulyadi Santosa Freelance Linux trainer and consultant
blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com
_______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
In principle, the linker will associate the kernel code/data to the Kernel virtual address space i.e. between 0xC000_0000 to 0xFFFF_FFFF and the same linker will associate the Application's code/data to the user virtual address space i.e. between 0x0000_0000 to 0xBFFF_FFFF. Linker itself cannot distinguish between the kernel code/data and user code/data but it is the linker script that will guide the linker to associate the code/data to the respective addresses. What you are seeing is the linker script provided to the linker with -T option when building the kernel. To build the user application the linker uses its default linker script which you get it by executing $ ld --verbose. To compare between the two just juxtapose the readelf output of both kernel executable (vmlinux) and any user application executable (a.out) $ readelf -a vmlinux $ readelf -a a.out Just inspect the section header and program header of both the outputs you will get the difference. Regards, Prabhu On Fri, Mar 1, 2013 at 11:07 AM, Arun KS <getarunks@gmail.com> wrote:
Hi Horseriver,
On Sun, Feb 24, 2013 at 7:26 AM, horseriver <horserivers@gmail.com> wrote:
On Sun, Feb 24, 2013 at 04:00:37PM +0700, Mulyadi Santosa wrote:
On Sat, Feb 23, 2013 at 6:45 AM, horseriver <horserivers@gmail.com> wrote:
hi:
I have built vmlinux at the top dir of kernel source ,then I use objdump to look into its section information.I find the statup_32 which is the start routine of kernel , locats at 0xc0100000. I know the 0x100000 is the defined address for locating protect-mode code .But which I can not understand is the 0xc prefix .where does it come from?
If my guess is right, that's because kernel mode code start at 0xc000000 a.k.a a bit above 3 GiB on x86 32 bit machine
I have find this answer . It is defined in lds script file .
here is the code : SECTIONS { . = 0xC0000000 + 0x100000; /* read-only */ _text = .; /* Text and read-only data */
why use 0xC0000000 as its start ? why not just use 0x100000 only ? if use 0xC0000000,every linked symbole will be prefixed by 0xc , what is the purpose ?
Usually, user kernel space split is 3G:1G. ie 1G for kernel space. And this starts from 0xC000_0000 till 0xFFFF_FFFF
All the address below 0xC000_0000(ie 3G from 0x0 to 0xBFFF_FFFF) is used for user space.
Thanks, Arun
thanks!
--
regards,
Mulyadi Santosa Freelance Linux trainer and consultant
blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com
_______________________________________________ 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
what linear address is the virtual address 0xc000 0000 respondable to ? the highest 10 bits 0x300 is pde , which means the 0x300th entry of the page dir. As I know ,at boot stage , that pde has not been ever filles . then how does the kernel code been addressed? 2013/3/1 Prabhu nath <gprabhunath@gmail.com>:
In principle, the linker will associate the kernel code/data to the Kernel virtual address space i.e. between 0xC000_0000 to 0xFFFF_FFFF and the same linker will associate the Application's code/data to the user virtual address space i.e. between 0x0000_0000 to 0xBFFF_FFFF.
Linker itself cannot distinguish between the kernel code/data and user code/data but it is the linker script that will guide the linker to associate the code/data to the respective addresses.
What you are seeing is the linker script provided to the linker with -T option when building the kernel.
To build the user application the linker uses its default linker script which you get it by executing $ ld --verbose.
To compare between the two just juxtapose the readelf output of both kernel executable (vmlinux) and any user application executable (a.out)
$ readelf -a vmlinux $ readelf -a a.out
Just inspect the section header and program header of both the outputs you will get the difference.
Regards, Prabhu
On Fri, Mar 1, 2013 at 11:07 AM, Arun KS <getarunks@gmail.com> wrote:
Hi Horseriver,
On Sun, Feb 24, 2013 at 7:26 AM, horseriver <horserivers@gmail.com> wrote:
On Sun, Feb 24, 2013 at 04:00:37PM +0700, Mulyadi Santosa wrote:
On Sat, Feb 23, 2013 at 6:45 AM, horseriver <horserivers@gmail.com> wrote:
hi:
I have built vmlinux at the top dir of kernel source ,then I use objdump to look into its section information.I find the statup_32 which is the start routine of kernel , locats at 0xc0100000. I know the 0x100000 is the defined address for locating protect-mode code .But which I can not understand is the 0xc prefix .where does it come from?
If my guess is right, that's because kernel mode code start at 0xc000000 a.k.a a bit above 3 GiB on x86 32 bit machine
I have find this answer . It is defined in lds script file .
here is the code : SECTIONS { . = 0xC0000000 + 0x100000; /* read-only */ _text = .; /* Text and read-only data */
why use 0xC0000000 as its start ? why not just use 0x100000 only ? if use 0xC0000000,every linked symbole will be prefixed by 0xc , what is the purpose ?
Usually, user kernel space split is 3G:1G. ie 1G for kernel space. And this starts from 0xC000_0000 till 0xFFFF_FFFF
All the address below 0xC000_0000(ie 3G from 0x0 to 0xBFFF_FFFF) is used for user space.
Thanks, Arun
thanks!
--
regards,
Mulyadi Santosa Freelance Linux trainer and consultant
blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com
_______________________________________________ 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
All, The issue I have is as follows. When writing to the MTD on NOR in Linux for a file of more than a few bytes, it fails with a MTD software timeout. Writing upto 100 bytes are fine, in this test when I jumped to 300 it failed. I also proved that the small writes do get written; I wrote zeros over my mtd1 "u-boot-env" and had to repair it on reboot. In Uboot there are no NOR or NAND read/write issues, erase appears to work fine etc. Under Linux MTD for the NAND remains flawless and MTD NOR read has no issues. Any thoughts appreciated: some information and the tests output below. LCPSH # flinfo Bank # 1: CFI conformant FLASH (8 x 8) Size: 64 MB in 512 Sectors AMD Standard command set, Manufacturer ID: 0x15, Device ID: 0x00 Erase timeout: 4096 ms, write timeout: 25 ms Buffer write timeout: 50 ms, buffer size: 1024 bytes Sector Start Addresses: 10000000 RO 10020000 RO 10040000 RO 10060000 RO 10080000 100A0000 100C0000 100E0000 10100000 10120000 10140000 10160000 10180000 101A0000 101C0000 101E0000 10200000 10220000 10240000 10260000 10280000 102A0000 102C0000 102E0000 10300000 10320000 10340000 10360000 10380000 103A0000 103C0000 103E0000 10400000 10420000 10440000 10460000 10480000 104A0000 104C0000 104E0000 10500000 10520000 10540000 10560000 10580000 105A0000 105C0000 105E0000 10600000 10620000 .... .... ... root@lvs15:/# uname -a Linux lvs15 2.6.35-lcp-arm1 #1 SMP Fri Mar 1 11:59:02 EST 2013 armv6l GNU/Linux root@lvs15:/# cat /proc/mtd dev: size erasesize name mtd0: 00080000 00020000 "u-boot" mtd1: 00040000 00020000 "u-boot-env" mtd2: 03f40000 00020000 "unused-nor" mtd3: 01e00000 00020000 "nand-linuxImg1" mtd4: 01e00000 00020000 "nand-linuxImg2" mtd5: 3c400000 00020000 "nandfs" root@lvs15:/# mtd_debug info /dev/mtd1 MTD_open MTD_ioctl MTD_ioctl MTD_close= MTD_NORFLASH mtd.flags = MTD_CAP_NORFLASH mtd.size = 262144 (256K) mtd.erasesize = 131072 (128K) mtd.writesize = 1 mtd.oobsize = 0 regions = 0 mtd_debug read /dev/mtd1 0 1000 read.txt Copied 1000 bytes from address 0x00000000 in flash to read.txt root@lvs15:/# cat read.txt Åý ôbootdelay=5baudrate=115200loadaddr=0x05000000mtdids=nor0=physmap-flash.0,nand0=lcp_nandmtdparts=mtdparts=physmap-flash.0:512k(u-boot),256k(u-boot-env),-(unused-nor);lcp_nand:30M(nand-linuxImg1),30M(nand-linuxImg2),-(nandfs)verify=nlcpethmac0cpathchnl=0lcpethmac0ethforcerate=1000lcpethmac0ethforcefulldplx=Ylcpethmac1cpathchnl=0lcpethmac1ethforcerate=1000lcpethmac1ethforcefulldplx=Yethprime=LCP_ETH_MAC0ethrotate=no netretry=no autostart=yessetupbootargs=setenv bootargs earlyprintk=serial,ttyAMA0,$(baudrate) console=ttyAMA0,$(baudrate)n8 root=/dev/ram mtdids=$(mtdids) $(mtdparts)bootcmd=fpgasetup;run setupbootargs;tftp ad_value=0x1e1lcpethmac1bcastfltr=onlcpethmac1mcastfltr=onlcpethmac1pausepktfltr=onlcpethmac1runtpktfltr=onlcpethmac1ucastfltr=onlcpethmac0bcastfltr=onlcpethmac0mcastfltr=onlcpethmac0pausepktfltr=onlcpethmac0runtpktfltr=onlcpethmac0ucastfltr=onlcpethmac0ucastfltrda2=00:00:00:00:00:00lcpethmac0ucastfltrda3=00:00:00:00:00:00lcp<d /dev/mtd2 0 1000 read.txtmtd_debug write /dev/mtd1 0 1000 read.txt I appreciate I do not do erases between writes but the data is the same and I have not had trouble with this, other than if you do write different data obviously all bets are off! root@lvs15:/# mtd_debug write /dev/mtd1 0 10 read.txt MTD_open MTD_write MTD do_write_buffer(): WRITE 0x00080000(0x000000c5) Copied 10 bytes from read.txt to address 0x00000000 in flash root@lvs15:/# mtd_debug write /dev/mtd1 0 100 read.txt MTD_open MTD_write MTD do_write_buffer(): WRITE 0x00080000(0x000000c5) Copied 100 bytes from read.txt to address 0x00000000 in flash root@lvs15:/# mtd_debug write /dev/mtd1 0 300 read.txt MTD_open MTD_write MTD do_write_buffer(): WRITE 0x00080000(0x000000c5) MTD do_write_buffer(): software timeout file_to_flash: write, size 0x12c, n 0x12c write(): Input/output error
participants (6)
-
Arun KS -
Holmes, Michael A (Mike) -
horseriver -
John Smith
-
Mulyadi Santosa -
Prabhu nath