Hi, I was just trying to understand the code flow of LinuxBIOS on x86 architecture. I understood that on a power on (cold boot), there is a wait for power good. Later there is a transition from real mode to protected mode (32 bit). The file that makes the transition is entry32.inc of src/cpu/x86/32bit directory. After this point I was not able to make able to make much progress as to which part of the code is executed. Any help in this regard will be helpful. I did check through the available documentation in documentation directory of the source tree, but would appreciate if there are any pointers at the code level.
Regards Anil
* Anil B G bg.anil@gmail.com [060721 16:24]:
I was just trying to understand the code flow of LinuxBIOS on x86 architecture. I understood that on a power on (cold boot), there is a wait for power good. Later there is a transition from real mode to protected mode (32 bit). The file that makes the transition is entry32.inc of src/cpu/x86/32bit directory. After this point I was not able to make able to make much progress as to which part of the code is executed. Any help in this regard will be helpful.
I wrote a small text about this when we started v2. It's obsolete in some parts but it might help here and there. See the attachment.
Anil B G wrote:
Hi, I was just trying to understand the code flow of LinuxBIOS on x86 architecture. I understood that on a power on (cold boot), there is a wait for power good. Later there is a transition from real mode to protected mode (32 bit). The file that makes the transition is entry32.inc of src/cpu/x86/32bit directory. After this point I was not able to make able to make much progress as to which part of the code is executed. Any help in this regard will be helpful. I did check through the available documentation in documentation directory of the source tree, but would appreciate if there are any pointers at the code level.
Regards Anil
build a target and cd into the directory and type 'make documentation'. not perfect but it can help.
ron
yes, just find the crt0.s in the build dir.
YH
On 7/21/06, Ronald G Minnich rminnich@lanl.gov wrote:
Anil B G wrote:
Hi, I was just trying to understand the code flow of LinuxBIOS on x86 architecture. I understood that on a power on (cold boot), there is a wait for power good. Later there is a transition from real mode to protected mode (32 bit). The file that makes the transition is entry32.inc of src/cpu/x86/32bit directory. After this point I was not able to make able to make much progress as to which part of the code is executed. Any help in this regard will be helpful. I did check through the available documentation in documentation directory of the source tree, but would appreciate if there are any pointers at the code level.
Regards Anil
build a target and cd into the directory and type 'make documentation'. not perfect but it can help.
ron
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Hi,
I am also trying to get a clear understanding of the LB logical flow. Our company has a hardware simulator which we will use for initial testing before trying on real hardware but it shouldn't make a difference to the LB flow. There are two flow charts that I've been looking at, you may have already looked at them, the first is in section 8.3 of the Mangrove project book under the documentation page of the web site. The other flow chart is in documentation/port guides/LinuxBios on AMD 64. this flowchart has other infomation and could be used with the first flowchart to fill in some details.
When we reset the board then single step into it, the flow seems to go first to crt0.s then C_start.s then to hardwaremain.c, but I'm not sure this is true for all boards and I assume certain include files are inserted into the code for different configurations.
I hope this helps,
Dan
On 7/21/06, Anil B G bg.anil@gmail.com wrote:
Hi, I was just trying to understand the code flow of LinuxBIOS on x86 architecture. I understood that on a power on (cold boot), there is a wait for power good. Later there is a transition from real mode to protected mode (32 bit). The file that makes the transition is entry32.inc of src/cpu/x86/32bit directory. After this point I was not able to make able to make much progress as to which part of the code is executed. Any help in this regard will be helpful. I did check through the available documentation in documentation directory of the source tree, but would appreciate if there are any pointers at the code level.
Regards Anil
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yhlu