Shao Miller
2016-Jan-12 00:20 UTC
[syslinux] Embedding com32 modules and ldlinux.sys into one file
Good day, Tal. Perhaps if you describe a little bit more about the rationale behind this single-file requirement, someone might be able to make an alternative suggestion that you haven't thought of. The BIOS- and disk-based Syslinux bootstrapping actually often has a filesystem-specific piece of code that lives in the filesystem's meta-data, as well as the primary file and COMBOOT32 modules that you are thinking of. Because of that first piece, it's not really possible to have this kind of Syslinux as a single file. But if you were to share a few more details, perhaps you're thinking of a PXE environment or a CD environment or a new filesystem or...? Are you able to describe the sequence of boot-up events that occur before the point you are thinking of? Yes, you can print debug-output from custom builds. -- Shao Miller Synthetel Corporation T: +1.9053927729 W: https://www.synthetel.com
Tal Lubko
2016-Jan-12 21:21 UTC
[syslinux] Embedding com32 modules and ldlinux.sys into one file
On Mon, Jan 11, 2016 at 07:20:20PM -0500, Shao Miller via Syslinux wrote:> Good day, Tal. > > Perhaps if you describe a little bit more about the rationale behind > this single-file requirement, someone might be able to make an > alternative suggestion that you haven't thought of. > > The BIOS- and disk-based Syslinux bootstrapping actually often has a > filesystem-specific piece of code that lives in the filesystem's > meta-data, as well as the primary file and COMBOOT32 modules that > you are thinking of. Because of that first piece, it's not really > possible to have this kind of Syslinux as a single file. > > But if you were to share a few more details, perhaps you're thinking > of a PXE environment or a CD environment or a new filesystem or...? > Are you able to describe the sequence of boot-up events that occur > before the point you are thinking of? > > Yes, you can print debug-output from custom builds. >Hi Shao The requirement is for the bootloader to be stored on the BIOS flash chip which will be read only. The BIOS will be modified to load bootloader from this chip. To simplify things and to avoid the need for a file system, I thought to store the bootloader as a single file. I don't reject the idea of using a very simple file-system to store the different bootloader files and loading it into RAM. Diving in I understand there are probably more difficulties I'll have to face. I'll be glad to get experts opinions and ideas about the difficulties I'll have to face and how to face it. Regarding my other question (debugging). I know it is possible to use prints for debugging. I wonder if there is another way. Regards, Tal
H. Peter Anvin
2016-Jan-12 21:36 UTC
[syslinux] Embedding com32 modules and ldlinux.sys into one file
On 01/12/16 13:21, Tal Lubko via Syslinux wrote:> > Hi Shao > > The requirement is for the bootloader to be stored on the BIOS flash chip > which will be read only. > The BIOS will be modified to load bootloader from this chip. > To simplify things and to avoid the need for a file system, I thought to > store the bootloader as a single file. > I don't reject the idea of using a very simple file-system to store the > different bootloader files and loading it into RAM. >The "single file" you describe *is* a filesystem. Currently the simplest such filesystem we have support for is iso9660, but that is very space-inefficient. Thus, it might be a good idea to add support for a very compact and maybe even compressed filesystem. -hpa
Celelibi
2016-Jan-13 00:22 UTC
[syslinux] Embedding com32 modules and ldlinux.sys into one file
2016-01-12 22:21 UTC+01:00, Tal Lubko via Syslinux <syslinux at zytor.com>:> On Mon, Jan 11, 2016 at 07:20:20PM -0500, Shao Miller via Syslinux wrote: >> Good day, Tal. >> >> Perhaps if you describe a little bit more about the rationale behind >> this single-file requirement, someone might be able to make an >> alternative suggestion that you haven't thought of. >> >> The BIOS- and disk-based Syslinux bootstrapping actually often has a >> filesystem-specific piece of code that lives in the filesystem's >> meta-data, as well as the primary file and COMBOOT32 modules that >> you are thinking of. Because of that first piece, it's not really >> possible to have this kind of Syslinux as a single file. >> >> But if you were to share a few more details, perhaps you're thinking >> of a PXE environment or a CD environment or a new filesystem or...? >> Are you able to describe the sequence of boot-up events that occur >> before the point you are thinking of? >> >> Yes, you can print debug-output from custom builds. >> > > Hi Shao > > The requirement is for the bootloader to be stored on the BIOS flash chip > which will be read only. > The BIOS will be modified to load bootloader from this chip. > To simplify things and to avoid the need for a file system, I thought to > store the bootloader as a single file. > I don't reject the idea of using a very simple file-system to store the > different bootloader files and loading it into RAM. > > Diving in I understand there are probably more difficulties I'll have to > face. > I'll be glad to get experts opinions and ideas about the difficulties I'll > have to face and how to face it. > > Regarding my other question (debugging). I know it is possible to use > prints > for debugging. > I wonder if there is another way.In qemu it is possible to have source-level debugging, all you need to know is the address at which the code is loaded to tell gdb where to relocate the debugging symbols. On real hardware, I think there's a support for serial port, but I've never used it.
BALATON Zoltan
2016-Jan-13 13:20 UTC
[syslinux] Embedding com32 modules and ldlinux.sys into one file
On Tue, 12 Jan 2016, Tal Lubko via Syslinux wrote:> The requirement is for the bootloader to be stored on the BIOS flash chip > which will be read only. > The BIOS will be modified to load bootloader from this chip.Have you looked at Coreboot.org and its payloads? It sounds similar to what that is aimed to do. Regards, BALATON Zoltan
Maybe Matching Threads
- Embedding com32 modules and ldlinux.sys into one file
- Embedding com32 modules and ldlinux.sys into one file
- Embedding com32 modules and ldlinux.sys into one file
- Embedding com32 modules and ldlinux.sys into one file
- Embedding com32 modules and ldlinux.sys into one file