Syslinux - Mar 2017 - [PATCH] Update chain.c32 v. 6.04-pre1 for current Reactos

Correct the "seg=" value(s) corresponding to the "reactos="
option
for chain.c32.

The correct segment parameter should be "seg=0x0F80",
instead of the incorrect / failing ones "seg=0:0x8000:0x8100".

References:
 https://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/notes.txt?revision=73859&view=markup&pathrev=73859#l24

 https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/notes.txt;hb=HEAD

 https://git.reactos.org/?p=reactos.git&a=search&h=HEAD&st=grep&s=FREELDR_BASE

 https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h;h=c747d145cb3b35f68caab5291dc65dcdca21f17d;hb=HEAD#l17

 https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h;hb=HEAD

At the time of writing this patch, the up-to-date bootsectors referring to
the above 'define' ("FREELDR_BASE") have a filename extension
ending with ".S".

There is also "multiboot.S", FWIW.

Regards,
Ady.


diff U3 com32/chain/options.c com32/chain/options.c
--- com32/chain/options.c	Wed Mar 02 07:06:29 2016
+++ com32/chain/options.c	Mon Feb 18 19:19:29 2017
@@ -224,15 +224,9 @@
 	    opt.setbpb = true;
 	    opt.hand = false;
 	} else if (!strncmp(argv[i], "reactos=", 8)) {
-	    /*
-	     * settings based on commit
-	     *   ad4cf1470977f648ee1dd45e97939589ccb0393c
-	     * note, conflicts with:
-	     *  
http://reactos.freedoors.org/Reactos%200.3.13/ReactOS-0.3.13-REL-src/boot/freeldr/notes.txt
-	     */
-	    opt.fseg = 0;
-	    opt.foff = 0x8000;
-	    opt.fip = 0x8100;
+	    opt.fseg = 0x0F80;
+	    opt.foff = 0;
+	    opt.fip = 0;
 	    opt.file = argv[i] + 8;
 	    opt.setbpb = true;
 	    opt.hand = false;
diff U3 doc/chain.txt doc/chain.txt
--- doc/chain.txt	Wed Mar 02 07:06:02 2016
+++ doc/chain.txt	Mon Feb 18 18:45:10 2017
@@ -296,7 +296,7 @@
 patched with "cmdcons\0". Remarks the same as in 'ntldr='.
 
 	reactos=<file>
-	sets: file=<file> seg=0:0x8000:0x8100 setbpb nohand
+	sets: file=<file> seg=0x0F80 setbpb nohand
 
 Prepares to load ReactOS's freeldr directly. You might want to add
'save'
 option to store corrected BPB values.

 --

On Mon, Feb 20, 2017 at 2:17 PM, Ady Ady via Syslinux
<syslinux at zytor.com> wrote:
> Correct the "seg=" value(s) corresponding to the
"reactos=" option
> for chain.c32.
>
> The correct segment parameter should be "seg=0x0F80",
> instead of the incorrect / failing ones "seg=0:0x8000:0x8100".
>
> References:
> 
https://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/notes.txt?revision=73859&view=markup&pathrev=73859#l24
>
> 
https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/notes.txt;hb=HEAD
>
> 
https://git.reactos.org/?p=reactos.git&a=search&h=HEAD&st=grep&s=FREELDR_BASE
>
> 
https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h;h=c747d145cb3b35f68caab5291dc65dcdca21f17d;hb=HEAD#l17
>
> 
https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h;hb=HEAD
>
> At the time of writing this patch, the up-to-date bootsectors referring to
> the above 'define' ("FREELDR_BASE") have a filename
extension ending with ".S".
>
> There is also "multiboot.S", FWIW.
>
> Regards,
> Ady.
It's a bit more complex.  At the time of writing, the data was perfect.

https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h;hb=28e58e6d01892c1f2f0e1d323745e6463cb9e6c9
dated 2011-06-14

https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h;hb=1dabbdfa6bbe244cd74bc912b94e514b85d63bbe

https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h;hb=0eb6daaf66127de803d36d45a4eea29d30a7ca36
dated 2011-06-18 finalized the shuffle.
> diff U3 com32/chain/options.c com32/chain/options.c
> --- com32/chain/options.c       Wed Mar 02 07:06:29 2016
> +++ com32/chain/options.c       Mon Feb 18 19:19:29 2017
> @@ -224,15 +224,9 @@
>             opt.setbpb = true;
>             opt.hand = false;
>         } else if (!strncmp(argv[i], "reactos=", 8)) {
> -           /*
> -            * settings based on commit
> -            *   ad4cf1470977f648ee1dd45e97939589ccb0393c
> -            * note, conflicts with:
> -            *  
http://reactos.freedoors.org/Reactos%200.3.13/ReactOS-0.3.13-REL-src/boot/freeldr/notes.txt
> -            */
> -           opt.fseg = 0;
> -           opt.foff = 0x8000;
> -           opt.fip = 0x8100;
> +           opt.fseg = 0x0F80;
> +           opt.foff = 0;
> +           opt.fip = 0;
>             opt.file = argv[i] + 8;
>             opt.setbpb = true;
>             opt.hand = false;
> diff U3 doc/chain.txt doc/chain.txt
> --- doc/chain.txt       Wed Mar 02 07:06:02 2016
> +++ doc/chain.txt       Mon Feb 18 18:45:10 2017
> @@ -296,7 +296,7 @@
>  patched with "cmdcons\0". Remarks the same as in
'ntldr='.
>
>         reactos=<file>
> -       sets: file=<file> seg=0:0x8000:0x8100 setbpb nohand
> +       sets: file=<file> seg=0x0F80 setbpb nohand
>
>  Prepares to load ReactOS's freeldr directly. You might want to add
'save'
>  option to store corrected BPB values.
This should have been put in place years ago by the looks but it's
going to need a big glaring warning in the release notes.

-- 
-Gene

> On Mon, Feb 20, 2017 at 2:17 PM, Ady Ady via Syslinux
> <syslinux at zytor.com> wrote:
> > Correct the "seg=" value(s) corresponding to the
"reactos=" option
> > for chain.c32.
> >
> > The correct segment parameter should be "seg=0x0F80",
> > instead of the incorrect / failing ones
"seg=0:0x8000:0x8100".
> >
> > References:
> > 
https://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/notes.txt?revision=73859&view=markup&pathrev=73859#l24
> >
> > 
https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/notes.txt;hb=HEAD
> >
> > 
https://git.reactos.org/?p=reactos.git&a=search&h=HEAD&st=grep&s=FREELDR_BASE
> >
> > 
https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h;h=c747d145cb3b35f68caab5291dc65dcdca21f17d;hb=HEAD#l17
> >
> > 
https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h;hb=HEAD
> >
> > At the time of writing this patch, the up-to-date bootsectors
referring to
> > the above 'define' ("FREELDR_BASE") have a filename
extension ending with ".S".
> >
> > There is also "multiboot.S", FWIW.
> >
> > Regards,
> > Ady.
> 
> It's a bit more complex.  At the time of writing, the data was perfect.
> 
>
https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h;hb=28e58e6d01892c1f2f0e1d323745e6463cb9e6c9
> dated 2011-06-14
> 
>
https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h;hb=1dabbdfa6bbe244cd74bc912b94e514b85d63bbe
> 
>
https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h;hb=0eb6daaf66127de803d36d45a4eea29d30a7ca36
> dated 2011-06-18 finalized the shuffle.
> 
 
 
Regarding the patch for chain.c32 (which is what it matters here now), 
I don't see complexity, nor the need to "extra" emphasize the
change in
the Syslinux changelog (see the end of this email).

Regarding prior versions of chain.c32, the "reactos=file" option never
worked, as the assumed values for the corresponding "seg=" option were
never _effectively_ correct (independently of what Reactos' source code 
seemingly said circa 2010-2011). In part, this can be seen in the 
(prior) source code itself (see "options.c" for the "chain"
module),
which mentions a conflicting information regarding adequate "seg=" 
values.

The effect is that, for prior Syslinux versions, the "reactos=file" 
option for chain.c32 should be considered invalid (or non-existent). It 
is only unfortunate that the "reactos=file" option was publicly 
announced years ago without having a more clear and stable information 
from the part of Reactos (and relevant testing), but that's history 
now.

The incorrect behavior of the "reactos=file" option (generated by 
inadequate segment values) has been reported in the past, several times 
by diverse channels. This patch corrects the "seg=" values for
Reactos.

The correct "seg=" values for the "reactos=file" option have
been
confirmed by developers of Reactos and also successfully tested using 
VMs. In the same way(s), the prior (incorrect) "seg=" values have been
also confirmed to fail.

Please keep in mind that this patch corrects the usage of the 
"reactos=file" option for SYSLINUX, but it is not enough for PXELINUX,
as Reactos needs "keeppxe" (also reported to The Syslinux Project 
several times by diverse channels), and the latter is not working since 
Syslinux 5.00 till today. Perhaps the patch for "keeppxe" sent by Adam
Goldman during 2016June ( 
http://www.syslinux.org/archives/2016-June/025216.html "Fix recognition 
of keeppxe option") might solve that matter (I wouldn't know).

 
 (snip) 

 
> 
> This should have been put in place years ago by the looks but it's
> going to need a big glaring warning in the release notes.
> 
> -- 
> -Gene
Of course, if my patch is applied to chain.c32, then it should  (and 
will) be part of the next Syslinux changelog, and I already have the 
item added in my local copy, for a future "NEWS" patch. As soon as I 
have confirmation of the Syslinux commit, I will also correct the 
Syslinux wiki for chain.c32 and the changelog wiki page.

If the "keeppxe" problem gets to be solved too (to be proven by tests 
from different users) in the Syslinux official code, I'll also add it 
to the relevant places.

Thank you and Best Regards,
Ady.

(snip) 
> 
> It's a bit more complex.  At the time of writing, the data was perfect.
> 
>
https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h;hb=28e58e6d01892c1f2f0e1d323745e6463cb9e6c9
> dated 2011-06-14
> 
>
https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h;hb=1dabbdfa6bbe244cd74bc912b94e514b85d63bbe
> 
>
https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h;hb=0eb6daaf66127de803d36d45a4eea29d30a7ca36
> dated 2011-06-18 finalized the shuffle.
> 
 
 
 (snip) 
 
 
> 
> This should have been put in place years ago by the looks but it's
> going to need a big glaring warning in the release notes.
> 
> -- 
> -Gene
 
 

* 2009Dec Reactos 0.3.11 - OK
* 2010Oct Reactos 0.3.12 - KO
* 2011Mar Reactos 0.3.13 - KO
* 2011Dec Syslinux 4.05 containing Shao's patch ("freeldr=")
* 2012Feb Reactos 0.3.14 - KO
* 2012Oct Syslinux 4.06 containing Michal Soltys' patch
("reactos=")
* 2013May Reactos 0.3.15 - KO

The above OK/KO results are from my own tests using chain.c32. 
There is always a chance that someone else might get different results.

Reactos is "alpha", so the only version of Reactos that its devs
support
is the "latest" at each time. Older versions of Reactos are not 
relevant / supported by Reactos' devs.

At the time the respective official release binaries were available, 
Syslinux's chain.c32 has never effectively supported chainloading 
(the "latest") Reactos with "built-in" options 
(neither "freeldr=" nor "reactos=", depending on
Syslinux's version).

Below, I am re-posting my patch (and its comments and title) with a slightly 
different wording in comparison to the one I posted during 2017Feb.

Regards,
Ady.


Update the "seg=" value(s) corresponding to the "reactos="
option
for chain.c32, according to newer/current versions of Reactos.

The updated segment parameter should be "seg=0x0F80",
instead of the older ones "seg=0:0x8000:0x8100".

References:
 https://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/notes.txt?revision=73859&view=markup&pathrev=73859#l24

 https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/notes.txt;hb=HEAD

 https://git.reactos.org/?p=reactos.git&a=search&h=HEAD&st=grep&s=FREELDR_BASE

 https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h;h=c747d145cb3b35f68caab5291dc65dcdca21f17d;hb=HEAD#l17

 https://git.reactos.org/?p=reactos.git;a=blob;f=reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h;hb=HEAD

At the time of writing this patch, the up-to-date bootsectors referring to
the above 'define' ("FREELDR_BASE") have a filename extension
ending with ".S".

There is also "multiboot.S", FWIW.



diff U3 com32/chain/options.c com32/chain/options.c
--- com32/chain/options.c	Wed Mar 02 07:06:29 2016
+++ com32/chain/options.c	Mon Feb 18 19:19:29 2017
@@ -224,15 +224,9 @@
 	    opt.setbpb = true;
 	    opt.hand = false;
 	} else if (!strncmp(argv[i], "reactos=", 8)) {
-	    /*
-	     * settings based on commit
-	     *   ad4cf1470977f648ee1dd45e97939589ccb0393c
-	     * note, conflicts with:
-	     *  
http://reactos.freedoors.org/Reactos%200.3.13/ReactOS-0.3.13-REL-src/boot/freeldr/notes.txt
-	     */
-	    opt.fseg = 0;
-	    opt.foff = 0x8000;
-	    opt.fip = 0x8100;
+	    opt.fseg = 0x0F80;
+	    opt.foff = 0;
+	    opt.fip = 0;
 	    opt.file = argv[i] + 8;
 	    opt.setbpb = true;
 	    opt.hand = false;
diff U3 doc/chain.txt doc/chain.txt
--- doc/chain.txt	Wed Mar 02 07:06:02 2016
+++ doc/chain.txt	Mon Feb 18 18:45:10 2017
@@ -296,7 +296,7 @@
 patched with "cmdcons\0". Remarks the same as in 'ntldr='.
 
 	reactos=<file>
-	sets: file=<file> seg=0:0x8000:0x8100 setbpb nohand
+	sets: file=<file> seg=0x0F80 setbpb nohand
 
 Prepares to load ReactOS's freeldr directly. You might want to add
'save'
 option to store corrected BPB values.

 --