loadlin with 2.5.?? kernels

loadlin with 2.5.?? kernels

[Mike Galbraith]

Greetings,

I hadn't had time to build/test kernels since 2.5.8-pre3.  I now find that 
loadlin doesn't work on my box any more.  Is this a known problem?  If so, 
when did it quit working?  (loadlin obsolete?  other?)

At the moment, the only way I have to boot is via floppy.

	tia for any tips,

	-Mike

Re: loadlin with 2.5.?? kernels

[Thomas Molina]

On Sun, 20 Oct 2002, Mike Galbraith wrote:

> Greetings,
> 
> I hadn't had time to build/test kernels since 2.5.8-pre3.  I now find that 
> loadlin doesn't work on my box any more.  Is this a known problem?  If so, 
> when did it quit working?  (loadlin obsolete?  other?)

I'm carrying an open problem report from Rene Blokland on this issue.  
What version of the kernel did you try?

Re: loadlin with 2.5.?? kernels

[Mike Galbraith]

At 08:17 AM 10/20/2002 -0500, Thomas Molina wrote:
>On Sun, 20 Oct 2002, Mike Galbraith wrote:
>
> > Greetings,
> >
> > I hadn't had time to build/test kernels since 2.5.8-pre3.  I now find that
> > loadlin doesn't work on my box any more.  Is this a known problem?  If so,
> > when did it quit working?  (loadlin obsolete?  other?)
>
>I'm carrying an open problem report from Rene Blokland on this issue.
>What version of the kernel did you try?

Only 2.5.42.virgin, 2.5.42-mm, 2.5.43-mm and 2.5.44.virgin.  Binary search 
pending.

         -Mike

Re: loadlin with 2.5.?? kernels

[Thomas Molina]

On Sun, 20 Oct 2002, Mike Galbraith wrote:

> At 08:17 AM 10/20/2002 -0500, Thomas Molina wrote:
> >On Sun, 20 Oct 2002, Mike Galbraith wrote:
> >
> > > Greetings,
> > >
> > > I hadn't had time to build/test kernels since 2.5.8-pre3.  I now find that
> > > loadlin doesn't work on my box any more.  Is this a known problem?  If so,
> > > when did it quit working?  (loadlin obsolete?  other?)
> >
> >I'm carrying an open problem report from Rene Blokland on this issue.
> >What version of the kernel did you try?
> 
> Only 2.5.42.virgin, 2.5.42-mm, 2.5.43-mm and 2.5.44.virgin.  Binary search 
> pending.

The report stated the problem was noted with 2.5.4x.  One of the 
developers might want to speak up as to whether finding the exact point of 
breakage is useful.

Re: loadlin with 2.5.?? kernels

[Denis Vlasenko]

On 20 October 2002 16:58, Thomas Molina wrote:
> On Sun, 20 Oct 2002, Mike Galbraith wrote:
> > At 08:17 AM 10/20/2002 -0500, Thomas Molina wrote:
> > >On Sun, 20 Oct 2002, Mike Galbraith wrote:
> > > > Greetings,
> > > >
> > > > I hadn't had time to build/test kernels since 2.5.8-pre3.  I
> > > > now find that loadlin doesn't work on my box any more.  Is this
> > > > a known problem?  If so, when did it quit working?  (loadlin
> > > > obsolete?  other?)
> > >
> > >I'm carrying an open problem report from Rene Blokland on this
> > > issue. What version of the kernel did you try?
> >
> > Only 2.5.42.virgin, 2.5.42-mm, 2.5.43-mm and 2.5.44.virgin.  Binary
> > search pending.
>
> The report stated the problem was noted with 2.5.4x.  One of the
> developers might want to speak up as to whether finding the exact
> point of breakage is useful.

Shameless plug time.

http://port-ilyichevsk.com.ua/linux/vda/linld/

linld095.tar.bz2 does contain source.

Get *devel.tar.bz2 only if you _don't have Borland C_ and want to recompile.
--
vda

Re: loadlin with 2.5.?? kernels

[Mike Galbraith]

At 01:58 PM 10/20/2002 -0500, Thomas Molina wrote:
>On Sun, 20 Oct 2002, Mike Galbraith wrote:
>
> > At 08:17 AM 10/20/2002 -0500, Thomas Molina wrote:
> > >On Sun, 20 Oct 2002, Mike Galbraith wrote:
> > >
> > > > Greetings,
> > > >
> > > > I hadn't had time to build/test kernels since 2.5.8-pre3.  I now 
> find that
> > > > loadlin doesn't work on my box any more.  Is this a known 
> problem?  If so,
> > > > when did it quit working?  (loadlin obsolete?  other?)
> > >
> > >I'm carrying an open problem report from Rene Blokland on this issue.
> > >What version of the kernel did you try?
> >
> > Only 2.5.42.virgin, 2.5.42-mm, 2.5.43-mm and 2.5.44.virgin.  Binary search
> > pending.
>
>The report stated the problem was noted with 2.5.4x.  One of the
>developers might want to speak up as to whether finding the exact point of
>breakage is useful.

2.5.32 is the breakage point here.  I hope someone _else_ can salvage 
loadlin :)

(lions and tigers and bears - oh my GDT!)

         -Dorothy

Re: loadlin with 2.5.?? kernels

[Eric W. Biederman]

Mike Galbraith <efault@gmx.de> writes:

> At 01:58 PM 10/20/2002 -0500, Thomas Molina wrote:
> >On Sun, 20 Oct 2002, Mike Galbraith wrote:
> >
> > > At 08:17 AM 10/20/2002 -0500, Thomas Molina wrote:
> > > >On Sun, 20 Oct 2002, Mike Galbraith wrote:
> > > >
> > > > > Greetings,
> > > > >
> > > > > I hadn't had time to build/test kernels since 2.5.8-pre3.  I now find
> > that
> > > > > loadlin doesn't work on my box any more.  Is this a known problem?  If
> > so,
> > > > > when did it quit working?  (loadlin obsolete?  other?)
> > > >
> > > >I'm carrying an open problem report from Rene Blokland on this issue.
> > > >What version of the kernel did you try?
> > >
> > > Only 2.5.42.virgin, 2.5.42-mm, 2.5.43-mm and 2.5.44.virgin.  Binary search
> > > pending.
> >
> >The report stated the problem was noted with 2.5.4x.  One of the
> >developers might want to speak up as to whether finding the exact point of
> >breakage is useful.
> 
> 2.5.32 is the breakage point here.  I hope someone _else_ can salvage loadlin :)
> 
> 
> (lions and tigers and bears - oh my GDT!)

Cool, thanks, for the confirmation.  Other people are seeing breaking a little
later.  Just to clarify.  .30 or .31 is the last version that worked and .32
does not?

If it is really the gdt I have some old patches that roughly do the
right thing, and I just need to dust them off.

Eric

Re: loadlin with 2.5.?? kernels

[Mike Galbraith]

(sorry, I have to use this pos at work)
----- Original Message -----
From: "Eric W. Biederman" <ebiederm@xmission.com>
To: "Mike Galbraith" <efault@gmx.de>
Cc: "Thomas Molina" <tmolina@cox.net>; <linux-kernel@vger.kernel.org>
Sent: Thursday, October 24, 2002 10:07 AM
Subject: Re: loadlin with 2.5.?? kernels


> Mike Galbraith <efault@gmx.de> writes:
>
> > At 01:58 PM 10/20/2002 -0500, Thomas Molina wrote:
> > >On Sun, 20 Oct 2002, Mike Galbraith wrote:
> > >
> > > > At 08:17 AM 10/20/2002 -0500, Thomas Molina wrote:
> > > > >On Sun, 20 Oct 2002, Mike Galbraith wrote:
> > > > >
> > > > > > Greetings,
> > > > > >
> > > > > > I hadn't had time to build/test kernels since 2.5.8-pre3.  I
now find
> > > that
> > > > > > loadlin doesn't work on my box any more.  Is this a known
problem?  If
> > > so,
> > > > > > when did it quit working?  (loadlin obsolete?  other?)
> > > > >
> > > > >I'm carrying an open problem report from Rene Blokland on this
issue.
> > > > >What version of the kernel did you try?
> > > >
> > > > Only 2.5.42.virgin, 2.5.42-mm, 2.5.43-mm and 2.5.44.virgin.
Binary search
> > > > pending.
> > >
> > >The report stated the problem was noted with 2.5.4x.  One of the
> > >developers might want to speak up as to whether finding the exact
point of
> > >breakage is useful.
> >
> > 2.5.32 is the breakage point here.  I hope someone _else_ can
salvage loadlin :)
> >
> >
> > (lions and tigers and bears - oh my GDT!)
>
> Cool, thanks, for the confirmation.  Other people are seeing breaking
a little
> later.  Just to clarify.  .30 or .31 is the last version that worked
and .32
> does not?

Yes.  .31 exploded on me after boot, but did not do the violent reboot
during boot.

> If it is really the gdt I have some old patches that roughly do the
> right thing, and I just need to dust them off.

You dust them off, and I'll be more than happy to test them.  I keep
entirely too many kernels resident to want to use lilo.

(kexec/bootimg wonderfulness solves my problem too.  boot into a stable
kernel, instant reboot into any one I want.  gimme gimme gimme:)

    -Mike

Re: loadlin with 2.5.?? kernels

[Eric W. Biederman]

[-- Attachment #1: Type: text/plain, Size: 888 bytes --]

"Mike Galbraith" <EFAULT@gmx.de> writes:

> (sorry, I have to use this pos at work)
> 
> Yes.  .31 exploded on me after boot, but did not do the violent reboot
> during boot.

Earlier you had said it was .38 or so where the failures kicked in,
so I figured it was some other problem.
 
> > If it is really the gdt I have some old patches that roughly do the
> > right thing, and I just need to dust them off.
> 
> You dust them off, and I'll be more than happy to test them.  I keep
> entirely too many kernels resident to want to use lilo.

Here you are.
The following patch cleans up and removes unnecessary dependencies from
the x86 boot path.
 
> (kexec/bootimg wonderfulness solves my problem too.  boot into a stable
> kernel, instant reboot into any one I want.  gimme gimme gimme:)

It is getting there...
I just need to find a formula that makes the linux kernel boot reliably.


[-- Attachment #2: linux-2.5.44.loadlin-fix.diff --]
[-- Type: text/plain, Size: 11348 bytes --]

diff -uNr linux-2.5.44/arch/i386/boot/compressed/head.S linux-2.5.44.loadlin-fix/arch/i386/boot/compressed/head.S
--- linux-2.5.44/arch/i386/boot/compressed/head.S	Fri Oct 11 22:22:19 2002
+++ linux-2.5.44.loadlin-fix/arch/i386/boot/compressed/head.S	Fri Oct 25 05:38:56 2002
@@ -28,22 +28,17 @@
 
 	.globl startup_32
 	
+/*
+ * On entry, %esi points to the real-mode code as a 32-bit pointer.
+ *   %ds, %es, %fs, %gs, %ss 32bit data segment base=0 mask=0xffffffff
+ */
 startup_32:
 	cld
 	cli
-	movl $(__KERNEL_DS),%eax
-	movl %eax,%ds
-	movl %eax,%es
-	movl %eax,%fs
-	movl %eax,%gs
-
-	lss stack_start,%esp
-	xorl %eax,%eax
-1:	incl %eax		# check that A20 really IS enabled
-	movl %eax,0x000000	# loop forever if it isn't
-	cmpl %eax,0x100000
-	je 1b
-
+/*
+ * Setup the stack
+ */
+	movl stack_start, %esp
 /*
  * Initialize eflags.  Some BIOS's leave bits like NT set.  This would
  * confuse the debugger if this code is traced.
@@ -73,8 +68,8 @@
 	jnz  3f
 	popl %esi	# discard address
 	popl %esi	# real mode pointer
-	xorl %ebx,%ebx
-	ljmp $(__KERNEL_CS), $0x100000
+	movl $0x100000, %ebp
+	jmpl *%ebp
 
 /*
  * We come here, if we were loaded high.
@@ -101,7 +96,8 @@
 	popl %eax	# hcount
 	movl $0x100000,%edi
 	cli		# make sure we don't get interrupted
-	ljmp $(__KERNEL_CS), $0x1000 # and jump to the move routine
+	movl $0x1000, %ebp
+	jmpl *%ebp	# and jump to the move routine
 
 /*
  * Routine (template) for moving the decompressed kernel in place,
@@ -123,6 +119,6 @@
 	rep
 	movsl
 	movl %ebx,%esi	# Restore setup pointer
-	xorl %ebx,%ebx
-	ljmp $(__KERNEL_CS), $0x100000
+	movl $0x100000, %ebp
+	jmpl *%ebp
 move_routine_end:
diff -uNr linux-2.5.44/arch/i386/boot/compressed/misc.c linux-2.5.44.loadlin-fix/arch/i386/boot/compressed/misc.c
--- linux-2.5.44/arch/i386/boot/compressed/misc.c	Fri Oct 11 22:22:09 2002
+++ linux-2.5.44.loadlin-fix/arch/i386/boot/compressed/misc.c	Fri Oct 25 04:36:22 2002
@@ -298,8 +298,7 @@
 
 struct {
 	long * a;
-	short b;
-	} stack_start = { & user_stack [STACK_SIZE] , __KERNEL_DS };
+	} stack_start = { & user_stack [STACK_SIZE] };
 
 static void setup_normal_output_buffer(void)
 {
diff -uNr linux-2.5.44/arch/i386/boot/setup.S linux-2.5.44.loadlin-fix/arch/i386/boot/setup.S
--- linux-2.5.44/arch/i386/boot/setup.S	Sat Oct 19 00:57:56 2002
+++ linux-2.5.44.loadlin-fix/arch/i386/boot/setup.S	Fri Oct 25 05:29:10 2002
@@ -63,6 +63,10 @@
 #define SIG1	0xAA55
 #define SIG2	0x5A5A
 
+/* Segments used by setup.S */
+#define __SETUP_CS	0x10
+#define __SETUP_DS	0x18
+
 INITSEG  = DEF_INITSEG		# 0x9000, we move boot here, out of the way
 SYSSEG   = DEF_SYSSEG		# 0x1000, system loaded at 0x10000 (65536).
 SETUPSEG = DEF_SETUPSEG		# 0x9020, this is the current segment
@@ -842,11 +846,19 @@
 	jmp	flush_instr
 
 flush_instr:
-	xorw	%bx, %bx			# Flag to indicate a boot
 	xorl	%esi, %esi			# Pointer to real-mode code
 	movw	%cs, %si
 	subw	$DELTA_INITSEG, %si
 	shll	$4, %esi			# Convert to 32-bit pointer
+
+# Setup the data segments
+	movw	$__SETUP_DS, %ax
+	movw	%ax, %ds
+	movw	%ax, %es
+	movw	%ax, %fs
+	movw	%ax, %gs
+	movw	%ax, %ss
+	
 # NOTE: For high loaded big kernels we need a
 #	jmpi    0x100000,__KERNEL_CS
 #
@@ -859,7 +871,7 @@
 	.byte 0x66, 0xea			# prefix + jmpi-opcode
 code32:	.long	0x1000				# will be set to 0x100000
 						# for big kernels
-	.word	__KERNEL_CS
+	.word	__SETUP_CS
 
 # Here's a bunch of information about your current kernel..
 kernel_version:	.ascii	UTS_RELEASE
@@ -1053,13 +1065,13 @@
 
 # Descriptor tables
 #
-# NOTE: if you think the GDT is large, you can make it smaller by just
-# defining the KERNEL_CS and KERNEL_DS entries and shifting the gdt
-# address down by GDT_ENTRY_KERNEL_CS*8. This puts bogus entries into
-# the GDT, but those wont be used so it's not a problem.
+# NOTE:	This descriptor table is completely seperate from the descriptor
+# table used by the kernel.  The descriptor numbers it uses are well
+# known and some bootloaders break if you change these entries.
 #
 gdt:
-	.fill GDT_ENTRY_KERNEL_CS,8,0
+	.word	0, 0, 0, 0			# dummy
+	.word	0, 0, 0, 0			# unused
 
 	.word	0xFFFF				# 4Gb - (0x100000*0x1000 = 4Gb)
 	.word	0				# base address = 0
@@ -1072,11 +1084,13 @@
 	.word	0x9200				# data read/write
 	.word	0x00CF				# granularity = 4096, 386
 						#  (+5th nibble of limit)
+gdt_end:
+
 idt_48:
 	.word	0				# idt limit = 0
 	.word	0, 0				# idt base = 0L
 gdt_48:
-	.word	GDT_ENTRY_KERNEL_CS*8 + 16 - 1	# gdt limit
+	.word	gdt_end - gdt - 1		# gdt limit
 
 	.word	0, 0				# gdt base (filled in later)
 
diff -uNr linux-2.5.44/arch/i386/kernel/head.S linux-2.5.44.loadlin-fix/arch/i386/kernel/head.S
--- linux-2.5.44/arch/i386/kernel/head.S	Fri Oct 11 22:21:31 2002
+++ linux-2.5.44.loadlin-fix/arch/i386/kernel/head.S	Fri Oct 25 05:36:23 2002
@@ -40,45 +40,24 @@
  * swapper_pg_dir is the main page directory, address 0x00101000
  *
  * On entry, %esi points to the real-mode code as a 32-bit pointer.
+ *   %ds, %es, %ss, %fs, %gs 32bit data segment base=0 mask=0xffffffff
  */
-startup_32:
+ENTRY(startup_32)
+	cld
+	cli
 /*
  * Set segments to known values
  */
-	cld
-	movl $(__KERNEL_DS),%eax
+	lgdt gdt_48-__PAGE_OFFSET
+	ljmp $__KERNEL_CS,$1f-__PAGE_OFFSET
+1:	movl $__KERNEL_DS, %eax
 	movl %eax,%ds
 	movl %eax,%es
 	movl %eax,%fs
 	movl %eax,%gs
-#ifdef CONFIG_SMP
-	orw %bx,%bx
-	jz 1f
+	movl %eax,%ss
 
 /*
- *	New page tables may be in 4Mbyte page mode and may
- *	be using the global pages. 
- *
- *	NOTE! If we are on a 486 we may have no cr4 at all!
- *	So we do not try to touch it unless we really have
- *	some bits in it to set.  This won't work if the BSP
- *	implements cr4 but this AP does not -- very unlikely
- *	but be warned!  The same applies to the pse feature
- *	if not equally supported. --macro
- *
- *	NOTE! We have to correct for the fact that we're
- *	not yet offset PAGE_OFFSET..
- */
-#define cr4_bits mmu_cr4_features-__PAGE_OFFSET
-	cmpl $0,cr4_bits
-	je 3f
-	movl %cr4,%eax		# Turn on paging options (PSE,PAE,..)
-	orl cr4_bits,%eax
-	movl %eax,%cr4
-	jmp 3f
-1:
-#endif
-/*
  * Initialize page tables
  */
 	movl $pg0-__PAGE_OFFSET,%edi /* initialize page tables */
@@ -106,15 +85,6 @@
 	/* Set up the stack pointer */
 	lss stack_start,%esp
 
-#ifdef CONFIG_SMP
-	orw  %bx,%bx
-	jz  1f				/* Initial CPU cleans BSS */
-	pushl $0
-	popfl
-	jmp checkCPUtype
-1:
-#endif CONFIG_SMP
-
 /*
  * Clear BSS first so that there are no surprises...
  * No need to cld as DF is already clear from cld above...
@@ -167,6 +137,85 @@
 	rep
 	movsl
 1:
+	call checkCPUtype
+	call start_kernel
+L6:
+	hlt			# main should never return here, but
+	jmp L6			# just in case, we know what happens.
+
+	
+#ifdef CONFIG_SMP
+/* 
+ * We enter here from trampoline.S
+ */
+ENTRY(secondary_startup_32)
+/*
+ * Set eflags to a safe state
+ */
+	cld
+	cli
+/*
+ * Set segmetns to known values
+ */
+	movl	$__KERNEL_DS, %eax
+	movl	%eax, %ds
+	movl	%eax, %es
+	movl	%eax, %fs
+	movl	%eax, %gs
+	movl	%eax, %ss
+
+/*
+ *	New page tables may be in 4Mbyte page mode and may
+ *	be using the global pages. 
+ *
+ *	NOTE! If we are on a 486 we may have no cr4 at all!
+ *	So we do not try to touch it unless we really have
+ *	some bits in it to set.  This won't work if the BSP
+ *	implements cr4 but this AP does not -- very unlikely
+ *	but be warned!  The same applies to the pse feature
+ *	if not equally supported. --macro
+ *
+ *	NOTE! We have to correct for the fact that we're
+ *	not yet offset PAGE_OFFSET..
+ */
+#define cr4_bits mmu_cr4_features-__PAGE_OFFSET
+	cmpl $0,cr4_bits
+	je 3f
+	movl %cr4,%eax		# Turn on paging options (PSE,PAE,..)
+	orl cr4_bits,%eax
+	movl %eax,%cr4
+
+/*
+ * Enable paging
+ */
+3:
+	movl $swapper_pg_dir-__PAGE_OFFSET,%eax
+	movl %eax,%cr3		/* set the page table pointer.. */
+	movl %cr0,%eax
+	orl $0x80000000,%eax
+	movl %eax,%cr0		/* ..and set paging (PG) bit */
+	jmp 1f			/* flush the prefetch-queue */
+1:
+	movl $1f,%eax
+	jmp *%eax		/* make sure eip is relocated */
+1:
+	/* Set up the stack pointer */
+	lss stack_start,%esp
+/*
+ * Initialize eflags.  Some BIOS's leave bits like NT set.  This would
+ * confuse the debugger if this code is traced.
+ * XXX - best to initialize before switching to protected mode.
+ */
+	pushl $0
+	popfl
+	
+	call checkCPUtype
+	call initialize_secondary
+L7:	hlt			# initialize_secondary should never return here, but
+	jmp L7			# just in case, we know what happens.
+				
+#endif /* CONFIG_SMP */	
+
 checkCPUtype:
 
 	movl $-1,X86_CPUID		#  -1 for no CPUID initially
@@ -230,7 +279,6 @@
 	movl %eax,%cr0
 
 	call check_x87
-	incb ready
 	lgdt cpu_gdt_descr
 	lidt idt_descr
 	ljmp $(__KERNEL_CS),$1f
@@ -243,21 +291,7 @@
 	xorl %eax,%eax
 	lldt %ax
 	cld			# gcc2 wants the direction flag cleared at all times
-#ifdef CONFIG_SMP
-	movb ready, %cl	
-	cmpb $1,%cl
-	je 1f			# the first CPU calls start_kernel
-				# all other CPUs call initialize_secondary
-	call initialize_secondary
-	jmp L6
-1:
-#endif
-	call start_kernel
-L6:
-	jmp L6			# main should never return here, but
-				# just in case, we know what happens.
-
-ready:	.byte 0
+	ret
 
 /*
  * We depend on ET to be correct. This checks for 287/387.
@@ -356,6 +390,10 @@
 
 	.fill NR_CPUS-1,6,0		# space for the other GDT descriptors
 
+# boot GDT descriptor used before paging is enabled
+gdt_48:
+	.word GDT_ENTRIES*8-1			# gdt limit
+	.long cpu_gdt_table-__PAGE_OFFSET	# gdt base
 /*
  * This is initialized to create an identity-mapping at 0-8M (for bootup
  * purposes) and another mapping of the 0-8M area at virtual address
diff -uNr linux-2.5.44/arch/i386/kernel/trampoline.S linux-2.5.44.loadlin-fix/arch/i386/kernel/trampoline.S
--- linux-2.5.44/arch/i386/kernel/trampoline.S	Fri Oct 11 22:21:41 2002
+++ linux-2.5.44.loadlin-fix/arch/i386/kernel/trampoline.S	Fri Oct 25 04:49:31 2002
@@ -12,10 +12,6 @@
  *	In fact we don't actually need a stack so we don't
  *	set one up.
  *
- *	We jump into the boot/compressed/head.S code. So you'd
- *	better be running a compressed kernel image or you
- *	won't get very far.
- *
  *	On entry to trampoline_data, the processor is in real mode
  *	with 16-bit addressing and 16-bit data.  CS has some value
  *	and IP is zero.  Thus, data addresses need to be absolute
@@ -23,12 +19,13 @@
  *
  *	If you work on this file, check the object module with objdump
  *	--full-contents --reloc to make sure there are no relocation
- *	entries except for the gdt one..
+ *	entries except for the gdt one, and secondary_startup_32..
  */
 
 #include <linux/linkage.h>
 #include <asm/segment.h>
 #include <asm/page.h>
+#include <asm/desc.h>
 
 .data
 
@@ -40,7 +37,6 @@
 	mov	%cs, %ax	# Code and data in the same place
 	mov	%ax, %ds
 
-	mov	$1, %bx		# Flag an SMP trampoline
 	cli			# We should be safe anyway
 
 	movl	$0xA5A5A5A5, trampoline_data - r_base
@@ -54,8 +50,8 @@
 	lmsw	%ax		# into protected mode
 	jmp	flush_instr
 flush_instr:
-	ljmpl	$__KERNEL_CS, $0x00100000
-			# jump to startup_32 in arch/i386/kernel/head.S
+	ljmpl	$__KERNEL_CS, $(secondary_startup_32 - __PAGE_OFFSET)
+			# jump to secondary_startup_32 in arch/i386/kernel/head.S
 
 idt_48:
 	.word	0			# idt limit = 0
@@ -67,7 +63,7 @@
 #
 
 gdt_48:
-	.word	0x0800			# gdt limit = 2048, 256 GDT entries
+	.word	GDT_ENTRIES*8-1			# gdt limit
 	.long	cpu_gdt_table-__PAGE_OFFSET	# gdt base = gdt (first SMP CPU)
 
 .globl trampoline_end

[-- Attachment #3: Type: text/plain, Size: 6 bytes --]


Eric

Re: loadlin with 2.5.?? kernels

[Mike Galbraith]

----- Original Message -----
From: "Eric W. Biederman" <ebiederm@xmission.com>
To: "Mike Galbraith" <EFAULT@gmx.de>
Cc: "Thomas Molina" <tmolina@cox.net>; <linux-kernel@vger.kernel.org>
Sent: Friday, October 25, 2002 2:21 PM
Subject: Re: loadlin with 2.5.?? kernels


> "Mike Galbraith" <EFAULT@gmx.de> writes:
>
> > (sorry, I have to use this pos at work)
> >
> > Yes.  .31 exploded on me after boot, but did not do the violent
reboot
> > during boot.
>
> Earlier you had said it was .38 or so where the failures kicked in,
> so I figured it was some other problem.

(that was someone else)

> > > If it is really the gdt I have some old patches that roughly do
the
> > > right thing, and I just need to dust them off.
> >
> > You dust them off, and I'll be more than happy to test them.  I keep
> > entirely too many kernels resident to want to use lilo.
>
> Here you are.
> The following patch cleans up and removes unnecessary dependencies
from
> the x86 boot path.

Much appreciated.  I will test/report back.

    -Mike

Re: loadlin with 2.5.?? kernels

[robert w hall]

which version of loadlin does this patch?
Hans Lermen changed the gdt structure in version 1.6b to enable it to
boot a win4lin-enabled kernel - he also changed things recently (1.6c)
to boot kernels of between 0.5 &1.5Mb compressed.

(IF I sat down for half an hour I could comment better.. but you
probably know the answer straight-off anyway :-))
Bob Hall


In article <m1bs5in1zh.fsf@frodo.biederman.org>, Eric W. Biederman
<ebiederm@xmission.com> writes
>"Mike Galbraith" <EFAULT@gmx.de> writes:
>
>> (sorry, I have to use this pos at work)
>> 
>> Yes.  .31 exploded on me after boot, but did not do the violent reboot
>> during boot.
>
>Earlier you had said it was .38 or so where the failures kicked in,
>so I figured it was some other problem.
> 
>> > If it is really the gdt I have some old patches that roughly do the
>> > right thing, and I just need to dust them off.
>> 
>> You dust them off, and I'll be more than happy to test them.  I keep
>> entirely too many kernels resident to want to use lilo.
>
>Here you are.
>The following patch cleans up and removes unnecessary dependencies from
>the x86 boot path.
> 
>> (kexec/bootimg wonderfulness solves my problem too.  boot into a stable
>> kernel, instant reboot into any one I want.  gimme gimme gimme:)
>
>It is getting there...
>I just need to find a formula that makes the linux kernel boot reliably.
>
>
>[ A MIME text / plain part was included here. ]
>
>
>Eric

-- 
robert w hall

Re: loadlin with 2.5.?? kernels

[Eric W. Biederman]

robert w hall <bobh@n-cantrell.demon.co.uk> writes:

> which version of loadlin does this patch?

It doesn't it patches the kernel so that it follows the documented
kernel boot protocol.

> Hans Lermen changed the gdt structure in version 1.6b to enable it to
> boot a win4lin-enabled kernel - he also changed things recently (1.6c)
> to boot kernels of between 0.5 &1.5Mb compressed.

With the small kernel restructuring a patch is unlikely to be needed
to boot a win4lin-enabled kernel either.
 
> (IF I sat down for half an hour I could comment better.. but you
> probably know the answer straight-off anyway :-))

Eric

Re: loadlin with 2.5.?? kernels

[Mike Galbraith]

At 11:00 PM 10/25/2002 +0100, robert w hall wrote:

>Hans Lermen changed the gdt structure in version 1.6b to enable it to
>boot a win4lin-enabled kernel - he also changed things recently (1.6c)
>to boot kernels of between 0.5 &1.5Mb compressed.

(1.5MB?  I remember hitting the 1MB wall even after grabbing 1.6c.  hmm..)

I went back and double-checked my loadlin version, and it turned out I was 
actually using 1.6a due to a fat finger.  Version 1.6c booted fine (only 
one kernel tested) without Eric's help.  1.6a definitely needs Eric's help 
to boot.

(gee, it works.  sure hope I don't hit the new lard limit any time soon;)

         -Mike

Re: loadlin with 2.5.?? kernels

[Eric W. Biederman]

Mike Galbraith <efault@gmx.de> writes:

> At 11:00 PM 10/25/2002 +0100, robert w hall wrote:
> 
> >Hans Lermen changed the gdt structure in version 1.6b to enable it to
> >boot a win4lin-enabled kernel - he also changed things recently (1.6c)
> >to boot kernels of between 0.5 &1.5Mb compressed.
> 
> (1.5MB?  I remember hitting the 1MB wall even after grabbing 1.6c.  hmm..)
> 
> I went back and double-checked my loadlin version, and it turned out I was
> actually using 1.6a due to a fat finger.  Version 1.6c booted fine (only one
> kernel tested) without Eric's help.  1.6a definitely needs Eric's help to boot.

Darn.  I guess the arguments for my patch may not be quite as good,
but I still think it may be worth while.
 
> (gee, it works.  sure hope I don't hit the new lard limit any time soon;)

I wonder what the change in 1.6b was....

Eric

Re: loadlin with 2.5.?? kernels

[Mike Galbraith]

At 11:20 PM 10/25/2002 -0600, Eric W. Biederman wrote:
>Mike Galbraith <efault@gmx.de> writes:
>
> > I went back and double-checked my loadlin version, and it turned out I was
> > actually using 1.6a due to a fat finger.  Version 1.6c booted fine 
> (only one
> > kernel tested) without Eric's help.  1.6a definitely needs Eric's help 
> to boot.
>
>Darn.  I guess the arguments for my patch may not be quite as good,
>but I still think it may be worth while.

Well, cleanup is always a pretty fine argument.  Since there only seem to 
be two of us loadlin users, you probably didn't loose much argument wise 
;-)  The other loadlin user reported failure at .38, so maybe your patch is 
needed sometimes even with loadlin-1.6c.  (other loadlin user listening?)

         -Mike

Re: loadlin with 2.5.?? kernels

[Rene Blokland]

In article <5.1.0.14.2.20021026073915.00b55008@pop.gmx.net>, Mike Galbraith wrote:
didn't loose much argument wise 
> ;-)  The other loadlin user reported failure at .38, so maybe your patch is 
> needed sometimes even with loadlin-1.6c.  (other loadlin user listening?)
Yes, I'm there and use 1.6c


-- 
Groeten / Regards, Rene J. Blokland

Re: loadlin with 2.5.?? kernels

[Mike Galbraith]

At 08:32 AM 10/26/2002 +0200, Rene Blokland wrote:
>In article <5.1.0.14.2.20021026073915.00b55008@pop.gmx.net>, Mike 
>Galbraith wrote:
>didn't loose much argument wise
> > ;-)  The other loadlin user reported failure at .38, so maybe your 
> patch is
> > needed sometimes even with loadlin-1.6c.  (other loadlin user listening?)
>Yes, I'm there and use 1.6c

Did Eric's patch fix your boot woes?

         -Mike

Re: loadlin with 2.5.?? kernels

[Eric W. Biederman]

Mike Galbraith <efault@gmx.de> writes:

> At 11:20 PM 10/25/2002 -0600, Eric W. Biederman wrote:
> >Mike Galbraith <efault@gmx.de> writes:
> >
> > > I went back and double-checked my loadlin version, and it turned out I was
> > > actually using 1.6a due to a fat finger.  Version 1.6c booted fine (only one
> 
> > > kernel tested) without Eric's help.  1.6a definitely needs Eric's help to
> > boot.
> >
> >Darn.  I guess the arguments for my patch may not be quite as good,
> >but I still think it may be worth while.
> 
> Well, cleanup is always a pretty fine argument.  Since there only seem to be two
> 
> of us loadlin users, you probably didn't loose much argument wise ;-) The other
> 
> loadlin user reported failure at .38, so maybe your patch is needed sometimes
> even with loadlin-1.6c.  (other loadlin user listening?)

Robert thanks for your reply.

I just looked at what the loadlin 1.6c code does, and it's heuristic
is just slightly more reliable.  It assumes %ds is %cs+8....  That
happens to work but there is nothing in the kernel keeping that from
being broken.  So in practice it looks to be worthwhile to stabilize 
this interface.  So loadlin, and other bootloaders can work by design
and not by chance.

Eric

Re: loadlin with 2.5.?? kernels

[robert w hall]

In article <m1vg3plfi7.fsf@frodo.biederman.org>, Eric W. Biederman
<ebiederm@xmission.com> writes
>Mike Galbraith <efault@gmx.de> writes:
>
>> At 11:20 PM 10/25/2002 -0600, Eric W. Biederman wrote:
>> >Mike Galbraith <efault@gmx.de> writes:
>> >
>> > > I went back and double-checked my loadlin version, and it turned out I was
>> > > actually using 1.6a due to a fat finger.  Version 1.6c booted fine (only 
>one
>> 
>> > > kernel tested) without Eric's help.  1.6a definitely needs Eric's help to
>> > boot.
>> >
>> >Darn.  I guess the arguments for my patch may not be quite as good,
>> >but I still think it may be worth while.
>> 
>> Well, cleanup is always a pretty fine argument.  Since there only seem to be 
>two
>> 
>> of us loadlin users, you probably didn't loose much argument wise ;-) The 
>other
>> 
>> loadlin user reported failure at .38, so maybe your patch is needed sometimes
>> even with loadlin-1.6c.  (other loadlin user listening?)
>
>Robert thanks for your reply.
(oops this thread is a bit messy now - sorry, I originally intended to
post  off-list, [so as not to parade my ignorance in this august forum
:-) ], and made a cockup of withdrawing a post to LK)
>
>I just looked at what the loadlin 1.6c code does, and it's heuristic
>is just slightly more reliable.  It assumes %ds is %cs+8.... 

well that relationship has held for about 9 years, so it was a fairly
safe bet when Hans was trying to fix 1.6a for win4lin :-)

> That
>happens to work but there is nothing in the kernel keeping that from
>being broken.  So in practice it looks to be worthwhile to stabilize 
>this interface.

agreed - 
/ignorant query/
but if you aim for too much generality are you not eventually going to
need Hans Lermen to revisit his loadlin version of the startup code
(which is based in part on old code from head.S & misc.c of course)?
//
>  So loadlin, and other bootloaders can work by design
>and not by chance.

might also be worth checking out linlod (which still is only a beta I
think) needs to run
>
>Eric
Bob
-- 
robert w hall

Re: loadlin with 2.5.?? kernels

[Eric W. Biederman]

robert w hall <bobh@n-cantrell.demon.co.uk> writes:

> > That
> >happens to work but there is nothing in the kernel keeping that from
> >being broken.  So in practice it looks to be worthwhile to stabilize 
> >this interface.
> 
> agreed - 
> /ignorant query/
> but if you aim for too much generality are you not eventually going to
> need Hans Lermen to revisit his loadlin version of the startup code
> (which is based in part on old code from head.S & misc.c of course)?

If I change the kernel so that it always will, and always can use 0x10
and 0x18.   loadlin works by design.  The rest of the kernel can use
some other GDT.  That is what my patch does.

> might also be worth checking out linlod (which still is only a beta I
> think) needs to run

If I could find a reference to the x86 and not the alpha one I might.

Eric

Re: loadlin with 2.5.?? kernels

[robert w hall]

In article <m14rb4yar2.fsf@frodo.biederman.org>, Eric W. Biederman
<ebiederm@xmission.com> writes
>
>> might also be worth checking out linlod (which still is only a beta I
>> think) needs to run
>
>If I could find a reference to the x86 and not the alpha one I might.
>
>Eric

my bad (! ugh!)

'linld' in google finds it (current version is 0.95)
(won't post the eastern european URL, I'd probably screw it)
have also sent you the .com & tar.bz2 versions of linld 0.94 direct
-- 
robert w hall

Re: loadlin with 2.5.?? kernels

[robert w hall]

In article <m13cqtn5cm.fsf@frodo.biederman.org>, Eric W. Biederman
<ebiederm@xmission.com> writes
>Mike Galbraith <efault@gmx.de> writes:
>I wonder what the change in 1.6b was....
>
>Eric

IIRC - kernel_cs & kernel_ds are taken at runtime rather than from the
header file (segment.h?).
(because win4lin bumps them up from their old default values)

(Wine went to using a similar trick I think)
this is all from fading memory - but it's in the README for 1.6b I think

Bob

-- 
robert w hall

Re: loadlin with 2.5.?? kernels

[Mike Galbraith]

At 12:55 PM 10/20/2002 -0400, Floydsmith@aol.com wrote:
>In a message dated 10/20/2002 9:03:34 AM Eastern Daylight Time, 
>efault@gmx.de writes:
>
>
>>Subj:loadlin with 2.5.?? kernels
>>Date:10/20/2002 9:03:34 AM Eastern Daylight Time
>>From:<mailto:efault@gmx.de>efault@gmx.de
>>To:<mailto:linux-kernel@vger.kernel.org>linux-kernel@vger.kernel.org
>>Sent from the Internet
>>
>>
>>
>>Greetings,
>>
>>I hadn't had time to build/test kernels since 2.5.8-pre3.  I now find that
>>loadlin doesn't work on my box any more.  Is this a known problem?  If so,
>>when did it quit working?  (loadlin obsolete?  other?)
>>
>>At the moment, the only way I have to boot is via floppy.
>
>
>loadlin will not work with any kernel that is 1024k or greater in size.
>There is a replacement named "linld" at:
>http://www.tux.org/pub/people/kent-robotti/looplinux/index.html
>which help you.

Yeah, that's always been a pain, but that's not what I'm hitting (violent 
reboot).  I'll give linld (thanks!) a shot, but mostly, I want my dearly 
beloved loadlin back ;-)

         -Mike

Re: loadlin with 2.5.?? kernels

[Mike Galbraith]

At 03:31 PM 10/25/2002 +0200, you wrote:

> > > You dust them off, and I'll be more than happy to test them.  I keep
> > > entirely too many kernels resident to want to use lilo.
> >
> > Here you are.

My little box suddenly remembered how to boot :)  Thanks for the rescue 
kind Sir.

         -Mike