Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 128 insertions, 0 deletions

diff --git a/arch/i386/boot/compressed/head.S b/arch/i386/boot/compressed/head.S
new file mode 100644
index 000000000000..c5e80b69e7d4
--- /dev/null
+++ b/arch/i386/boot/compressed/head.S
@@ -0,0 +1,128 @@
+/*
+ *  linux/boot/head.S
+ *
+ *  Copyright (C) 1991, 1992, 1993  Linus Torvalds
+ */
+
+/*
+ *  head.S contains the 32-bit startup code.
+ *
+ * NOTE!!! Startup happens at absolute address 0x00001000, which is also where
+ * the page directory will exist. The startup code will be overwritten by
+ * the page directory. [According to comments etc elsewhere on a compressed
+ * kernel it will end up at 0x1000 + 1Mb I hope so as I assume this. - AC]
+ *
+ * Page 0 is deliberately kept safe, since System Management Mode code in 
+ * laptops may need to access the BIOS data stored there.  This is also
+ * useful for future device drivers that either access the BIOS via VM86 
+ * mode.
+ */
+
+/*
+ * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
+ */
+.text
+
+#include <linux/linkage.h>
+#include <asm/segment.h>
+
+        .globl startup_32
+        
+startup_32:
+        cld
+        cli
+        movl $(__BOOT_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
+
+/*
+ * 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
+/*
+ * Clear BSS
+ */
+        xorl %eax,%eax
+        movl $_edata,%edi
+        movl $_end,%ecx
+        subl %edi,%ecx
+        cld
+        rep
+        stosb
+/*
+ * Do the decompression, and jump to the new kernel..
+ */
+        subl $16,%esp   # place for structure on the stack
+        movl %esp,%eax
+        pushl %esi      # real mode pointer as second arg
+        pushl %eax      # address of structure as first arg
+        call decompress_kernel
+        orl  %eax,%eax 
+        jnz  3f
+        popl %esi       # discard address
+        popl %esi       # real mode pointer
+        xorl %ebx,%ebx
+        ljmp $(__BOOT_CS), $0x100000
+
+/*
+ * We come here, if we were loaded high.
+ * We need to move the move-in-place routine down to 0x1000
+ * and then start it with the buffer addresses in registers,
+ * which we got from the stack.
+ */
+3:
+        movl $move_routine_start,%esi
+        movl $0x1000,%edi
+        movl $move_routine_end,%ecx
+        subl %esi,%ecx
+        addl $3,%ecx
+        shrl $2,%ecx
+        cld
+        rep
+        movsl
+
+        popl %esi       # discard the address
+        popl %ebx       # real mode pointer
+        popl %esi       # low_buffer_start
+        popl %ecx       # lcount
+        popl %edx       # high_buffer_start
+        popl %eax       # hcount
+        movl $0x100000,%edi
+        cli             # make sure we don't get interrupted
+        ljmp $(__BOOT_CS), $0x1000 # and jump to the move routine
+
+/*
+ * Routine (template) for moving the decompressed kernel in place,
+ * if we were high loaded. This _must_ PIC-code !
+ */
+move_routine_start:
+        movl %ecx,%ebp
+        shrl $2,%ecx
+        rep
+        movsl
+        movl %ebp,%ecx
+        andl $3,%ecx
+        rep
+        movsb
+        movl %edx,%esi
+        movl %eax,%ecx  # NOTE: rep movsb won't move if %ecx == 0
+        addl $3,%ecx
+        shrl $2,%ecx
+        rep
+        movsl
+        movl %ebx,%esi  # Restore setup pointer
+        xorl %ebx,%ebx
+        ljmp $(__BOOT_CS), $0x100000
+move_routine_end: