[coreboot] suspend/resume in v3

[Kevin O'Connor]

On Mon, Sep 08, 2008 at 05:38:59PM +0200, Carl-Daniel Hailfinger wrote:
> On 08.09.2008 17:23, Stefan Reinauer wrote:
> > No. There is no RAM at that position.
> >   
> 
> That means we either
> - have to tell gcc that the stack moved in the middle of a function or
> - redesign v3 stage1 completely.

I don't think that is true.

As before, I think _moving_ the stack is a bad idea.  However, I don't
see any reason not to start using a new stack and discard the old.
Doing so is both simple and reliable.

I've attached a code snippet below - it's only to illustrate the
general idea.

That said, I think having disable_car() jump to the next stage is
probably faster and more flexible.

-Kevin


Index: arch/x86/stage1.c
===================================================================
--- arch/x86/stage1.c	(revision 861)
+++ arch/x86/stage1.c	(working copy)
@@ -139,6 +139,8 @@
 }
 #endif /* CONFIG_PAYLOAD_ELF_LOADER */
 
+static struct mem_file GlobalArchive;
+
 /**
  * This function is called from assembler code with its argument on the
  * stack. Force the compiler to generate always correct code for this case.
@@ -232,6 +234,20 @@
 
 	printk(BIOS_DEBUG, "Done RAM init code\n");
 
+        // Memory running - copy variables in CAR area that are needed
+        // to a permanent area.
+        GlobalArchive = archive;
+
+        // Jump to second part of stage1 with a permanent stack.
+        asm volatile (
+            "movl 0x200000, %esp\n"
+            "jmp stage1_main_post_initram\n");
+}
+
+void stage1_main_post_initram()
+{
+        struct mem_file archive = GlobalArchive;
+
 	/* Turn off Cache-As-Ram */
 	disable_car();