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Towards a(nother) new real-mode infrastructure, in which we take

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advantage of the fact that we have to have a permanently-resident block
in base memory.
This commit is contained in:
Michael Brown
2006-05-02 15:41:21 +00:00
parent 8f62b39c03
commit 9fcded3d23
10 changed files with 464 additions and 1186 deletions
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78
src/arch/i386/core/relocate.c
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@@ -1,30 +1,11 @@
#include "virtaddr.h"
#include "memsizes.h"
#include "osdep.h"
#include "etherboot.h"
#include <gpxe/init.h>
#include "relocate.h"
#ifndef KEEP_IT_REAL
/* by Eric Biederman */
/* On some platforms etherboot is compiled as a shared library, and we use
* the ELF pic support to make it relocateable. This works very nicely
* for code, but since no one has implemented PIC data yet pointer
* values in variables are a a problem. Global variables are a
* pain but the return addresses on the stack are the worst. On these
* platforms relocate_to will restart etherboot, to ensure the stack
* is reinitialize and hopefully get the global variables
* appropriately reinitialized as well.
*
*/
#include <virtaddr.h>
#include <registers.h>
#include <memsizes.h>
/*
* relocate() must be called without any hardware resources pointing
* at the current copy of Etherboot. The easiest way to achieve this
* is to call relocate() from within arch_initialise(), before the NIC
* gets touched in any way.
* Originally by Eric Biederman
*
* Heavily modified by Michael Brown
*
*/
@@ -40,14 +21,27 @@ extern char _max_align[];
extern char _text[];
extern char _end[];
/* Post-relocation function table */
static struct post_reloc_fn post_reloc_fns[0] __table_start(post_reloc_fn);
static struct post_reloc_fn post_reloc_fns_end[0] __table_end(post_reloc_fn);
/* within 1MB of 4GB is too close.
* MAX_ADDR is the maximum address we can easily do DMA to.
*
* Not sure where this constraint comes from, but kept it from Eric's
* old code - mcb30
*/
#define MAX_ADDR (0xfff00000UL)
static void relocate ( void ) {
/**
* Relocate Etherboot
*
* @v ix86 x86 register dump from prefix
* @ret ix86 x86 registers to return to prefix
*
* This copies Etherboot to a suitable location near the top of 32-bit
* address space, and returns the physical address of the new location
* to the prefix in %edi.
*/
void relocate ( struct i386_all_regs *ix86 ) {
unsigned long addr, eaddr, size;
unsigned i;
struct post_reloc_fn *post_reloc_fn;
/* Walk through the memory map and find the highest address
* below 4GB that etherboot will fit into. Ensure etherboot
@@ -183,25 +177,9 @@ static void relocate ( void ) {
virt_to_phys ( _text ), virt_to_phys ( _end ),
addr, addr + _end - _text );
relocate_to ( addr );
/* Note that we cannot make real-mode calls
* (e.g. printf) at this point, because librm has just
* been moved to high memory.
*/
/* Call any registered post-relocation functions.
* librm has a post-relocation function to install a
* new librm into base memory.
*/
for ( post_reloc_fn = post_reloc_fns;
post_reloc_fn < post_reloc_fns_end ; post_reloc_fn++ ) {
if ( post_reloc_fn->post_reloc )
post_reloc_fn->post_reloc ();
}
memcpy ( phys_to_virt ( addr ), _text, _end - _text );
}
/* Let prefix know where the new copy is */
ix86->regs.edi = addr;
}
INIT_FN ( INIT_RELOCATE, relocate, NULL, NULL );
#endif /* ! KEEP_IT_REAL */