[librm] Add phys_call() wrapper for calling code with physical addressing

Add a phys_call() wrapper function (analogous to the existing
real_call() wrapper function) for calling code with flat physical
addressing, and use this wrapper within the PHYS_CODE() macro.

Move the relevant functionality inside librm.S, where it more
naturally belongs.

The COMBOOT code currently uses explicit calls to _virt_to_phys and
_phys_to_virt.  These will need to be rewritten if our COMBOOT support
is ever generalised to be able to run in a 64-bit build.
Specifically:

  - com32_exec_loop() should be restructured to use PHYS_CODE()

  - com32_wrapper.S should be restructured to use an equivalent of
    prot_call(), passing parameters via a struct i386_all_regs

  - there appears to be no need for com32_wrapper.S to switch between
    external and internal stacks; this could be omitted to simplify
    the design.

For now, librm.S continues to expose _virt_to_phys and _phys_to_virt
for use by com32.c and com32_wrapper.S.  Similarly, librm.S continues
to expose _intr_to_virt for use by gdbidt.S.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 0 insertions, 145 deletions

diff --git a/src/arch/x86/core/virtaddr.S b/src/arch/x86/core/virtaddr.S
deleted file mode 100644
index 45beb16..0000000
--- a/src/arch/x86/core/virtaddr.S
+++ /dev/null
@@ -1,145 +0,0 @@
-/*
- * Functions to support the virtual addressing method of relocation
- * that Etherboot uses.
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL )
-
-#include "librm.h"
-		
-	.arch i386
-	.text
-	.code32
-	
-/****************************************************************************
- * _virt_to_phys (virtual addressing)
- *
- * Switch from virtual to flat physical addresses.  %esp is adjusted
- * to a physical value.  Segment registers are set to flat physical
- * selectors.  All other registers are preserved.  Flags are
- * preserved.
- *
- * Parameters: none
- * Returns: none
- ****************************************************************************
- */
-	.globl _virt_to_phys
-_virt_to_phys:
-	/* Preserve registers and flags */
-	pushfl
-	pushl	%eax
-	pushl	%ebp
-
-	/* Change return address to a physical address */
-	movl	VIRTUAL(virt_offset), %ebp
-	addl	%ebp, 12(%esp)
-
-	/* Switch to physical code segment */
-	cli
-	pushl	$PHYSICAL_CS
-	leal	VIRTUAL(1f)(%ebp), %eax
-	pushl	%eax
-	lret
-1:
-	/* Reload other segment registers and adjust %esp */
-	movl	$PHYSICAL_DS, %eax
-	movl	%eax, %ds
-	movl	%eax, %es
-	movl	%eax, %fs
-	movl	%eax, %gs
-	movl	%eax, %ss
-	addl	%ebp, %esp
-
-	/* Restore registers and flags, and return */
-	popl	%ebp
-	popl	%eax
-	popfl
-	ret
-
-/****************************************************************************
- * _phys_to_virt (flat physical addressing)
- *
- * Switch from flat physical to virtual addresses.  %esp is adjusted
- * to a virtual value.  Segment registers are set to virtual
- * selectors.  All other registers are preserved.  Flags are
- * preserved.
- *
- * Parameters: none
- * Returns: none
- ****************************************************************************
- */
-	.globl _phys_to_virt
-_phys_to_virt:
-	/* Preserve registers and flags */
-	pushfl
-	pushl	%eax
-	pushl	%ebp
-
-	/* Switch to virtual code segment */
-	cli
-	ljmp	$VIRTUAL_CS, $VIRTUAL(1f)
-1:
-	/* Reload data segment registers */
-	movl	$VIRTUAL_DS, %eax
-	movl	%eax, %ds
-	movl	%eax, %es
-	movl	%eax, %fs
-	movl	%eax, %gs
-
-	/* Reload stack segment and adjust %esp */
-	movl	VIRTUAL(virt_offset), %ebp
-	movl	%eax, %ss
-	subl	%ebp, %esp
-
-	/* Change the return address to a virtual address */
-	subl	%ebp, 12(%esp)
-
-	/* Restore registers and flags, and return */
-	popl	%ebp
-	popl	%eax
-	popfl
-	ret
-
-/****************************************************************************
- * _intr_to_virt (virtual code segment, virtual or physical stack segment)
- *
- * Switch from virtual code segment with either a virtual or physical
- * stack segment to using virtual addressing.  %esp is adjusted if
- * necessary to a virtual value.  Segment registers are set to virtual
- * selectors.  All other registers are preserved.  Flags are
- * preserved.
- *
- * Parameters: none
- * Returns: none
- ****************************************************************************
- */
-	.globl _intr_to_virt
-_intr_to_virt:
-	/* Preserve registers and flags */
-	pushfl
-	pushl	%eax
-	pushl	%ebp
-
-	/* Check whether stack segment is physical or virtual */
-	movl	%ss, %eax
-	cmpw	$VIRTUAL_DS, %ax
-	movl	$VIRTUAL_DS, %eax
-
-	/* Reload data segment registers */
-	movl	%eax, %ds
-	movl	%eax, %es
-	movl	%eax, %fs
-	movl	%eax, %gs
-
-	/* Reload stack segment and adjust %esp if necessary */
-	je	1f
-	movl	VIRTUAL(virt_offset), %ebp
-	movl	%eax, %ss
-	subl	%ebp, %esp
-1:
-	/* Restore registers and flags, and return */
-	popl	%ebp
-	popl	%eax
-	popfl
-	ret