From 8bf63395ca00458da14b0b3e37a63761ea6767ab Mon Sep 17 00:00:00 2001
From: "H. Peter Anvin" <hpa@zytor.com>
Date: Sun, 17 May 2009 13:39:42 -0700
Subject: [PATCH] core: move 32-bit code out of the .text16 segment

Move all 32-bit code out of the .text16 segment.  The code that is
used during the relocation of the .text segment (i.e. anywhere on the
bcopy path) is moved to .textnr (other than the code already in
.bcopyxx) for "no relocate", the rest of the code to .text.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 core/com32.inc   | 13 +++++++++----
 core/pm.inc      | 20 ++++++++++++++------
 core/syslinux.ld | 14 ++++++++++++++
 3 files changed, 37 insertions(+), 10 deletions(-)

diff --git a/core/com32.inc b/core/com32.inc
index 632f973..0165c0f 100644
--- a/core/com32.inc
+++ b/core/com32.inc
@@ -62,7 +62,7 @@ com32_start:
 		mov eax,[HighMemRsvd]
 		xor ax,ax			; Align to a 64K boundary
 		mov [PMESP],eax
-		mov bx,.pm			; Where to go in PM
+		mov ebx,.pm			; Where to go in PM
 		jmp enter_pm
 
 ;
@@ -70,6 +70,7 @@ com32_start:
 ; progam, in 32-bit mode...
 ;
 		bits 32
+		section .text
 .pm:
 		; Set up the calling stack frame
 
@@ -90,6 +91,7 @@ com32_exit:
 		jmp enter_rm
 
 		bits 16
+		section .text16
 .rm:
 		mov dword [PMESP],__stack_end	; Stop use of COM32 stack
 		sti
@@ -99,6 +101,7 @@ com32_exit:
 ; 16-bit intcall/farcall handling code
 ;
 		bits 16
+		section .text16
 
 com32_sys_rm:
 		pop gs
@@ -119,7 +122,7 @@ com32_sys_rm:
 		push es
 		push fs
 		push gs
-		mov bx,com32_syscall.resume
+		mov ebx,com32_syscall.resume
 		jmp enter_pm
 
 ;
@@ -130,13 +133,14 @@ com32_cfar_rm:
 .return:
 		mov sp,[cs:Com32SysSP]
 		mov esi,eax
-		mov bx,core_cfarcall.resume
+		mov ebx,core_cfarcall.resume
 		jmp enter_pm
 
 ;
 ; 32-bit support code
 ;
 		bits 32
+		section .text
 
 ;
 ; Intcall/farcall invocation.  We manifest a structure on the real-mode stack,
@@ -272,9 +276,10 @@ core_cfarcall:
 		ret
 
 		bits 16
-
 		section .bss16
 		alignb 4
 Com32SysSP	resd 1			; SP saved during COM32 syscall
 
+		bits 16
 		section .text16
+
diff --git a/core/pm.inc b/core/pm.inc
index 3b7dab4..0f2fbb4 100644
--- a/core/pm.inc
+++ b/core/pm.inc
@@ -20,6 +20,7 @@
 ;; PM refers to 32-bit flat protected mode; RM to 16-bit real mode.
 ;;
 
+		bits 16
 		section .text16
 ;
 ; _pm_call: call PM routine in low memory from RM
@@ -34,7 +35,6 @@
 ;
 ;	This routine is invoked by the pm_call macro.
 ;
-		bits 16
 _pm_call:
 		pushfd
 		pushad
@@ -44,11 +44,12 @@ _pm_call:
 		push gs
 		mov bp,sp
 		mov ax,cs
-		mov bx,.pm
+		mov ebx,.pm
 		mov ds,ax
 		jmp enter_pm
 
 		bits 32
+		section .textnr
 .pm:
 		; EAX points to the top of the RM stack, which is EFLAGS
 		test RM_FLAGSH,02h		; RM EFLAGS.IF
@@ -60,6 +61,7 @@ _pm_call:
 		jmp enter_rm
 
 		bits 16
+		section .text16
 .rm:
 		pop gs
 		pop fs
@@ -71,7 +73,7 @@ _pm_call:
 
 ;
 ; enter_pm: Go to PM with interrupt service configured
-;	BX	  = PM entry point (in low memory)
+;	EBX	  = PM entry point
 ;	EAX = EBP = on exit, points to the RM stack as a 32-bit value
 ;	ECX, EDX, ESI, EDI preserved across this routine
 ;
@@ -81,6 +83,7 @@ _pm_call:
 ; can enable interrupts by executing STI.
 ;
 		bits 16
+		section .text16
 enter_pm:
 		cli
 		xor eax,eax
@@ -105,6 +108,7 @@ enter_pm:
 		jmp PM_CS32:.in_pm
 
 		bits 32
+		section .textnr
 .in_pm:
 		xor eax,eax		; Available for future use...
 		mov fs,eax
@@ -121,7 +125,7 @@ enter_pm:
 
 		mov esp,[PMESP]		; Load protmode %esp
 		mov eax,ebp		; EAX -> top of real-mode stack
-		jmp bx			; Go to where we need to go
+		jmp ebx			; Go to where we need to go
 
 ;
 ; enter_rm: Return to RM from PM
@@ -135,6 +139,7 @@ enter_pm:
 ; can enable interrupts by executing STI.
 ;
 		bits 32
+		section .textnr
 enter_rm:
 		cli
 		cld
@@ -142,6 +147,7 @@ enter_rm:
 		jmp PM_CS16:.in_pm16	; Return to 16-bit mode first
 
 		bits 16
+		section .text16
 .in_pm16:
 		mov ax,PM_DS16		; Real-mode-like segment
 		mov es,ax
@@ -184,14 +190,15 @@ PM_IDT_ptr:	dw 8*256-1		; Length
 ; AL contains the register number.
 ;
 		bits 32
-		section .text16
+		section .textnr
 pm_irq:
 		pushad
 		movzx esi,byte [esp+8*4] ; Interrupt number
-		mov bx,.rm
+		mov ebx,.rm
 		jmp enter_rm		; Go to real mode
 
 		bits 16
+		section .text16
 .rm:
 		pushf			; Flags on stack
 		call far [cs:esi*4]	; Call IVT entry
@@ -199,6 +206,7 @@ pm_irq:
 		jmp enter_pm		; Go back to PM
 
 		bits 32
+		section .textnr
 .pm:
 		popad
 		add esp,4		; Drop interrupt number
diff --git a/core/syslinux.ld b/core/syslinux.ld
index 6e965c0..9149b9b 100644
--- a/core/syslinux.ld
+++ b/core/syslinux.ld
@@ -96,6 +96,20 @@ SECTIONS
 	__text16_len = __text16_end - __text16_start;
 	__text16_dwords = (__text16_len + 3) >> 2;
 
+	/*
+	 * .textnr is used for 32-bit code that is used on the code
+	 * path to initialize the .text segment
+	 */
+	. = ALIGN(16);
+	.textnr : {
+		FILL(0x90909090)
+		__textnr_start = .;
+		*(.textnr)
+		__textnr_end = .;
+	}
+	__textnr_len = __textnr_end - __textnr_start;
+	__textnr_dwords = (__textnr_len + 3) >> 2;
+
 	. = ALIGN(16);
 	.bcopyxx : {
 		FILL(0x90909090)
-- 
2.7.4