x86: drop legacy (PC BIOS) boot in favor of EFI

The 16-bit port has experienced bitrot and failed to compile with more
recent linkers for at least a year. Fixing the linker error is insufficient
to restore a barebox that can boot to shell. This continued breakage likely
means that there are no users interested in updating. As new x86 projects
should be using MACH_EFI_GENERIC anyway, retire support for 16-bit legacy
boot (MACH_X86_GENERIC).

Acked-by: Juergen Borleis <jbe@pengutronix.de>
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 0 insertions, 166 deletions

diff --git a/arch/x86/bios/traveler.S b/arch/x86/bios/traveler.S
deleted file mode 100644
index 1c11c9dc74..0000000000
--- a/arch/x86/bios/traveler.S
+++ /dev/null
@@ -1,166 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-/* SPDX-FileCopyrightText: 2009 Juergen Beisert, Pengutronix */
-
-/* Mostly stolen from the GRUB2 project */
-
-/**
- * @file
- * @brief Switch from the flat mode world into the real mode world and vice versa
- *
- * Note: These functions are *called* and return in a different operating mode
- */
-
-/**
- * @fn void real_to_prot(void)
- * @brief Switch from temp. real mode back to flat mode
- *
- * Called from a 32 bit flat mode segment and returns into a 16 bit segment
- */
-
-/**
- * @fn void prot_to_real(void)
- * @brief Switch from flat mode to real mode
- *
- * Called from a 16 bit real mode segment and returns into a 32 bit segment
- */
-
-#include <asm/modes.h>
-
-	.file "walkyrie.S"
-
-/* keep the current flat mode stack pointer, while playing in real mode */
-	.section .boot.data.protstack
-	.code32
-protstack: .long 4
-/* temp. store */
-return_addr: .long 4
-
-
-	.section .boot.text.real_to_prot, "ax"
-	.code16
-	.globl	real_to_prot
-	.type	real_to_prot, @function
-
-/* Note: This routine should not change any other standard registers than eax */
-real_to_prot:
-	/*
-	 * Always disable the interrupts, when returning to flat mode
-	 */
-	cli
-
-	/* turn on protected mode */
-	movl %cr0, %eax
-	orl $0x00000001, %eax
-	movl %eax, %cr0
-
-	/* jump to relocation, flush prefetch queue, and reload %cs */
-	DATA32 ljmp $__BOOT_CS, $return_to_flatmode
-	.size real_to_prot, .-real_to_prot
-
-/* ----------------------------------------------------------------------- */
-	.section .boot.text.return_to_flatmode, "ax"
-	.type return_to_flatmode, @function
-	.code32
-
-return_to_flatmode:
-	/* reload other segment registers */
-	movw $__BOOT_DS, %ax
-	movw %ax, %ds
-	movw %ax, %es
-	movw %ax, %fs
-	movw %ax, %gs
-	movw %ax, %ss
-
-	/* move the return address from the real mode to the flat mode stack */
-	movl (%esp), %eax
-	movl %eax, return_addr
-
-	/* setup again the flat mode stack */
-	movl protstack, %eax
-	movl %eax, %esp
-	movl %eax, %ebp
-
-	movl return_addr, %eax
-	movl %eax, (%esp)
-
-	/* flag we returned happy here */
-	xorl %eax, %eax
-	ret
-	.size return_to_flatmode, .-return_to_flatmode
-
-/* ------------------------------------------------------------------------ */
-
-/* Note: This routine should not change any other standard registers than eax */
-
-	.section .boot.text.prot_to_real, "ax"
-	.globl prot_to_real
-	.type prot_to_real, @function
-	.extern boot_stack
-	.code32
-
-prot_to_real:
-	/* save the protected mode stack */
-	movl %esp, %eax
-	movl %eax, protstack
-
-	/* prepare the real mode stack */
-	/* - address to call to the top of this stack */
-	movl (%esp), %eax
-	movl %eax, boot_stack - 4
-
-	/* - the stack itself */
-	movl $boot_stack - 4, %eax
-	movl %eax, %esp
-	movl %eax, %ebp
-
-	/* prepare segments limits to 16 bit */
-	movw $__REAL_DS, %ax
-	movw %ax, %ds
-	movw %ax, %es
-	movw %ax, %fs
-	movw %ax, %gs
-	movw %ax, %ss
-
-	/* at last, also limit the code segment to 16 bit */
-	ljmp $__REAL_CS, $return_to_realmode
-	.size prot_to_real, .-prot_to_real
-
-/* ----------------------------------------------------------------------- */
-
-	.section .boot.text.return_to_realmode, "ax"
-	.globl return_to_realmode
-	.type return_to_realmode, @function
-	.code16
-
-return_to_realmode:
-	/* disable protected mode */
-	movl %cr0, %eax
-	andl $(~0x00000001), %eax
-	movl %eax, %cr0
-
-	/*
-	 * all the protected mode settings are still cached in the CPU.
-	 * Refresh them by re-loading all registers in realmode
-	 * Start with the CS, continue with the data registers
-	 */
-	ljmp $0, $enter_realmode
-
-enter_realmode:
-	xorl %eax, %eax
-	movw %ax, %ds
-	movw %ax, %es
-	movw %ax, %fs
-	movw %ax, %gs
-	movw %ax, %ss
-	/*
-	 * back in plain real mode now, we can play again with the BIOS
-	 */
-
-	/* restore interrupts */
-	sti
-
-	/* return on realmode stack! */
-	DATA32 ret
-
-	.size return_to_realmode, .-return_to_realmode
-