mirror of
https://github.com/ipxe/ipxe
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030e5a064e
Some binutils versions will drag in an object to satisfy the entry symbol; some won't. Try to cope with this exciting variety of behaviour by ensuring that all entry symbols are unique. Remove the explicit inclusion of the prefix object on the linker command line, since the entry symbol now provides all the information needed to identify the prefix. Signed-off-by: Michael Brown <mcb30@ipxe.org>
435 lines
9.5 KiB
ArmAsm
435 lines
9.5 KiB
ArmAsm
/*
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* Copyright (C) 2010 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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FILE_LICENCE ( GPL2_OR_LATER )
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#define PCIBIOS_READ_CONFIG_WORD 0xb109
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#define PCIBIOS_READ_CONFIG_DWORD 0xb10a
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#define PCIBIOS_WRITE_CONFIG_WORD 0xb10c
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#define PCIBIOS_WRITE_CONFIG_DWORD 0xb10d
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#define PCI_COMMAND 0x04
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#define PCI_COMMAND_MEM 0x02
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#define PCI_BAR_0 0x10
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#define PCI_BAR_5 0x24
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#define PCI_BAR_EXPROM 0x30
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#define ROMPREFIX_EXCLUDE_PAYLOAD 1
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#define _rom_start _mrom_start
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#include "romprefix.S"
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.text
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.arch i386
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.code16
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/* Obtain access to payload by exposing the expansion ROM BAR at the
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* address currently used by a suitably large memory BAR on the same
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* device. The memory BAR is temporarily disabled. Using a memory
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* BAR on the same device means that we don't have to worry about the
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* configuration of any intermediate PCI bridges.
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*
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* Parameters:
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* %ds:0000 : Prefix
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* %esi : Buffer for copy of image source (or zero if no buffer available)
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* Returns:
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* %esi : Valid image source address (buffered or unbuffered)
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* CF set on error
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*/
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.section ".text16.early", "awx", @progbits
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.globl open_payload
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open_payload:
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/* Preserve registers */
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pushl %eax
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pushw %bx
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pushl %ecx
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pushl %edx
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pushl %edi
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pushw %bp
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pushw %ds
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/* Retrieve bus:dev.fn and image source length from .prefix */
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movw init_pci_busdevfn, %bx
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movl image_source_len_dword, %ecx
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/* Set up %ds for access to .text16.early */
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pushw %cs
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popw %ds
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/* Store bus:dev.fn and image source length to .text16.early */
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movw %bx, payload_pci_busdevfn
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movl %ecx, rom_bar_copy_len_dword
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/* Get expansion ROM BAR current value */
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movw $PCI_BAR_EXPROM, %di
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call pci_read_bar
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movl %eax, rom_bar_orig_value
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/* Get expansion ROM BAR size */
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call pci_size_mem_bar_low
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movl %ecx, rom_bar_size
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/* Find a suitable memory BAR to use */
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movw $PCI_BAR_0, %di /* %di is PCI BAR register */
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xorw %bp, %bp /* %bp is increment */
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find_mem_bar:
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/* Move to next BAR */
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addw %bp, %di
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cmpw $PCI_BAR_5, %di
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jle 1f
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stc
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jmp 99f
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1: movw $4, %bp
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/* Get BAR current value */
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call pci_read_bar
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/* Skip non-existent BARs */
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notl %eax
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testl %eax, %eax
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notl %eax
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jz find_mem_bar
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/* Skip I/O BARs */
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testb $0x01, %al
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jnz find_mem_bar
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/* Set increment to 8 for 64-bit BARs */
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testb $0x04, %al
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jz 1f
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movw $8, %bp
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1:
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/* Skip 64-bit BARs with high dword set; we couldn't use this
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* address for the (32-bit) expansion ROM BAR anyway
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*/
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testl %edx, %edx
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jnz find_mem_bar
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/* Get low dword of BAR size */
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call pci_size_mem_bar_low
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/* Skip BARs smaller than the expansion ROM BAR */
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cmpl %ecx, rom_bar_size
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ja find_mem_bar
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/* We have a memory BAR with a 32-bit address that is large
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* enough to use. Store BAR number and original value.
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*/
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movw %di, stolen_bar_register
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movl %eax, stolen_bar_orig_value
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/* Remove flags from BAR address */
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xorb %al, %al
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/* Write zero to our stolen BAR. This doesn't technically
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* disable it, but it's a pretty safe bet that the PCI bridge
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* won't pass through accesses to this region anyway. Note
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* that the high dword (if any) must already be zero.
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*/
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xorl %ecx, %ecx
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call pci_write_config_dword
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/* Enable expansion ROM BAR at stolen BAR's address */
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movl %eax, %ecx
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orb $0x1, %cl
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movw $PCI_BAR_EXPROM, %di
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call pci_write_config_dword
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/* Copy payload to buffer, or set buffer address to BAR address */
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testl %esi, %esi
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jz 1f
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/* We have a buffer; copy payload to it. Since .mrom is
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* designed specifically for real hardware, we assume that
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* flat real mode is working properly. (In the unlikely event
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* that this code is run inside a hypervisor that doesn't
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* properly support flat real mode, it will die horribly.)
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*/
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pushl %esi
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pushw %es
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movl %esi, %edi
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movl %eax, %esi
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movl rom_bar_copy_len_dword, %ecx
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xorw %ax, %ax
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movw %ax, %es
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addr32 es rep movsl
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popw %es
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popl %esi
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jmp 2f
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1: /* We have no buffer; set %esi to the BAR address */
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movl %eax, %esi
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2:
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clc
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/* Restore registers and return */
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99: popw %ds
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popw %bp
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popl %edi
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popl %edx
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popl %ecx
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popw %bx
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popl %eax
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lret
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.size open_payload, . - open_payload
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.section ".text16.early.data", "aw", @progbits
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payload_pci_busdevfn:
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.word 0
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.size payload_pci_busdevfn, . - payload_pci_busdevfn
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.section ".text16.early.data", "aw", @progbits
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rom_bar_orig_value:
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.long 0
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.size rom_bar_orig_value, . - rom_bar_orig_value
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.section ".text16.early.data", "aw", @progbits
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rom_bar_size:
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.long 0
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.size rom_bar_size, . - rom_bar_size
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.section ".text16.early.data", "aw", @progbits
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rom_bar_copy_len_dword:
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.long 0
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.size rom_bar_copy_len_dword, . - rom_bar_copy_len_dword
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.section ".text16.early.data", "aw", @progbits
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stolen_bar_register:
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.word 0
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.size stolen_bar_register, . - stolen_bar_register
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.section ".text16.early.data", "aw", @progbits
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stolen_bar_orig_value:
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.long 0
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.size stolen_bar_orig_value, . - stolen_bar_orig_value
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/* Restore original BAR values
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*
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* Parameters:
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* none
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* Returns:
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* none
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*/
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.section ".text16.early", "awx", @progbits
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.globl close_payload
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close_payload:
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/* Preserve registers */
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pushw %bx
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pushw %di
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pushl %ecx
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pushw %ds
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/* Set up %ds for access to .text16.early */
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pushw %cs
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popw %ds
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/* Retrieve stored bus:dev.fn */
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movw payload_pci_busdevfn, %bx
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/* Restore expansion ROM BAR original value */
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movw $PCI_BAR_EXPROM, %di
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movl rom_bar_orig_value, %ecx
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call pci_write_config_dword
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/* Restore stolen BAR original value */
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movw stolen_bar_register, %di
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movl stolen_bar_orig_value, %ecx
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call pci_write_config_dword
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/* Restore registers and return */
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popw %ds
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popl %ecx
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popw %di
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popw %bx
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lret
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.size close_payload, . - close_payload
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/* Get PCI BAR value
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*
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* Parameters:
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* %bx : PCI bus:dev.fn
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* %di : PCI BAR register number
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* Returns:
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* %edx:%eax : PCI BAR value
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*/
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.section ".text16.early", "awx", @progbits
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pci_read_bar:
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/* Preserve registers */
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pushl %ecx
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pushw %di
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/* Read low dword value */
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call pci_read_config_dword
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movl %ecx, %eax
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/* Read high dword value, if applicable */
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xorl %edx, %edx
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andb $0x07, %cl
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cmpb $0x04, %cl
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jne 1f
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addw $4, %di
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call pci_read_config_dword
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movl %ecx, %edx
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1:
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/* Restore registers and return */
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popw %di
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popl %ecx
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ret
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.size pci_read_bar, . - pci_read_bar
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/* Get low dword of PCI memory BAR size
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*
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* Parameters:
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* %bx : PCI bus:dev.fn
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* %di : PCI BAR register number
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* %eax : Low dword of current PCI BAR value
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* Returns:
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* %ecx : PCI BAR size
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*/
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.section ".text16.early", "awx", @progbits
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pci_size_mem_bar_low:
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/* Preserve registers */
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pushw %dx
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/* Disable memory accesses */
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xorw %dx, %dx
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call pci_set_mem_access
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/* Write all ones to BAR */
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xorl %ecx, %ecx
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decl %ecx
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call pci_write_config_dword
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/* Read back BAR */
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call pci_read_config_dword
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/* Calculate size */
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notl %ecx
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orb $0x0f, %cl
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incl %ecx
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/* Restore original value */
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pushl %ecx
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movl %eax, %ecx
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call pci_write_config_dword
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popl %ecx
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/* Enable memory accesses */
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movw $PCI_COMMAND_MEM, %dx
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call pci_set_mem_access
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/* Restore registers and return */
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popw %dx
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ret
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.size pci_size_mem_bar_low, . - pci_size_mem_bar_low
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/* Read PCI config dword
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*
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* Parameters:
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* %bx : PCI bus:dev.fn
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* %di : PCI register number
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* Returns:
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* %ecx : Dword value
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*/
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.section ".text16.early", "awx", @progbits
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pci_read_config_dword:
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/* Preserve registers */
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pushl %eax
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pushl %ebx
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pushl %edx
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/* Issue INT 0x1a,b10a */
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movw $PCIBIOS_READ_CONFIG_DWORD, %ax
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int $0x1a
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/* Restore registers and return */
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popl %edx
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popl %ebx
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popl %eax
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ret
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.size pci_read_config_dword, . - pci_read_config_dword
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/* Write PCI config dword
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*
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* Parameters:
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* %bx : PCI bus:dev.fn
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* %di : PCI register number
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* %ecx : PCI BAR value
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* Returns:
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* none
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*/
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.section ".text16.early", "awx", @progbits
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pci_write_config_dword:
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/* Preserve registers */
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pushal
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/* Issue INT 0x1a,b10d */
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movw $PCIBIOS_WRITE_CONFIG_DWORD, %ax
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int $0x1a
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/* Restore registers and return */
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popal
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ret
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.size pci_write_config_dword, . - pci_write_config_dword
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/* Enable/disable memory access response in PCI command word
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*
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* Parameters:
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* %bx : PCI bus:dev.fn
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* %dx : PCI_COMMAND_MEM, or zero
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* Returns:
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* none
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*/
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.section ".text16.early", "awx", @progbits
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pci_set_mem_access:
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/* Preserve registers */
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pushal
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/* Read current value of command register */
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pushw %bx
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pushw %dx
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movw $PCI_COMMAND, %di
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movw $PCIBIOS_READ_CONFIG_WORD, %ax
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int $0x1a
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popw %dx
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popw %bx
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/* Set memory access enable as appropriate */
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andw $~PCI_COMMAND_MEM, %cx
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orw %dx, %cx
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/* Write new value of command register */
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movw $PCIBIOS_WRITE_CONFIG_WORD, %ax
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int $0x1a
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/* Restore registers and return */
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popal
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ret
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.size pci_set_mem_access, . - pci_set_mem_access
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/* Image source area length (in dwords)
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*
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*/
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.section ".prefix", "ax", @progbits
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image_source_len_dword:
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.long 0
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.size image_source_len_dword, . - image_source_len_dword
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.section ".zinfo.fixup", "a", @progbits /* Compressor fixups */
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.ascii "ADDL"
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.long image_source_len_dword
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.long 4
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.long 0
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.previous
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