diff options
Diffstat (limited to 'gpxe/src/arch/i386/firmware/pcbios/e820mangler.S')
| -rw-r--r-- | gpxe/src/arch/i386/firmware/pcbios/e820mangler.S | 596 |
1 files changed, 0 insertions, 596 deletions
diff --git a/gpxe/src/arch/i386/firmware/pcbios/e820mangler.S b/gpxe/src/arch/i386/firmware/pcbios/e820mangler.S deleted file mode 100644 index 99ca519b..00000000 --- a/gpxe/src/arch/i386/firmware/pcbios/e820mangler.S +++ /dev/null @@ -1,596 +0,0 @@ -/* - * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>. - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License as - * published by the Free Software Foundation; either version 2 of the - * License, or any later version. - * - * This program is distributed in the hope that it will be useful, but - * WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. - */ - -FILE_LICENCE ( GPL2_OR_LATER ) - - .text - .arch i386 - .code16 - -#define SMAP 0x534d4150 - -/* Most documentation refers to the E820 buffer as being 20 bytes, and - * the API makes it perfectly legitimate to pass only a 20-byte buffer - * and expect to get valid data. However, some morons at ACPI decided - * to extend the data structure by adding an extra "extended - * attributes" field and by including critical information within this - * field, such as whether or not the region is enabled. A caller who - * passes in only a 20-byte buffer therefore risks getting very, very - * misleading information. - * - * I have personally witnessed an HP BIOS that returns a value of - * 0x0009 in the extended attributes field. If we don't pass this - * value through to the caller, 32-bit WinPE will die, usually with a - * PAGE_FAULT_IN_NONPAGED_AREA blue screen of death. - * - * Allow a ridiculously large maximum value (64 bytes) for the E820 - * buffer as a guard against insufficiently creative idiots in the - * future. - */ -#define E820MAXSIZE 64 - -/**************************************************************************** - * - * Allowed memory windows - * - * There are two ways to view this list. The first is as a list of - * (non-overlapping) allowed memory regions, sorted by increasing - * address. The second is as a list of (non-overlapping) hidden - * memory regions, again sorted by increasing address. The second - * view is offset by half an entry from the first: think about this - * for a moment and it should make sense. - * - * xxx_memory_window is used to indicate an "allowed region" - * structure, hidden_xxx_memory is used to indicate a "hidden region" - * structure. Each structure is 16 bytes in length. - * - **************************************************************************** - */ - .section ".data16", "aw", @progbits - .align 16 - .globl hidemem_base - .globl hidemem_umalloc - .globl hidemem_textdata -memory_windows: -base_memory_window: .long 0x00000000, 0x00000000 /* Start of memory */ - -hidemem_base: .long 0x000a0000, 0x00000000 /* Changes at runtime */ -ext_memory_window: .long 0x000a0000, 0x00000000 /* 640kB mark */ - -hidemem_umalloc: .long 0xffffffff, 0xffffffff /* Changes at runtime */ - .long 0xffffffff, 0xffffffff /* Changes at runtime */ - -hidemem_textdata: .long 0xffffffff, 0xffffffff /* Changes at runtime */ - .long 0xffffffff, 0xffffffff /* Changes at runtime */ - - .long 0xffffffff, 0xffffffff /* End of memory */ -memory_windows_end: - -/**************************************************************************** - * Truncate region to memory window - * - * Parameters: - * %edx:%eax Start of region - * %ecx:%ebx Length of region - * %si Memory window - * Returns: - * %edx:%eax Start of windowed region - * %ecx:%ebx Length of windowed region - **************************************************************************** - */ - .section ".text16", "ax", @progbits -window_region: - /* Convert (start,len) to (start, end) */ - addl %eax, %ebx - adcl %edx, %ecx - /* Truncate to window start */ - cmpl 4(%si), %edx - jne 1f - cmpl 0(%si), %eax -1: jae 2f - movl 4(%si), %edx - movl 0(%si), %eax -2: /* Truncate to window end */ - cmpl 12(%si), %ecx - jne 1f - cmpl 8(%si), %ebx -1: jbe 2f - movl 12(%si), %ecx - movl 8(%si), %ebx -2: /* Convert (start, end) back to (start, len) */ - subl %eax, %ebx - sbbl %edx, %ecx - /* If length is <0, set length to 0 */ - jae 1f - xorl %ebx, %ebx - xorl %ecx, %ecx - ret - .size window_region, . - window_region - -/**************************************************************************** - * Patch "memory above 1MB" figure - * - * Parameters: - * %ax Memory above 1MB, in 1kB blocks - * Returns: - * %ax Modified memory above 1M in 1kB blocks - **************************************************************************** - */ - .section ".text16", "ax", @progbits -patch_1m: - pushal - /* Convert to (start,len) format and call truncate */ - xorl %ecx, %ecx - movzwl %ax, %ebx - shll $10, %ebx - xorl %edx, %edx - movl $0x100000, %eax - movw $ext_memory_window, %si - call window_region - /* Convert back to "memory above 1MB" format and return via %ax */ - pushfw - shrl $10, %ebx - popfw - movw %sp, %bp - movw %bx, 28(%bp) - popal - ret - .size patch_1m, . - patch_1m - -/**************************************************************************** - * Patch "memory above 16MB" figure - * - * Parameters: - * %bx Memory above 16MB, in 64kB blocks - * Returns: - * %bx Modified memory above 16M in 64kB blocks - **************************************************************************** - */ - .section ".text16", "ax", @progbits -patch_16m: - pushal - /* Convert to (start,len) format and call truncate */ - xorl %ecx, %ecx - shll $16, %ebx - xorl %edx, %edx - movl $0x1000000, %eax - movw $ext_memory_window, %si - call window_region - /* Convert back to "memory above 16MB" format and return via %bx */ - pushfw - shrl $16, %ebx - popfw - movw %sp, %bp - movw %bx, 16(%bp) - popal - ret - .size patch_16m, . - patch_16m - -/**************************************************************************** - * Patch "memory between 1MB and 16MB" and "memory above 16MB" figures - * - * Parameters: - * %ax Memory between 1MB and 16MB, in 1kB blocks - * %bx Memory above 16MB, in 64kB blocks - * Returns: - * %ax Modified memory between 1MB and 16MB, in 1kB blocks - * %bx Modified memory above 16MB, in 64kB blocks - **************************************************************************** - */ - .section ".text16", "ax", @progbits -patch_1m_16m: - call patch_1m - call patch_16m - /* If 1M region is no longer full-length, kill off the 16M region */ - cmpw $( 15 * 1024 ), %ax - je 1f - xorw %bx, %bx -1: ret - .size patch_1m_16m, . - patch_1m_16m - -/**************************************************************************** - * Get underlying e820 memory region to underlying_e820 buffer - * - * Parameters: - * As for INT 15,e820 - * Returns: - * As for INT 15,e820 - * - * Wraps the underlying INT 15,e820 call so that the continuation - * value (%ebx) is a 16-bit simple sequence counter (with the high 16 - * bits ignored), and termination is always via CF=1 rather than - * %ebx=0. - * - **************************************************************************** - */ - .section ".text16", "ax", @progbits -get_underlying_e820: - - /* If the requested region is in the cache, return it */ - cmpw %bx, underlying_e820_index - jne 2f - pushw %di - pushw %si - movw $underlying_e820_cache, %si - cmpl underlying_e820_cache_size, %ecx - jbe 1f - movl underlying_e820_cache_size, %ecx -1: pushl %ecx - rep movsb - popl %ecx - popw %si - popw %di - incw %bx - movl %edx, %eax - clc - ret -2: - /* If the requested region is earlier than the cached region, - * invalidate the cache. - */ - cmpw %bx, underlying_e820_index - jbe 1f - movw $0xffff, underlying_e820_index -1: - /* If the cache is invalid, reset the underlying %ebx */ - cmpw $0xffff, underlying_e820_index - jne 1f - andl $0, underlying_e820_ebx -1: - /* If the cache is valid but the continuation value is zero, - * this means that the previous underlying call returned with - * %ebx=0. Return with CF=1 in this case. - */ - cmpw $0xffff, underlying_e820_index - je 1f - cmpl $0, underlying_e820_ebx - jne 1f - stc - ret -1: - /* Get the next region into the cache */ - pushl %eax - pushl %ebx - pushl %ecx - pushl %edx - pushl %esi /* Some implementations corrupt %esi, so we */ - pushl %edi /* preserve %esi, %edi and %ebp to be paranoid */ - pushl %ebp - pushw %es - pushw %ds - popw %es - movw $underlying_e820_cache, %di - cmpl $E820MAXSIZE, %ecx - jbe 1f - movl $E820MAXSIZE, %ecx -1: movl underlying_e820_ebx, %ebx - stc - pushfw - lcall *%cs:int15_vector - popw %es - popl %ebp - popl %edi - popl %esi - /* Check for error return from underlying e820 call */ - jc 2f /* CF set: error */ - cmpl $SMAP, %eax - je 3f /* 'SMAP' missing: error */ -2: /* An error occurred: return values returned by underlying e820 call */ - stc /* Force CF set if SMAP was missing */ - addr32 leal 16(%esp), %esp /* avoid changing other flags */ - ret -3: /* No error occurred */ - movl %ebx, underlying_e820_ebx - movl %ecx, underlying_e820_cache_size - popl %edx - popl %ecx - popl %ebx - popl %eax - /* Mark cache as containing this result */ - incw underlying_e820_index - - /* Loop until found */ - jmp get_underlying_e820 - .size get_underlying_e820, . - get_underlying_e820 - - .section ".data16", "aw", @progbits -underlying_e820_index: - .word 0xffff /* Initialise to an invalid value */ - .size underlying_e820_index, . - underlying_e820_index - - .section ".bss16", "aw", @nobits -underlying_e820_ebx: - .long 0 - .size underlying_e820_ebx, . - underlying_e820_ebx - - .section ".bss16", "aw", @nobits -underlying_e820_cache: - .space E820MAXSIZE - .size underlying_e820_cache, . - underlying_e820_cache - - .section ".bss16", "aw", @nobits -underlying_e820_cache_size: - .long 0 - .size underlying_e820_cache_size, . - underlying_e820_cache_size - -/**************************************************************************** - * Get windowed e820 region, without empty region stripping - * - * Parameters: - * As for INT 15,e820 - * Returns: - * As for INT 15,e820 - * - * Wraps the underlying INT 15,e820 call so that each underlying - * region is returned N times, windowed to fit within N visible-memory - * windows. Termination is always via CF=1. - * - **************************************************************************** - */ - .section ".text16", "ax", @progbits -get_windowed_e820: - - /* Preserve registers */ - pushl %esi - pushw %bp - - /* Split %ebx into %si:%bx, store original %bx in %bp */ - pushl %ebx - popw %bp - popw %si - - /* %si == 0 => start of memory_windows list */ - testw %si, %si - jne 1f - movw $memory_windows, %si -1: - /* Get (cached) underlying e820 region to buffer */ - call get_underlying_e820 - jc 99f /* Abort on error */ - - /* Preserve registers */ - pushal - /* start => %edx:%eax, len => %ecx:%ebx */ - movl %es:0(%di), %eax - movl %es:4(%di), %edx - movl %es:8(%di), %ebx - movl %es:12(%di), %ecx - /* Truncate region to current window */ - call window_region -1: /* Store modified values in e820 map entry */ - movl %eax, %es:0(%di) - movl %edx, %es:4(%di) - movl %ebx, %es:8(%di) - movl %ecx, %es:12(%di) - /* Restore registers */ - popal - - /* Derive continuation value for next call */ - addw $16, %si - cmpw $memory_windows_end, %si - jne 1f - /* End of memory windows: reset %si and allow %bx to continue */ - xorw %si, %si - jmp 2f -1: /* More memory windows to go: restore original %bx */ - movw %bp, %bx -2: /* Construct %ebx from %si:%bx */ - pushw %si - pushw %bx - popl %ebx - -98: /* Clear CF */ - clc -99: /* Restore registers and return */ - popw %bp - popl %esi - ret - .size get_windowed_e820, . - get_windowed_e820 - -/**************************************************************************** - * Get windowed e820 region, with empty region stripping - * - * Parameters: - * As for INT 15,e820 - * Returns: - * As for INT 15,e820 - * - * Wraps the underlying INT 15,e820 call so that each underlying - * region is returned up to N times, windowed to fit within N - * visible-memory windows. Empty windows are never returned. - * Termination is always via CF=1. - * - **************************************************************************** - */ - .section ".text16", "ax", @progbits -get_nonempty_e820: - - /* Record entry parameters */ - pushl %eax - pushl %ecx - pushl %edx - - /* Get next windowed region */ - call get_windowed_e820 - jc 99f /* abort on error */ - - /* If region is non-empty, finish here */ - cmpl $0, %es:8(%di) - jne 98f - cmpl $0, %es:12(%di) - jne 98f - - /* Region was empty: restore entry parameters and go to next region */ - popl %edx - popl %ecx - popl %eax - jmp get_nonempty_e820 - -98: /* Clear CF */ - clc -99: /* Return values from underlying call */ - addr32 leal 12(%esp), %esp /* avoid changing flags */ - ret - .size get_nonempty_e820, . - get_nonempty_e820 - -/**************************************************************************** - * Get mangled e820 region, with empty region stripping - * - * Parameters: - * As for INT 15,e820 - * Returns: - * As for INT 15,e820 - * - * Wraps the underlying INT 15,e820 call so that underlying regions - * are windowed to the allowed memory regions. Empty regions are - * stripped from the map. Termination is always via %ebx=0. - * - **************************************************************************** - */ - .section ".text16", "ax", @progbits -get_mangled_e820: - - /* Get a nonempty region */ - call get_nonempty_e820 - jc 99f /* Abort on error */ - - /* Peek ahead to see if there are any further nonempty regions */ - pushal - pushw %es - movw %sp, %bp - subw %cx, %sp - movl $0xe820, %eax - movl $SMAP, %edx - pushw %ss - popw %es - movw %sp, %di - call get_nonempty_e820 - movw %bp, %sp - popw %es - popal - jnc 99f /* There are further nonempty regions */ - - /* No futher nonempty regions: zero %ebx and clear CF */ - xorl %ebx, %ebx - -99: /* Return */ - ret - .size get_mangled_e820, . - get_mangled_e820 - -/**************************************************************************** - * Set/clear CF on the stack as appropriate, assumes stack is as it should - * be immediately before IRET - **************************************************************************** - */ -patch_cf: - pushw %bp - movw %sp, %bp - setc 8(%bp) /* Set/reset CF; clears PF, AF, ZF, SF */ - popw %bp - ret - -/**************************************************************************** - * INT 15,e820 handler - **************************************************************************** - */ - .section ".text16", "ax", @progbits -int15_e820: - pushw %ds - pushw %cs:rm_ds - popw %ds - call get_mangled_e820 - popw %ds - call patch_cf - iret - .size int15_e820, . - int15_e820 - -/**************************************************************************** - * INT 15,e801 handler - **************************************************************************** - */ - .section ".text16", "ax", @progbits -int15_e801: - /* Call previous handler */ - pushfw - lcall *%cs:int15_vector - call patch_cf - /* Edit result */ - pushw %ds - pushw %cs:rm_ds - popw %ds - call patch_1m_16m - xchgw %ax, %cx - xchgw %bx, %dx - call patch_1m_16m - xchgw %ax, %cx - xchgw %bx, %dx - popw %ds - iret - .size int15_e801, . - int15_e801 - -/**************************************************************************** - * INT 15,88 handler - **************************************************************************** - */ - .section ".text16", "ax", @progbits -int15_88: - /* Call previous handler */ - pushfw - lcall *%cs:int15_vector - call patch_cf - /* Edit result */ - pushw %ds - pushw %cs:rm_ds - popw %ds - call patch_1m - popw %ds - iret - .size int15_88, . - int15_88 - -/**************************************************************************** - * INT 15 handler - **************************************************************************** - */ - .section ".text16", "ax", @progbits - .globl int15 -int15: - /* See if we want to intercept this call */ - pushfw - cmpw $0xe820, %ax - jne 1f - cmpl $SMAP, %edx - jne 1f - popfw - jmp int15_e820 -1: cmpw $0xe801, %ax - jne 2f - popfw - jmp int15_e801 -2: cmpb $0x88, %ah - jne 3f - popfw - jmp int15_88 -3: popfw - ljmp *%cs:int15_vector - .size int15, . - int15 - - .section ".text16.data", "aw", @progbits - .globl int15_vector -int15_vector: - .long 0 - .size int15_vector, . - int15_vector |