diff options
Diffstat (limited to 'contrib/syslinux-4.02/com32/mboot/mem.c')
| -rw-r--r-- | contrib/syslinux-4.02/com32/mboot/mem.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/com32/mboot/mem.c b/contrib/syslinux-4.02/com32/mboot/mem.c new file mode 100644 index 0000000..6a31fac --- /dev/null +++ b/contrib/syslinux-4.02/com32/mboot/mem.c @@ -0,0 +1,205 @@ +/* ----------------------------------------------------------------------- * + * + * Copyright 2007-2009 H. Peter Anvin - All Rights Reserved + * Copyright 2009 H. Peter Anvin - All Rights Reserved + * + * Permission is hereby granted, free of charge, to any person + * obtaining a copy of this software and associated documentation + * files (the "Software"), to deal in the Software without + * restriction, including without limitation the rights to use, + * copy, modify, merge, publish, distribute, sublicense, and/or + * sell copies of the Software, and to permit persons to whom + * the Software is furnished to do so, subject to the following + * conditions: + * + * The above copyright notice and this permission notice shall + * be included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES + * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT + * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, + * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR + * OTHER DEALINGS IN THE SOFTWARE. + * + * ----------------------------------------------------------------------- */ + +/* + * mem.c + * + * Obtain a memory map for a Multiboot OS + * + * This differs from the libcom32 memory map functions in that it doesn't + * attempt to filter out memory regions... + */ + +#include "mboot.h" +#include <com32.h> + +struct e820_entry { + uint64_t start; + uint64_t len; + uint32_t type; +}; + +#define RANGE_ALLOC_BLOCK 128 + +static int mboot_scan_memory(struct AddrRangeDesc **ardp, uint32_t * dosmem) +{ + com32sys_t ireg, oreg; + struct e820_entry *e820buf = __com32.cs_bounce; + struct AddrRangeDesc *ard; + size_t ard_count, ard_space; + + /* Use INT 12h to get DOS memory */ + __intcall(0x12, &__com32_zero_regs, &oreg); + *dosmem = oreg.eax.w[0] << 10; + if (*dosmem < 32 * 1024 || *dosmem > 640 * 1024) { + /* INT 12h reports nonsense... now what? */ + uint16_t ebda_seg = *(uint16_t *) 0x40e; + if (ebda_seg >= 0x8000 && ebda_seg < 0xa000) + *dosmem = ebda_seg << 4; + else + *dosmem = 640 * 1024; /* Hope for the best... */ + } + + /* Allocate initial space */ + *ardp = ard = malloc(RANGE_ALLOC_BLOCK * sizeof *ard); + if (!ard) + return 0; + + ard_count = 0; + ard_space = RANGE_ALLOC_BLOCK; + + /* First try INT 15h AX=E820h */ + memset(&ireg, 0, sizeof ireg); + ireg.eax.l = 0xe820; + ireg.edx.l = 0x534d4150; + /* ireg.ebx.l = 0; */ + ireg.ecx.l = sizeof(*e820buf); + ireg.es = SEG(e820buf); + ireg.edi.w[0] = OFFS(e820buf); + memset(e820buf, 0, sizeof *e820buf); + + do { + __intcall(0x15, &ireg, &oreg); + + if ((oreg.eflags.l & EFLAGS_CF) || + (oreg.eax.l != 0x534d4150) || (oreg.ecx.l < 20)) + break; + + if (ard_count >= ard_space) { + ard_space += RANGE_ALLOC_BLOCK; + *ardp = ard = realloc(ard, ard_space * sizeof *ard); + if (!ard) + return ard_count; + } + + ard[ard_count].size = 20; + ard[ard_count].BaseAddr = e820buf->start; + ard[ard_count].Length = e820buf->len; + ard[ard_count].Type = e820buf->type; + ard_count++; + + ireg.ebx.l = oreg.ebx.l; + } while (oreg.ebx.l); + + if (ard_count) + return ard_count; + + ard[0].size = 20; + ard[0].BaseAddr = 0; + ard[0].Length = *dosmem << 10; + ard[0].Type = 1; + + /* Next try INT 15h AX=E801h */ + ireg.eax.w[0] = 0xe801; + __intcall(0x15, &ireg, &oreg); + + if (!(oreg.eflags.l & EFLAGS_CF) && oreg.ecx.w[0]) { + ard[1].size = 20; + ard[1].BaseAddr = 1 << 20; + ard[1].Length = oreg.ecx.w[0] << 10; + ard[1].Type = 1; + + if (oreg.edx.w[0]) { + ard[2].size = 20; + ard[2].BaseAddr = 16 << 20; + ard[2].Length = oreg.edx.w[0] << 16; + ard[2].Type = 1; + return 3; + } else { + return 2; + } + } + + /* Finally try INT 15h AH=88h */ + ireg.eax.w[0] = 0x8800; + if (!(oreg.eflags.l & EFLAGS_CF) && oreg.eax.w[0]) { + ard[1].size = 20; + ard[1].BaseAddr = 1 << 20; + ard[1].Length = oreg.ecx.w[0] << 10; + ard[1].Type = 1; + return 2; + } + + return 1; /* ... problematic ... */ +} + +void mboot_make_memmap(void) +{ + int i, nmap; + struct AddrRangeDesc *ard; + uint32_t lowmem, highmem; + uint32_t highrsvd; + + /* Always report DOS memory as "lowmem", this may be overly conservative + (e.g. if we're dropping PXE), but it should be *safe*... */ + + nmap = mboot_scan_memory(&ard, &lowmem); + + highmem = 0x100000; + highrsvd = 0xfff00000; + +again: + for (i = 0; i < nmap; i++) { + uint64_t start, end; + + start = ard[i].BaseAddr; + end = start + ard[i].Length; + + if (end < start) + end = ~0ULL; + + if (start & 0xffffffff00000000ULL) + continue; /* Not interested in 64-bit memory */ + + if (start < highmem) + start = highmem; + + if (end <= start) + continue; + + if (ard[i].Type == 1 && start == highmem) { + highmem = end; + goto again; + } else if (ard[i].Type != 1 && start < highrsvd) + highrsvd = start; + } + + if (highmem > highrsvd) + highmem = highrsvd; + + mbinfo.mem_lower = lowmem >> 10; + mbinfo.mem_upper = (highmem - 0x100000) >> 10; + mbinfo.flags |= MB_INFO_MEMORY; + + /* The spec says this address should be +4, but Grub disagrees */ + mbinfo.mmap_addr = map_data(ard, nmap * sizeof *ard, 4, false); + if (mbinfo.mmap_addr) { + mbinfo.mmap_length = nmap * sizeof *ard; + mbinfo.flags |= MB_INFO_MEM_MAP; + } +} |