--- /dev/null
+/*
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stdint.h>
+#include <errno.h>
+#include <realmode.h>
+#include <bios.h>
+#include <memsizes.h>
+#include <ipxe/io.h>
+
+/**
+ * @file
+ *
+ * Memory mapping
+ *
+ */
+
+/** Magic value for INT 15,e820 calls */
+#define SMAP ( 0x534d4150 )
+
+/** An INT 15,e820 memory map entry */
+struct e820_entry {
+ /** Start of region */
+ uint64_t start;
+ /** Length of region */
+ uint64_t len;
+ /** Type of region */
+ uint32_t type;
+ /** Extended attributes (optional) */
+ uint32_t attrs;
+} __attribute__ (( packed ));
+
+#define E820_TYPE_RAM 1 /**< Normal memory */
+#define E820_TYPE_RESERVED 2 /**< Reserved and unavailable */
+#define E820_TYPE_ACPI 3 /**< ACPI reclaim memory */
+#define E820_TYPE_NVS 4 /**< ACPI NVS memory */
+
+#define E820_ATTR_ENABLED 0x00000001UL
+#define E820_ATTR_NONVOLATILE 0x00000002UL
+#define E820_ATTR_UNKNOWN 0xfffffffcUL
+
+#define E820_MIN_SIZE 20
+
+/** Buffer for INT 15,e820 calls */
+static struct e820_entry __bss16 ( e820buf );
+#define e820buf __use_data16 ( e820buf )
+
+/** We are running during POST; inhibit INT 15,e820 and INT 15,e801 */
+uint8_t __bss16 ( memmap_post );
+#define memmap_post __use_data16 ( memmap_post )
+
+/**
+ * Get size of extended memory via INT 15,e801
+ *
+ * @ret extmem Extended memory size, in kB, or 0
+ */
+static unsigned int extmemsize_e801 ( void ) {
+ uint16_t extmem_1m_to_16m_k, extmem_16m_plus_64k;
+ uint16_t confmem_1m_to_16m_k, confmem_16m_plus_64k;
+ unsigned int flags;
+ unsigned int extmem;
+
+ /* Inhibit INT 15,e801 during POST */
+ if ( memmap_post ) {
+ DBG ( "INT 15,e801 not available during POST\n" );
+ return 0;
+ }
+
+ __asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
+ "int $0x15\n\t"
+ "pushfw\n\t"
+ "popw %w0\n\t" )
+ : "=r" ( flags ),
+ "=a" ( extmem_1m_to_16m_k ),
+ "=b" ( extmem_16m_plus_64k ),
+ "=c" ( confmem_1m_to_16m_k ),
+ "=d" ( confmem_16m_plus_64k )
+ : "a" ( 0xe801 ) );
+
+ if ( flags & CF ) {
+ DBG ( "INT 15,e801 failed with CF set\n" );
+ return 0;
+ }
+
+ if ( ! ( extmem_1m_to_16m_k | extmem_16m_plus_64k ) ) {
+ DBG ( "INT 15,e801 extmem=0, using confmem\n" );
+ extmem_1m_to_16m_k = confmem_1m_to_16m_k;
+ extmem_16m_plus_64k = confmem_16m_plus_64k;
+ }
+
+ extmem = ( extmem_1m_to_16m_k + ( extmem_16m_plus_64k * 64 ) );
+ DBG ( "INT 15,e801 extended memory size %d+64*%d=%d kB "
+ "[100000,%llx)\n", extmem_1m_to_16m_k, extmem_16m_plus_64k,
+ extmem, ( 0x100000 + ( ( ( uint64_t ) extmem ) * 1024 ) ) );
+
+ /* Sanity check. Some BIOSes report the entire 4GB address
+ * space as available, which cannot be correct (since that
+ * would leave no address space available for 32-bit PCI
+ * BARs).
+ */
+ if ( extmem == ( 0x400000 - 0x400 ) ) {
+ DBG ( "INT 15,e801 reported whole 4GB; assuming insane\n" );
+ return 0;
+ }
+
+ return extmem;
+}
+
+/**
+ * Get size of extended memory via INT 15,88
+ *
+ * @ret extmem Extended memory size, in kB
+ */
+static unsigned int extmemsize_88 ( void ) {
+ uint16_t extmem;
+
+ /* Ignore CF; it is not reliable for this call */
+ __asm__ __volatile__ ( REAL_CODE ( "int $0x15" )
+ : "=a" ( extmem ) : "a" ( 0x8800 ) );
+
+ DBG ( "INT 15,88 extended memory size %d kB [100000, %x)\n",
+ extmem, ( 0x100000 + ( extmem * 1024 ) ) );
+ return extmem;
+}
+
+/**
+ * Get size of extended memory
+ *
+ * @ret extmem Extended memory size, in kB
+ *
+ * Note that this is only an approximation; for an accurate picture,
+ * use the E820 memory map obtained via get_memmap();
+ */
+unsigned int extmemsize ( void ) {
+ unsigned int extmem_e801;
+ unsigned int extmem_88;
+
+ /* Try INT 15,e801 first, then fall back to INT 15,88 */
+ extmem_88 = extmemsize_88();
+ extmem_e801 = extmemsize_e801();
+ return ( extmem_e801 ? extmem_e801 : extmem_88 );
+}
+
+/**
+ * Get e820 memory map
+ *
+ * @v memmap Memory map to fill in
+ * @ret rc Return status code
+ */
+static int meme820 ( struct memory_map *memmap ) {
+ struct memory_region *region = memmap->regions;
+ struct memory_region *prev_region = NULL;
+ uint32_t next = 0;
+ uint32_t smap;
+ size_t size;
+ unsigned int flags;
+ unsigned int discard_D;
+
+ /* Inhibit INT 15,e820 during POST */
+ if ( memmap_post ) {
+ DBG ( "INT 15,e820 not available during POST\n" );
+ return -ENOTTY;
+ }
+
+ /* Clear the E820 buffer. Do this once before starting,
+ * rather than on each call; some BIOSes rely on the contents
+ * being preserved between calls.
+ */
+ memset ( &e820buf, 0, sizeof ( e820buf ) );
+
+ do {
+ /* Some BIOSes corrupt %esi for fun. Guard against
+ * this by telling gcc that all non-output registers
+ * may be corrupted.
+ */
+ __asm__ __volatile__ ( REAL_CODE ( "pushl %%ebp\n\t"
+ "stc\n\t"
+ "int $0x15\n\t"
+ "pushfw\n\t"
+ "popw %%dx\n\t"
+ "popl %%ebp\n\t" )
+ : "=a" ( smap ), "=b" ( next ),
+ "=c" ( size ), "=d" ( flags ),
+ "=D" ( discard_D )
+ : "a" ( 0xe820 ), "b" ( next ),
+ "D" ( __from_data16 ( &e820buf ) ),
+ "c" ( sizeof ( e820buf ) ),
+ "d" ( SMAP )
+ : "esi", "memory" );
+
+ if ( smap != SMAP ) {
+ DBG ( "INT 15,e820 failed SMAP signature check\n" );
+ return -ENOTSUP;
+ }
+
+ if ( size < E820_MIN_SIZE ) {
+ DBG ( "INT 15,e820 returned only %zd bytes\n", size );
+ return -EINVAL;
+ }
+
+ if ( flags & CF ) {
+ DBG ( "INT 15,e820 terminated on CF set\n" );
+ break;
+ }
+
+ /* If first region is not RAM, assume map is invalid */
+ if ( ( memmap->count == 0 ) &&
+ ( e820buf.type != E820_TYPE_RAM ) ) {
+ DBG ( "INT 15,e820 failed, first entry not RAM\n" );
+ return -EINVAL;
+ }
+
+ DBG ( "INT 15,e820 region [%llx,%llx) type %d",
+ e820buf.start, ( e820buf.start + e820buf.len ),
+ ( int ) e820buf.type );
+ if ( size > offsetof ( typeof ( e820buf ), attrs ) ) {
+ DBG ( " (%s", ( ( e820buf.attrs & E820_ATTR_ENABLED )
+ ? "enabled" : "disabled" ) );
+ if ( e820buf.attrs & E820_ATTR_NONVOLATILE )
+ DBG ( ", non-volatile" );
+ if ( e820buf.attrs & E820_ATTR_UNKNOWN )
+ DBG ( ", other [%08x]", e820buf.attrs );
+ DBG ( ")" );
+ }
+ DBG ( "\n" );
+
+ /* Discard non-RAM regions */
+ if ( e820buf.type != E820_TYPE_RAM )
+ continue;
+
+ /* Check extended attributes, if present */
+ if ( size > offsetof ( typeof ( e820buf ), attrs ) ) {
+ if ( ! ( e820buf.attrs & E820_ATTR_ENABLED ) )
+ continue;
+ if ( e820buf.attrs & E820_ATTR_NONVOLATILE )
+ continue;
+ }
+
+ region->start = e820buf.start;
+ region->end = e820buf.start + e820buf.len;
+
+ /* Check for adjacent regions and merge them */
+ if ( prev_region && ( region->start == prev_region->end ) ) {
+ prev_region->end = region->end;
+ } else {
+ prev_region = region;
+ region++;
+ memmap->count++;
+ }
+
+ if ( memmap->count >= ( sizeof ( memmap->regions ) /
+ sizeof ( memmap->regions[0] ) ) ) {
+ DBG ( "INT 15,e820 too many regions returned\n" );
+ /* Not a fatal error; what we've got so far at
+ * least represents valid regions of memory,
+ * even if we couldn't get them all.
+ */
+ break;
+ }
+ } while ( next != 0 );
+
+ /* Sanity checks. Some BIOSes report complete garbage via INT
+ * 15,e820 (especially at POST time), despite passing the
+ * signature checks. We currently check for a base memory
+ * region (starting at 0) and at least one high memory region
+ * (starting at 0x100000).
+ */
+ if ( memmap->count < 2 ) {
+ DBG ( "INT 15,e820 returned only %d regions; assuming "
+ "insane\n", memmap->count );
+ return -EINVAL;
+ }
+ if ( memmap->regions[0].start != 0 ) {
+ DBG ( "INT 15,e820 region 0 starts at %llx (expected 0); "
+ "assuming insane\n", memmap->regions[0].start );
+ return -EINVAL;
+ }
+ if ( memmap->regions[1].start != 0x100000 ) {
+ DBG ( "INT 15,e820 region 1 starts at %llx (expected 100000); "
+ "assuming insane\n", memmap->regions[0].start );
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/**
+ * Get memory map
+ *
+ * @v memmap Memory map to fill in
+ */
+void x86_get_memmap ( struct memory_map *memmap ) {
+ unsigned int basemem, extmem;
+ int rc;
+
+ DBG ( "Fetching system memory map\n" );
+
+ /* Clear memory map */
+ memset ( memmap, 0, sizeof ( *memmap ) );
+
+ /* Get base and extended memory sizes */
+ basemem = basememsize();
+ DBG ( "FBMS base memory size %d kB [0,%x)\n",
+ basemem, ( basemem * 1024 ) );
+ extmem = extmemsize();
+
+ /* Try INT 15,e820 first */
+ if ( ( rc = meme820 ( memmap ) ) == 0 ) {
+ DBG ( "Obtained system memory map via INT 15,e820\n" );
+ return;
+ }
+
+ /* Fall back to constructing a map from basemem and extmem sizes */
+ DBG ( "INT 15,e820 failed; constructing map\n" );
+ memmap->regions[0].end = ( basemem * 1024 );
+ memmap->regions[1].start = 0x100000;
+ memmap->regions[1].end = 0x100000 + ( extmem * 1024 );
+ memmap->count = 2;
+}
+
+PROVIDE_IOAPI ( x86, get_memmap, x86_get_memmap );
Code Review / kvmfornfv.git / blobdiff