This is the assembly-side fancy memory detection patch that I've been
shilling like a cheap Bulova clone for the past few months. I'm setting
up the sidewalk stall again because
1) it still works (this patch was last modified a long time ago and
it still patches in without complaint)
2) it deals with bioses that lie and return e820 maps that include
memory in the 639k-1mb region.
3) it makes the debugging output a bit prettier.
4) it gives a better foundation for my and Nathan Zook's current hacking
on memory allocation, injecting, and detecting.
____
david parsons \bi/ 2.3.99 is fairly fragile, but I don't think this
\/ will make it any more fragile.
--- linux/include/asm-i386/e820.h.orig Thu Nov 18 19:25:28 1999
+++ linux/include/asm-i386/e820.h Sat Mar 11 08:59:26 2000
@@ -5,16 +5,18 @@
* In a nutshell, arch/i386/boot/setup.S populates a scratch table
* in the empty_zero_block that contains a list of usable address/size
* duples. In arch/i386/kernel/setup.c, this information is
- * transferred into the e820map, and in arch/i386/mm/init.c, that
- * new information is used to mark pages reserved or not.
+ * transferred into the bios[], then converted into a list of valid
+ * memory regions in region[], and that new information is used in
+ * arch/i386/mm/init.c to mark pages available or not.
*
*/
#ifndef __E820_HEADER
#define __E820_HEADER
-#define E820MAP 0x2d0 /* our map */
-#define E820MAX 32 /* number of entries in E820MAP */
-#define E820NR 0x1e8 /* # entries in E820MAP */
+#define E820MAP 0x2d0 /* our map */
+#define E820MAX 32 /* number of entries in E820MAP */
+#define E820NR 0x1e8 /* # entries in E820MAP */
+#define E820LEN 20 /* size of an e820 entry */
#define E820_RAM 1
#define E820_RESERVED 2
@@ -23,18 +25,76 @@
#define HIGH_MEMORY (1024*1024)
+/* HACK: These macros map between page numbers and physical addresses.
+ * They used to be in arch/i386/kernel/setup.c, but have been moved here
+ * so that they can also be used in arch/i386/mm/init.c.
+ */
+#define PFN_UP(x) (((x) + PAGE_SIZE-1) >> PAGE_SHIFT)
+#define PFN_DOWN(x) ((x) >> PAGE_SHIFT)
+#define PFN_PHYS(x) ((x) << PAGE_SHIFT)
+
+/*
+ * FLAG_E820_DEBUG enables bunches of debug messages.
+ */
+#define FLAG_E820_DEBUG 1
+
+/*
+ * FLAG_E820_GULLIBLE tells check_memory_region() to believe the bios
+ * when it says that memory in the 0x9fc00-0x100000 region is okay. In
+ * most cases, this will NOT be the case and attempting to use this will
+ * result in your machine being converted to gravel as Linux scribbles
+ * in that memory region, but if you're trying to install Linux on an
+ * ultra-low memory machine and you can make this region usable, this
+ * might be useful. If you enable this flag, you also need to set the
+ * corresponding flag in physical_memory.pflag before the memory will
+ * actually be used.
+ */
+#define FLAG_E820_GULLIBLE 0
+
+
+/* FLAG_E820_RECLAIM tells add_memory_region/check_memory_region to
+ * attempt to use E820 reclaim memory sections. To have reclaim work,
+ * you need to configure it on, _plus_ CONFIG_ACPI needs to be turned off.
+ */
+#if defined(CONFIG_E820_RECLAIM) && !defined(CONFIG_ACPI)
+# define FLAG_E820_RECLAIM 1
+#else
+# define FLAG_E820_RECLAIM 0
+#endif
+
+/* FLAG_E820_4GB_ONLY tells the memory region adder to truncate memory
+ * segments to the first 4 gb of memory.
+ */
+#define FLAG_E820_4GB_ONLY 0
+
+
#ifndef __ASSEMBLY__
-struct e820map {
- int nr_map;
- struct {
- long long addr; /* start of memory segment */
- long long size; /* size of memory segment */
- long type; /* type of memory segment */
- } map[E820MAX];
-};
+struct e820 {
+ __u64 addr; /* addr,size,type are returned by e820 bios call */
+ __u64 size;
+ __u32 type;
+ __u16 len; /* %ecx(out) from the e820 bios call */
+} __attribute__ ((__packed__));
+
+struct physical_region {
+ __u64 start;
+ __u64 end;
+} ;
+
+struct physical_memory {
+ int p_flags; /* assert sizeof(int) >= 3 bits */
+
+#define CHK_PMEM_GULLIBLE 0x02 /* user-settable in smap= */
+#define CHK_PMEM_RECLAIM 0x04 /* command line */
+
+ int nr_bios; /* bios[] holds memory region */
+ int nr_region; /* region[] holds valid mem */
+ struct e820 bios[E820MAX]; /* returned by the bios */
+ struct physical_region region[E820MAX]; /* that we want to allocate */
+} ;
-extern struct e820map e820;
+extern struct physical_memory physical_memory;
#endif/*!__ASSEMBLY__*/
#endif/*__E820_HEADER*/
--- linux/arch/i386/boot/setup.S.orig Sun Feb 20 20:37:09 2000
+++ linux/arch/i386/boot/setup.S Sat Mar 11 08:47:52 2000
@@ -32,6 +32,9 @@
*
* Transcribed from Intel (as86) -> AT&T (gas) by Chris Noe, May 1999.
* <stiker@northlink.com>
+ *
+ * Extended memory detection made more paranoid by orc@pell.chi.il.us (david
+ * parsons) and Nathan Zook (nathan.zook@amd.com), December 1999-February 2000.
*/
#define __ASSEMBLY__
@@ -255,91 +258,110 @@
loader_panic_mess: .string "Wrong loader, giving up..."
loader_ok:
-# Get memory size (extended mem, kB)
+/* MEMORY DETECTION CODE */
xorl %eax, %eax
- movl %eax, (0x1e0)
-#ifndef STANDARD_MEMORY_BIOS_CALL
- movb %al, (E820NR)
-# Try three different memory detection schemes. First, try
-# e820h, which lets us assemble a memory map, then try e801h,
-# which returns a 32-bit memory size, and finally 88h, which
-# returns 0-64m
-
-# method E820H:
-# the memory map from hell. e820h returns memory classified into
-# a whole bunch of different types, and allows memory holes and
-# everything. We scan through this memory map and build a list
-# of the first 32 memory areas, which we return at [E820MAP].
-#
+ movl %eax, (0x1e0) # zero alt_mem_k
+ movb %al, (E820NR) # e820_nr
-meme820:
- movl $0x534d4150, %edx # ascii `SMAP'
- xorl %ebx, %ebx # continuation counter
- movw $E820MAP, %di # point into the whitelist
- # so we can have the bios
- # directly write into it.
+/*
+ * Try three different memory detection schemes. First, try
+ * e820h, which lets us assemble a memory map, then try e801h,
+ * which returns a 32-bit memory size, and finally 88h, which
+ * returns 0-64m
+ */
-jmpe820:
- movl $0x0000e820, %eax # e820, upper word zeroed
- movl $20, %ecx # size of the e820rec
- pushw %ds # data record.
- popw %es
- int $0x15 # make the call
- jc bail820 # fall to e801 if it fails
+#ifdef CONFIG_MEM_E820
- cmpl $0x534d4150, %eax # check the return is `SMAP'
- jne bail820 # fall to e801 if it fails
+/*
+ * method E820H:
+ * the memory map from hell. e820h returns memory classified into
+ * a whole bunch of different types, and allows memory holes and
+ * everything. We scan through this memory map and build a list
+ * of the first E820MAX memory areas, which we return at [E820MAP].
+ */
+meme820:
+ xorl %ebx, %ebx # continuation counter
-# cmpl $1, 16(%di) # is this usable memory?
-# jne again820
+ pushw %ds # es:di points at the whitelist
+ popw %es
+ movw $E820MAP, %di
+jmpe820:
+ movl $0x534d4150, %edx # ascii `SMAP'
+ movl $0x0000e820, %eax # e820, upper word zeroed
+ movl $E820LEN, %ecx # 20 bytes is what we want.
+
+ int $0x15 # make the call
+ jc fin820 # fall out if it fails
+
+ cmpl $0x534d4150, %eax # did the bios move for you?
+ je stash820
+
+ xor %ah, %ah # no? chuck the whole thing.
+ movb %ah, (E820NR)
+ jmp fin820
+
+stash820:
+ incb (E820NR) # up the # of records
+ movb (E820NR), %al # If the table fills up
+ cmpb $E820MAX, %al # we must flee
+ jnl fin820
+
+ movw %cx, E820LEN(%di) # stash recsize
+ cmp $0, %ebx # any more records in the pipe?
+ jz fin820 # apparently not
- # If this is usable memory, we save it by simply advancing %di by
- # sizeof(e820rec).
- #
-good820:
- movb (E820NR), %al # up to 32 entries
- cmpb $E820MAX, %al
- jnl bail820
-
- incb (E820NR)
- movw %di, %ax
- addw $20, %ax
+ movw %di, %ax # point %es:%di at the next
+ addw $E820LEN+2, %ax # record
movw %ax, %di
-again820:
- cmpl $0, %ebx # check to see if
- jne jmpe820 # %ebx is set to EOF
-bail820:
+ jmp jmpe820
+fin820:
+#endif/*CONFIG_MEM_E820*/
-# method E801H:
-# memory size is in 1k chunksizes, to avoid confusing loadlin.
-# we store the 0xe801 memory size in a completely different place,
-# because it will most likely be longer than 16 bits.
-# (use 1e0 because that's what Larry Augustine uses in his
-# alternative new memory detection scheme, and it's sensible
-# to write everything into the same place.)
+#ifdef CONFIG_MEM_E801
+/*
+ * method E801H:
+ * memory size is in 1k chunksizes, to avoid confusing loadlin.
+ * we store the 0xe801 memory size in a completely different place,
+ * because it will most likely be longer than 16 bits.
+ * (use 1e0 because that's what Larry Augustine uses in his
+ * alternative new memory detection scheme, and it's sensible
+ * to write everything into the same place.)
+ *
+ * This scheme does not write to a memory map, but returns an
+ * accumulator containing all memory from 1-16mb + all memory from
+ * 16->up mb. If a memory hole exists, all memory above that hole
+ * is ignored.
+ */
meme801:
movw $0xe801, %ax
int $0x15
- jc mem88
+ jc fine801
+ andl $0xffff, %ecx # clear sign extend
+ movl %ecx, (0x1e0) # store 1kb between 1-16mb
+ cmpl $0x3C00, %ecx # if 1-16mb region isn't 15mb
+ jne fine801 # there's a memory hole and
+ # memory above the hole can't
+ # be used.
andl $0xffff, %edx # clear sign extend
shll $6, %edx # and go from 64k to 1k chunks
- movl %edx, (0x1e0) # store extended memory size
- andl $0xffff, %ecx # clear sign extend
- addl %ecx, (0x1e0) # and add lower memory into
- # total size.
+ addl %edx, (0x1e0) # add high memory size.
+fine801:
-# Ye Olde Traditional Methode. Returns the memory size (up to 16mb or
-# 64mb, depending on the bios) in ax.
-mem88:
+#endif/*CONFIG_MEM_E801*/
-#endif
+/*
+ * Ye Olde Traditional Methode. Returns the memory size (up to 16mb or
+ * 64mb, depending on the bios) in ax.
+ */
movb $0x88, %ah
int $0x15
movw %ax, (2)
+
+/* END OF MEMORY DETECTION CODE */
# Set the keyboard repeat rate to the max
movw $0x0305, %ax
--- linux/arch/i386/mm/init.c.orig Sat Mar 11 08:44:32 2000
+++ linux/arch/i386/mm/init.c Sat Mar 11 08:46:34 2000
@@ -516,21 +516,11 @@
{
int i;
- for (i = 0; i < e820.nr_map; i++) {
- unsigned long addr, end;
-
- if (e820.map[i].type != E820_RAM) /* not usable memory */
- continue;
- /*
- * !!!FIXME!!! Some BIOSen report areas as RAM that
- * are not. Notably the 640->1Mb area. We need a sanity
- * check here.
- */
- addr = (e820.map[i].addr+PAGE_SIZE-1) >> PAGE_SHIFT;
- end = (e820.map[i].addr+e820.map[i].size) >> PAGE_SHIFT;
- if ((pagenr >= addr) && (pagenr < end))
+ for (i = 0; i < physical_memory.nr_region; i++)
+ if (pagenr >= PFN_UP(physical_memory.region[i].start)
+ && pagenr < PFN_DOWN(physical_memory.region[i].end) )
return 1;
- }
+
return 0;
}
--- linux/arch/i386/kernel/setup.c.orig Sat Mar 11 08:44:07 2000
+++ linux/arch/i386/kernel/setup.c Sat Mar 11 08:46:34 2000
@@ -108,7 +108,7 @@
unsigned char table[0];
};
-struct e820map e820 = { 0 };
+struct physical_memory physical_memory;
unsigned char aux_device_present;
@@ -131,6 +131,11 @@
#define ALT_MEM_K (*(unsigned long *) (PARAM+0x1e0))
#define E820_MAP_NR (*(char*) (PARAM+E820NR))
#define E820_MAP ((unsigned long *) (PARAM+E820MAP))
+#define E820_ERR (*(unsigned short *) (PARAM+E820MAP))
+
+#define Region physical_memory.region
+#define Bios physical_memory.bios
+
#define APM_BIOS_INFO (*(struct apm_bios_info *) (PARAM+0x40))
#define DRIVE_INFO (*(struct drive_info_struct *) (PARAM+0x80))
#define SYS_DESC_TABLE (*(struct sys_desc_table_struct*)(PARAM+0xa0))
@@ -382,40 +387,233 @@
ret <<= 20;
(*retptr)++;
}
+ else if (**retptr == 'G' || **retptr == 'g') {
+ ret <<= 30;
+ (*retptr)++;
+ }
return ret;
} /* memparse */
-void __init add_memory_region(unsigned long start,
- unsigned long size, int type)
+enum region_flags { RF_RECLAIM =0x01,
+ RF_NOT_RAM =0x02,
+ RF_OVERFLOW=0x04,
+ RF_ZERO =0x08,
+ RF_MERGED =0x10,
+ RF_ADDED =0x20,
+ RF_SHORT =0x40,
+ RF_TOOLONG =0x80 } ;
+
+enum region_flags __init add_memory_region(__u64 start, __u64 end, __u32 type)
{
- int x = e820.nr_map;
+ int i, x;
+ enum region_flags flag = 0;
- if (x == E820MAX) {
- printk("Ooops! Too many entries in the memory map!\n");
- return;
+#if FLAG_E820_RECLAIM
+ if ( (physical_memory.p_flags & CHK_PMEM_RECLAIM) && (type == E820_ACPI) )
+ flag |= RF_RECLAIM;
+ else if (type != E820_RAM)
+ return RF_NOT_RAM;
+#else
+ if (type != E820_RAM)
+ return RF_NOT_RAM;
+#endif
+
+ if (start == end)
+ return flag|RF_ZERO;
+
+ if (start > end)
+ return RF_TOOLONG;
+
+ #ifdef CONFIG_E820_MERGE
+ /* see if we can merge this region with an existing one */
+
+ for (x=0; x < physical_memory.nr_region; x++)
+ if (end == Region[x].start) {
+ /* glue memory region onto the start of this one */
+ Region[x].start = start;
+ break;
+ }
+ else if (Region[x].end == start) {
+ /* glue memory region onto the end of this one */
+ Region[x].end = end;
+ break;
+ }
+ if (x < physical_memory.nr_region) {
+ /* If we've merged a region, check to see if the new region
+ * want to merge with anyone else.
+ */
+ if (x > 0 && Region[x].start == Region[x-1].end) {
+ Region[x-1].end = Region[x].end;
+ for (i=x; i < physical_memory.nr_region; i++)
+ Region[x] = Region[x+1];
+ physical_memory.nr_region--;
+ x--;
+ }
+ if (x < physical_memory.nr_region-1 && Region[x].end == Region[x+1].start) {
+ Region[x].end = Region[x+1].end;
+ for (i=x+1; i < physical_memory.nr_region-1; i++)
+ Region[x] = Region[x+1];
+ physical_memory.nr_region--;
+ }
+ else
+ return flag|RF_MERGED;
}
+#endif
- e820.map[x].addr = start;
- e820.map[x].size = size;
- e820.map[x].type = type;
- e820.nr_map++;
+ if (physical_memory.nr_region == E820MAX)
+ return flag|RF_OVERFLOW;
+
+ /* insert the new region in order */
+ for (x=0; x < physical_memory.nr_region; x++)
+ if (end < Region[x].start) {
+ /* add it in here */
+ for (i=physical_memory.nr_region; i>x; --i)
+ Region[i] = Region[i-1];
+ Region[x].start = start;
+ Region[x].end = end;
+ physical_memory.nr_region++;
+ return flag|RF_ADDED;
+ }
+ Region[physical_memory.nr_region].start = start;
+ Region[physical_memory.nr_region].end = end;
+ physical_memory.nr_region++;
+ return flag|RF_ADDED;
} /* add_memory_region */
+#define GIGABYTE(x) ((x) * 1024LL * 1024LL * 1024LL)
+#if FLAG_E820_DEBUG
+# define E820DBG(x) printk x
+#else
+# define E820DBG(x)
+#endif
+
/*
* Do NOT EVER look at the BIOS memory size location.
* It does not work on many machines.
*/
-#define LOWMEMSIZE() (0x9f000)
+#define LOWMEMSIZE() (639 * 1024)
+
+
+#if FLAG_E820_DEBUG
+void
+report(enum region_flags code)
+{
+ if (code & RF_RECLAIM)
+ printk(" reclaimed");
+ if (code & RF_ADDED)
+ printk(" added");
+ if (code & RF_MERGED)
+ printk(" merged");
+ if (code & RF_NOT_RAM)
+ printk(" rom");
+ if (code & RF_ZERO)
+ printk(" zero-length");
+
+ if (code & RF_SHORT)
+ printk(" ERROR: short record");
+ else if (code & RF_OVERFLOW)
+ printk(" ERROR: table overflow");
+ else if (code & RF_TOOLONG)
+ printk(" ERROR: start+size > 64 bits");
+}
+#endif
+
+
+/*
+ * region_check() validates the physical_memory map, plus lops out memory
+ * that lives in suspicious places.
+ */
+int __init
+region_check(void)
+{
+ unsigned int x, i;
+
+ for (x=0; x < physical_memory.nr_region; x++) {
+ if (x < physical_memory.nr_region-1
+ && Region[x].end >= Region[x+1].start) {
+ printk("SMAP: region %d (%010Lx - %010Lx) overlaps region %d (%010Lx - %010Lx) -- map dropped\n",
+ x, Region[x].start,
+ Region[x].end,
+ x+1, Region[x+1].start,
+ Region[x+1].end);
+ return 1;
+ }
+#if FLAG_E820_GULLIBLE
+ if (physical_memory.p_flag & CHK_PMEM_GULLIBLE)
+ continue;
+#endif
+
+#if FLAG_E820_4GB_ONLY
+ if (Region[x].start >= GIGABYTE(4)) {
+ E820DBG(("SMAP: region %010Lx - %010Lx dropped\n",
+ Region[x].start, Region[x].end));
+ for (i=x; i < physical_memory.nr_region; i++)
+ Region[i] = Region[i+1];
+ x--;
+ physical_memory.nr_region--;
+ continue;
+ }
+
+ if (Region[x].end > GIGABYTE(4)) {
+ E820DBG(("SMAP: region %010Lx - %010Lx truncated to %010Lx - %010Lx\n",
+ Region[x].start, Region[x].end, Region[x].start,
+ GIGABYTE(4)));
+ Region[x].end = GIGABYTE(4);
+ }
+#endif
+
+ if (Region[x].start >= HIGH_MEMORY || Region[x].end <= LOWMEMSIZE())
+ continue;
+
+ if (Region[x].start >= LOWMEMSIZE()) {
+ if (Region[x].end < HIGH_MEMORY) {
+ E820DBG(("%010Lx - %010Lx dropped\n",
+ Region[x].start, Region[x].end));
+ for (i=x; i < physical_memory.nr_region; i++)
+ Region[i] = Region[i+1];
+ x--;
+ physical_memory.nr_region--;
+ }
+ else {
+ E820DBG(("SMAP: %010Lx - %010Lx trimmed to %010lx - %010Lx\n",
+ Region[x].start, Region[x].end,
+ (unsigned long)HIGH_MEMORY, Region[x].end));
+ Region[x].start = HIGH_MEMORY;
+ }
+ }
+ else if (Region[x].end < HIGH_MEMORY) {
+ E820DBG(("%010Lx - %010Lx trimmed to %010Lx - %010lx\n",
+ Region[x].start, Region[x].end,
+ Region[x].start, (unsigned long)LOWMEMSIZE()));
+ Region[x].end = LOWMEMSIZE();
+ }
+ else {
+ E820DBG(("%010Lx - %010Lx split to %010Lx - 640k, 1m - %010Lx\n",
+ Region[x].start, Region[x].end,
+ Region[x].start, Region[x].end));
+ for (i=physical_memory.nr_region; i > x; --i)
+ Region[i+1] = Region[i];
+
+ Region[x+1].start = HIGH_MEMORY;
+ Region[x+1].end = Region[x].end;
+ Region[x].end = LOWMEMSIZE();
+ x++;
+ physical_memory.nr_region++;
+ }
+ }
+ return 0;
+} /* region_check */
+
void __init setup_memory_region(void)
{
-#define E820_DEBUG 1
-#ifdef E820_DEBUG
int i;
-#endif
+ enum region_flags ret;
+ unsigned long mem_size;
+#ifdef CONFIG_MEM_E820
/*
* If we're lucky and live on a modern system, the setup code
* will have given us a memory map that we can use to properly
@@ -424,52 +622,82 @@
* We check to see that the memory map contains at least 2 elements
* before we'll use it, because the detection code in setup.S may
* not be perfect and most every PC known to man has two memory
- * regions: one from 0 to 640k, and one from 1mb up. (The IBM
- * thinkpad 560x, for example, does not cooperate with the memory
- * detection code.)
+ * regions: one from 0 to 640k, and one from 1mb up.
*/
- if (E820_MAP_NR > 1) {
+ if ( (E820_MAP_NR > 1) && (E820_MAP_NR < E820MAX) ) {
/* got a memory map; copy it into a safe place.
*/
- e820.nr_map = E820_MAP_NR;
- if (e820.nr_map > E820MAX)
- e820.nr_map = E820MAX;
- memcpy(e820.map, E820_MAP, e820.nr_map * sizeof e820.map[0]);
-#ifdef E820_DEBUG
- for (i=0; i < e820.nr_map; i++) {
- printk("e820: %08x @ %08x ", (int)e820.map[i].size,
- (int)e820.map[i].addr);
- switch (e820.map[i].type) {
- case E820_RAM: printk("(usable)\n");
+ physical_memory.p_flags = (FLAG_E820_GULLIBLE ? CHK_PMEM_GULLIBLE : 0)
+ | (FLAG_E820_RECLAIM ? CHK_PMEM_RECLAIM : 0) ;
+ physical_memory.nr_bios = E820_MAP_NR;
+ memcpy(&(Bios), E820_MAP, E820_MAP_NR * sizeof Bios[0]);
+ for (i=0; i < E820_MAP_NR; i++) {
+#if FLAG_E820_DEBUG
+ printk("SMAP: %010Lx - %010Lx ",
+ Bios[i].addr,
+ Bios[i].addr + Bios[i].size);
+#endif
+ if ( Bios[i].len < E820LEN)
+ ret = RF_SHORT;
+ else
+ ret = add_memory_region(Bios[i].addr,
+ Bios[i].addr + Bios[i].size,
+ Bios[i].type);
+#if FLAG_E820_DEBUG
+ switch (Bios[i].type) {
+ case E820_RAM: printk("(usable)");
break;
case E820_RESERVED:
- printk("(reserved)\n");
+ printk("(reserved)");
break;
case E820_ACPI:
- printk("(ACPI data)\n");
+ printk("(ACPI data)");
break;
case E820_NVS:
- printk("(ACPI NVS)\n");
+ printk("(ACPI NVS)");
break;
- default: printk("type %lu\n", e820.map[i].type);
+ default:
+ printk("(type %lu)",
+ (unsigned long)Bios[i].type);
break;
}
- }
+ if ( Bios[i].len != E820LEN )
+ printk(" [record is %d bytes long]", Bios[i].len);
+
+ report(ret);
+ printk("\n");
#endif
- }
- else {
- /* otherwise fake a memory map; one section from 0k->640k,
- * the next section from 1mb->appropriate_mem_k
+ if (ret & (RF_SHORT|RF_TOOLONG|RF_OVERFLOW))
+ goto oldstyle;
+ }
+ /* after putting in the e820 map, massage it into shape
+ * for use by the kernel. If region_check returns anything
+ * except 0, something is very ill in the state of the
+ * bios map.
*/
- unsigned long mem_size;
+ if (region_check() == 0)
+ return /* the map is fine, so we'll use it */;
+ }
+#endif
- mem_size = (ALT_MEM_K < EXT_MEM_K) ? EXT_MEM_K : ALT_MEM_K;
+ oldstyle:
+ /* otherwise fake a memory map; one section from 0k->640k,
+ * the next section from 1mb->appropriate_mem_k
+ */
- add_memory_region(0, LOWMEMSIZE(), E820_RAM);
- add_memory_region(HIGH_MEMORY, mem_size << 10, E820_RAM);
- }
-} /* setup_memory_region */
+ physical_memory.nr_region = 0;
+ physical_memory.p_flags = 0;
+
+#ifdef CONFIG_MEM_E801
+ mem_size = (ALT_MEM_K < EXT_MEM_K) ? EXT_MEM_K : ALT_MEM_K;
+#else
+ mem_size = EXT_MEM_K;
+#endif
+ add_memory_region(0, LOWMEMSIZE(), E820_RAM);
+ add_memory_region(HIGH_MEMORY,
+ HIGH_MEMORY + (mem_size << 10), E820_RAM);
+} /* setup_memory_region */
static inline void parse_mem_cmdline (char ** cmdline_p)
{
@@ -507,7 +735,7 @@
* and reinitialize it with the
* standard low-memory region.
*/
- e820.nr_map = 0;
+ physical_memory.nr_region = 0;
usermem = 1;
add_memory_region(0, LOWMEMSIZE(), E820_RAM);
}
@@ -575,10 +803,6 @@
parse_mem_cmdline(cmdline_p);
-#define PFN_UP(x) (((x) + PAGE_SIZE-1) >> PAGE_SHIFT)
-#define PFN_DOWN(x) ((x) >> PAGE_SHIFT)
-#define PFN_PHYS(x) ((x) << PAGE_SHIFT)
-
/*
* 128MB for vmalloc and initrd
*/
@@ -594,21 +818,16 @@
start_pfn = PFN_UP(__pa(&_end));
/*
- * Find the highest page frame number we have available
- */
- max_pfn = 0;
- for (i = 0; i < e820.nr_map; i++) {
- unsigned long start, end;
- /* RAM? */
- if (e820.map[i].type != E820_RAM)
- continue;
- start = PFN_UP(e820.map[i].addr);
- end = PFN_DOWN(e820.map[i].addr + e820.map[i].size);
- if (start >= end)
- continue;
- if (end > max_pfn)
- max_pfn = end;
- }
+ * Find the highest page frame number we have available
+ */
+ max_pfn = 0;
+ for (i = 0; i < physical_memory.nr_region; i++) {
+ unsigned long start, end;
+ start = PFN_UP(Region[i].start);
+ end = PFN_DOWN(Region[i].end);
+ if ( (start < end) && (end > max_pfn) )
+ max_pfn = end;
+ }
/*
* Determine low and high memory ranges:
@@ -651,23 +870,19 @@
/*
* Register fully available low RAM pages with the bootmem allocator.
*/
- for (i = 0; i < e820.nr_map; i++) {
+ for (i = 0; i < physical_memory.nr_region; i++) {
unsigned long curr_pfn, last_pfn, size;
- /*
- * Reserve usable low memory
- */
- if (e820.map[i].type != E820_RAM)
- continue;
+
/*
* We are rounding up the start address of usable memory:
*/
- curr_pfn = PFN_UP(e820.map[i].addr);
+ curr_pfn = PFN_UP(Region[i].start);
if (curr_pfn >= max_low_pfn)
continue;
/*
* ... and at the end of the usable range downwards:
*/
- last_pfn = PFN_DOWN(e820.map[i].addr + e820.map[i].size);
+ last_pfn = PFN_DOWN(Region[i].end);
if (last_pfn > max_low_pfn)
last_pfn = max_low_pfn;
@@ -748,30 +963,39 @@
* and also for regions reported as reserved by the e820.
*/
probe_roms();
- for (i = 0; i < e820.nr_map; i++) {
+ for (i = 0; i < physical_memory.nr_region; i++) {
struct resource *res;
- if (e820.map[i].addr + e820.map[i].size > 0x100000000ULL)
+ res = alloc_bootmem_low(sizeof(struct resource));
+ res->start = Region[i].start;
+ res->end = Region[i].end-1;
+ res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+ res->name = "System RAM";
+ request_resource(&iomem_resource, res);
+ /*
+ * We dont't know which RAM region contains the
+ * kernel data, so we try it repeatedly and let
+ * the resource manager test it.
+ */
+ request_resource(res, &code_resource);
+ request_resource(res, &data_resource);
+ }
+ for (i = 0; i < physical_memory.nr_bios; i++) {
+ struct resource *res;
+ if (Bios[i].addr + Bios[i].size > GIGABYTE(4))
+ continue;
+ if (Bios[i].type == E820_RAM)
continue;
+
res = alloc_bootmem_low(sizeof(struct resource));
- switch (e820.map[i].type) {
- case E820_RAM: res->name = "System RAM"; break;
+ switch (Bios[i].type) {
case E820_ACPI: res->name = "ACPI Tables"; break;
case E820_NVS: res->name = "ACPI Non-volatile Storage"; break;
default: res->name = "reserved";
}
- res->start = e820.map[i].addr;
- res->end = res->start + e820.map[i].size - 1;
+ res->start = Bios[i].addr;
+ res->end = Bios[i].addr + Bios[i].size - 1;
res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
request_resource(&iomem_resource, res);
- if (e820.map[i].type == E820_RAM) {
- /*
- * We dont't know which RAM region contains kernel data,
- * so we try it repeatedly and let the resource manager
- * test it.
- */
- request_resource(res, &code_resource);
- request_resource(res, &data_resource);
- }
}
request_resource(&iomem_resource, &vram_resource);
--- linux/arch/i386/config.in.orig Sat Mar 11 08:44:46 2000
+++ linux/arch/i386/config.in Sat Mar 11 08:46:34 2000
@@ -64,6 +64,16 @@
define_bool CONFIG_X86_PAE y
fi
+mainmenu_option next_comment
+comment 'Memory detection'
+bool 'Use extended bios calls to detect memory' CONFIG_MEM_E820
+if [ "$CONFIG_MEM_E820" = "y" ]; then
+ bool ' Merge adjacent memory regions' CONFIG_E820_MERGE
+ bool ' Reclaim ACPI table memory (DANGEROUS)' CONFIG_E820_RECLAIM
+ bool ' Also try bios call E801' CONFIG_MEM_E801
+fi
+endmenu
+
bool 'Math emulation' CONFIG_MATH_EMULATION
bool 'MTRR (Memory Type Range Register) support' CONFIG_MTRR
bool 'Symmetric multi-processing support' CONFIG_SMP
--- linux/arch/i386/defconfig.orig Sat Mar 11 08:44:46 2000
+++ linux/arch/i386/defconfig Sat Mar 11 08:46:34 2000
@@ -29,6 +29,10 @@
CONFIG_X86_PGE=y
# CONFIG_MICROCODE is not set
CONFIG_NOHIGHMEM=y
+CONFIG_MEM_E820=y
+CONFIG_MEM_E801=y
+CONFIG_E820_MERGE=y
+#CONFIG_MEM_RECLAIM is not set
# CONFIG_HIGHMEM4G is not set
# CONFIG_HIGHMEM64G is not set
# CONFIG_MATH_EMULATION is not set
--- linux/Documentation/Configure.help.orig Sat Mar 11 08:44:45 2000
+++ linux/Documentation/Configure.help Sat Mar 11 08:46:34 2000
@@ -182,6 +182,40 @@
on the Alpha. The only time you would ever not say Y is to say M in
order to debug the code. Say Y unless you know what you are doing.
+Use extended bios calls to detect memory
+CONFIG_MEM_E820
+ The traditional Linux memory detection code for ia32 machines is
+ restricted to detecting 64mb (or 16mb!) of core. The E820 call,
+ which is used by many operating systems, is a modern replacement
+ for it, which gives back a detailed memory map of usable memory,
+ rom, and ACPI tables. Older machines ignore this detection method,
+ so you should be able to say Y here unless your machine has
+ problems correctly detecting memory.
+
+Merge adjacent memory regions
+CONFIG_E820_MERGE
+ The E820 bios call may return a fragmented map where many segments
+ of the map are too small to fit a Linux memory table entry onto.
+ This option merges adjacent memory sections together before
+ initializing the Linux memory tables.
+
+Reclaim ACPI table memory (DANGEROUS)
+CONFIG_E820_RECLAIM
+ If you are not using ACPI (CONFIG_ACPI) on this machine, you can
+ use this option to use ACPI tables as regular memory. This is a
+ dangerous option -- some people have reported that attempting to
+ reclaim ACPI tables result in Linux crashing -- so only answer Y
+ if you know what you are doing.
+
+Use bios call e801 to detect memory
+CONFIG_MEM_E801
+ The E801 bios call was an earlier method for detecting memory on
+ ia32 machines. It has fallen out of favor, and some modern
+ bioses have broken it so that it returns garbage. The kernel
+ will attempt to use this call if the e820 bios call does not
+ exist on the machine. It's probably safe to answer Y here,
+ though 99% of the machines out there won't use this call.
+
High Memory support
CONFIG_NOHIGHMEM
If you are compiling a kernel which will never run on a machine
-
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