svn commit: r213226 - head/sys/i386/i386
John Baldwin
jhb at FreeBSD.org
Mon Sep 27 19:36:16 UTC 2010
Author: jhb
Date: Mon Sep 27 19:36:15 2010
New Revision: 213226
URL: http://svn.freebsd.org/changeset/base/213226
Log:
Rewrite the i386 memory probe:
- Check for SMAP data from the loader first. If it exists, don't bother
doing any VM86 calls at all. This will be more friendly for non-BIOS
boot environments such as EFI, etc.
- Move the base memory setup into a new basemem_setup() routine instead
of duplicating it.
- Simplify the XEN case by removing all of the VM86/SMAP parsing code rather
than just jumping over it.
- Adjust some comments to better explain the code flow.
MFC after: 2 weeks
Modified:
head/sys/i386/i386/machdep.c
Modified: head/sys/i386/i386/machdep.c
==============================================================================
--- head/sys/i386/i386/machdep.c Mon Sep 27 19:26:56 2010 (r213225)
+++ head/sys/i386/i386/machdep.c Mon Sep 27 19:36:15 2010 (r213226)
@@ -1950,6 +1950,7 @@ sdtossd(sd, ssd)
ssd->ssd_gran = sd->sd_gran;
}
+#ifndef XEN
static int
add_smap_entry(struct bios_smap *smap, vm_paddr_t *physmap, int *physmap_idxp)
{
@@ -2029,78 +2030,13 @@ add_smap_entry(struct bios_smap *smap, v
return (1);
}
-/*
- * Populate the (physmap) array with base/bound pairs describing the
- * available physical memory in the system, then test this memory and
- * build the phys_avail array describing the actually-available memory.
- *
- * If we cannot accurately determine the physical memory map, then use
- * value from the 0xE801 call, and failing that, the RTC.
- *
- * Total memory size may be set by the kernel environment variable
- * hw.physmem or the compile-time define MAXMEM.
- *
- * XXX first should be vm_paddr_t.
- */
static void
-getmemsize(int first)
+basemem_setup(void)
{
- int i, off, physmap_idx, pa_indx, da_indx;
- int hasbrokenint12, has_smap;
- u_long physmem_tunable;
- u_int extmem;
- struct vm86frame vmf;
- struct vm86context vmc;
- vm_paddr_t pa, physmap[PHYSMAP_SIZE];
+ vm_paddr_t pa;
pt_entry_t *pte;
- struct bios_smap *smap, *smapbase, *smapend;
- u_int32_t smapsize;
- quad_t dcons_addr, dcons_size;
- caddr_t kmdp;
-
- has_smap = 0;
-#ifdef XBOX
- if (arch_i386_is_xbox) {
- /*
- * We queried the memory size before, so chop off 4MB for
- * the framebuffer and inform the OS of this.
- */
- physmap[0] = 0;
- physmap[1] = (arch_i386_xbox_memsize * 1024 * 1024) - XBOX_FB_SIZE;
- physmap_idx = 0;
- goto physmap_done;
- }
-#endif
-#if defined(XEN)
- has_smap = 0;
- Maxmem = xen_start_info->nr_pages - init_first;
- physmem = Maxmem;
- basemem = 0;
- physmap[0] = init_first << PAGE_SHIFT;
- physmap[1] = ptoa(Maxmem) - round_page(MSGBUF_SIZE);
- physmap_idx = 0;
- goto physmap_done;
-#endif
- hasbrokenint12 = 0;
- TUNABLE_INT_FETCH("hw.hasbrokenint12", &hasbrokenint12);
- bzero(&vmf, sizeof(vmf));
- bzero(physmap, sizeof(physmap));
- basemem = 0;
-
- /*
- * Some newer BIOSes has broken INT 12H implementation which cause
- * kernel panic immediately. In this case, we need to scan SMAP
- * with INT 15:E820 first, then determine base memory size.
- */
- if (hasbrokenint12) {
- goto int15e820;
- }
+ int i;
- /*
- * Perform "base memory" related probes & setup
- */
- vm86_intcall(0x12, &vmf);
- basemem = vmf.vmf_ax;
if (basemem > 640) {
printf("Preposterous BIOS basemem of %uK, truncating to 640K\n",
basemem);
@@ -2140,12 +2076,69 @@ getmemsize(int first)
pte = (pt_entry_t *)vm86paddr;
for (i = basemem / 4; i < 160; i++)
pte[i] = (i << PAGE_SHIFT) | PG_V | PG_RW | PG_U;
+}
+#endif
+
+/*
+ * Populate the (physmap) array with base/bound pairs describing the
+ * available physical memory in the system, then test this memory and
+ * build the phys_avail array describing the actually-available memory.
+ *
+ * If we cannot accurately determine the physical memory map, then use
+ * value from the 0xE801 call, and failing that, the RTC.
+ *
+ * Total memory size may be set by the kernel environment variable
+ * hw.physmem or the compile-time define MAXMEM.
+ *
+ * XXX first should be vm_paddr_t.
+ */
+static void
+getmemsize(int first)
+{
+ int has_smap, off, physmap_idx, pa_indx, da_indx;
+ u_long physmem_tunable;
+ vm_paddr_t physmap[PHYSMAP_SIZE];
+ pt_entry_t *pte;
+ quad_t dcons_addr, dcons_size;
+#ifndef XEN
+ int hasbrokenint12, i;
+ u_int extmem;
+ struct vm86frame vmf;
+ struct vm86context vmc;
+ vm_paddr_t pa;
+ struct bios_smap *smap, *smapbase, *smapend;
+ u_int32_t smapsize;
+ caddr_t kmdp;
+#endif
+
+ has_smap = 0;
+#if defined(XEN)
+ Maxmem = xen_start_info->nr_pages - init_first;
+ physmem = Maxmem;
+ basemem = 0;
+ physmap[0] = init_first << PAGE_SHIFT;
+ physmap[1] = ptoa(Maxmem) - round_page(MSGBUF_SIZE);
+ physmap_idx = 0;
+#else
+#ifdef XBOX
+ if (arch_i386_is_xbox) {
+ /*
+ * We queried the memory size before, so chop off 4MB for
+ * the framebuffer and inform the OS of this.
+ */
+ physmap[0] = 0;
+ physmap[1] = (arch_i386_xbox_memsize * 1024 * 1024) - XBOX_FB_SIZE;
+ physmap_idx = 0;
+ goto physmap_done;
+ }
+#endif
+ bzero(&vmf, sizeof(vmf));
+ bzero(physmap, sizeof(physmap));
+ basemem = 0;
-int15e820:
/*
- * Fetch the memory map with INT 15:E820. First, check to see
- * if the loader supplied it and use that if so. Otherwise,
- * use vm86 to invoke the BIOS call directly.
+ * Check if the loader supplied an SMAP memory map. If so,
+ * use that and do not make any VM86 calls.
*/
physmap_idx = 0;
smapbase = NULL;
@@ -2156,9 +2149,10 @@ int15e820:
smapbase = (struct bios_smap *)preload_search_info(kmdp,
MODINFO_METADATA | MODINFOMD_SMAP);
if (smapbase != NULL) {
- /* subr_module.c says:
+ /*
+ * subr_module.c says:
* "Consumer may safely assume that size value precedes data."
- * ie: an int32_t immediately precedes smap.
+ * ie: an int32_t immediately precedes SMAP.
*/
smapsize = *((u_int32_t *)smapbase - 1);
smapend = (struct bios_smap *)((uintptr_t)smapbase + smapsize);
@@ -2167,33 +2161,50 @@ int15e820:
for (smap = smapbase; smap < smapend; smap++)
if (!add_smap_entry(smap, physmap, &physmap_idx))
break;
- } else {
- /*
- * map page 1 R/W into the kernel page table so we can use it
- * as a buffer. The kernel will unmap this page later.
- */
- pmap_kenter(KERNBASE + (1 << PAGE_SHIFT), 1 << PAGE_SHIFT);
- vmc.npages = 0;
- smap = (void *)vm86_addpage(&vmc, 1, KERNBASE +
- (1 << PAGE_SHIFT));
- vm86_getptr(&vmc, (vm_offset_t)smap, &vmf.vmf_es, &vmf.vmf_di);
-
- vmf.vmf_ebx = 0;
- do {
- vmf.vmf_eax = 0xE820;
- vmf.vmf_edx = SMAP_SIG;
- vmf.vmf_ecx = sizeof(struct bios_smap);
- i = vm86_datacall(0x15, &vmf, &vmc);
- if (i || vmf.vmf_eax != SMAP_SIG)
- break;
- has_smap = 1;
- if (!add_smap_entry(smap, physmap, &physmap_idx))
- break;
- } while (vmf.vmf_ebx != 0);
+ goto have_smap;
}
/*
- * Perform "base memory" related probes & setup based on SMAP
+ * Some newer BIOSes have a broken INT 12H implementation
+ * which causes a kernel panic immediately. In this case, we
+ * need use the SMAP to determine the base memory size.
+ */
+ hasbrokenint12 = 0;
+ TUNABLE_INT_FETCH("hw.hasbrokenint12", &hasbrokenint12);
+ if (hasbrokenint12 == 0) {
+ /* Use INT12 to determine base memory size. */
+ vm86_intcall(0x12, &vmf);
+ basemem = vmf.vmf_ax;
+ basemem_setup();
+ }
+
+ /*
+ * Fetch the memory map with INT 15:E820. Map page 1 R/W into
+ * the kernel page table so we can use it as a buffer. The
+ * kernel will unmap this page later.
+ */
+ pmap_kenter(KERNBASE + (1 << PAGE_SHIFT), 1 << PAGE_SHIFT);
+ vmc.npages = 0;
+ smap = (void *)vm86_addpage(&vmc, 1, KERNBASE + (1 << PAGE_SHIFT));
+ vm86_getptr(&vmc, (vm_offset_t)smap, &vmf.vmf_es, &vmf.vmf_di);
+
+ vmf.vmf_ebx = 0;
+ do {
+ vmf.vmf_eax = 0xE820;
+ vmf.vmf_edx = SMAP_SIG;
+ vmf.vmf_ecx = sizeof(struct bios_smap);
+ i = vm86_datacall(0x15, &vmf, &vmc);
+ if (i || vmf.vmf_eax != SMAP_SIG)
+ break;
+ has_smap = 1;
+ if (!add_smap_entry(smap, physmap, &physmap_idx))
+ break;
+ } while (vmf.vmf_ebx != 0);
+
+have_smap:
+ /*
+ * If we didn't fetch the "base memory" size from INT12,
+ * figure it out from the SMAP (or just guess).
*/
if (basemem == 0) {
for (i = 0; i <= physmap_idx; i += 2) {
@@ -2203,49 +2214,39 @@ int15e820:
}
}
- /*
- * XXX this function is horribly organized and has to the same
- * things that it does above here.
- */
+ /* XXX: If we couldn't find basemem from SMAP, just guess. */
if (basemem == 0)
basemem = 640;
- if (basemem > 640) {
- printf(
- "Preposterous BIOS basemem of %uK, truncating to 640K\n",
- basemem);
- basemem = 640;
- }
-
- /*
- * Let vm86 scribble on pages between basemem and
- * ISA_HOLE_START, as above.
- */
- for (pa = trunc_page(basemem * 1024);
- pa < ISA_HOLE_START; pa += PAGE_SIZE)
- pmap_kenter(KERNBASE + pa, pa);
- pte = (pt_entry_t *)vm86paddr;
- for (i = basemem / 4; i < 160; i++)
- pte[i] = (i << PAGE_SHIFT) | PG_V | PG_RW | PG_U;
+ basemem_setup();
}
if (physmap[1] != 0)
goto physmap_done;
/*
- * If we failed above, try memory map with INT 15:E801
+ * If we failed to find an SMAP, figure out the extended
+ * memory size. We will then build a simple memory map with
+ * two segments, one for "base memory" and the second for
+ * "extended memory". Note that "extended memory" starts at a
+ * physical address of 1MB and that both basemem and extmem
+ * are in units of 1KB.
+ *
+ * First, try to fetch the extended memory size via INT 15:E801.
*/
vmf.vmf_ax = 0xE801;
if (vm86_intcall(0x15, &vmf) == 0) {
extmem = vmf.vmf_cx + vmf.vmf_dx * 64;
} else {
+ /*
+ * If INT15:E801 fails, this is our last ditch effort
+ * to determine the extended memory size. Currently
+ * we prefer the RTC value over INT15:88.
+ */
#if 0
vmf.vmf_ah = 0x88;
vm86_intcall(0x15, &vmf);
extmem = vmf.vmf_ax;
-#elif !defined(XEN)
- /*
- * Prefer the RTC value for extended memory.
- */
+#else
extmem = rtcin(RTC_EXTLO) + (rtcin(RTC_EXTHI) << 8);
#endif
}
@@ -2270,6 +2271,7 @@ int15e820:
physmap[physmap_idx + 1] = physmap[physmap_idx] + extmem * 1024;
physmap_done:
+#endif
/*
* Now, physmap contains a map of physical memory.
*/
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