x86_32: trim memory by updating e820
when MTRRs are not covering the whole e820 table, we need to trim the
RAM and need to update e820.
reuse some code on 64-bit as well.
here need to add early_get_cap and use it in early_cpu_detect, and move
mtrr_bp_init early.
The code successfully trimmed the memory map on Justin's system:
from:
[ 0.000000] BIOS-e820: 0000000100000000 - 000000022c000000 (usable)
to:
[ 0.000000] modified: 0000000100000000 - 0000000228000000 (usable)
[ 0.000000] modified: 0000000228000000 - 000000022c000000 (reserved)
According to Justin it makes quite a difference:
| When I boot the box without any trimming it acts like a 286 or 386,
| takes about 10 minutes to boot (using raptor disks).
Signed-off-by: Yinghai Lu <yinghai.lu@sun.com>
Tested-by: Justin Piszcz <jpiszcz@lucidpixels.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 56cc341..bba850b 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -278,6 +278,33 @@
c->x86_cache_alignment = ((misc >> 8) & 0xff) * 8;
}
}
+static void __cpuinit early_get_cap(struct cpuinfo_x86 *c)
+{
+ u32 tfms, xlvl;
+ int ebx;
+
+ memset(&c->x86_capability, 0, sizeof c->x86_capability);
+ if (have_cpuid_p()) {
+ /* Intel-defined flags: level 0x00000001 */
+ if (c->cpuid_level >= 0x00000001) {
+ u32 capability, excap;
+ cpuid(0x00000001, &tfms, &ebx, &excap, &capability);
+ c->x86_capability[0] = capability;
+ c->x86_capability[4] = excap;
+ }
+
+ /* AMD-defined flags: level 0x80000001 */
+ xlvl = cpuid_eax(0x80000000);
+ if ((xlvl & 0xffff0000) == 0x80000000) {
+ if (xlvl >= 0x80000001) {
+ c->x86_capability[1] = cpuid_edx(0x80000001);
+ c->x86_capability[6] = cpuid_ecx(0x80000001);
+ }
+ }
+
+ }
+
+}
/* Do minimum CPU detection early.
Fields really needed: vendor, cpuid_level, family, model, mask, cache alignment.
@@ -306,6 +333,8 @@
early_init_intel(c);
break;
}
+
+ early_get_cap(c);
}
static void __cpuinit generic_identify(struct cpuinfo_x86 * c)
@@ -485,7 +514,6 @@
identify_cpu(&boot_cpu_data);
sysenter_setup();
enable_sep_cpu();
- mtrr_bp_init();
}
void __cpuinit identify_secondary_cpu(struct cpuinfo_x86 *c)