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// CPU count detection
//
// Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net>
// Copyright (C) 2006 Fabrice Bellard
//
// This file may be distributed under the terms of the GNU LGPLv3 license.
#include "util.h" // dprintf
#include "config.h" // CONFIG_*
#include "cmos.h" // CMOS_BIOS_SMP_COUNT
#define APIC_ICR_LOW ((u8*)BUILD_APIC_ADDR + 0x300)
#define APIC_SVR ((u8*)BUILD_APIC_ADDR + 0x0F0)
#define APIC_LINT0 ((u8*)BUILD_APIC_ADDR + 0x350)
#define APIC_LINT1 ((u8*)BUILD_APIC_ADDR + 0x360)
#define APIC_ENABLED 0x0100
struct { u32 ecx, eax, edx; } smp_mtrr[32] VARFSEG;
u32 smp_mtrr_count VARFSEG;
void
wrmsr_smp(u32 index, u64 val)
{
wrmsr(index, val);
if (smp_mtrr_count >= ARRAY_SIZE(smp_mtrr)) {
warn_noalloc();
return;
}
smp_mtrr[smp_mtrr_count].ecx = index;
smp_mtrr[smp_mtrr_count].eax = val;
smp_mtrr[smp_mtrr_count].edx = val >> 32;
smp_mtrr_count++;
}
u32 CountCPUs VARFSEG;
u32 MaxCountCPUs;
// 256 bits for the found APIC IDs
u32 FoundAPICIDs[256/32] VARFSEG;
extern void smp_ap_boot_code(void);
ASM16(
" .global smp_ap_boot_code\n"
"smp_ap_boot_code:\n"
// Setup data segment
" movw $" __stringify(SEG_BIOS) ", %ax\n"
" movw %ax, %ds\n"
// MTRR setup
" movl $smp_mtrr, %esi\n"
" movl smp_mtrr_count, %ebx\n"
"1:testl %ebx, %ebx\n"
" jz 2f\n"
" movl 0(%esi), %ecx\n"
" movl 4(%esi), %eax\n"
" movl 8(%esi), %edx\n"
" wrmsr\n"
" addl $12, %esi\n"
" decl %ebx\n"
" jmp 1b\n"
"2:\n"
// get apic ID on EBX, set bit on FoundAPICIDs
" movl $1, %eax\n"
" cpuid\n"
" shrl $24, %ebx\n"
" lock btsl %ebx, FoundAPICIDs\n"
// Increment the cpu counter
" lock incl CountCPUs\n"
// Halt the processor.
"1:hlt\n"
" jmp 1b\n"
);
int apic_id_is_present(u8 apic_id)
{
return !!(FoundAPICIDs[apic_id/32] & (1ul << (apic_id % 32)));
}
// find and initialize the CPUs by launching a SIPI to them
void
smp_setup(void)
{
if (!CONFIG_QEMU)
return;
ASSERT32FLAT();
u32 eax, ebx, ecx, cpuid_features;
cpuid(1, &eax, &ebx, &ecx, &cpuid_features);
if (eax < 1 || !(cpuid_features & CPUID_APIC)) {
// No apic - only the main cpu is present.
dprintf(1, "No apic - only the main cpu is present.\n");
CountCPUs= 1;
MaxCountCPUs = 1;
return;
}
// mark the BSP initial APIC ID as found, too:
u8 apic_id = ebx>>24;
FoundAPICIDs[apic_id/32] |= (1 << (apic_id % 32));
// Init the counter.
writel(&CountCPUs, 1);
// Setup jump trampoline to counter code.
u64 old = *(u64*)BUILD_AP_BOOT_ADDR;
// ljmpw $SEG_BIOS, $(smp_ap_boot_code - BUILD_BIOS_ADDR)
u64 new = (0xea | ((u64)SEG_BIOS<<24)
| (((u32)smp_ap_boot_code - BUILD_BIOS_ADDR) << 8));
*(u64*)BUILD_AP_BOOT_ADDR = new;
// enable local APIC
u32 val = readl(APIC_SVR);
writel(APIC_SVR, val | APIC_ENABLED);
/* Set LINT0 as Ext_INT, level triggered */
writel(APIC_LINT0, 0x8700);
/* Set LINT1 as NMI, level triggered */
writel(APIC_LINT1, 0x8400);
// broadcast SIPI
barrier();
writel(APIC_ICR_LOW, 0x000C4500);
u32 sipi_vector = BUILD_AP_BOOT_ADDR >> 12;
writel(APIC_ICR_LOW, 0x000C4600 | sipi_vector);
// Wait for other CPUs to process the SIPI.
u8 cmos_smp_count = inb_cmos(CMOS_BIOS_SMP_COUNT);
while (cmos_smp_count + 1 != readl(&CountCPUs))
yield();
// Restore memory.
*(u64*)BUILD_AP_BOOT_ADDR = old;
MaxCountCPUs = romfile_loadint("etc/max-cpus", 0);
if (!MaxCountCPUs || MaxCountCPUs < CountCPUs)
MaxCountCPUs = CountCPUs;
dprintf(1, "Found %d cpu(s) max supported %d cpu(s)\n", readl(&CountCPUs),
MaxCountCPUs);
}
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