3 // Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net>
4 // Copyright (C) 2006 Fabrice Bellard
6 // This file may be distributed under the terms of the GNU GPLv3 license.
8 #include "util.h" // dprintf
9 #include "config.h" // CONFIG_*
11 #define CPUID_APIC (1 << 9)
13 #define APIC_ICR_LOW ((u8*)BUILD_APIC_ADDR + 0x300)
14 #define APIC_SVR ((u8*)BUILD_APIC_ADDR + 0x0F0)
16 #define APIC_ENABLED 0x0100
18 static inline void writel(void *addr, u32 val)
20 *(volatile u32 *)addr = val;
23 static inline void writew(void *addr, u16 val)
25 *(volatile u16 *)addr = val;
28 static inline void writeb(void *addr, u8 val)
30 *(volatile u8 *)addr = val;
33 static inline u32 readl(const void *addr)
35 return *(volatile const u32 *)addr;
38 static inline u16 readw(const void *addr)
40 return *(volatile const u16 *)addr;
43 static inline u8 readb(const void *addr)
45 return *(volatile const u8 *)addr;
48 extern void smp_ap_boot_code();
51 u32 smp_cpus VISIBLE16;
53 " .global smp_ap_boot_code\n"
55 // Increment the cpu counter
56 " movw $" __stringify(SEG_BIOS) ", %ax\n"
58 " lock incl smp_cpus\n"
59 // Halt the processor.
60 " jmp permanent_halt\n"
64 /* find the number of CPUs by launching a SIPI to them */
71 u32 eax, ebx, ecx, cpuid_features;
72 cpuid(1, &eax, &ebx, &ecx, &cpuid_features);
73 if (! (cpuid_features & CPUID_APIC)) {
74 // No apic - only the main cpu is present.
82 // Setup jump trampoline to counter code.
83 u64 old = *(u64*)BUILD_AP_BOOT_ADDR;
84 // ljmpw $SEG_BIOS, $(smp_ap_boot_code - BUILD_BIOS_ADDR)
85 u64 new = (0xea | ((u64)SEG_BIOS<<24)
86 | (((u32)smp_ap_boot_code - BUILD_BIOS_ADDR) << 8));
87 *(u64*)BUILD_AP_BOOT_ADDR = new;
90 u32 val = readl(APIC_SVR);
91 writel(APIC_SVR, val | APIC_ENABLED);
94 writel(APIC_ICR_LOW, 0x000C4500);
95 u32 sipi_vector = BUILD_AP_BOOT_ADDR >> 12;
96 writel(APIC_ICR_LOW, 0x000C4600 | sipi_vector);
98 // Wait for other CPUs to process the SIPI.
102 writel(APIC_SVR, val);
103 *(u64*)BUILD_AP_BOOT_ADDR = old;
105 u32 count = readl(&smp_cpus);
106 dprintf(1, "Found %d cpu(s)\n", count);
110 // Reset smp_cpus to zero (forces a recheck on reboots).
112 smp_probe_setup(void)