add IPIs to shoot down the TLB on all cores

hermit/arch/x86/include/asm/processor.h

@@ -352,6 +352,9 @@ inline static void invalidate_cache(void) {
 	asm volatile ("invd" ::: "memory");
 }
 
+/// Send IPIs to the other core, which flush the TLB on the other cores.
+int ipi_tlb_flush(void);
+
 /** @brief Flush Translation Lookaside Buffer
  *
  * Just reads cr3 and writes the same value back into it.
@@ -362,6 +365,10 @@ static inline void flush_tlb(void)
 
 	if (val)
 		write_cr3(val);
+
+#if MAX_CORES > 1
+	ipi_tlb_flush();
+#endif
 }
 
 /** @brief Flush a specific page entry in TLB
@@ -370,6 +377,10 @@ static inline void flush_tlb(void)
 static inline void tlb_flush_one_page(size_t addr)
 {
 	asm volatile("invlpg (%0)" : : "r"(addr) : "memory");
+
+#if MAX_CORES > 1
+	ipi_tlb_flush();
+#endif
 }
 
 /** @brief Invalidate cache

hermit/arch/x86/kernel/apic.c

@@ -70,11 +70,15 @@ static uint32_t icr = 0;
 static uint32_t ncores = 1;
 static uint8_t irq_redirect[16] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0xA, 0xB, 0xC, 0xD, 0xE, 0xF};
 static uint8_t initialized = 0;
+static uint8_t online[MAX_CORES] = {[0 ... MAX_CORES-1] = 0};
+
 spinlock_t bootlock = SPINLOCK_INIT;
 
 // forward declaration
 static int lapic_reset(void);
 
+extern atomic_int32_t cpu_online;
+
 static uint32_t lapic_read_default(uint32_t addr)
 {
 	return *((const volatile uint32_t*) (lapic+addr));
@@ -586,6 +590,7 @@ int smp_start(void)
 	cpu_detection();
 
 	//kprintf("CR0 of core %u: 0x%x\n", apic_cpu_id(), read_cr0());
+	online[apic_cpu_id()] = 1;
 
 	set_idle_task();
 
@@ -594,6 +599,60 @@ int smp_start(void)
 	return smp_main();
 }
 
+#if MAX_CORES > 1
+static inline void set_ipi_dest(uint32_t cpu_id) {
+	uint32_t tmp;
+
+	tmp = lapic_read(APIC_ICR2);
+	tmp &= 0x00FFFFFF;
+	tmp |= (cpu_id << 24);
+	lapic_write(APIC_ICR2, tmp);
+}
+
+int ipi_tlb_flush(void)
+{
+	uint32_t core_id = CORE_ID;
+	uint32_t flags;
+	uint32_t i, j;
+
+	if (atomic_int32_read(&cpu_online) == 1)
+		return 0;
+
+	if (lapic_read(APIC_ICR1) & APIC_ICR_BUSY) {
+		kputs("ERROR: previous send not complete");
+		return -EIO;
+	}
+
+	flags = irq_nested_disable();
+	for(i=0; i<MAX_CORES; i++)
+	{
+		if (i == core_id)
+			continue;
+		if (!online[i])
+			continue;
+
+		set_ipi_dest(i);
+		lapic_write(APIC_ICR1, APIC_INT_ASSERT|APIC_DM_FIXED|124);
+
+		j = 0;
+		while((lapic_read(APIC_ICR1) & APIC_ICR_BUSY) && (j < 1000))
+			j++; // wait for it to finish, give up eventualy tho
+	}
+	irq_nested_enable(flags);
+
+	return 0;
+}
+
+static void apic_tlb_handler(struct state *s)
+{
+	uint32_t val = read_cr3();
+
+	if (val)
+		write_cr3(val);
+	//kputs("Flush TLB!\n");
+}
+#endif
+
 static void apic_err_handler(struct state *s)
 {
 	kprintf("Got APIC error 0x%x\n", lapic_read(APIC_ESR));
@@ -612,7 +671,11 @@ int apic_init(void)
 
 	// set APIC error handler
 	irq_install_handler(126, apic_err_handler);
+#if MAX_CORES > 1
+	irq_install_handler(124, apic_tlb_handler);
+#endif
 	kprintf("Boot processor %u (ID %u)\n", boot_processor, apic_processors[boot_processor]->id);
+	online[boot_processor] = 1;
 
 	return 0;
 }

hermit/kernel/main.c

@@ -87,6 +87,7 @@ int smp_main(void)
 
 	create_kernel_task(NULL, foo, "foo2", NORMAL_PRIO);
 
+	flush_tlb();
 	while(1) {
                 HALT;
         }