logging: make term and printf smp safe

kernel-src/arch/x86-64/main.c

@@ -30,11 +30,14 @@
 #include <kernel/block.h>
 #include <kernel/ext2.h>
 #include <kernel/cmdline.h>
+#include <arch/smp.h>
+#include <kernel/e1000.h>
 
 static cpu_t bsp_cpu;
 
 void kernel_entry() {
 	cpu_set(&bsp_cpu);
+	logging_init();
 	logging_sethook(arch_e9_putc);
 	arch_gdt_reload();
 	arch_idt_setup();

kernel-src/include/logging.h

@@ -3,9 +3,27 @@
 
 #include <printf.h>
 #include <panic.h>
+#include <mutex.h>
+#include <arch/cpu.h>
 
 void _putchar(char c);
 void logging_sethook(void (*fun)(char));
+void logging_init();
+extern mutex_t printf_mutex;
+
+#ifdef printf
+#undef printf
+#endif
+
+#define printf(...) { \
+	if (_cpu()->thread) {\
+		MUTEX_ACQUIRE(&printf_mutex, false); \
+	} else { \
+		while (MUTEX_TRY(&printf_mutex) == false) CPU_PAUSE(); \
+	} \
+	printf_(__VA_ARGS__); \
+	MUTEX_RELEASE(&printf_mutex); \
+}
 
 #define __assert(x) \
 	if (!(x)){ \

kernel-src/include/semaphore.h

@@ -1,6 +1,7 @@
 #ifndef _SEMAPHORE_H
 #define _SEMAPHORE_H
 
+#include <stddef.h>
 #include <stdbool.h>
 #include <spinlock.h>
 

kernel-src/include/x86-64/arch/cpu.h

@@ -34,6 +34,7 @@ typedef struct cpu_t {
 } cpu_t;
 
 #define CPU_HALT() asm volatile("hlt")
+#define CPU_PAUSE() asm volatile("pause")
 
 static inline cpu_t *_cpu() {
 	return (cpu_t *)rdmsr(MSR_GSBASE);

kernel-src/io/logging.c

@@ -1,3 +1,7 @@
+#include <mutex.h>
+
+mutex_t printf_mutex;
+
 static void nohook(char c) {
 
 }
@@ -12,3 +16,7 @@ void _putchar(char c) {
 void logging_sethook(void (*fun)(char)) {
 	hook = fun;
 }
+
+void logging_init() {
+	MUTEX_INIT(&printf_mutex);
+}

kernel-src/io/term.c

@@ -20,9 +20,12 @@ static void *internalalloc(size_t n) {
 }
 
 static struct flanterm_context *term_ctx;
+static mutex_t term_mutex;
 
 void term_write(char *str, size_t count) {
+	MUTEX_ACQUIRE(&term_mutex, false);
 	flanterm_write(term_ctx, str, count);
+	MUTEX_RELEASE(&term_mutex);
 }
 
 void term_putchar(char c) {
@@ -55,4 +58,6 @@ void term_init() {
 	ys = term_ctx->rows;
 	fbxs = fb->width;
 	fbys = fb->height;
+
+	MUTEX_INIT(&term_mutex);
 }

kernel-src/mm/vmm.c

@@ -339,10 +339,11 @@ bool vmm_pagefault(void *addr, bool user, int actions) {
 		} else {
 			// anonymous memory. map the zero'd page
 			status = arch_mmu_map(_cpu()->vmmctx->pagetable, zeropage, addr, range->mmuflags & ~ARCH_MMU_FLAGS_WRITE);
-			if (!status)
+			if (!status) {
 				printf("vmm: out of memory to map zero page into address space\n");
-			else
+			} else {
 				pmm_hold(zeropage);
+			}
 		}
 	} else if (arch_mmu_iswritable(_cpu()->vmmctx->pagetable, addr) == false){
 		// page present but not writeable in the page tables