arch/x86: Enable UMIP, SMEP and SMAP

Qwinci · Nov 1, 2023 · 284e657 · 284e657
1 parent 13a462c
commit 284e657
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Showing 5 changed files with 55 additions and 4 deletions.
diff --git a/src/arch/x86/cpu.h b/src/arch/x86/cpu.h
@@ -35,6 +35,9 @@ typedef struct {
 	bool xsave;
 	bool avx;
 	bool avx512;
+	bool umip;
+	bool smep;
+	bool smap;
 } CpuFeatures;
 
 extern CpuFeatures CPU_FEATURES;

diff --git a/src/arch/x86/mem/misc.S b/src/arch/x86/mem/misc.S
@@ -18,7 +18,9 @@ arch_mem_copy_to_user:
 	mov %rax, %gs:X86TASK_HANDLER_IP_OFF
 	mov %rsp, %gs:X86TASK_HANDLER_SP_OFF
 
+	stac
 	call memcpy
+	clac
 
 	xor %edi, %edi
 	mov %rdi, %gs:X86TASK_HANDLER_IP_OFF
@@ -44,7 +46,9 @@ arch_mem_copy_to_kernel:
 	mov %rax, %gs:X86TASK_HANDLER_IP_OFF
 	mov %rsp, %gs:X86TASK_HANDLER_SP_OFF
 
+	stac
 	call memcpy
+	clac
 
 	xor %edi, %edi
 	mov %rdi, %gs:X86TASK_HANDLER_IP_OFF

diff --git a/src/arch/x86/sched/usermode.S b/src/arch/x86/sched/usermode.S
@@ -14,8 +14,12 @@
 
 x86_usermode_ret:
 	swapgs
+	// rip
 	pop %rcx
+	// arg
 	pop %rdi
+	// rsp
+	pop %rsp
 
 	xor %eax, %eax
 	xor %edx, %edx

diff --git a/src/arch/x86/sched/x86_task.c b/src/arch/x86/sched/x86_task.c
@@ -30,6 +30,7 @@ typedef struct {
 	void (*usermode_ret)();
 	void (*fn)(void*);
 	void* arg;
+	void* rsp;
 	u64 null_rbp;
 	u64 null_rip;
 } UserInitStackFrame;
@@ -81,14 +82,15 @@ Task* arch_create_user_task(Process* process, const char* name, void (*fn)(void*
 	u8* stack_base = stack;
 	memset(stack, 0, USER_STACK_SIZE);
 	task->stack_base = (usize) user_stack;
-	stack += USER_STACK_SIZE - sizeof(UserInitStackFrame);
-	user_stack += USER_STACK_SIZE - sizeof(UserInitStackFrame);
+	stack += USER_STACK_SIZE;
+	user_stack += USER_STACK_SIZE;
 
-	UserInitStackFrame* frame = (UserInitStackFrame*) stack;
+	UserInitStackFrame* frame = (UserInitStackFrame*) (task->kernel_rsp - sizeof(UserInitStackFrame));
 	frame->after_switch = x86_switch_from_init;
 	frame->usermode_ret = x86_usermode_ret;
 	frame->fn = fn;
 	frame->arg = arg;
+	frame->rsp = user_stack;
 	frame->null_rbp = 0;
 	frame->null_rip = 0;
 
@@ -97,7 +99,7 @@ Task* arch_create_user_task(Process* process, const char* name, void (*fn)(void*
 	strncpy(task->common.name, name, sizeof(task->common.name));
 	task->common.status = TASK_STATUS_READY;
 
-	task->rsp = (usize) user_stack;
+	task->rsp = (usize) frame;
 	task->common.level = SCHED_MAX_LEVEL - 1;
 	task->user = true;
 	task->common.priority = 0;

diff --git a/src/arch/x86/smp.c b/src/arch/x86/smp.c
@@ -109,6 +109,19 @@ static void init_simd() {
 
 	init_simd();
 
+	u64 cr4;
+	__asm__ volatile("mov %%cr4, %0" : "=r"(cr4));
+	if (CPU_FEATURES.umip) {
+		cr4 |= 1 << 11;
+	}
+	if (CPU_FEATURES.smep) {
+		cr4 |= 1 << 20;
+	}
+	if (CPU_FEATURES.smap) {
+		cr4 |= 1 << 21;
+	}
+	__asm__ volatile("mov %0, %%cr4" : : "r"(cr4));
+
 	lapic_init();
 	lapic_timer_init();
 
@@ -145,6 +158,16 @@ static void detect_cpu_features() {
 
 		CPU_FEATURES.xsave_area_size = cpuid(0xD, 0).ecx;
 	}
+	info = cpuid(7, 0);
+	if (info.ecx & 1 << 2) {
+		CPU_FEATURES.umip = true;
+	}
+	if (info.ebx & 1 << 7) {
+		CPU_FEATURES.smep = true;
+	}
+	if (info.ebx & 1 << 20) {
+		CPU_FEATURES.smap = true;
+	}
 }
 
 void arch_init_smp() {
@@ -180,6 +203,21 @@ void arch_init_smp() {
 	kprintf("[kernel][timer]: apic frequency %uhz\n", CPUS[0].lapic_timer.freq);
 
 	init_simd();
+	u64 cr4;
+	__asm__ volatile("mov %%cr4, %0" : "=r"(cr4));
+	if (CPU_FEATURES.umip) {
+		kprintf("[kernel][x86]: enabling UMIP\n");
+		cr4 |= 1 << 11;
+	}
+	if (CPU_FEATURES.smep) {
+		kprintf("[kernel][x86]: enabling SMEP\n");
+		cr4 |= 1 << 20;
+	}
+	if (CPU_FEATURES.smap) {
+		kprintf("[kernel][x86]: enabling SMAP\n");
+		cr4 |= 1 << 21;
+	}
+	__asm__ volatile("mov %0, %%cr4" : : "r"(cr4));
 
 	x86_init_usermode();
 	sched_init(true);