change copy-out routines

- restrict copy_to_user() to only current process.
- add write_process_vm() to write specified process space.

arch/x86/kernel/memory.c

@@ -2200,9 +2200,9 @@ int read_process_vm(struct process_vm *vm, void *kdst, const void *usrc, size_t
 	return 0;
 } /* read_process_vm() */
 
-int copy_to_user(struct process *proc, void *dst, const void *src, size_t siz)
+int copy_to_user(void *dst, const void *src, size_t siz)
 {
-	struct process_vm *vm = proc->vm;
+	struct process_vm *vm = cpu_local_var(current)->vm;
 	struct vm_range *range;
 	size_t pos;
 	size_t wsiz;
@@ -2229,3 +2229,56 @@ int copy_to_user(struct process *proc, void *dst, const void *src, size_t siz)
 	memcpy(dst, src, siz);
 	return 0;
 }
+
+int write_process_vm(struct process_vm *vm, void *udst, const void *ksrc, size_t siz)
+{
+	const uintptr_t ustart = (uintptr_t)udst;
+	const uintptr_t uend = ustart + siz;
+	uint64_t reason;
+	uintptr_t addr;
+	int error;
+	const void *from;
+	void *to;
+	size_t remain;
+	size_t cpsize;
+	unsigned long pa;
+	void *va;
+
+	if ((ustart < vm->region.user_start)
+			|| (vm->region.user_end <= ustart)
+			|| ((vm->region.user_end - ustart) < siz)) {
+		return -EFAULT;
+	}
+
+	reason = PF_POPULATE | PF_WRITE | PF_USER;
+	for (addr = ustart & PAGE_MASK; addr < uend; addr += PAGE_SIZE) {
+		error = page_fault_process_vm(vm, (void *)addr, reason);
+		if (error) {
+			return error;
+		}
+	}
+
+	from = ksrc;
+	to = udst;
+	remain = siz;
+	while (remain > 0) {
+		cpsize = PAGE_SIZE - ((uintptr_t)to & (PAGE_SIZE - 1));
+		if (cpsize > remain) {
+			cpsize = remain;
+		}
+
+		error = ihk_mc_pt_virt_to_phys(vm->page_table, to, &pa);
+		if (error) {
+			return error;
+		}
+
+		va = phys_to_virt(pa);
+		memcpy(va, from, cpsize);
+
+		from += cpsize;
+		to += cpsize;
+		remain -= cpsize;
+	}
+
+	return 0;
+} /* write_process_vm() */

arch/x86/kernel/syscall.c

@@ -26,7 +26,8 @@
 
 void terminate(int, int, ihk_mc_user_context_t *);
 int copy_from_user(void *dst, const void *src, size_t siz);
-int copy_to_user(struct process *proc, void *dst, const void *src, size_t siz);
+int copy_to_user(void *dst, const void *src, size_t siz);
+int write_process_vm(struct process_vm *vm, void *dst, const void *src, size_t siz);
 long do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact);
 
 //#define DEBUG_PRINT_SC
@@ -103,7 +104,6 @@ int obtain_clone_cpuid() {
 
 SYSCALL_DECLARE(rt_sigaction)
 {
-	struct process *proc = cpu_local_var(current);
 	int sig = ihk_mc_syscall_arg0(ctx);
 	const struct sigaction *act = (const struct sigaction *)ihk_mc_syscall_arg1(ctx);
 	struct sigaction *oact = (struct sigaction *)ihk_mc_syscall_arg2(ctx);
@@ -122,7 +122,7 @@ SYSCALL_DECLARE(rt_sigaction)
 		}
 	rc = do_sigaction(sig, act? &new_sa: NULL, oact? &old_sa: NULL);
 	if(rc == 0 && oact)
-		if(copy_to_user(proc, oact, &old_sa.sa, sizeof old_sa.sa)){
+		if(copy_to_user(oact, &old_sa.sa, sizeof old_sa.sa)){
 			goto fault;
 		}
 
@@ -474,11 +474,11 @@ do_signal(unsigned long rc, void *regs0, struct process *proc, struct sig_pendin
 		}
 		sigsp = ((struct sigsp *)usp) - 1;
 		sigsp = (struct sigsp *)((unsigned long)sigsp & 0xfffffffffffffff0UL);
-		if(copy_to_user(proc, &sigsp->regs, regs, sizeof(struct x86_user_context)) ||
-		   copy_to_user(proc, &sigsp->sigrc, &rc, sizeof(long))){
+		if(write_process_vm(proc->vm, &sigsp->regs, regs, sizeof(struct x86_user_context)) ||
+		   write_process_vm(proc->vm, &sigsp->sigrc, &rc, sizeof(long))){
 			kfree(pending);
 			ihk_mc_spinlock_unlock(&proc->sighandler->lock, irqstate);
-			kprintf("do_signal,copy_to_user failed\n");
+			kprintf("do_signal,write_process_vm failed\n");
 			terminate(0, sig, (ihk_mc_user_context_t *)regs->gpr.rsp);
 			return;
 		}