fork: fpregs: return error code.

Change-Id: I6ff150a39cd8952adad9b21d0c9f8514126ef957

arch/arm64/kernel/cpu.c

@@ -1,4 +1,4 @@
-/* cpu.c COPYRIGHT FUJITSU LIMITED 2015-2018 */
+/* cpu.c COPYRIGHT FUJITSU LIMITED 2015-2019 */
 #include <ihk/cpu.h>
 #include <ihk/mm.h>
 #include <types.h>
@@ -1240,7 +1240,6 @@ err:
 }
 
 static int check_and_allocate_fp_regs(struct thread *thread);
-void save_fp_regs(struct thread *thread);
 
 void arch_clone_thread(struct thread *othread, unsigned long pc,
 			unsigned long sp, struct thread *nthread)
@@ -1481,8 +1480,7 @@ check_and_allocate_fp_regs(struct thread *thread)
 
 		if (!thread->fp_regs) {
 			kprintf("error: allocating fp_regs pages\n");
-			result = 1;
-			panic("panic: error allocating fp_regs pages");
+			result = -ENOMEM;
 			goto out;
 		}
 
@@ -1491,37 +1489,51 @@ check_and_allocate_fp_regs(struct thread *thread)
 
 #ifdef CONFIG_ARM64_SVE
 	if (likely(elf_hwcap & HWCAP_SVE)) {
-		sve_alloc(thread);
+		result = sve_alloc(thread);
 	}
 #endif /* CONFIG_ARM64_SVE */
 out:
+	if (result) {
+		release_fp_regs(thread);
+	}
 	return result;
 }
 
 /*@
   @ requires \valid(thread);
   @*/
-void
+int
 save_fp_regs(struct thread *thread)
 {
+	int ret = 0;
 	if (thread == &cpu_local_var(idle)) {
-		return;
+		goto out;
 	}
 
 	if (likely(elf_hwcap & (HWCAP_FP | HWCAP_ASIMD))) {
-		if (check_and_allocate_fp_regs(thread) != 0) {
-			// alloc error.
-			return;
+		ret = check_and_allocate_fp_regs(thread);
+		if (ret) {
+			goto out;
 		}
 		thread_fpsimd_save(thread);
 	}
+out:
+	return ret;
 }
 
-void copy_fp_regs(struct thread *from, struct thread *to)
+int copy_fp_regs(struct thread *from, struct thread *to)
 {
-	if ((from->fp_regs != NULL) && (check_and_allocate_fp_regs(to) == 0)) {
-		memcpy(to->fp_regs, from->fp_regs, sizeof(fp_regs_struct));
+	int ret = 0;
+
+	if (from->fp_regs != NULL) {
+		ret = check_and_allocate_fp_regs(to);
+		if (!ret) {
+			memcpy(to->fp_regs,
+			       from->fp_regs,
+			       sizeof(fp_regs_struct));
+		}
 	}
+	return ret;
 }
 
 void clear_fp_regs(void)

arch/arm64/kernel/fpsimd.c

@@ -119,17 +119,19 @@ void sve_free(struct thread *thread)
 	}
 }
 
-void sve_alloc(struct thread *thread)
+int sve_alloc(struct thread *thread)
 {
 	if (thread->ctx.thread->sve_state) {
-		return;
+		return 0;
 	}
 
 	thread->ctx.thread->sve_state =
 		kmalloc(sve_state_size(thread), IHK_MC_AP_NOWAIT);
-	BUG_ON(!thread->ctx.thread->sve_state);
-
+	if (thread->ctx.thread->sve_state == NULL) {
+		return -ENOMEM;
+	}
 	memset(thread->ctx.thread->sve_state, 0, sve_state_size(thread));
+	return 0;
 }
 
 static int get_nr_threads(struct process *proc)

arch/arm64/kernel/include/fpsimd.h

@@ -42,7 +42,7 @@ extern void thread_sve_to_fpsimd(struct thread *thread, fp_regs_struct *fp_regs)
 
 extern size_t sve_state_size(struct thread const *thread);
 extern void sve_free(struct thread *thread);
-extern void sve_alloc(struct thread *thread);
+extern int sve_alloc(struct thread *thread);
 extern void sve_save_state(void *state, unsigned int *pfpsr);
 extern void sve_load_state(void const *state, unsigned int const *pfpsr, unsigned long vq_minus_1);
 extern unsigned int sve_get_vl(void);

arch/x86_64/kernel/cpu.c

@@ -1,4 +1,4 @@
-/* cpu.c COPYRIGHT FUJITSU LIMITED 2018 */
+/* cpu.c COPYRIGHT FUJITSU LIMITED 2018-2019 */
 /**
  * \file cpu.c
  *  License details are found in the file LICENSE.
@@ -1709,7 +1709,7 @@ check_and_allocate_fp_regs(struct thread *thread)
 
 		if (!thread->fp_regs) {
 			kprintf("error: allocating fp_regs pages\n");
-			result = 1;
+			result = -ENOMEM;
 			goto out;
 		}
 
@@ -1722,12 +1722,14 @@ out:
 /*@
   @ requires \valid(thread);
   @*/
-void
+int
 save_fp_regs(struct thread *thread)
 {
-	if (check_and_allocate_fp_regs(thread) != 0) {
-		// alloc error
-		return;
+	int ret = 0;
+
+	ret = check_and_allocate_fp_regs(thread);
+	if (ret) {
+		goto out;
 	}
 
 	if (xsave_available) {
@@ -1742,13 +1744,23 @@ save_fp_regs(struct thread *thread)
 
 		dkprintf("fp_regs for TID %d saved\n", thread->tid);
 	}
+out:
+	return ret;
 }
 
-void copy_fp_regs(struct thread *from, struct thread *to)
+int copy_fp_regs(struct thread *from, struct thread *to)
 {
-	if ((from->fp_regs != NULL) && (check_and_allocate_fp_regs(to) == 0)) {
-		memcpy(to->fp_regs, from->fp_regs, sizeof(fp_regs_struct));
+	int ret = 0;
+
+	if (from->fp_regs != NULL) {
+		ret = check_and_allocate_fp_regs(to);
+		if (!ret) {
+			memcpy(to->fp_regs,
+				from->fp_regs,
+				sizeof(fp_regs_struct));
+		}
 	}
+	return ret;
 }
 
 /*@

kernel/include/process.h

@@ -9,7 +9,7 @@
 /*
  * HISTORY
  */
-/* process.h COPYRIGHT FUJITSU LIMITED 2015-2018 */
+/* process.h COPYRIGHT FUJITSU LIMITED 2015-2019 */
 
 #ifndef HEADER_PROCESS_H
 #define HEADER_PROCESS_H
@@ -914,8 +914,8 @@ extern void check_sig_pending(void);
 void clear_single_step(struct thread *thread);
 
 void release_fp_regs(struct thread *proc);
-void save_fp_regs(struct thread *proc);
-void copy_fp_regs(struct thread *from, struct thread *to);
+int save_fp_regs(struct thread *proc);
+int copy_fp_regs(struct thread *from, struct thread *to);
 void restore_fp_regs(struct thread *proc);
 void clear_fp_regs(void);