1 files changed, 115 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/ptrace/ptrace-altivec.c b/arch/powerpc/kernel/ptrace/ptrace-altivec.c
new file mode 100644
index 000000000000..0d9bc4bd4972
--- /dev/null
+++ b/arch/powerpc/kernel/ptrace/ptrace-altivec.c
@@ -0,0 +1,115 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/regset.h>
+#include <linux/elf.h>
+
+#include <asm/switch_to.h>
+
+#include "ptrace-decl.h"
+
+/*
+ * Get/set all the altivec registers vr0..vr31, vscr, vrsave, in one go.
+ * The transfer totals 34 quadword.  Quadwords 0-31 contain the
+ * corresponding vector registers.  Quadword 32 contains the vscr as the
+ * last word (offset 12) within that quadword.  Quadword 33 contains the
+ * vrsave as the first word (offset 0) within the quadword.
+ *
+ * This definition of the VMX state is compatible with the current PPC32
+ * ptrace interface.  This allows signal handling and ptrace to use the
+ * same structures.  This also simplifies the implementation of a bi-arch
+ * (combined (32- and 64-bit) gdb.
+ */
+
+int vr_active(struct task_struct *target, const struct user_regset *regset)
+{
+	flush_altivec_to_thread(target);
+	return target->thread.used_vr ? regset->n : 0;
+}
+
+/*
+ * Regardless of transactions, 'vr_state' holds the current running
+ * value of all the VMX registers and 'ckvr_state' holds the last
+ * checkpointed value of all the VMX registers for the current
+ * transaction to fall back on in case it aborts.
+ *
+ * Userspace interface buffer layout:
+ *
+ * struct data {
+ *	vector128	vr[32];
+ *	vector128	vscr;
+ *	vector128	vrsave;
+ * };
+ */
+int vr_get(struct task_struct *target, const struct user_regset *regset,
+	   struct membuf to)
+{
+	union {
+		elf_vrreg_t reg;
+		u32 word;
+	} vrsave;
+
+	flush_altivec_to_thread(target);
+
+	BUILD_BUG_ON(offsetof(struct thread_vr_state, vscr) !=
+		     offsetof(struct thread_vr_state, vr[32]));
+
+	membuf_write(&to, &target->thread.vr_state, 33 * sizeof(vector128));
+	/*
+	 * Copy out only the low-order word of vrsave.
+	 */
+	memset(&vrsave, 0, sizeof(vrsave));
+	vrsave.word = target->thread.vrsave;
+	return membuf_write(&to, &vrsave, sizeof(vrsave));
+}
+
+/*
+ * Regardless of transactions, 'vr_state' holds the current running
+ * value of all the VMX registers and 'ckvr_state' holds the last
+ * checkpointed value of all the VMX registers for the current
+ * transaction to fall back on in case it aborts.
+ *
+ * Userspace interface buffer layout:
+ *
+ * struct data {
+ *	vector128	vr[32];
+ *	vector128	vscr;
+ *	vector128	vrsave;
+ * };
+ */
+int vr_set(struct task_struct *target, const struct user_regset *regset,
+	   unsigned int pos, unsigned int count,
+	   const void *kbuf, const void __user *ubuf)
+{
+	int ret;
+
+	flush_altivec_to_thread(target);
+
+	BUILD_BUG_ON(offsetof(struct thread_vr_state, vscr) !=
+		     offsetof(struct thread_vr_state, vr[32]));
+
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				 &target->thread.vr_state, 0,
+				 33 * sizeof(vector128));
+	if (!ret && count > 0) {
+		/*
+		 * We use only the first word of vrsave.
+		 */
+		int start, end;
+		union {
+			elf_vrreg_t reg;
+			u32 word;
+		} vrsave;
+		memset(&vrsave, 0, sizeof(vrsave));
+
+		vrsave.word = target->thread.vrsave;
+
+		start = 33 * sizeof(vector128);
+		end = start + sizeof(vrsave);
+		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &vrsave,
+					 start, end);
+		if (!ret)
+			target->thread.vrsave = vrsave.word;
+	}
+
+	return ret;
+}