powerpc/ptrace: Enable support for NT_PPPC_TAR, NT_PPC_PPR, NT_PPC_DSCR

This patch enables support for running TAR, PPR, DSCR registers
related ELF core notes NT_PPPC_TAR, NT_PPC_PPR, NT_PPC_DSCR based
ptrace requests through PTRACE_GETREGSET, PTRACE_SETREGSET calls.
This is achieved through adding three new register sets REGSET_TAR,
REGSET_PPR, REGSET_DSCR in powerpc corresponding to the ELF core
note sections added in this regad. It implements the get, set and
active functions for all these new register sets added.
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/ptrace.c

@@ -1689,6 +1689,78 @@ static int tm_dscr_set(struct task_struct *target,
 }
 #endif	/* CONFIG_PPC_TRANSACTIONAL_MEM */
 
+#ifdef CONFIG_PPC64
+static int ppr_get(struct task_struct *target,
+		      const struct user_regset *regset,
+		      unsigned int pos, unsigned int count,
+		      void *kbuf, void __user *ubuf)
+{
+	int ret;
+
+	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+				&target->thread.ppr, 0, sizeof(u64));
+	return ret;
+}
+
+static int ppr_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;
+
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				&target->thread.ppr, 0, sizeof(u64));
+	return ret;
+}
+
+static int dscr_get(struct task_struct *target,
+		      const struct user_regset *regset,
+		      unsigned int pos, unsigned int count,
+		      void *kbuf, void __user *ubuf)
+{
+	int ret;
+
+	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+				&target->thread.dscr, 0, sizeof(u64));
+	return ret;
+}
+static int dscr_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;
+
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				&target->thread.dscr, 0, sizeof(u64));
+	return ret;
+}
+#endif
+#ifdef CONFIG_PPC_BOOK3S_64
+static int tar_get(struct task_struct *target,
+		      const struct user_regset *regset,
+		      unsigned int pos, unsigned int count,
+		      void *kbuf, void __user *ubuf)
+{
+	int ret;
+
+	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+				&target->thread.tar, 0, sizeof(u64));
+	return ret;
+}
+static int tar_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;
+
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				&target->thread.tar, 0, sizeof(u64));
+	return ret;
+}
+#endif
 /*
  * These are our native regset flavors.
  */
@@ -1714,6 +1786,13 @@ enum powerpc_regset {
 	REGSET_TM_CPPR,		/* TM checkpointed PPR register */
 	REGSET_TM_CDSCR,	/* TM checkpointed DSCR register */
 #endif
+#ifdef CONFIG_PPC64
+	REGSET_PPR,		/* PPR register */
+	REGSET_DSCR,		/* DSCR register */
+#endif
+#ifdef CONFIG_PPC_BOOK3S_64
+	REGSET_TAR,		/* TAR register */
+#endif
 };
 
 static const struct user_regset native_regsets[] = {
@@ -1790,6 +1869,25 @@ static const struct user_regset native_regsets[] = {
 		.active = tm_dscr_active, .get = tm_dscr_get, .set = tm_dscr_set
 	},
 #endif
+#ifdef CONFIG_PPC64
+	[REGSET_PPR] = {
+		.core_note_type = NT_PPC_PPR, .n = 1,
+		.size = sizeof(u64), .align = sizeof(u64),
+		.get = ppr_get, .set = ppr_set
+	},
+	[REGSET_DSCR] = {
+		.core_note_type = NT_PPC_DSCR, .n = 1,
+		.size = sizeof(u64), .align = sizeof(u64),
+		.get = dscr_get, .set = dscr_set
+	},
+#endif
+#ifdef CONFIG_PPC_BOOK3S_64
+	[REGSET_TAR] = {
+		.core_note_type = NT_PPC_TAR, .n = 1,
+		.size = sizeof(u64), .align = sizeof(u64),
+		.get = tar_get, .set = tar_set
+	},
+#endif
 };
 
 static const struct user_regset_view user_ppc_native_view = {
@@ -2057,6 +2155,25 @@ static const struct user_regset compat_regsets[] = {
 		.active = tm_dscr_active, .get = tm_dscr_get, .set = tm_dscr_set
 	},
 #endif
+#ifdef CONFIG_PPC64
+	[REGSET_PPR] = {
+		.core_note_type = NT_PPC_PPR, .n = 1,
+		.size = sizeof(u64), .align = sizeof(u64),
+		.get = ppr_get, .set = ppr_set
+	},
+	[REGSET_DSCR] = {
+		.core_note_type = NT_PPC_DSCR, .n = 1,
+		.size = sizeof(u64), .align = sizeof(u64),
+		.get = dscr_get, .set = dscr_set
+	},
+#endif
+#ifdef CONFIG_PPC_BOOK3S_64
+	[REGSET_TAR] = {
+		.core_note_type = NT_PPC_TAR, .n = 1,
+		.size = sizeof(u64), .align = sizeof(u64),
+		.get = tar_get, .set = tar_set
+	},
+#endif
 };
 
 static const struct user_regset_view user_ppc_compat_view = {