[PATCH V4 4/8] powerpc, ptrace: Enable fpr_(get/set) for transactional memory

From: Anshuman Khandual
Date: Tue Nov 11 2014 - 00:27:20 EST


This patch enables the fpr_get which gets the running value of all
the FPR registers and the fpr_set which sets the running value of
of all the FPR registers to accommodate in transaction ptrace
interface based requests.

Signed-off-by: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>
---
arch/powerpc/kernel/ptrace.c | 103 ++++++++++++++++++++++++++++++++++++++++---
1 file changed, 97 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index f21897b..fd36b32 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -357,6 +357,33 @@ static int gpr_set(struct task_struct *target, const struct user_regset *regset,
return ret;
}

+
+/*
+ * fpr_get
+ *
+ * When the transaction is active, 'transact_fp' holds the current running
+ * value of all FPR registers and 'fp_state' holds the last checkpointed
+ * value of all FPR registers for the current transaction. When transaction
+ * is not active 'fp_state' holds the current running state of all the FPR
+ * registers. So this function which returns the current running values of
+ * all the FPR registers, needs to know whether any transaction is active
+ * or not.
+ *
+ * Userspace interface buffer layout:
+ *
+ * struct data {
+ * u64 fpr[32];
+ * u64 fpscr;
+ * };
+ *
+ * There are two config options CONFIG_VSX and CONFIG_PPC_TRANSACTIONAL_MEM
+ * which determines the final code in this function. All the combinations of
+ * these two config options are possible except the one below as transactional
+ * memory config pulls in CONFIG_VSX automatically.
+ *
+ * !defined(CONFIG_VSX) && defined(CONFIG_PPC_TRANSACTIONAL_MEM)
+ *
+ */
static int fpr_get(struct task_struct *target, const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
@@ -367,22 +394,64 @@ static int fpr_get(struct task_struct *target, const struct user_regset *regset,
#endif
flush_fp_to_thread(target);

-#ifdef CONFIG_VSX
+#if defined(CONFIG_VSX) && defined(CONFIG_PPC_TRANSACTIONAL_MEM)
+ /* copy to local buffer then write that out */
+ if (MSR_TM_ACTIVE(target->thread.regs->msr)) {
+ flush_altivec_to_thread(target);
+ flush_tmregs_to_thread(target);
+ for (i = 0; i < 32 ; i++)
+ buf[i] = target->thread.TS_TRANS_FPR(i);
+ buf[32] = target->thread.transact_fp.fpscr;
+ } else {
+ for (i = 0; i < 32 ; i++)
+ buf[i] = target->thread.TS_FPR(i);
+ buf[32] = target->thread.fp_state.fpscr;
+ }
+ return user_regset_copyout(&pos, &count, &kbuf, &ubuf, buf, 0, -1);
+#endif
+
+#if defined(CONFIG_VSX) && !defined(CONFIG_PPC_TRANSACTIONAL_MEM)
/* copy to local buffer then write that out */
for (i = 0; i < 32 ; i++)
buf[i] = target->thread.TS_FPR(i);
buf[32] = target->thread.fp_state.fpscr;
return user_regset_copyout(&pos, &count, &kbuf, &ubuf, buf, 0, -1);
+#endif

-#else
+
+#if !defined(CONFIG_VSX) && !defined(CONFIG_PPC_TRANSACTIONAL_MEM)
BUILD_BUG_ON(offsetof(struct thread_fp_state, fpscr) !=
offsetof(struct thread_fp_state, fpr[32][0]));
-
return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
&target->thread.fp_state, 0, -1);
#endif
}

+/*
+ * fpr_set
+ *
+ * When the transaction is active, 'transact_fp' holds the current running
+ * value of all FPR registers and 'fp_state' holds the last checkpointed
+ * value of all FPR registers for the current transaction. When transaction
+ * is not active 'fp_state' holds the current running state of all the FPR
+ * registers. So this function which setss the current running values of
+ * all the FPR registers, needs to know whether any transaction is active
+ * or not.
+ *
+ * Userspace interface buffer layout:
+ *
+ * struct data {
+ * u64 fpr[32];
+ * u64 fpscr;
+ * };
+ *
+ * There are two config options CONFIG_VSX and CONFIG_PPC_TRANSACTIONAL_MEM
+ * which determines the final code in this function. All the combinations of
+ * these two config options are possible except the one below as transactional
+ * memory config pulls in CONFIG_VSX automatically.
+ *
+ * !defined(CONFIG_VSX) && defined(CONFIG_PPC_TRANSACTIONAL_MEM)
+ */
static int fpr_set(struct task_struct *target, const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
@@ -393,7 +462,27 @@ static int fpr_set(struct task_struct *target, const struct user_regset *regset,
#endif
flush_fp_to_thread(target);

-#ifdef CONFIG_VSX
+#if defined(CONFIG_VSX) && defined(CONFIG_PPC_TRANSACTIONAL_MEM)
+ /* copy to local buffer then write that out */
+ i = user_regset_copyin(&pos, &count, &kbuf, &ubuf, buf, 0, -1);
+ if (i)
+ return i;
+
+ if (MSR_TM_ACTIVE(target->thread.regs->msr)) {
+ flush_altivec_to_thread(target);
+ flush_tmregs_to_thread(target);
+ for (i = 0; i < 32 ; i++)
+ target->thread.TS_TRANS_FPR(i) = buf[i];
+ target->thread.transact_fp.fpscr = buf[32];
+ } else {
+ for (i = 0; i < 32 ; i++)
+ target->thread.TS_FPR(i) = buf[i];
+ target->thread.fp_state.fpscr = buf[32];
+ }
+ return 0;
+#endif
+
+#if defined(CONFIG_VSX) && !defined(CONFIG_PPC_TRANSACTIONAL_MEM)
/* copy to local buffer then write that out */
i = user_regset_copyin(&pos, &count, &kbuf, &ubuf, buf, 0, -1);
if (i)
@@ -402,12 +491,14 @@ static int fpr_set(struct task_struct *target, const struct user_regset *regset,
target->thread.TS_FPR(i) = buf[i];
target->thread.fp_state.fpscr = buf[32];
return 0;
-#else
+#endif
+
+#if !defined(CONFIG_VSX) && !defined(CONFIG_PPC_TRANSACTIONAL_MEM)
BUILD_BUG_ON(offsetof(struct thread_fp_state, fpscr) !=
offsetof(struct thread_fp_state, fpr[32][0]));
-
return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
&target->thread.fp_state, 0, -1);
+
#endif
}

--
1.9.3

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