[PATCH V10 08/28] powerpc, ptrace: Enable support for NT_PPC_CFPR

From: Anshuman Khandual
Date: Tue Feb 16 2016 - 04:15:17 EST


This patch enables support for TM checkpointed FPR register
set ELF core note NT_PPC_CFPR based ptrace requests through
PTRACE_GETREGSET, PTRACE_SETREGSET calls. This is achieved
through adding a register set REGSET_CFPR in powerpc
corresponding to the ELF core note section added. It
implements the get, set and active functions for this new
register set added.

Signed-off-by: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>
---
arch/powerpc/kernel/ptrace.c | 126 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 126 insertions(+)

diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 8462c7e..13b3ec6 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -1032,6 +1032,121 @@ static int tm_cgpr_set(struct task_struct *target,

return ret;
}
+
+/**
+ * tm_cfpr_active - get active number of registers in CFPR
+ * @target: The target task.
+ * @regset: The user regset structure.
+ *
+ * This function checks for the active number of available
+ * regisers in transaction checkpointed FPR category.
+ */
+static int tm_cfpr_active(struct task_struct *target,
+ const struct user_regset *regset)
+{
+ if (!cpu_has_feature(CPU_FTR_TM))
+ return -ENODEV;
+
+ if (!MSR_TM_ACTIVE(target->thread.regs->msr))
+ return 0;
+
+ return regset->n;
+}
+
+/**
+ * tm_cfpr_get - get CFPR registers
+ * @target: The target task.
+ * @regset: The user regset structure.
+ * @pos: The buffer position.
+ * @count: Number of bytes to copy.
+ * @kbuf: Kernel buffer to copy from.
+ * @ubuf: User buffer to copy into.
+ *
+ * This function gets in transaction checkpointed FPR registers.
+ *
+ * When the transaction is active 'fp_state' holds the checkpointed
+ * values for the current transaction to fall back on if it aborts
+ * in between. This function gets those checkpointed FPR registers.
+ * The userspace interface buffer layout is as follows.
+ *
+ * struct data {
+ * u64 fpr[32];
+ * u64 fpscr;
+ *};
+ */
+static int tm_cfpr_get(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ void *kbuf, void __user *ubuf)
+{
+ u64 buf[33];
+ int i;
+
+ if (!cpu_has_feature(CPU_FTR_TM))
+ return -ENODEV;
+
+ if (!MSR_TM_ACTIVE(target->thread.regs->msr))
+ return -ENODATA;
+
+ flush_fp_to_thread(target);
+ flush_altivec_to_thread(target);
+ flush_tmregs_to_thread(target);
+
+ /* 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);
+}
+
+/**
+ * tm_cfpr_set - set CFPR registers
+ * @target: The target task.
+ * @regset: The user regset structure.
+ * @pos: The buffer position.
+ * @count: Number of bytes to copy.
+ * @kbuf: Kernel buffer to copy into.
+ * @ubuf: User buffer to copy from.
+ *
+ * This function sets in transaction checkpointed FPR registers.
+ *
+ * When the transaction is active 'fp_state' holds the checkpointed
+ * FPR register values for the current transaction to fall back on
+ * if it aborts in between. This function sets these checkpointed
+ * FPR registers. The userspace interface buffer layout is as follows.
+ *
+ * struct data {
+ * u64 fpr[32];
+ * u64 fpscr;
+ *};
+ */
+static int tm_cfpr_set(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ const void *kbuf, const void __user *ubuf)
+{
+ u64 buf[33];
+ int i;
+
+ if (!cpu_has_feature(CPU_FTR_TM))
+ return -ENODEV;
+
+ if (!MSR_TM_ACTIVE(target->thread.regs->msr))
+ return -ENODATA;
+
+ flush_fp_to_thread(target);
+ flush_altivec_to_thread(target);
+ flush_tmregs_to_thread(target);
+
+ /* copy to local buffer then write that out */
+ i = user_regset_copyin(&pos, &count, &kbuf, &ubuf, buf, 0, -1);
+ if (i)
+ return i;
+ for (i = 0; i < 32 ; i++)
+ target->thread.TS_FPR(i) = buf[i];
+ target->thread.fp_state.fpscr = buf[32];
+ return 0;
+}
#endif

/*
@@ -1051,6 +1166,7 @@ enum powerpc_regset {
#endif
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
REGSET_TM_CGPR, /* TM checkpointed GPR registers */
+ REGSET_TM_CFPR, /* TM checkpointed FPR registers */
#endif
};

@@ -1092,6 +1208,11 @@ static const struct user_regset native_regsets[] = {
.size = sizeof(long), .align = sizeof(long),
.active = tm_cgpr_active, .get = tm_cgpr_get, .set = tm_cgpr_set
},
+ [REGSET_TM_CFPR] = {
+ .core_note_type = NT_PPC_TM_CFPR, .n = ELF_NFPREG,
+ .size = sizeof(double), .align = sizeof(double),
+ .active = tm_cfpr_active, .get = tm_cfpr_get, .set = tm_cfpr_set
+ },
#endif
};

@@ -1324,6 +1445,11 @@ static const struct user_regset compat_regsets[] = {
.active = tm_cgpr_active,
.get = tm_cgpr32_get, .set = tm_cgpr32_set
},
+ [REGSET_TM_CFPR] = {
+ .core_note_type = NT_PPC_TM_CFPR, .n = ELF_NFPREG,
+ .size = sizeof(double), .align = sizeof(double),
+ .active = tm_cfpr_active, .get = tm_cfpr_get, .set = tm_cfpr_set
+ },
#endif
};

--
2.1.0