powerpc/ptrace: Enable support for NT_PPC_CVSX

This patch enables support for TM checkpointed VSX register
set ELF core note NT_PPC_CVSX based ptrace requests through
PTRACE_GETREGSET, PTRACE_SETREGSET calls. This is achieved
through adding a register set REGSET_CVSX 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@linux.vnet.ibm.com>
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/include/uapi/asm/elf.h b/arch/powerpc/include/uapi/asm/elf.h
index ecb4e84..1549172 100644 (file)
--- a/arch/powerpc/include/uapi/asm/elf.h
+++ b/arch/powerpc/include/uapi/asm/elf.h
@@ -92,6 +92,7 @@
 #define ELF_NGREG      48      /* includes nip, msr, lr, etc. */
 #define ELF_NFPREG     33      /* includes fpscr */
 #define ELF_NVMX       34      /* includes all vector registers */
+#define ELF_NVSX       32      /* includes all VSX registers */
 
 typedef unsigned long elf_greg_t64;
 typedef elf_greg_t64 elf_gregset_t64[ELF_NGREG];

diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 6e42137..df6afe7 100644 (file)
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -65,6 +65,7 @@ struct pt_regs_offset {
 #define REG_OFFSET_END {.name = NULL, .offset = 0}
 
 #define TVSO(f)        (offsetof(struct thread_vr_state, f))
+#define TFSO(f)        (offsetof(struct thread_fp_state, f))
 
 static const struct pt_regs_offset regoffset_table[] = {
        GPR_OFFSET_NAME(0),
@@ -1294,6 +1295,123 @@ static int tm_cvmx_set(struct task_struct *target,
 
        return ret;
 }
+
+/**
+ * tm_cvsx_active - get active number of registers in CVSX
+ * @target:    The target task.
+ * @regset:    The user regset structure.
+ *
+ * This function checks for the active number of available
+ * regisers in transaction checkpointed VSX category.
+ */
+static int tm_cvsx_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;
+
+       flush_vsx_to_thread(target);
+       return target->thread.used_vsr ? regset->n : 0;
+}
+
+/**
+ * tm_cvsx_get - get CVSX 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 VSX 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 VSX registers.
+ * The userspace interface buffer layout is as follows.
+ *
+ * struct data {
+ *     u64     vsx[32];
+ *};
+ */
+static int tm_cvsx_get(struct task_struct *target,
+                       const struct user_regset *regset,
+                       unsigned int pos, unsigned int count,
+                       void *kbuf, void __user *ubuf)
+{
+       u64 buf[32];
+       int ret, i;
+
+       if (!cpu_has_feature(CPU_FTR_TM))
+               return -ENODEV;
+
+       if (!MSR_TM_ACTIVE(target->thread.regs->msr))
+               return -ENODATA;
+
+       /* Flush the state */
+       flush_fp_to_thread(target);
+       flush_altivec_to_thread(target);
+       flush_tmregs_to_thread(target);
+       flush_vsx_to_thread(target);
+
+       for (i = 0; i < 32 ; i++)
+               buf[i] = target->thread.fp_state.fpr[i][TS_VSRLOWOFFSET];
+       ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+                                 buf, 0, 32 * sizeof(double));
+
+       return ret;
+}
+
+/**
+ * tm_cvsx_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 VSX registers.
+ *
+ * When the transaction is active 'fp_state' holds the checkpointed
+ * VSX 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     vsx[32];
+ *};
+ */
+static int tm_cvsx_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[32];
+       int ret, i;
+
+       if (!cpu_has_feature(CPU_FTR_TM))
+               return -ENODEV;
+
+       if (!MSR_TM_ACTIVE(target->thread.regs->msr))
+               return -ENODATA;
+
+       /* Flush the state */
+       flush_fp_to_thread(target);
+       flush_altivec_to_thread(target);
+       flush_tmregs_to_thread(target);
+       flush_vsx_to_thread(target);
+
+       ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+                                buf, 0, 32 * sizeof(double));
+       for (i = 0; i < 32 ; i++)
+               target->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = buf[i];
+
+       return ret;
+}
 #endif
 
 /*
@@ -1315,6 +1433,7 @@ enum powerpc_regset {
        REGSET_TM_CGPR,         /* TM checkpointed GPR registers */
        REGSET_TM_CFPR,         /* TM checkpointed FPR registers */
        REGSET_TM_CVMX,         /* TM checkpointed VMX registers */
+       REGSET_TM_CVSX,         /* TM checkpointed VSX registers */
 #endif
 };
 
@@ -1366,6 +1485,11 @@ static const struct user_regset native_regsets[] = {
                .size = sizeof(vector128), .align = sizeof(vector128),
                .active = tm_cvmx_active, .get = tm_cvmx_get, .set = tm_cvmx_set
        },
+       [REGSET_TM_CVSX] = {
+               .core_note_type = NT_PPC_TM_CVSX, .n = ELF_NVSX,
+               .size = sizeof(double), .align = sizeof(double),
+               .active = tm_cvsx_active, .get = tm_cvsx_get, .set = tm_cvsx_set
+       },
 #endif
 };
 
@@ -1608,6 +1732,11 @@ static const struct user_regset compat_regsets[] = {
                .size = sizeof(vector128), .align = sizeof(vector128),
                .active = tm_cvmx_active, .get = tm_cvmx_get, .set = tm_cvmx_set
        },
+       [REGSET_TM_CVSX] = {
+               .core_note_type = NT_PPC_TM_CVSX, .n = ELF_NVSX,
+               .size = sizeof(double), .align = sizeof(double),
+               .active = tm_cvsx_active, .get = tm_cvsx_get, .set = tm_cvsx_set
+       },
 #endif
 };