On 11/19/2014 02:48 AM, Sukadev Bhattiprolu wrote:
> Anshuman Khandual [khand...@linux.vnet.ibm.com] wrote:
> | This patch enables get and set of transactional memory related register
> | sets through PTRACE_GETREGSET-PTRACE_SETREGSET interface by implementing
> | four new powerpc specific register sets i.e REGSET_TM_SPR, REGSET_TM_CGPR,
> | REGSET_TM_CFPR, REGSET_CVMX support corresponding to these following new
> | ELF core note types added previously in this regard.
> | 
> |     (1) NT_PPC_TM_SPR
> |     (2) NT_PPC_TM_CGPR
> |     (3) NT_PPC_TM_CFPR
> |     (4) NT_PPC_TM_CVMX
> | 
> | Signed-off-by: Anshuman Khandual <khand...@linux.vnet.ibm.com>
> | ---
> |  arch/powerpc/include/uapi/asm/elf.h |   2 +
> |  arch/powerpc/kernel/ptrace.c        | 666 
> +++++++++++++++++++++++++++++++++++-
> |  2 files changed, 653 insertions(+), 15 deletions(-)
> | 
> | diff --git a/arch/powerpc/include/uapi/asm/elf.h 
> b/arch/powerpc/include/uapi/asm/elf.h
> | index 59dad11..fdc8e2f 100644
> | --- a/arch/powerpc/include/uapi/asm/elf.h
> | +++ b/arch/powerpc/include/uapi/asm/elf.h
> | @@ -91,6 +91,8 @@
> | 
> |  #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_NTMSPRREG      7       /* includes TM sprs, org_msr, dscr, 
> tar, ppr */
> | 
> |  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 2bbbd10..b279947 100644
> | --- a/arch/powerpc/kernel/ptrace.c
> | +++ b/arch/powerpc/kernel/ptrace.c
> | @@ -63,6 +63,11 @@ struct pt_regs_offset {
> |     {.name = STR(gpr##num), .offset = offsetof(struct pt_regs, gpr[num])}
> |  #define REG_OFFSET_END {.name = NULL, .offset = 0}
> | 
> | +/* Some common structure offsets */
> | +#define TSO(f)     (offsetof(struct thread_struct, f))
> | +#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),
> |     GPR_OFFSET_NAME(1),
> | @@ -792,6 +797,534 @@ static int evr_set(struct task_struct *target, const 
> struct user_regset *regset,
> |  }
> |  #endif /* CONFIG_SPE */
> | 
> | +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> | +/*
> | + * tm_spr_active
> | + *
> | + * This function checks number of available regisers in
> | + * the transactional memory SPR category.
> | + */
> | +static int tm_spr_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_spr_get
> | + *
> | + * This function gets transactional memory related SPR registers
> | + *
> | + * Userspace interface buffer layout:
> | + *
> | + * struct {
> | + * u64             tm_tfhar;
> | + * u64             tm_texasr;
> | + * u64             tm_tfiar;
> | + * unsigned long   tm_orig_msr;
> | + * unsigned long   tm_tar;
> | + * unsigned long   tm_ppr;
> | + * unsigned long   tm_dscr;
> | + * };
> | + */
> | +static int tm_spr_get(struct task_struct *target,
> | +                 const struct user_regset *regset,
> | +                 unsigned int pos, unsigned int count,
> | +                 void *kbuf, void __user *ubuf)
> | +{
> | +   int ret;
> | +
> | +   /* Build tests */
> | +   BUILD_BUG_ON(TSO(tm_tfhar) + sizeof(u64) != TSO(tm_texasr));
> | +   BUILD_BUG_ON(TSO(tm_texasr) + sizeof(u64) != TSO(tm_tfiar));
> | +   BUILD_BUG_ON(TSO(tm_tfiar) + sizeof(u64) != TSO(tm_orig_msr));
> | +   BUILD_BUG_ON(TSO(tm_orig_msr) + sizeof(unsigned long) +
> Can we replace TSO(tm_orig_msr) + sizeof(unsigned long) with
> TSO(ckpt_regs) ?

Yeah we can.

> | +                           sizeof(struct pt_regs) != TSO(tm_tar));
> | +   BUILD_BUG_ON(TSO(tm_tar) + sizeof(unsigned long) != TSO(tm_ppr));
> | +   BUILD_BUG_ON(TSO(tm_ppr) + sizeof(unsigned long) != TSO(tm_dscr));
> | +
> | +   if (!cpu_has_feature(CPU_FTR_TM))
> | +           return -ENODEV;
> | +
> | +   if (!MSR_TM_ACTIVE(target->thread.regs->msr))
> | +           return -ENODATA;
> | +
> | +   /* Flush the states */
> | +   flush_fp_to_thread(target);
> | +   flush_altivec_to_thread(target);
> | +   flush_tmregs_to_thread(target);
> | +
> | +   /* TFHAR register */
> | +   ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> | +                           &target->thread.tm_tfhar, 0, sizeof(u64));
> 
> The last two parameters, (start_pos, end_pos) are easy to understand
> here, but...

Okay.

> 
> | +
> | +   /* TEXASR register */
> | +   if (!ret)
> | +           ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> | +                           &target->thread.tm_texasr, sizeof(u64),
> | +                           2 * sizeof(u64));
> 
> ... gets harder to understand here and subsequent fields below.
> 
> Given that you already do the BUILD_BUG_ON() tests above, how about
> using TSO(tm_texasr) and TSO(tfiar) here for start_pos and end_pos ?

Hmm, I understand that as it looks kind of ugly, but writing to/from
the user level buffer is done looking at the user interface buffer
structure layout mentioned below.

 * struct {
 *      u64             tm_tfhar;
 *      u64             tm_texasr;
 *      u64             tm_tfiar;
 *      unsigned long   tm_orig_msr;
 *      unsigned long   tm_tar;
 *      unsigned long   tm_ppr;
 *      unsigned long   tm_dscr;
 * };

Looking at this structure will help some one understand the copy in/out
process and it's order better.
 
> 
> Also, how about just returning if the copyout fails ?  If the first
> copyout fails, we will still check 'if(!ret)' several times below.

Hmm, thats true. But the code flow is very similar to that of gpr_get/
gpr_set functions though it has a BUILD_BUG_ON check in between. The
rational is to stop copyout/in when we hit the first error and not to 
proceed any further. We can return from the first error itself.

> 
> | +
> | +   /* TFIAR register */
> | +   if (!ret)
> | +           ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> | +                           &target->thread.tm_tfiar,
> | +                           2 * sizeof(u64), 3 * sizeof(u64));
> | +
> | +   /* TM checkpointed original MSR */
> | +   if (!ret)
> | +           ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> | +                           &target->thread.tm_orig_msr, 3 * sizeof(u64),
> | +                           3 * sizeof(u64) + sizeof(unsigned long));
> | +
> | +   /* TM checkpointed TAR register */
> | +   if (!ret)
> | +           ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> | +                           &target->thread.tm_tar, 3 * sizeof(u64) +
> | +                           sizeof(unsigned long) ,
> | +                           3 * sizeof(u64) + 2 * sizeof(unsigned long));
> | +
> | +   /* TM checkpointed PPR register */
> | +   if (!ret)
> | +           ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> | +                           &target->thread.tm_ppr, 3 * sizeof(u64) +
> | +                           2 * sizeof(unsigned long),
> | +                           3 * sizeof(u64) + 3 * sizeof(unsigned long));
> | +
> | +   /* TM checkpointed DSCR register */
> | +   if (!ret)
> | +           ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> | +                           &target->thread.tm_dscr, 3 * sizeof(u64) +
> | +                           3 * sizeof(unsigned long),
> | +                           3 * sizeof(u64) + 4 * sizeof(unsigned long));
> | +   return ret;
> | +}
> | +
> | +/*
> | + * tm_spr_set
> | + *
> | + * This function sets transactional memory related SPR registers
> | + *
> | + * Userspace interface buffer layout:
> | + *
> | + * struct {
> | + * u64             tm_tfhar;
> | + * u64             tm_texasr;
> | + * u64             tm_tfiar;
> | + * unsigned long   tm_orig_msr;
> | + * unsigned long   tm_tar;
> | + * unsigned long   tm_ppr;
> | + * unsigned long   tm_dscr;
> | + * };
> | + */
> | +static int tm_spr_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;
> | +
> | +   /* Build tests */
> | +   BUILD_BUG_ON(TSO(tm_tfhar) + sizeof(u64) != TSO(tm_texasr));
> | +   BUILD_BUG_ON(TSO(tm_texasr) + sizeof(u64) != TSO(tm_tfiar));
> | +   BUILD_BUG_ON(TSO(tm_orig_msr) + sizeof(unsigned long)
> 
> Can we replace TSO(tm_orig_msr) + sizeof(unsigned long) with
> TSO(ckpt_regs) ?

Yeah we can.

> 
> | +                           + sizeof(struct pt_regs) != TSO(tm_tar));
> | +   BUILD_BUG_ON(TSO(tm_tar) + sizeof(unsigned long) != TSO(tm_ppr));
> | +   BUILD_BUG_ON(TSO(tm_ppr) + sizeof(unsigned long) != TSO(tm_dscr));
> | +   BUILD_BUG_ON(TSO(tm_tfiar) + sizeof(u64) != TSO(tm_orig_msr));
> 
> How about moving this last line up after the check for TSO(tm_tfiar) ?

Done.

> | +
> | +   if (!cpu_has_feature(CPU_FTR_TM))
> | +           return -ENODEV;
> | +
> | +   if (!MSR_TM_ACTIVE(target->thread.regs->msr))
> | +           return -ENODATA;
> | +
> | +   /* Flush the states */
> | +   flush_fp_to_thread(target);
> | +   flush_altivec_to_thread(target);
> | +   flush_tmregs_to_thread(target);
> | +
> | +   /* TFHAR register */
> | +   ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
> | +                           &target->thread.tm_tfhar, 0, sizeof(u64));
> | +
> | +   /* TEXASR register */
> | +   if (!ret)
> | +           ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
> | +                           &target->thread.tm_texasr, sizeof(u64),
> | +                           2 * sizeof(u64));
> 
> Return if copyin() fails ?

Yeah both the cases are similar.

> 
> | +
> | +   /* TFIAR register */
> | +   if (!ret)
> | +           ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
> | +                           &target->thread.tm_tfiar,
> | +                            2 * sizeof(u64), 3 * sizeof(u64));
> | +
> | +
> | +   /* TM checkpointed orig MSR */
> | +   if (!ret)
> | +           ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
> | +                           &target->thread.tm_orig_msr, 3 * sizeof(u64),
> | +                           3 * sizeof(u64) + sizeof(unsigned long));
> | +
> | +
> | +   /* TM checkpointed TAR register */
> | +   if (!ret)
> | +           ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
> | +                           &target->thread.tm_tar, 3 * sizeof(u64) +
> | +                           sizeof(unsigned long), 3 * sizeof(u64) +
> | +                           2 * sizeof(unsigned long));
> | +
> | +   /* TM checkpointed PPR register */
> | +   if (!ret)
> | +           ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
> | +                           &target->thread.tm_ppr, 3 * sizeof(u64) +
> | +                           2 * sizeof(unsigned long), 3 * sizeof(u64) +
> | +                           3 * sizeof(unsigned long));
> | +
> | +   /* TM checkpointed DSCR register */
> | +   if (!ret)
> | +           ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
> | +                           &target->thread.tm_dscr, 3 * sizeof(u64) +
> | +                           3 * sizeof(unsigned long), 3 * sizeof(u64) +
> | +                           4 * sizeof(unsigned long));
> | +   return ret;
> | +}
> | +
> | +/*
> | + * tm_cgpr_active
> | + *
> | + * This function checks the number of available regisers in
> | + * transaction checkpointed GPR category.
> | + */
> | +static int tm_cgpr_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_cgpr_get
> | + *
> | + * This function gets transaction checkpointed GPR registers
> | + *
> | + * When the transaction is active, 'ckpt_regs' holds all the checkpointed
> | + * GPR register values for the current transaction to fall back on if it
> | + * aborts in between. This function gets those checkpointed GPR registers.
> | + *
> | + * Userspace interface buffer layout:
> | + *
> | + * struct data {
> | + * struct pt_regs ckpt_regs;
> | + * };
> | + */
> | +static int tm_cgpr_get(struct task_struct *target,
> | +                   const struct user_regset *regset,
> | +                   unsigned int pos, unsigned int count,
> | +                   void *kbuf, void __user *ubuf)
> | +{
> | +   int ret;
> | +
> | +   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);
> | +   ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> | +                                   &target->thread.ckpt_regs, 0,
> | +                                   sizeof(struct pt_regs));
> | +   return ret;
> | +}
> | +
> | +/*
> | + * tm_cgpr_set
> | + *
> | + * This function sets in transaction checkpointed GPR registers
> | + *
> | + * When the transaction is active, 'ckpt_regs' holds the checkpointed
> | + * GPR register values for the current transaction to fall back on if it
> | + * aborts in between. This function sets those checkpointed GPR registers.
> | + *
> | + * Userspace intaerface buffer:
> | + *
> | + * struct data {
> | + * struct pt_regs ckpt_regs;
> | + * };
> | + */
> | +static int tm_cgpr_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;
> | +
> | +   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);
> | +   ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
> | +                                   &target->thread.ckpt_regs, 0,
> | +                                   sizeof(struct pt_regs));
> | +   return ret;
> | +}
> | +
> | +/*
> | + * tm_cfpr_active
> | + *
> | + * This function checks 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
> | + *
> | + * 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.
> | + *
> | + * Userspace interface buffer layout:
> | + *
> | + * 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
> | + *
> | + * 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.
> | + *
> | + * Userspace interface buffer layout:
> | + *
> | + * 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;
> | +}
> | +
> | +/*
> | + * tm_cvmx_active
> | + *
> | + * This function checks the number of available regisers in
> | + * checkpointed VMX category.
> | + */
> | +static int tm_cvmx_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_cvmx_get
> | + *
> | + * This function gets in transaction checkpointed VMX registers
> | + *
> | + * When the transaction is active 'vr_state' and 'vr_save' hold
> | + * the checkpointed values for the current transaction to fall
> | + * back on if it aborts in between.
> | + *
> | + * User interface buffer:
> | + *
> | + * struct data {
> | + * vector128       vr[32];
> | + * vector128       vscr;
> | + * vector128       vrsave;
> | + *};
> | + */
> | +static int tm_cvmx_get(struct task_struct *target,
> | +                   const struct user_regset *regset,
> | +                   unsigned int pos, unsigned int count,
> | +                   void *kbuf, void __user *ubuf)
> | +{
> | +   int ret;
> | +
> | +   BUILD_BUG_ON(TVSO(vscr) != TVSO(vr[32]));
> | +
> | +   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);
> | +
> | +   ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> | +                                   &target->thread.vr_state, 0,
> | +                                   33 * sizeof(vector128));
> | +   if (!ret) {
> | +           /*
> | +            * Copy out only the low-order word of vrsave.
> | +            */
> | +           union {
> | +                   elf_vrreg_t reg;
> | +                   u32 word;
> | +           } vrsave;
> | +           memset(&vrsave, 0, sizeof(vrsave));
> | +           vrsave.word = target->thread.vrsave;
> | +           ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &vrsave,
> | +                                           33 * sizeof(vector128), -1);
> | +   }
> | +
> | +   return ret;
> | +}
> | +
> | +/*
> | + * tm_cvmx_set
> | + *
> | + * This function sets in transaction checkpointed VMX registers
> | + *
> | + * When the transaction is active 'vr_state' and 'vr_save' hold
> | + * the checkpointed values for the current transaction to fall
> | + * back on if it aborts in between.
> | + *
> | + * Userspace interface buffer:
> | + *
> | + * struct data {
> | + * vector128       vr[32];
> | + * vector128       vscr;
> | + * vector128       vrsave;
> | + *};
> | + */
> | +static int tm_cvmx_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;
> | +
> | +   BUILD_BUG_ON(TVSO(vscr) != TVSO(vr[32]));
> | +
> | +   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);
> | +
> | +   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.
> 
> For consistency with the _get() function above, s/first/low-order/ ?

Done.

> | +            */
> | +           union {
> | +                   elf_vrreg_t reg;
> | +                   u32 word;
> | +           } vrsave;
> | +           memset(&vrsave, 0, sizeof(vrsave));
> | +           vrsave.word = target->thread.vrsave;
> | +           ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &vrsave,
> | +                                           33 * sizeof(vector128), -1);
> | +           if (!ret)
> | +                   target->thread.vrsave = vrsave.word;
> | +   }
> | +
> | +   return ret;
> | +}
> | +#endif     /* CONFIG_PPC_TRANSACTIONAL_MEM */
> | 
> |  /*
> |   * These are our native regset flavors.
> | @@ -808,6 +1341,12 @@ enum powerpc_regset {
> |  #ifdef CONFIG_SPE
> |     REGSET_SPE,
> |  #endif
> | +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> | +   REGSET_TM_SPR,          /* TM specific SPR registers */
> | +   REGSET_TM_CGPR,         /* TM checkpointed GPR registers */
> | +   REGSET_TM_CFPR,         /* TM checkpointed FPR registers */
> | +   REGSET_TM_CVMX,         /* TM checkpointed VMX registers */
> | +#endif
> |  };
> | 
> |  static const struct user_regset native_regsets[] = {
> | @@ -842,6 +1381,28 @@ static const struct user_regset native_regsets[] = {
> |             .active = evr_active, .get = evr_get, .set = evr_set
> |     },
> |  #endif
> | +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> | +   [REGSET_TM_SPR] = {
> | +           .core_note_type = NT_PPC_TM_SPR, .n = ELF_NTMSPRREG,
> | +           .size = sizeof(u64), .align = sizeof(u64),
> | +           .active = tm_spr_active, .get = tm_spr_get, .set = tm_spr_set
> | +   },
> | +   [REGSET_TM_CGPR] = {
> | +           .core_note_type = NT_PPC_TM_CGPR, .n = ELF_NGREG,
> | +           .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
> | +   },
> | +   [REGSET_TM_CVMX] = {
> | +           .core_note_type = NT_PPC_TM_CVMX, .n = ELF_NVMX,
> | +           .size = sizeof(vector128), .align = sizeof(vector128),
> | +           .active = tm_cvmx_active, .get = tm_cvmx_get, .set = tm_cvmx_set
> | +   },
> | +#endif
> |  };
> | 
> |  static const struct user_regset_view user_ppc_native_view = {
> | @@ -852,24 +1413,35 @@ static const struct user_regset_view 
> user_ppc_native_view = {
> |  #ifdef CONFIG_PPC64
> |  #include <linux/compat.h>
> | 
> | -static int gpr32_get(struct task_struct *target,
> | +static int common_gpr32_get(struct task_struct *target,
> |                  const struct user_regset *regset,
> |                  unsigned int pos, unsigned int count,
> | -                void *kbuf, void __user *ubuf)
> | +                       void *kbuf, void __user *ubuf, bool in_tm)
> |  {
> | -   const unsigned long *regs = &target->thread.regs->gpr[0];
> | +   const unsigned long *regs;
> |     compat_ulong_t *k = kbuf;
> |     compat_ulong_t __user *u = ubuf;
> |     compat_ulong_t reg;
> |     int i;
> | 
> | -   if (target->thread.regs == NULL)
> | -           return -EIO;
> | +   if (in_tm) {
> | +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> | +           regs = &target->thread.ckpt_regs.gpr[0];
> | +#endif
> 
> regs uninitialized if in_tm is true and CONFIG_PPC_TRANSACTIONAL_MEM
> is false ? It appears that it cannot/should not happen, how about BUGON() ?
> or at least regs = NULL to silence compiler warnings ?

Yeah it cannot happen, seems like compiler is able to figure that out as
I dont get any warning because of that. BUG_ON sounds like a good option
after the if-else block to verify whether the regs variable got any valid
address value to it or not. Also we can start with regs = NULL at the
starting of the function as well.

> 
> 
> | +   } else {
> | +           regs = &target->thread.regs->gpr[0];
> | 
> | -   if (!FULL_REGS(target->thread.regs)) {
> | -           /* We have a partial register set.  Fill 14-31 with bogus 
> values */
> | -           for (i = 14; i < 32; i++)
> | -                   target->thread.regs->gpr[i] = NV_REG_POISON; 
> | +           if (target->thread.regs == NULL)
> | +                   return -EIO;
> | +
> | +           if (!FULL_REGS(target->thread.regs)) {
> | +                   /*
> | +                    * We have a partial register set.
> | +                    * Fill 14-31 with bogus values.
> | +                    */
> | +                   for (i = 14; i < 32; i++)
> | +                           target->thread.regs->gpr[i] = NV_REG_POISON;
> | +           }
> |     }
> | 
> |     pos /= sizeof(reg);
> | @@ -909,20 +1481,28 @@ static int gpr32_get(struct task_struct *target,
> |                                     PT_REGS_COUNT * sizeof(reg), -1);
> |  }
> | 
> | -static int gpr32_set(struct task_struct *target,
> | +static int common_gpr32_set(struct task_struct *target,
> |                  const struct user_regset *regset,
> |                  unsigned int pos, unsigned int count,
> | -                const void *kbuf, const void __user *ubuf)
> | +                const void *kbuf, const void __user *ubuf, bool in_tm)
> |  {
> | -   unsigned long *regs = &target->thread.regs->gpr[0];
> | +   unsigned long *regs;
> |     const compat_ulong_t *k = kbuf;
> |     const compat_ulong_t __user *u = ubuf;
> |     compat_ulong_t reg;
> | 
> | -   if (target->thread.regs == NULL)
> | -           return -EIO;
> | +   if (in_tm) {
> | +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> | +           regs = &target->thread.ckpt_regs.gpr[0];
> | +#endif
> 
> ditto

Done.

> 
> | +   } else {
> | +           regs = &target->thread.regs->gpr[0];
> | 
> | -   CHECK_FULL_REGS(target->thread.regs);
> | +           if (target->thread.regs == NULL)
> | +                   return -EIO;
> | +
> | +           CHECK_FULL_REGS(target->thread.regs);
> | +   }
> | 
> |     pos /= sizeof(reg);
> |     count /= sizeof(reg);
> | @@ -982,6 +1562,39 @@ static int gpr32_set(struct task_struct *target,
> |                                      (PT_TRAP + 1) * sizeof(reg), -1);
> |  }
> | 
> | +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> | +static int tm_cgpr32_get(struct task_struct *target,
> | +                const struct user_regset *regset,
> | +                unsigned int pos, unsigned int count,
> | +                void *kbuf, void __user *ubuf)
> | +{
> | +   return common_gpr32_get(target, regset, pos, count, kbuf, ubuf, 1);
> | +}
> | +
> | +static int tm_cgpr32_set(struct task_struct *target,
> | +                const struct user_regset *regset,
> | +                unsigned int pos, unsigned int count,
> | +                const void *kbuf, const void __user *ubuf)
> | +{
> | +   return common_gpr32_set(target, regset, pos, count, kbuf, ubuf, 0);
> | +}
> | +#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
> | +
> | +static int gpr32_get(struct task_struct *target,
> | +                const struct user_regset *regset,
> | +                unsigned int pos, unsigned int count,
> | +                void *kbuf, void __user *ubuf)
> | +{
> | +   return common_gpr32_get(target, regset, pos, count, kbuf, ubuf, 0);
> | +}
> | +
> | +static int gpr32_set(struct task_struct *target,
> | +                const struct user_regset *regset,
> | +                unsigned int pos, unsigned int count,
> | +                const void *kbuf, const void __user *ubuf)
> | +{
> | +   return common_gpr32_set(target, regset, pos, count, kbuf, ubuf, 0);
> | +}
> |  /*
> |   * These are the regset flavors matching the CONFIG_PPC32 native set.
> |   */
> | @@ -1010,6 +1623,29 @@ static const struct user_regset compat_regsets[] = {
> |             .active = evr_active, .get = evr_get, .set = evr_set
> |     },
> |  #endif
> | +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> | +   [REGSET_TM_SPR] = {
> | +           .core_note_type = NT_PPC_TM_SPR, .n = ELF_NTMSPRREG,
> | +           .size = sizeof(u64), .align = sizeof(u64),
> | +           .active = tm_spr_active, .get = tm_spr_get, .set = tm_spr_set
> | +   },
> | +   [REGSET_TM_CGPR] = {
> | +           .core_note_type = NT_PPC_TM_CGPR, .n = ELF_NGREG,
> | +           .size = sizeof(long), .align = sizeof(long),
> | +           .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
> | +   },
> | +   [REGSET_TM_CVMX] = {
> | +           .core_note_type = NT_PPC_TM_CVMX, .n = ELF_NVMX,
> | +           .size = sizeof(vector128), .align = sizeof(vector128),
> | +           .active = tm_cvmx_active, .get = tm_cvmx_get, .set = tm_cvmx_set
> | +   },
> | +#endif
> |  };
> | 
> |  static const struct user_regset_view user_ppc_compat_view = {
> | -- 
> | 1.9.3
> 

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