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SubjectRe: [PATCH V3 2/3] powerpc, ptrace: Enable support for transactional memory register sets
On 24/05/14 01:15, Anshuman Khandual 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 <khandual@linux.vnet.ibm.com>

Hi Anshuman,

I'm not Ben but I've reviewed your patch as well as I can and I have
some comments that might be useful to you.

First of all, I couldn't get this to compile without CONFIG_VSX and
CONFIG_PPC_TRANSACTIONAL_MEM defined: there are obvious typos ("esle"
instead of "else") and references to fields that aren't defined for
those cases. I haven't mentioned any of those issues below as the
compiler will do that but you should definitely test those configurations.

Also some of the code seems to assume that if CONFIG_VSX is defined then
CONFIG_PPC_TRANSACTIONAL_MEM must also be defined, but that isn't the
case (it's the other way round: CONFIG_PPC_TRANSACTIONAL_MEM implies
CONFIG_VSX).

> ---
> arch/powerpc/include/asm/switch_to.h | 8 +
> arch/powerpc/kernel/process.c | 24 ++
> arch/powerpc/kernel/ptrace.c | 792 +++++++++++++++++++++++++++++++++--
> 3 files changed, 795 insertions(+), 29 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/switch_to.h b/arch/powerpc/include/asm/switch_to.h
> index 0e83e7d..2737f46 100644
> --- a/arch/powerpc/include/asm/switch_to.h
> +++ b/arch/powerpc/include/asm/switch_to.h
> @@ -80,6 +80,14 @@ static inline void flush_spe_to_thread(struct task_struct *t)
> }
> #endif
>
> +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> +extern void flush_tmregs_to_thread(struct task_struct *);
> +#else
> +static inline void flush_tmregs_to_thread(struct task_struct *t)
> +{
> +}
> +#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
> +
> static inline void clear_task_ebb(struct task_struct *t)
> {
> #ifdef CONFIG_PPC_BOOK3S_64
> diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
> index 31d0215..e247898 100644
> --- a/arch/powerpc/kernel/process.c
> +++ b/arch/powerpc/kernel/process.c
> @@ -695,6 +695,30 @@ static inline void __switch_to_tm(struct task_struct *prev)
> }
> }
>
> +void flush_tmregs_to_thread(struct task_struct *tsk)
> +{
> + /*
> + * If task is not current, it should have been flushed
> + * already to it's thread_struct during __switch_to().
> + */
> + if (tsk != current)
> + return;
> +
> + preempt_disable();
> + if (tsk->thread.regs) {
> + /*
> + * If we are still current, the TM state need to
> + * be flushed to thread_struct as it will be still
> + * present in the current cpu.
> + */
> + if (MSR_TM_ACTIVE(tsk->thread.regs->msr)) {
> + __switch_to_tm(tsk);
> + tm_recheckpoint_new_task(tsk);

There is at least one other usage of this pair of calls in order to
"flush" the TM state (in arch_dup_task_struct()), so rather than copying
it you might want to create a new function and call it from both places.
(And include the nice comment from arch_dup_task_struct() that explains
how it works and why.)

> + }
> + }
> + preempt_enable();
> +}
> +
> /*
> * This is called if we are on the way out to userspace and the
> * TIF_RESTORE_TM flag is set. It checks if we need to reload
> diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
> index 2e3d2bf..17642ef 100644
> --- a/arch/powerpc/kernel/ptrace.c
> +++ b/arch/powerpc/kernel/ptrace.c
> @@ -357,6 +357,17 @@ static int gpr_set(struct task_struct *target, const struct user_regset *regset,
> return ret;
> }
>
> +/*
> + * When any transaction is active, "thread_struct->transact_fp" holds
> + * the current running value of all FPR registers and "thread_struct->
> + * fp_state" holds the last checkpointed FPR registers state for the
> + * current transaction.
> + *
> + * struct data {
> + * u64 fpr[32];
> + * u64 fpscr;
> + * };

It would be nice to say why you've included "struct data" in the comment.

> + */
> static int fpr_get(struct task_struct *target, const struct user_regset *regset,
> unsigned int pos, unsigned int count,
> void *kbuf, void __user *ubuf)
> @@ -365,21 +376,41 @@ static int fpr_get(struct task_struct *target, const struct user_regset *regset,
> u64 buf[33];
> int i;
> #endif
> - flush_fp_to_thread(target);
> + if (MSR_TM_ACTIVE(target->thread.regs->msr)) {
> + flush_fp_to_thread(target);
> + flush_altivec_to_thread(target);
> + flush_tmregs_to_thread(target);
> + } else {
> + flush_fp_to_thread(target);
> + }

I don't see why you need the else. Could this be:

flush_fp_to_thread(target);
if (MSR_TM_ACTIVE(target->thread.regs->msr)) {
flush_altivec_to_thread(target);
flush_tmregs_to_thread(target);
}

>
> #ifdef CONFIG_VSX
> /* 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;
> + if (MSR_TM_ACTIVE(target->thread.regs->msr)) {
> + 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;
> + }

I see several cases of similar code needing to access either fp_state or
transact_fp, or other similar pairs, so maybe you could use a macro.
Something like this (I'm not sure about the name!):

#define MABYE_TM(TSK,X,TM_X) \
((MSR_TM_ACTIVE((TSK)->thread.regs->msr) \
? &((TSK)->thread.(TM_X) \
: &((TSK)->thread.(X))

Then you could do this:

struct thread_fp_state *fp;

fp = MAYBE_TM(target,fp_state,transact_fp);
for (i = 0; i < 32; i++)
buf[i] = (*fp)[i][TS_FPROFFSET];

> return user_regset_copyout(&pos, &count, &kbuf, &ubuf, buf, 0, -1);
>
> #else
> - BUILD_BUG_ON(offsetof(struct thread_fp_state, fpscr) !=
> - offsetof(struct thread_fp_state, fpr[32][0]));
> + if (MSR_TM_ACTIVE(tsk->thread.regs->msr)) {
> + BUILD_BUG_ON(offsetof(struct transact_fp, fpscr) !=
> + offsetof(struct transact_fp, fpr[32][0]));
>
> - return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> + return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> + &target->thread.transact_fp, 0, -1);
> + } esle {
> + 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);
> + }

The BUILD_BUG_ON() statements don't need to be in the "if", since
they're compile-time (and "struct transact_fp" is not a type so that one
isn't needed), and you could use the utility function (above) to shorten
this a lot, i.e.:
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,
MAYBE_TM(target,fp_state,transact_fp)
, 0, -1);

> #endif
> }
>
> @@ -391,23 +422,44 @@ static int fpr_set(struct task_struct *target, const struct user_regset *regset,
> u64 buf[33];
> int i;
> #endif
> - flush_fp_to_thread(target);
> + if (MSR_TM_ACTIVE(target->thread.regs->msr)) {
> + flush_fp_to_thread(target);
> + flush_altivec_to_thread(target);
> + flush_tmregs_to_thread(target);
> + } else {
> + flush_fp_to_thread(target);
> + }

This could be simplified like the similar case above.

> #ifdef CONFIG_VSX
> /* 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];
> + for (i = 0; i < 32 ; i++) {
> + if (MSR_TM_ACTIVE(target->thread.regs->msr))
> + target->thread.TS_TRANS_FPR(i) = buf[i];
> + else
> + target->thread.TS_FPR(i) = buf[i];
> + }
> + if (MSR_TM_ACTIVE(target->thread.regs->msr))
> + target->thread.transact_fp.fpscr = buf[32];
> + else
> + target->thread.fp_state.fpscr = buf[32];
> return 0;

This could be shorted using the above macro.

> #else
> - BUILD_BUG_ON(offsetof(struct thread_fp_state, fpscr) !=
> - offsetof(struct thread_fp_state, fpr[32][0]));
> + if (MSR_TM_ACTIVE(target->thread.regs->msr)) {
> + BUILD_BUG_ON(offsetof(struct transact_fp, fpscr) !=
> + offsetof(struct transact_fp, fpr[32][0]));
>
> - return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
> - &target->thread.fp_state, 0, -1);
> + return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
> + &target->thread.transact_fp, 0, -1);
> + } else {
> + 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

... as could this.

> }
>
> @@ -432,20 +484,44 @@ static int vr_active(struct task_struct *target,
> return target->thread.used_vr ? regset->n : 0;
> }
>
> +/*
> + * When any transaction is active, "thread_struct->transact_vr" holds
> + * the current running value of all VMX registers and "thread_struct->
> + * vr_state" holds the last checkpointed value of VMX registers for the
> + * current transaction.
> + *
> + * struct data {
> + * vector128 vr[32];
> + * vector128 vscr;
> + * vector128 vrsave;
> + * };
> + */

Again a comment about "struct data" would be nice.

> static int vr_get(struct task_struct *target, const struct user_regset *regset,
> unsigned int pos, unsigned int count,
> void *kbuf, void __user *ubuf)
> {
> int ret;
> + struct thread_vr_state *addr;
>
> - flush_altivec_to_thread(target);
> + if (MSR_TM_ACTIVE(target->thread.regs->msr)) {
> + flush_fp_to_thread(target);
> + flush_altivec_to_thread(target);
> + flush_tmregs_to_thread(target);
> + } else {
> + flush_altivec_to_thread(target);
> + }

As above.

>
> BUILD_BUG_ON(offsetof(struct thread_vr_state, vscr) !=
> offsetof(struct thread_vr_state, vr[32]));
>
> + if (MSR_TM_ACTIVE(target->thread.regs->msr))
> + addr = &target->thread.transact_vr;
> + else
> + addr = &target->thread.vr_state;
> +
> ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> - &target->thread.vr_state, 0,
> - 33 * sizeof(vector128));
> + addr, 0, 33 * sizeof(vector128));
> +

As above.

> if (!ret) {
> /*
> * Copy out only the low-order word of vrsave.
> @@ -455,11 +531,14 @@ static int vr_get(struct task_struct *target, const struct user_regset *regset,
> u32 word;
> } vrsave;
> memset(&vrsave, 0, sizeof(vrsave));
> - vrsave.word = target->thread.vrsave;
> + if (MSR_TM_ACTIVE(target->thread.regs->msr))
> + vrsave.word = target->thread.transact_vrsave;
> + else
> + vrsave.word = target->thread.vrsave;
> +

As above.

> ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &vrsave,
> 33 * sizeof(vector128), -1);
> }
> -
> return ret;
> }
>
> @@ -467,16 +546,27 @@ static int vr_set(struct task_struct *target, const struct user_regset *regset,
> unsigned int pos, unsigned int count,
> const void *kbuf, const void __user *ubuf)
> {
> + struct thread_vr_state *addr;
> int ret;
>
> - flush_altivec_to_thread(target);
> + if (MSR_TM_ACTIVE(target->thread.regs->msr)) {
> + flush_fp_to_thread(target);
> + flush_altivec_to_thread(target);
> + flush_tmregs_to_thread(target);
> + } else {
> + flush_altivec_to_thread(target);
> + }

Could flush_altivec_to_thread() be pulled out of the "if" or is it
important to call flush_fp_to_thread() first?

>
> BUILD_BUG_ON(offsetof(struct thread_vr_state, vscr) !=
> offsetof(struct thread_vr_state, vr[32]));
>
> + if (MSR_TM_ACTIVE(target->thread.regs->msr))
> + addr = &target->thread.transact_vr;
> + else
> + addr = &target->thread.vr_state;
> ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
> - &target->thread.vr_state, 0,
> - 33 * sizeof(vector128));
> + addr, 0, 33 * sizeof(vector128));
> +

As above, and as a result you could remove "addr".

> if (!ret && count > 0) {
> /*
> * We use only the first word of vrsave.
> @@ -486,13 +576,21 @@ static int vr_set(struct task_struct *target, const struct user_regset *regset,
> u32 word;
> } vrsave;
> memset(&vrsave, 0, sizeof(vrsave));
> - vrsave.word = target->thread.vrsave;
> +
> + if (MSR_TM_ACTIVE(target->thread.regs->msr))
> + vrsave.word = target->thread.transact_vrsave;
> + else
> + vrsave.word = target->thread.vrsave;
> +

As above.

> ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &vrsave,
> 33 * sizeof(vector128), -1);
> - if (!ret)
> - target->thread.vrsave = vrsave.word;
> + if (!ret) {
> + if (MSR_TM_ACTIVE(target->thread.regs->msr))
> + target->thread.transact_vrsave = vrsave.word;
> + else
> + target->thread.vrsave = vrsave.word;
> + }

As above.

> }
> -
> return ret;
> }
> #endif /* CONFIG_ALTIVEC */
> @@ -613,6 +711,442 @@ static int evr_set(struct task_struct *target, const struct user_regset *regset,
> }
> #endif /* CONFIG_SPE */
>
> +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> +
> +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;
> +}
> +/*
> + * Transactional memory SPR
> + *
> + * 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;
> +
> + 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);
> +
> + /* TFHAR register */
> + ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> + &target->thread.tm_tfhar, 0, sizeof(u64));
> +
> + BUILD_BUG_ON(offsetof(struct thread_struct, tm_tfhar) +
> + sizeof(u64) != offsetof(struct thread_struct, tm_texasr));
> +
> + /* TEXASR register */
> + if (!ret)
> + ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> + &target->thread.tm_texasr, sizeof(u64), 2 * sizeof(u64));
> +
> + BUILD_BUG_ON(offsetof(struct thread_struct, tm_texasr) +
> + sizeof(u64) != offsetof(struct thread_struct, tm_tfiar));
> +
> + /* TFIAR register */
> + if (!ret)
> + ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> + &target->thread.tm_tfiar, 2 * sizeof(u64), 3 * sizeof(u64));
> +
> + BUILD_BUG_ON(offsetof(struct thread_struct, tm_tfiar) +
> + sizeof(u64) != offsetof(struct thread_struct, tm_orig_msr));
> +
> + /* 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));
> +
> + BUILD_BUG_ON(offsetof(struct thread_struct, tm_orig_msr) +
> + sizeof(unsigned long) + sizeof(struct pt_regs)
> + != offsetof(struct thread_struct, tm_tar));
> +
> + /* 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));
> +
> + BUILD_BUG_ON(offsetof(struct thread_struct, tm_tar)
> + + sizeof(unsigned long) !=
> + offsetof(struct thread_struct, tm_ppr));
> +
> + /* 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));
> +
> + BUILD_BUG_ON(offsetof(struct thread_struct, tm_ppr) +
> + sizeof(unsigned long) !=
> + offsetof(struct thread_struct, tm_dscr));
> +
> + /* 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;
> +}
> +
> +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;
> +
> + 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);
> +
> + /* TFHAR register */
> + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
> + &target->thread.tm_tfhar, 0, sizeof(u64));
> +
> + BUILD_BUG_ON(offsetof(struct thread_struct, tm_tfhar)
> + + sizeof(u64) != offsetof(struct thread_struct, tm_texasr));
> +
> + /* TEXASR register */
> + if (!ret)
> + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
> + &target->thread.tm_texasr, sizeof(u64), 2 * sizeof(u64));
> +
> + BUILD_BUG_ON(offsetof(struct thread_struct, tm_texasr)
> + + sizeof(u64) != offsetof(struct thread_struct, tm_tfiar));
> +
> + /* TFIAR register */
> + if (!ret)
> + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
> + &target->thread.tm_tfiar, 2 * sizeof(u64), 3 * sizeof(u64));
> +
> + BUILD_BUG_ON(offsetof(struct thread_struct, tm_tfiar)
> + + sizeof(u64) != offsetof(struct thread_struct, tm_orig_msr));
> +
> + /* 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));
> +
> + BUILD_BUG_ON(offsetof(struct thread_struct, tm_orig_msr)
> + + sizeof(unsigned long) + sizeof(struct pt_regs) !=
> + offsetof(struct thread_struct, tm_tar));
> +
> + /* 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));
> +
> + BUILD_BUG_ON(offsetof(struct thread_struct, tm_tar)
> + + sizeof(unsigned long) != offsetof(struct thread_struct, tm_ppr));
> +
> + /* 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));
> +
> + BUILD_BUG_ON(offsetof(struct thread_struct, tm_ppr) +
> + sizeof(unsigned long) !=
> + offsetof(struct thread_struct, tm_dscr));
> +
> + /* 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;
> +}

I don't understand why tm_spr_set() and tm_spr_get() are structured like
this. It looks like they're expecting user_regset_copyin() to fail part
of the way through and are being careful to set the registers until that
point, even if it's going to return a failure.

This seems strange because other functions are careful to construct an
intermediate buffer so that they can either succeed or fail entirely. If
there's a reason that this needs to be this way, it might be a good idea
to explain that in a comment.

If they dont need to act like that, wouldn't all the BUILD_BUG_ONs
guarantee that the thread_struct registers are contiguous and therefore
you could set them all with a single call to user_regset_copyin()? If
you don't need them to be contiguous then what are the BUILD_BUG_ONs for?

> +
> +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 Checkpointed GPR
> + *
> + * 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);

I see this pattern of checking for TM and calling flush_fp_to_thread(),
flush_altivec_to_thread() and flush_tmregs_to_thread() in many places;
maybe it should be factored out to a function.

> + ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> + &target->thread.ckpt_regs, 0,
> + sizeof(struct pt_regs));
> + return ret;
> +}
> +
> +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;
> +}
> +
> +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 Checkpointed FPR
> + *
> + * 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)
> +{
> +#ifdef CONFIG_VSX
> + u64 buf[33];
> + int i;
> +#endif
> + 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);
> +
> +#ifdef CONFIG_VSX
> + /* 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);
> +
> +#else
> + 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.thread_fp_state, 0, -1);
> +#endif
> +}
> +
> +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)
> +{
> +#ifdef CONFIG_VSX
> + u64 buf[33];
> + int i;
> +#endif
> + 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);
> +
> +#ifdef CONFIG_VSX
> + /* 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;
> +#else
> + 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
> +}
> +
> +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 Checkpointed VMX
> + *
> + * 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;
> +
> + 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);
> +
> + BUILD_BUG_ON(offsetof(struct thread_vr_state, vscr) !=
> + offsetof(struct thread_vr_state, vr[32]));
> +
> + 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);
I see this pattern of returning only the low-order word several times.
Maybe it should be factored out, or there is already a function
somewhere to do this (it seems like a fairly generic operation).

> + }
> + return ret;
> +}
> +
> +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;
> +
> + 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);
> +
> + BUILD_BUG_ON(offsetof(struct thread_vr_state, vscr) !=
> + offsetof(struct thread_vr_state, vr[32]));
> +
> + 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.
> + */
> + 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.
> @@ -629,6 +1163,12 @@ enum powerpc_regset {
> #ifdef CONFIG_SPE
> REGSET_SPE,
> #endif
> +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> + REGSET_TM_SPR, /* TM specific SPR */
> + REGSET_TM_CGPR, /* TM checkpointed GPR */
> + REGSET_TM_CFPR, /* TM checkpointed FPR */
> + REGSET_TM_CVMX, /* TM checkpointed VMX */
> +#endif
> };
>
> static const struct user_regset native_regsets[] = {
> @@ -663,6 +1203,28 @@ 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 = 7,
> + .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 = 34,
> + .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 = {
> @@ -690,7 +1252,7 @@ static int gpr32_get(struct task_struct *target,
> 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;
> + target->thread.regs->gpr[i] = NV_REG_POISON;
> }
>
> pos /= sizeof(reg);
> @@ -803,6 +1365,157 @@ static int gpr32_set(struct task_struct *target,
> (PT_TRAP + 1) * sizeof(reg), -1);
> }
>
> +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)
> +{
> + const unsigned long *regs = &target->thread.ckpt_regs.gpr[0];
> + compat_ulong_t *k = kbuf;
> + compat_ulong_t __user *u = ubuf;
> + compat_ulong_t reg;
> + 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);
> +
> + 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;

The line above adds a whitespace error. (Did you run it through
checkpatch.pl?)

> + }
> +
> + pos /= sizeof(reg);
> + count /= sizeof(reg);
> +
> + if (kbuf)
> + for (; count > 0 && pos < PT_MSR; --count)
> + *k++ = regs[pos++];
> + else
> + for (; count > 0 && pos < PT_MSR; --count)
> + if (__put_user((compat_ulong_t) regs[pos++], u++))
> + return -EFAULT;
> +
> + if (count > 0 && pos == PT_MSR) {
> + reg = get_user_msr(target);
> + if (kbuf)
> + *k++ = reg;
> + else if (__put_user(reg, u++))
> + return -EFAULT;
> + ++pos;
> + --count;
> + }
> +
> + if (kbuf)
> + for (; count > 0 && pos < PT_REGS_COUNT; --count)
> + *k++ = regs[pos++];
> + else
> + for (; count > 0 && pos < PT_REGS_COUNT; --count)
> + if (__put_user((compat_ulong_t) regs[pos++], u++))
> + return -EFAULT;
> +
> + kbuf = k;
> + ubuf = u;
> + pos *= sizeof(reg);
> + count *= sizeof(reg);
> + return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
> + PT_REGS_COUNT * sizeof(reg), -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)
> +{
> + unsigned long *regs = &target->thread.ckpt_regs.gpr[0];
> + const compat_ulong_t *k = kbuf;
> + const compat_ulong_t __user *u = ubuf;
> + compat_ulong_t reg;
> +
> + 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);
> +
> + if (target->thread.regs == NULL)
> + return -EIO;
> +
> + CHECK_FULL_REGS(target->thread.regs);
> +
> + pos /= sizeof(reg);
> + count /= sizeof(reg);
> +
> + if (kbuf)
> + for (; count > 0 && pos < PT_MSR; --count)
> + regs[pos++] = *k++;
> + else
> + for (; count > 0 && pos < PT_MSR; --count) {
> + if (__get_user(reg, u++))
> + return -EFAULT;
> + regs[pos++] = reg;
> + }
> +
> +
> + if (count > 0 && pos == PT_MSR) {
> + if (kbuf)
> + reg = *k++;
> + else if (__get_user(reg, u++))
> + return -EFAULT;
> + set_user_msr(target, reg);
> + ++pos;
> + --count;
> + }
> +
> + if (kbuf) {
> + for (; count > 0 && pos <= PT_MAX_PUT_REG; --count)
> + regs[pos++] = *k++;
> + for (; count > 0 && pos < PT_TRAP; --count, ++pos)
> + ++k;
> + } else {
> + for (; count > 0 && pos <= PT_MAX_PUT_REG; --count) {
> + if (__get_user(reg, u++))
> + return -EFAULT;
> + regs[pos++] = reg;
> + }
> + for (; count > 0 && pos < PT_TRAP; --count, ++pos)
> + if (__get_user(reg, u++))
> + return -EFAULT;
> + }
> +
> + if (count > 0 && pos == PT_TRAP) {
> + if (kbuf)
> + reg = *k++;
> + else if (__get_user(reg, u++))
> + return -EFAULT;
> + set_user_trap(target, reg);
> + ++pos;
> + --count;
> + }
> +
> + kbuf = k;
> + ubuf = u;
> + pos *= sizeof(reg);
> + count *= sizeof(reg);
> + return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
> + (PT_TRAP + 1) * sizeof(reg), -1);
> +}
> +
> +
> /*
> * These are the regset flavors matching the CONFIG_PPC32 native set.
> */
> @@ -831,6 +1544,28 @@ 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 = 7,
> + .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 = 34,
> + .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 = {
> @@ -1754,7 +2489,6 @@ long arch_ptrace(struct task_struct *child, long request,
> REGSET_SPE, 0, 35 * sizeof(u32),
> datavp);
> #endif
> -
> default:
> ret = ptrace_request(child, request, addr, data);
> break;
>



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