Le 19/06/2018 à 21:54, Pedro Franco de Carvalho a écrit :
> Would something like this be ok?
>
> I factored out the calls to flush_fp_to_thread and flush_altivec_to_thread,
> although I don't really understand why these are necessary. The
> tm_cvsx_get/set
> functions also calls flush_vsx_to_thread (outside of the helper function).
>
> I also noticed that tm_ppr/dscr/tar_get/set functions don't flush the tm
> state. Should they do it, and if so, should they also flush the fp and altivec
> state?
>
> Thanks!
> Pedro
>
> -- >8 --
> Currently ptrace doesn't flush the register state when the
> checkpointed GPRs of a 32-bit thread are accessed. This can cause core
> dumps to have stale data in the checkpointed GPR note.
>
> This patch adds a helper function to flush the TM, fpu and altivec
> state and calls it from the tm_cgpr32_get/set functions.
This patch is almost 6 yr old and doesn't apply anymore.
If someone thinks it is still relevant, please rebase and resubmit.
Thanks
Christophe
>
> Signed-off-by: Pedro Franco de Carvalho <pedro...@linux.vnet.ibm.com>
> ---
> arch/powerpc/kernel/ptrace.c | 33 +++++++++++++++++++++++++++++++++
> 1 file changed, 33 insertions(+)
>
> diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
> index 9667666eb18e..0d56857e1e89 100644
> --- a/arch/powerpc/kernel/ptrace.c
> +++ b/arch/powerpc/kernel/ptrace.c
> @@ -778,6 +778,29 @@ static int evr_set(struct task_struct *target, const
> struct user_regset *regset,
>
> #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> /**
> + * tm_flush_if_active - flush TM, fpu and altivec state if TM active
> + * @target: The target task.
> + *
> + * This function flushes the TM, fpu and altivec state to the target
> + * task and returns 0 if TM is available and active in the target, and
> + * returns an error code suitable for ptrace otherwise.
> + */
> +static int tm_flush_if_active (struct task_struct *target)
> +{
> + if (!cpu_has_feature(CPU_FTR_TM))
> + return -ENODEV;
> +
> + if (!MSR_TM_ACTIVE(target->thread.regs->msr))
> + return -ENODATA;
> +
> + flush_tmregs_to_thread(target);
> + flush_fp_to_thread(target);
> + flush_altivec_to_thread(target);
> +
> + return 0;
> +}
> +
> +/**
> * tm_cgpr_active - get active number of registers in CGPR
> * @target: The target task.
> * @regset: The user regset structure.
> @@ -2124,6 +2147,11 @@ static int tm_cgpr32_get(struct task_struct *target,
> unsigned int pos, unsigned int count,
> void *kbuf, void __user *ubuf)
> {
> + int ret = tm_flush_if_active(target);
> +
> + if (ret)
> + return ret;
> +
> return gpr32_get_common(target, regset, pos, count, kbuf, ubuf,
> &target->thread.ckpt_regs.gpr[0]);
> }
> @@ -2133,6 +2161,11 @@ static int tm_cgpr32_set(struct task_struct *target,
> unsigned int pos, unsigned int count,
> const void *kbuf, const void __user *ubuf)
> {
> + int ret = tm_flush_if_active(target);
> +
> + if (ret)
> + return ret;
> +
> return gpr32_set_common(target, regset, pos, count, kbuf, ubuf,
> &target->thread.ckpt_regs.gpr[0]);
> }
