[PATCH V4 7/8] powerpc, ptrace: Enable support for miscellaneous debug registers

[Denis Kirjanov]

On 11/13/14, Anshuman Khandual <khandual at linux.vnet.ibm.com> wrote:
> On 11/11/2014 10:56 AM, Anshuman Khandual wrote:
>> This patch enables get and set of miscellaneous debug registers through
>> ptrace PTRACE_GETREGSET-PTRACE_SETREGSET interface by implementing new
>> powerpc specific register set REGSET_MISC support corresponding to the
>> new ELF core note NT_PPC_MISC added previously in this regard.
>
> Right now this one does not compile for "ppc64e_defconfig" and
> "pmac32_defconfig" config options. The patch below will fix it
> and would be part of next revision.

It would be great to have a test tool for that under
tools/testing/selftests/ptrace/

> diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
> index 61a2581..be566eb 100644
> --- a/arch/powerpc/kernel/ptrace.c
> +++ b/arch/powerpc/kernel/ptrace.c
> @@ -1326,6 +1326,7 @@ static int tm_cvmx_set(struct task_struct *target,
>  }
>  #endif	/* CONFIG_PPC_TRANSACTIONAL_MEM */
>
> +#ifdef CONFIG_PPC64
>  /*
>   * get_misc_dbg
>   *
> @@ -1339,6 +1340,9 @@ static int tm_cvmx_set(struct task_struct *target,
>   *	unsigned long ppr;
>   *	unsigned long tar;
>   * };
> + *
> + * The data element 'tar' will be valid only if the
> + * kernel has CONFIG_PPC_BOOK3S_64 config option enabled.
>   */
>  static int get_misc_dbg(struct task_struct *target,
>  			const struct user_regset *regset, unsigned int pos,
> @@ -1348,7 +1352,10 @@ static int get_misc_dbg(struct task_struct *target,
>
>  	/* Build test */
>  	BUILD_BUG_ON(TSO(dscr) + 2 * sizeof(unsigned long) != TSO(ppr));
> +
> +#ifdef CONFIG_PPC_BOOK3S_64
>  	BUILD_BUG_ON(TSO(ppr) + sizeof(unsigned long) != TSO(tar));
> +#endif
>
>  	/* DSCR register */
>  	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> @@ -1362,12 +1369,14 @@ static int get_misc_dbg(struct task_struct *target,
>  						sizeof(unsigned long),
>  						2 * sizeof(unsigned long));
>
> +#ifdef CONFIG_PPC_BOOK3S_64
>  	/* TAR register */
>  	if (!ret)
>  		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
>  						&target->thread.tar,
>  						2 * sizeof(unsigned long),
>  						3 * sizeof(unsigned long));
> +#endif
>  	return ret;
>  }
>
> @@ -1384,6 +1393,9 @@ static int get_misc_dbg(struct task_struct *target,
>   *	unsigned long ppr;
>   *	unsigned long tar;
>   * };
> + *
> + * The data element 'tar' will be valid only if the
> + * kernel has CONFIG_PPC_BOOK3S_64 config option enabled.
>   */
>  static int set_misc_dbg(struct task_struct *target,
>  			const struct user_regset *regset, unsigned int pos,
> @@ -1394,7 +1406,10 @@ static int set_misc_dbg(struct task_struct *target,
>
>  	/* Build test */
>  	BUILD_BUG_ON(TSO(dscr) + 2 * sizeof(unsigned long) != TSO(ppr));
> +
> +#ifdef CONFIG_PPC_BOOK3S_64
>  	BUILD_BUG_ON(TSO(ppr) + sizeof(unsigned long) != TSO(tar));
> +#endif
>
>  	/* DSCR register */
>  	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
> @@ -1407,15 +1422,17 @@ static int set_misc_dbg(struct task_struct *target,
>  						&target->thread.ppr,
>  						sizeof(unsigned long),
>  						2 * sizeof(unsigned long));
> -
> +#ifdef CONFIG_PPC_BOOK3S_64
>  	/* TAR register */
>  	if (!ret)
>  		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
>  						&target->thread.tar,
>  						2 * sizeof(unsigned long),
>  						3 * sizeof(unsigned long));
> +#endif
>  	return ret;
>  }
> +#endif /* CONFIG_PPC64 */
>
>  /*
>   * These are our native regset flavors.
> @@ -1438,7 +1455,9 @@ enum powerpc_regset {
>  	REGSET_TM_CFPR,		/* TM checkpointed FPR registers */
>  	REGSET_TM_CVMX,		/* TM checkpointed VMX registers */
>  #endif
> +#ifdef CONFIG_PPC64
>  	REGSET_MISC		/* Miscellaneous debug registers */
> +#endif
>  };
>
>  static const struct user_regset native_regsets[] = {
> @@ -1495,11 +1514,13 @@ static const struct user_regset native_regsets[] = {
>  		.active = tm_cvmx_active, .get = tm_cvmx_get, .set = tm_cvmx_set
>  	},
>  #endif
> +#ifdef CONFIG_PPC64
>  	[REGSET_MISC] = {
>  		.core_note_type = NT_PPC_MISC, .n = ELF_NMISCREG,
>  		.size = sizeof(u64), .align = sizeof(u64),
>  		.get = get_misc_dbg, .set = set_misc_dbg
>  	},
> +#endif
>  };
>
>  static const struct user_regset_view user_ppc_native_view = {
>
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-- 
Regards,
Denis