[Ltrace-devel] [PATCH] Support for ppc64le (Little Endian and ABIv2) Add new testsuite/ltrace.main/parameters-str.exp file Handles HFA and irelative support

Petr Machata pmachata at redhat.com
Wed Apr 30 15:55:54 UTC 2014


This looks all pretty good.  I compile-tested it on plain PPC64 --it's
desirable to keep ltrace building on old toolchains as well-- and hit a
couple problems with the several new symbols that you use.  I think we
should have a fallback that disables the new code if the definitions are
just unavailable.

> diff --git a/sysdeps/linux-gnu/ppc/fetch.c b/sysdeps/linux-gnu/ppc/fetch.c
> index ed38336..b42cd95 100644
> --- a/sysdeps/linux-gnu/ppc/fetch.c
> +++ b/sysdeps/linux-gnu/ppc/fetch.c
[...]
>  
> +static int
> +get_return_info(struct arg_type_info *info, struct process *proc,
> +		struct fetch_context *context)

For non-ELFv2 host, I'm getting:
sysdeps/linux-gnu/ppc/fetch.c:119:1: error: 'get_return_info' defined but not used [-Werror=unused-function]
sysdeps/linux-gnu/ppc/fetch.c:392:1: error: 'allocate_hfa' defined but not used [-Werror=unused-function]

> diff --git a/sysdeps/linux-gnu/ppc/plt.c b/sysdeps/linux-gnu/ppc/plt.c
> index 332daa8..a16e182 100644
> --- a/sysdeps/linux-gnu/ppc/plt.c
> +++ b/sysdeps/linux-gnu/ppc/plt.c
[...]
> @@ -430,7 +448,12 @@ reloc_copy_if_irelative(GElf_Rela *rela, void *data)
>  int
>  arch_elf_init(struct ltelf *lte, struct library *lib)
>  {
> +
> +	/* Check for ABIv2 in ELF header processor specific flag.  */
> +	lte->arch.elfv2_abi = ((lte->ehdr.e_flags & EF_PPC64_ABI) == 2);
> +

So, I don't think we should turn off detection.  It seems appropriate to
me to do something like:

+#ifndef EF_PPC64_ABI
+# define EF_PPC64_ABI 3
+#endif

somewhere around here (or possibly at the top of this file).  If
EF_PPC64_ABI is undefined, and we detect elfv2_abi, we should bail out
with a message about unsupported ABI.

> @@ -629,9 +652,45 @@ arch_elf_add_func_entry(struct process *proc, struct ltelf *lte,
>  			arch_addr_t addr, const char *name,
>  			struct library_symbol **ret)
>  {
> -	if (lte->ehdr.e_machine != EM_PPC || lte->ehdr.e_type == ET_DYN)
> +	/* With ABIv2 st_other field contains an offset.  */
> +	 if (lte->arch.elfv2_abi)
> +		addr += PPC64_LOCAL_ENTRY_OFFSET(sym->st_other);

Similar problem.  This should be ifdef'd away I think.  I.e. something
like:

#ifndef PPC64_LOCAL_ENTRY_OFFSET
        assert(! lte->arch.elfv2_abi);
#else
        if (lte->arch.elfv2_abi)
                addr += ...
#endif

Thank you,
PM



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