From: Sathvika Vasireddy <sv@linux.vnet.ibm.com>
To: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"jpoimboe@redhat.com" <jpoimboe@redhat.com>,
"peterz@infradead.org" <peterz@infradead.org>,
"mbenes@suse.cz" <mbenes@suse.cz>,
"aik@ozlabs.ru" <aik@ozlabs.ru>,
"mpe@ellerman.id.au" <mpe@ellerman.id.au>,
"rostedt@goodmis.org" <rostedt@goodmis.org>,
"naveen.n.rao@linux.vnet.ibm.com"
<naveen.n.rao@linux.vnet.ibm.com>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
Sathvika Vasireddy <sv@linux.ibm.com>
Subject: Re: [RFC PATCH 4/4] objtool/powerpc: Add --mcount specific implementation
Date: Tue, 24 May 2022 16:30:13 +0530 [thread overview]
Message-ID: <59170f18-1356-1140-70e3-30cb627f00bc@linux.vnet.ibm.com> (raw)
In-Reply-To: <6be5c941-07b0-64d5-7f36-fe5770fb5244@csgroup.eu>
On 24/05/22 15:05, Christophe Leroy wrote:
>
> Le 23/05/2022 à 19:55, Sathvika Vasireddy a écrit :
>> This patch enables objtool --mcount on powerpc, and
>> adds implementation specific to powerpc.
>>
>> Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com>
>> ---
>> arch/powerpc/Kconfig | 1 +
>> tools/objtool/arch/powerpc/decode.c | 14 ++++++++++++++
>> tools/objtool/check.c | 12 +++++++-----
>> tools/objtool/elf.c | 13 +++++++++++++
>> tools/objtool/include/objtool/elf.h | 1 +
>> 5 files changed, 36 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
>> index 732a3f91ee5e..3373d44a1298 100644
>> --- a/arch/powerpc/Kconfig
>> +++ b/arch/powerpc/Kconfig
>> @@ -233,6 +233,7 @@ config PPC
>> select HAVE_NMI if PERF_EVENTS || (PPC64 && PPC_BOOK3S)
>> select HAVE_OPTPROBES
>> select HAVE_OBJTOOL if PPC64
>> + select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL
>> select HAVE_PERF_EVENTS
>> select HAVE_PERF_EVENTS_NMI if PPC64
>> select HAVE_PERF_REGS
>> diff --git a/tools/objtool/arch/powerpc/decode.c b/tools/objtool/arch/powerpc/decode.c
>> index e3b77a6ce357..ad3d79fffac2 100644
>> --- a/tools/objtool/arch/powerpc/decode.c
>> +++ b/tools/objtool/arch/powerpc/decode.c
>> @@ -40,12 +40,26 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
>> struct list_head *ops_list)
>> {
>> u32 insn;
>> + unsigned int opcode;
>>
>> *immediate = 0;
>> memcpy(&insn, sec->data->d_buf+offset, 4);
>> *len = 4;
>> *type = INSN_OTHER;
>>
>> + opcode = (insn >> 26);
> You dont need the brackets here.
>
>> +
>> + switch (opcode) {
>> + case 18: /* bl */
>> + if ((insn & 3) == 1) {
>> + *type = INSN_CALL;
>> + *immediate = insn & 0x3fffffc;
>> + if (*immediate & 0x2000000)
>> + *immediate -= 0x4000000;
>> + }
>> + break;
>> + }
>> +
>> return 0;
>> }
>>
>> diff --git a/tools/objtool/check.c b/tools/objtool/check.c
>> index 056302d58e23..fd8bad092f89 100644
>> --- a/tools/objtool/check.c
>> +++ b/tools/objtool/check.c
>> @@ -832,7 +832,7 @@ static int create_mcount_loc_sections(struct objtool_file *file)
>>
>> if (elf_add_reloc_to_insn(file->elf, sec,
>> idx * sizeof(unsigned long),
>> - R_X86_64_64,
>> + elf_reloc_type_long(file->elf),
>> insn->sec, insn->offset))
>> return -1;
>>
>> @@ -2183,7 +2183,7 @@ static int classify_symbols(struct objtool_file *file)
>> if (arch_is_retpoline(func))
>> func->retpoline_thunk = true;
>>
>> - if (!strcmp(func->name, "__fentry__"))
>> + if ((!strcmp(func->name, "__fentry__")) || (!strcmp(func->name, "_mcount")))
>> func->fentry = true;
>>
>> if (is_profiling_func(func->name))
>> @@ -2259,9 +2259,11 @@ static int decode_sections(struct objtool_file *file)
>> * Must be before add_jump_destinations(), which depends on 'func'
>> * being set for alternatives, to enable proper sibling call detection.
>> */
>> - ret = add_special_section_alts(file);
>> - if (ret)
>> - return ret;
>> + if (opts.stackval || opts.orc || opts.uaccess || opts.noinstr) {
>> + ret = add_special_section_alts(file);
>> + if (ret)
>> + return ret;
>> + }
> I think this change should be a patch by itself, it's not related to
> powerpc.
Makes sense. I'll make this a separate patch in the next revision.
>
>>
>> ret = add_jump_destinations(file);
>> if (ret)
>> diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
>> index c25e957c1e52..95763060d551 100644
>> --- a/tools/objtool/elf.c
>> +++ b/tools/objtool/elf.c
>> @@ -793,6 +793,19 @@ elf_create_section_symbol(struct elf *elf, struct section *sec)
>> return sym;
>> }
>>
>> +int elf_reloc_type_long(struct elf *elf)
> Not sure it's a good name, because for 32 bits we have to use 'int'.
Sure, I'll rename it to elf_reloc_type() or some such.
>
>> +{
>> + switch (elf->ehdr.e_machine) {
>> + case EM_X86_64:
>> + return R_X86_64_64;
>> + case EM_PPC64:
>> + return R_PPC64_ADDR64;
>> + default:
>> + WARN("unknown machine...");
>> + exit(-1);
>> + }
>> +}
> Wouldn't it be better to make that function arch specific ?
This is so that we can support cross architecture builds.
Thanks for reviewing!
- Sathvika
next prev parent reply other threads:[~2022-05-24 11:00 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-23 17:55 [RFC PATCH 0/4] objtool: Enable and implement --mcount option on powerpc Sathvika Vasireddy
2022-05-23 17:55 ` [RFC PATCH 1/4] objtool: Add --mnop as an option to --mcount Sathvika Vasireddy
2022-05-24 8:54 ` Christophe Leroy
2022-05-24 10:15 ` Naveen N. Rao
2022-05-24 10:20 ` Christophe Leroy
2022-05-24 10:31 ` Naveen N. Rao
2022-05-25 11:36 ` Peter Zijlstra
2022-05-26 11:51 ` Naveen N. Rao
2022-05-23 17:55 ` [RFC PATCH 2/4] objtool: Enable objtool to run only on files with ftrace enabled Sathvika Vasireddy
2022-05-24 8:57 ` Christophe Leroy
2022-05-24 10:53 ` Sathvika Vasireddy
2022-05-24 13:28 ` Christophe Leroy
2022-05-23 17:55 ` [RFC PATCH 3/4] objtool/powerpc: Enable objtool to be built on ppc Sathvika Vasireddy
2022-05-24 9:13 ` Christophe Leroy
2022-05-23 17:55 ` [RFC PATCH 4/4] objtool/powerpc: Add --mcount specific implementation Sathvika Vasireddy
2022-05-24 9:35 ` Christophe Leroy
2022-05-24 11:00 ` Sathvika Vasireddy [this message]
2022-05-24 13:33 ` Christophe Leroy
2022-05-25 17:27 ` Christophe Leroy
2022-05-31 6:20 ` Christophe Leroy
2022-06-16 13:34 ` Naveen N. Rao
2022-06-16 13:40 ` Christophe Leroy
2022-06-16 13:57 ` Peter Zijlstra
2022-06-16 14:06 ` Christophe Leroy
2022-06-17 14:04 ` Naveen N. Rao
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