From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Sathvika Vasireddy <sv@linux.ibm.com>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Cc: "jpoimboe@redhat.com" <jpoimboe@redhat.com>,
"peterz@infradead.org" <peterz@infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"aik@ozlabs.ru" <aik@ozlabs.ru>,
"mpe@ellerman.id.au" <mpe@ellerman.id.au>,
"mingo@redhat.com" <mingo@redhat.com>,
"rostedt@goodmis.org" <rostedt@goodmis.org>,
"mbenes@suse.cz" <mbenes@suse.cz>,
"npiggin@gmail.com" <npiggin@gmail.com>,
"chenzhongjin@huawei.com" <chenzhongjin@huawei.com>,
"naveen.n.rao@linux.vnet.ibm.com"
<naveen.n.rao@linux.vnet.ibm.com>
Subject: Re: [PATCH v4 11/16] objtool: Add --mnop as an option to --mcount
Date: Sun, 2 Oct 2022 17:40:41 +0000 [thread overview]
Message-ID: <172590d6-8e46-4992-acc5-a2d01504636b@csgroup.eu> (raw)
In-Reply-To: <20221002104240.1316480-12-sv@linux.ibm.com>
Le 02/10/2022 à 12:42, Sathvika Vasireddy a écrit :
> Some architectures (powerpc) may not support ftrace locations being nop'ed
> out at build time. Introduce CONFIG_HAVE_OBJTOOL_NOP_MCOUNT for objtool, as
> a means for architectures to enable nop'ing of ftrace locations. Add --mnop
> as an option to objtool --mcount, to indicate support for the same.
>
> Also, make sure that --mnop can be passed as an option to objtool only when
> --mcount is passed.
>
> Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> ---
> Makefile | 4 +++-
> arch/x86/Kconfig | 1 +
> kernel/trace/Kconfig | 7 +++++++
> scripts/Makefile.lib | 1 +
> tools/objtool/builtin-check.c | 14 ++++++++++++++
> tools/objtool/check.c | 19 ++++++++++---------
> tools/objtool/include/objtool/builtin.h | 1 +
> 7 files changed, 37 insertions(+), 10 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index a5e9d9388649..b2230ad14748 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -857,7 +857,9 @@ ifdef CONFIG_FTRACE_MCOUNT_USE_CC
> endif
> endif
> ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL
> - CC_FLAGS_USING += -DCC_USING_NOP_MCOUNT
> + ifdef CONFIG_HAVE_OBJTOOL_NOP_MCOUNT
> + CC_FLAGS_USING += -DCC_USING_NOP_MCOUNT
> + endif
> endif
> ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
> ifdef CONFIG_HAVE_C_RECORDMCOUNT
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index f9920f1341c8..2a79a05c4402 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -189,6 +189,7 @@ config X86
> select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER
> select HAVE_C_RECORDMCOUNT
> select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL
> + select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT
> select HAVE_BUILDTIME_MCOUNT_SORT
> select HAVE_DEBUG_KMEMLEAK
> select HAVE_DMA_CONTIGUOUS
> diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
> index 1052126bdca2..9c696cb24756 100644
> --- a/kernel/trace/Kconfig
> +++ b/kernel/trace/Kconfig
> @@ -76,6 +76,13 @@ config HAVE_OBJTOOL_MCOUNT
> help
> Arch supports objtool --mcount
>
> +config HAVE_OBJTOOL_NOP_MCOUNT
> + bool
> + help
> + Arch supports the objtool options --mcount with --mnop.
> + An architecture can select this if it wants to enable nop'ing
> + of ftrace locations.
> +
> config HAVE_C_RECORDMCOUNT
> bool
> help
> diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> index 3fb6a99e78c4..ce14e3b8577f 100644
> --- a/scripts/Makefile.lib
> +++ b/scripts/Makefile.lib
> @@ -234,6 +234,7 @@ objtool_args = \
> $(if $(CONFIG_HAVE_NOINSTR_HACK), --hacks=noinstr) \
> $(if $(CONFIG_X86_KERNEL_IBT), --ibt) \
> $(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount) \
> + $(if $(CONFIG_HAVE_OBJTOOL_NOP_MCOUNT), --mnop) \
> $(if $(CONFIG_UNWINDER_ORC), --orc) \
> $(if $(CONFIG_RETPOLINE), --retpoline) \
> $(if $(CONFIG_RETHUNK), --rethunk) \
> diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
> index 24fbe803a0d3..9bd347d3c244 100644
> --- a/tools/objtool/builtin-check.c
> +++ b/tools/objtool/builtin-check.c
> @@ -82,6 +82,7 @@ const struct option check_options[] = {
> OPT_BOOLEAN(0, "dry-run", &opts.dryrun, "don't write modifications"),
> OPT_BOOLEAN(0, "link", &opts.link, "object is a linked object"),
> OPT_BOOLEAN(0, "module", &opts.module, "object is part of a kernel module"),
> + OPT_BOOLEAN(0, "mnop", &opts.mnop, "nop out mcount call sites"),
> OPT_BOOLEAN(0, "no-unreachable", &opts.no_unreachable, "skip 'unreachable instruction' warnings"),
> OPT_BOOLEAN(0, "sec-address", &opts.sec_address, "print section addresses in warnings"),
> OPT_BOOLEAN(0, "stats", &opts.stats, "print statistics"),
> @@ -150,6 +151,16 @@ static bool opts_valid(void)
> return false;
> }
>
> +static bool mnop_opts_valid(void)
> +{
> + if (opts.mnop && !opts.mcount) {
> + ERROR("--mnop requires --mcount");
> + return false;
> + }
> +
> + return true;
> +}
> +
> static bool link_opts_valid(struct objtool_file *file)
> {
> if (opts.link)
> @@ -198,6 +209,9 @@ int objtool_run(int argc, const char **argv)
> if (!file)
> return 1;
>
> + if (!mnop_opts_valid())
> + return 1;
> +
> if (!link_opts_valid(file))
> return 1;
>
> diff --git a/tools/objtool/check.c b/tools/objtool/check.c
> index 738de23cb9e8..35827e6c6df9 100644
> --- a/tools/objtool/check.c
> +++ b/tools/objtool/check.c
> @@ -1233,17 +1233,18 @@ static void annotate_call_site(struct objtool_file *file,
> if (opts.mcount && sym->fentry) {
> if (sibling)
> WARN_FUNC("Tail call to __fentry__ !?!?", insn->sec, insn->offset);
> + if (opts.mnop) {
> + if (reloc) {
> + reloc->type = R_NONE;
> + elf_write_reloc(file->elf, reloc);
> + }
>
> - if (reloc) {
> - reloc->type = R_NONE;
> - elf_write_reloc(file->elf, reloc);
> - }
> -
> - elf_write_insn(file->elf, insn->sec,
> - insn->offset, insn->len,
> - arch_nop_insn(insn->len));
> + elf_write_insn(file->elf, insn->sec,
> + insn->offset, insn->len,
> + arch_nop_insn(insn->len));
>
> - insn->type = INSN_NOP;
> + insn->type = INSN_NOP;
> + }
>
> list_add_tail(&insn->call_node, &file->mcount_loc_list);
> return;
> diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h
> index 42a52f1a0add..0785707c5a92 100644
> --- a/tools/objtool/include/objtool/builtin.h
> +++ b/tools/objtool/include/objtool/builtin.h
> @@ -31,6 +31,7 @@ struct opts {
> bool backup;
> bool dryrun;
> bool link;
> + bool mnop;
> bool module;
> bool no_unreachable;
> bool sec_address;
next prev parent reply other threads:[~2022-10-02 17:40 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-02 10:42 [PATCH v4 00/16] objtool: Enable and implement --mcount option on powerpc Sathvika Vasireddy
2022-10-02 10:42 ` [PATCH v4 01/16] powerpc: Fix __WARN_FLAGS() for use with Objtool Sathvika Vasireddy
2022-10-02 10:42 ` [PATCH v4 02/16] powerpc: Override __ALIGN and __ALIGN_STR macros Sathvika Vasireddy
2022-10-02 17:41 ` Christophe Leroy
2022-10-02 10:42 ` [PATCH v4 03/16] powerpc: Fix objtool unannotated intra-function call warnings Sathvika Vasireddy
2022-10-10 11:34 ` Naveen N. Rao
2022-10-02 10:42 ` [PATCH v4 04/16] powerpc: Curb objtool unannotated intra-function warnings Sathvika Vasireddy
2022-10-02 10:42 ` [PATCH v4 05/16] powerpc: Skip objtool from running on drivers/crypto/vmx/aesp8-ppc.o Sathvika Vasireddy
2022-10-02 10:42 ` [PATCH v4 06/16] powerpc: Fix objtool unannotated intra-function call warnings on PPC32 Sathvika Vasireddy
2022-10-02 10:42 ` [PATCH v4 07/16] powerpc: Skip objtool from running on VDSO files Sathvika Vasireddy
2022-10-02 10:42 ` [PATCH v4 08/16] objtool: Fix SEGFAULT Sathvika Vasireddy
2022-10-02 10:42 ` [PATCH v4 09/16] objtool: Use target file endianness instead of a compiled constant Sathvika Vasireddy
2022-10-02 10:42 ` [PATCH v4 10/16] objtool: Use target file class size " Sathvika Vasireddy
2022-10-02 10:42 ` [PATCH v4 11/16] objtool: Add --mnop as an option to --mcount Sathvika Vasireddy
2022-10-02 17:40 ` Christophe Leroy [this message]
2022-10-10 11:37 ` Naveen N. Rao
2022-10-11 20:33 ` Josh Poimboeuf
2022-10-12 13:47 ` Naveen N. Rao
2022-10-02 10:42 ` [PATCH v4 12/16] objtool: Read special sections with alts only when specific options are selected Sathvika Vasireddy
2022-10-02 17:42 ` Christophe Leroy
2022-10-02 10:42 ` [PATCH v4 13/16] objtool: Use macros to define arch specific reloc types Sathvika Vasireddy
2022-10-02 10:42 ` [PATCH v4 14/16] objtool: Add arch specific function arch_ftrace_match() Sathvika Vasireddy
2022-10-02 10:42 ` [PATCH v4 15/16] objtool/powerpc: Enable objtool to be built on ppc Sathvika Vasireddy
2022-10-02 10:42 ` [PATCH v4 16/16] objtool/powerpc: Add --mcount specific implementation Sathvika Vasireddy
2022-10-02 17:42 ` Christophe Leroy
2022-10-10 11:49 ` [PATCH v4 00/16] objtool: Enable and implement --mcount option on powerpc Naveen N. Rao
[not found] ` <notmuch-sha1-66fb111b87471c685a53b80a0502d959f90d07a7>
2022-10-13 0:05 ` Josh Poimboeuf
2022-10-13 3:40 ` Naveen N. Rao
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