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From: Fangrui Song <maskray@google.com>
To: Nathan Chancellor <nathan@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	clang-built-linux@googlegroups.com, stable@vger.kernel.org
Subject: Re: [PATCH 1/3] scripts/recordmcount.pl: Fix RISC-V regex for clang
Date: Thu, 25 Mar 2021 16:36:40 -0700	[thread overview]
Message-ID: <20210325233640.jzi7uvaohvqwixiu@google.com> (raw)
In-Reply-To: <20210325223807.2423265-2-nathan@kernel.org>

On 2021-03-25, Nathan Chancellor wrote:
>Clang can generate R_RISCV_CALL_PLT relocations to _mcount:
>
>$ llvm-objdump -dr build/riscv/init/main.o | rg mcount
>                000000000000000e:  R_RISCV_CALL_PLT     _mcount
>                000000000000004e:  R_RISCV_CALL_PLT     _mcount
>
>After this, the __start_mcount_loc section is properly generated and
>function tracing still works.
>

R_RISCV_CALL_PLT can replace R_RISCV_CALL in all use cases.
R_RISCV_CALL can/may be deprecated:
https://github.com/ClangBuiltLinux/linux/issues/1331#issuecomment-802468296

Reviewed-by: Fangrui Song <maskray@google.com>


>Cc: stable@vger.kernel.org
>Link: https://github.com/ClangBuiltLinux/linux/issues/1331
>Signed-off-by: Nathan Chancellor <nathan@kernel.org>
>---
> scripts/recordmcount.pl | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
>index 867860ea57da..a36df04cfa09 100755
>--- a/scripts/recordmcount.pl
>+++ b/scripts/recordmcount.pl
>@@ -392,7 +392,7 @@ if ($arch eq "x86_64") {
>     $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s_mcount\$";
> } elsif ($arch eq "riscv") {
>     $function_regex = "^([0-9a-fA-F]+)\\s+<([^.0-9][0-9a-zA-Z_\\.]+)>:";
>-    $mcount_regex = "^\\s*([0-9a-fA-F]+):\\sR_RISCV_CALL\\s_mcount\$";
>+    $mcount_regex = "^\\s*([0-9a-fA-F]+):\\sR_RISCV_CALL(_PLT)?\\s_mcount\$";
>     $type = ".quad";
>     $alignment = 2;
> } elsif ($arch eq "nds32") {
>-- 
>2.31.0
>
>-- 
>You received this message because you are subscribed to the Google Groups "Clang Built Linux" group.
>To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@googlegroups.com.
>To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/20210325223807.2423265-2-nathan%40kernel.org.

WARNING: multiple messages have this Message-ID (diff)
From: Fangrui Song <maskray@google.com>
To: Nathan Chancellor <nathan@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	clang-built-linux@googlegroups.com, stable@vger.kernel.org
Subject: Re: [PATCH 1/3] scripts/recordmcount.pl: Fix RISC-V regex for clang
Date: Thu, 25 Mar 2021 16:36:40 -0700	[thread overview]
Message-ID: <20210325233640.jzi7uvaohvqwixiu@google.com> (raw)
In-Reply-To: <20210325223807.2423265-2-nathan@kernel.org>

On 2021-03-25, Nathan Chancellor wrote:
>Clang can generate R_RISCV_CALL_PLT relocations to _mcount:
>
>$ llvm-objdump -dr build/riscv/init/main.o | rg mcount
>                000000000000000e:  R_RISCV_CALL_PLT     _mcount
>                000000000000004e:  R_RISCV_CALL_PLT     _mcount
>
>After this, the __start_mcount_loc section is properly generated and
>function tracing still works.
>

R_RISCV_CALL_PLT can replace R_RISCV_CALL in all use cases.
R_RISCV_CALL can/may be deprecated:
https://github.com/ClangBuiltLinux/linux/issues/1331#issuecomment-802468296

Reviewed-by: Fangrui Song <maskray@google.com>


>Cc: stable@vger.kernel.org
>Link: https://github.com/ClangBuiltLinux/linux/issues/1331
>Signed-off-by: Nathan Chancellor <nathan@kernel.org>
>---
> scripts/recordmcount.pl | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
>index 867860ea57da..a36df04cfa09 100755
>--- a/scripts/recordmcount.pl
>+++ b/scripts/recordmcount.pl
>@@ -392,7 +392,7 @@ if ($arch eq "x86_64") {
>     $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s_mcount\$";
> } elsif ($arch eq "riscv") {
>     $function_regex = "^([0-9a-fA-F]+)\\s+<([^.0-9][0-9a-zA-Z_\\.]+)>:";
>-    $mcount_regex = "^\\s*([0-9a-fA-F]+):\\sR_RISCV_CALL\\s_mcount\$";
>+    $mcount_regex = "^\\s*([0-9a-fA-F]+):\\sR_RISCV_CALL(_PLT)?\\s_mcount\$";
>     $type = ".quad";
>     $alignment = 2;
> } elsif ($arch eq "nds32") {
>-- 
>2.31.0
>
>-- 
>You received this message because you are subscribed to the Google Groups "Clang Built Linux" group.
>To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@googlegroups.com.
>To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/20210325223807.2423265-2-nathan%40kernel.org.

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  reply	other threads:[~2021-03-25 23:37 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-25 22:38 [PATCH 0/3] Fix CONFIG_FUNCTION_TRACER with clang Nathan Chancellor
2021-03-25 22:38 ` Nathan Chancellor
2021-03-25 22:38 ` [PATCH 1/3] scripts/recordmcount.pl: Fix RISC-V regex for clang Nathan Chancellor
2021-03-25 22:38   ` Nathan Chancellor
2021-03-25 23:36   ` Fangrui Song [this message]
2021-03-25 23:36     ` Fangrui Song
2021-03-25 22:38 ` [PATCH 2/3] riscv: Workaround mcount name prior to clang-13 Nathan Chancellor
2021-03-25 22:38   ` Nathan Chancellor
2021-03-29 18:32   ` Nick Desaulniers
2021-03-29 18:32     ` Nick Desaulniers
2021-03-25 22:38 ` [PATCH 3/3] riscv: Select HAVE_DYNAMIC_FTRACE when -fpatchable-function-entry is available Nathan Chancellor
2021-03-25 22:38   ` Nathan Chancellor
2021-03-25 23:38   ` Fangrui Song
2021-03-25 23:38     ` Fangrui Song
2021-03-26  8:37 ` [PATCH 0/3] Fix CONFIG_FUNCTION_TRACER with clang Sedat Dilek
2021-03-26  8:37   ` Sedat Dilek
2021-03-26 13:07   ` Nathan Chancellor
2021-03-26 13:07     ` Nathan Chancellor
2021-03-27 12:16     ` Sedat Dilek
2021-03-27 12:16       ` Sedat Dilek
2021-04-11 21:27 ` Palmer Dabbelt
2021-04-11 21:27   ` Palmer Dabbelt

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