[1/3] scripts/recordmcount.pl: Fix RISC-V regex for clang
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Message ID 20210325223807.2423265-2-nathan@kernel.org
State Accepted
Commit 2f095504f4b9cf75856d6a9cf90299cf75aa46c5
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Series
  • Fix CONFIG_FUNCTION_TRACER with clang
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Commit Message

Nathan Chancellor March 25, 2021, 10:38 p.m. UTC
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.

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(-)

Comments

Fangrui Song March 25, 2021, 11:36 p.m. UTC | #1
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
>
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Patch
diff mbox series

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") {