parisc: Do not export __lshrdi3 on 64-bit with gcc >= 11

Commit Message

Helge Deller Nov. 27, 2021, 10:58 a.m. UTC

It seems the __lshrdi3 symbol was dropped from libgcc.a from gcc-11 for
64-bit executables.

Signed-off-by: Helge Deller <[e-mail]>
---
 arch/parisc/kernel/parisc_ksyms.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--
2.31.1

Comments

John David Anglin Nov. 27, 2021, 4:32 p.m. UTC | #1

On 2021-11-27 5:58 a.m., Helge Deller wrote:
> It seems the __lshrdi3 symbol was dropped from libgcc.a from gcc-11 for
> 64-bit executables.
This is gcc bug.  There's a typo in libgcc/config/pa/t-dimode:

# Extra DImode libgcc2 functions to build.
lib2difuncs = _muldi3 _negdi2 _lshrdi _ashldi3 _ashrdi3 _cmpdi2 _ucmpdi2

Will fix.

__lshrdi3 isn't needed anymore for 64-bit binaries with gcc-11 and later.  Not sure for other shifts
but it should be possible to handle them in pa.md.

Dave

John David Anglin Nov. 27, 2021, 9:52 p.m. UTC | #2

On 2021-11-27 11:32 a.m., John David Anglin wrote:
> On 2021-11-27 5:58 a.m., Helge Deller wrote:
>> It seems the __lshrdi3 symbol was dropped from libgcc.a from gcc-11 for
>> 64-bit executables.
> This is gcc bug.  There's a typo in libgcc/config/pa/t-dimode:
>
> # Extra DImode libgcc2 functions to build.
> lib2difuncs = _muldi3 _negdi2 _lshrdi _ashldi3 _ashrdi3 _cmpdi2 _ucmpdi2
>
> Will fix.
This is now fixed in upstream gcc source.

Dave

Helge Deller Nov. 27, 2021, 10:08 p.m. UTC | #3

On 11/27/21 22:52, John David Anglin wrote:
> On 2021-11-27 11:32 a.m., John David Anglin wrote:
>> On 2021-11-27 5:58 a.m., Helge Deller wrote:
>>> It seems the __lshrdi3 symbol was dropped from libgcc.a from gcc-11 for
>>> 64-bit executables.
>> This is gcc bug.  There's a typo in libgcc/config/pa/t-dimode:
>>
>> # Extra DImode libgcc2 functions to build.
>> lib2difuncs = _muldi3 _negdi2 _lshrdi _ashldi3 _ashrdi3 _cmpdi2 _ucmpdi2
>>
>> Will fix.
> This is now fixed in upstream gcc source.

Thanks for fixing, Dave!

So, my patch:
https://patchwork.kernel.org/project/linux-parisc/patch/[e-mail]/
and Mikulas patch:
https://patchwork.kernel.org/project/linux-parisc/patch/[e-mail]/
won't be needed.

Good to know.

Helge

John David Anglin Nov. 27, 2021, 10:25 p.m. UTC | #4

On 2021-11-27 5:08 p.m., Helge Deller wrote:
> On 11/27/21 22:52, John David Anglin wrote:
>> On 2021-11-27 11:32 a.m., John David Anglin wrote:
>>> On 2021-11-27 5:58 a.m., Helge Deller wrote:
>>>> It seems the __lshrdi3 symbol was dropped from libgcc.a from gcc-11 for
>>>> 64-bit executables.
>>> This is gcc bug.  There's a typo in libgcc/config/pa/t-dimode:
>>>
>>> # Extra DImode libgcc2 functions to build.
>>> lib2difuncs = _muldi3 _negdi2 _lshrdi _ashldi3 _ashrdi3 _cmpdi2 _ucmpdi2
>>>
>>> Will fix.
>> This is now fixed in upstream gcc source.
> Thanks for fixing, Dave!
>
> So, my patch:
> https://patchwork.kernel.org/project/linux-parisc/patch/[e-mail]/
> and Mikulas patch:
> https://patchwork.kernel.org/project/linux-parisc/patch/[e-mail]/
> won't be needed.
Yes.  I will rebuild gcc-11 with fix but that will take a day or so.  In the meantime, gcc-10 should work.

But it would be good to know if the shift routines in libgcc are needed with gcc-11.  All the shifts should be inline.

Dave

Patch

diff --git a/arch/parisc/kernel/parisc_ksyms.c b/arch/parisc/kernel/parisc_ksyms.c
index 00297e8e1c88..f26c51370255 100644
--- a/arch/parisc/kernel/parisc_ksyms.c
+++ b/arch/parisc/kernel/parisc_ksyms.c
@@ -14,6 +14,7 @@ 
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/syscalls.h>
+#include <linux/compiler.h>

 #include <linux/string.h>
 EXPORT_SYMBOL(memset);
@@ -94,16 +95,19 @@  EXPORT_SYMBOL($$divI_15);

 extern void __ashrdi3(void);
 extern void __ashldi3(void);
-extern void __lshrdi3(void);
 extern void __muldi3(void);
 extern void __ucmpdi2(void);

 EXPORT_SYMBOL(__ashrdi3);
 EXPORT_SYMBOL(__ashldi3);
-EXPORT_SYMBOL(__lshrdi3);
 EXPORT_SYMBOL(__muldi3);
 EXPORT_SYMBOL(__ucmpdi2);

+#if !(defined(CONFIG_64BIT) && (GCC_VERSION >= 110000))
+extern void __lshrdi3(void);
+EXPORT_SYMBOL(__lshrdi3);
+#endif
+
 asmlinkage void * __canonicalize_funcptr_for_compare(void *);
 EXPORT_SYMBOL(__canonicalize_funcptr_for_compare);