| Message ID | 20220511185001.3269404-1-nathan@kernel.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | Link the PowerPC vDSO with ld.lld | expand |
On Wed, 11 May 2022 11:49:59 -0700, Nathan Chancellor wrote: > This series is an alternative to the one proposed by Nick before the > PowerPC vDSO unification in commit fd1feade75fb ("powerpc/vdso: Merge > vdso64 and vdso32 into a single directory"): > > https://lore.kernel.org/20200901222523.1941988-1-ndesaulniers@google.com/ > > Normally, we try to make compiling and linking two separate stages so > that they can be done by $(CC) and $(LD) respectively, which is more in > line with what the user expects, versus using the compiler as a linker > driver and relying on the implicit default linker value. However, as > shown in the above thread, getting this right for the PowerPC vDSO is a > little tricky due to the linker emulation values. > > [...] Applied to powerpc/next. [1/2] powerpc/vdso: Remove unused ENTRY in linker scripts https://git.kernel.org/powerpc/c/e247172854a57d1a7213bb835ecb4a40ce9bb2b9 [2/2] powerpc/vdso: Link with ld.lld when requested https://git.kernel.org/powerpc/c/4406b12214f6592909b63dabdea86d69f1b5ba2e cheers
Hi all, This series is an alternative to the one proposed by Nick before the PowerPC vDSO unification in commit fd1feade75fb ("powerpc/vdso: Merge vdso64 and vdso32 into a single directory"): https://lore.kernel.org/20200901222523.1941988-1-ndesaulniers@google.com/ Normally, we try to make compiling and linking two separate stages so that they can be done by $(CC) and $(LD) respectively, which is more in line with what the user expects, versus using the compiler as a linker driver and relying on the implicit default linker value. However, as shown in the above thread, getting this right for the PowerPC vDSO is a little tricky due to the linker emulation values. The unification might make this easier but that needs further investigation. To avoid regressing ld.bfd while enabling support for linking the vDSO with ld.lld, we can tell the compiler to use ld.lld via either '--ld-path=' (clang 12.0.0) or '-fuse-ld=lld'. The first patch avoids a warning from ld.lld when linking both vDSO objects and the second patch adds the flags. This should help avoid the issue noticed during Alexey's LTO bring up: https://lore.kernel.org/CAKwvOdmUMhqhQhDCpWjMNiQQPvwOJB9MbUkF3RR0BL+H+DagmA@mail.gmail.com/ Changelog: v1 -> v2: https://lore.kernel.org/20220509204635.2539549-1-nathan@kernel.org/ * Flush out the second commit message much more with information from this cover letter and the other threads (Alexey's LTO enablement and Nick's initial stab at converting to $(CC) + $(LD)) [Nick]. * Add Nick and Alexey's tags. Nathan Chancellor (2): powerpc/vdso: Remove unused ENTRY in linker scripts powerpc/vdso: Link with ld.lld when requested arch/powerpc/kernel/vdso/Makefile | 1 + arch/powerpc/kernel/vdso/vdso32.lds.S | 1 - arch/powerpc/kernel/vdso/vdso64.lds.S | 1 - 3 files changed, 1 insertion(+), 2 deletions(-) base-commit: b6b1c3ce06ca438eb24e0f45bf0e63ecad0369f5