Re: [PATCH v2 10/18] arm64: add a workaround for GNU gold with ARM64_MODULE_PLTS

2017-11-16 Thread Will Deacon
On Thu, Nov 16, 2017 at 08:41:01AM -0800, Sami Tolvanen wrote: > On Thu, Nov 16, 2017 at 11:50:12AM +, Will Deacon wrote: > > Why don't we just not do LTO if the toolchain is busted? > > Because LTO can not only potentially improve performance, especially > when combined with PGO (Profile

Re: [PATCH v2 10/18] arm64: add a workaround for GNU gold with ARM64_MODULE_PLTS

2017-11-16 Thread Will Deacon
On Thu, Nov 16, 2017 at 08:41:01AM -0800, Sami Tolvanen wrote: > On Thu, Nov 16, 2017 at 11:50:12AM +, Will Deacon wrote: > > Why don't we just not do LTO if the toolchain is busted? > > Because LTO can not only potentially improve performance, especially > when combined with PGO (Profile

Re: [PATCH v2 10/18] arm64: add a workaround for GNU gold with ARM64_MODULE_PLTS

2017-11-16 Thread Sami Tolvanen
On Thu, Nov 16, 2017 at 11:50:12AM +, Will Deacon wrote: > Why don't we just not do LTO if the toolchain is busted? Because LTO can not only potentially improve performance, especially when combined with PGO (Profile Guided Optimization), but it also makes it possible to enable features like

Re: [PATCH v2 10/18] arm64: add a workaround for GNU gold with ARM64_MODULE_PLTS

2017-11-16 Thread Sami Tolvanen
On Thu, Nov 16, 2017 at 11:50:12AM +, Will Deacon wrote: > Why don't we just not do LTO if the toolchain is busted? Because LTO can not only potentially improve performance, especially when combined with PGO (Profile Guided Optimization), but it also makes it possible to enable features like

Re: [PATCH v2 10/18] arm64: add a workaround for GNU gold with ARM64_MODULE_PLTS

2017-11-16 Thread Will Deacon
On Wed, Nov 15, 2017 at 01:34:20PM -0800, Sami Tolvanen wrote: > CONFIG_CLANG_LTO depends on GNU gold and due to a known bug, the > linker crashes when ARM64_MODULE_PLTS is enabled: > > https://sourceware.org/bugzilla/show_bug.cgi?id=14592 > > To work around the problem, this change removes

Re: [PATCH v2 10/18] arm64: add a workaround for GNU gold with ARM64_MODULE_PLTS

2017-11-16 Thread Will Deacon
On Wed, Nov 15, 2017 at 01:34:20PM -0800, Sami Tolvanen wrote: > CONFIG_CLANG_LTO depends on GNU gold and due to a known bug, the > linker crashes when ARM64_MODULE_PLTS is enabled: > > https://sourceware.org/bugzilla/show_bug.cgi?id=14592 > > To work around the problem, this change removes

[PATCH v2 10/18] arm64: add a workaround for GNU gold with ARM64_MODULE_PLTS

2017-11-15 Thread Sami Tolvanen
CONFIG_CLANG_LTO depends on GNU gold and due to a known bug, the linker crashes when ARM64_MODULE_PLTS is enabled: https://sourceware.org/bugzilla/show_bug.cgi?id=14592 To work around the problem, this change removes NOLOAD from .plt and .init.plt, which allows us to link modules with ld.gold.

[PATCH v2 10/18] arm64: add a workaround for GNU gold with ARM64_MODULE_PLTS

2017-11-15 Thread Sami Tolvanen
CONFIG_CLANG_LTO depends on GNU gold and due to a known bug, the linker crashes when ARM64_MODULE_PLTS is enabled: https://sourceware.org/bugzilla/show_bug.cgi?id=14592 To work around the problem, this change removes NOLOAD from .plt and .init.plt, which allows us to link modules with ld.gold.