Messages in this thread | | | From | Nick Desaulniers <> | Date | Tue, 31 May 2022 15:08:50 -0700 | Subject | Re: arch/x86/entry/entry: RFC on recent kernels building error with llvm 11.0.2 internal assembler |
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On Sun, May 29, 2022 at 10:52 AM Mauro Rossi <issor.oruam@gmail.com> wrote: > > > > On Mon, May 9, 2022 at 2:07 AM Nathan Chancellor <nathan@kernel.org> wrote: >> >> On Sat, May 07, 2022 at 02:19:00PM +0200, Mauro Rossi wrote: >> > > > Alternatively, you could apply the hack that Nick inserted into Android >> > > > for this issue if upgrading your toolchain or turning off the integrated >> > > > assembler is not possible: >> > > > >> > > > https://android.googlesource.com/kernel/common/+/e58f084735b8abf744d61083b92172ee23d45aae >> > > > >> > > > I really do not mean to sound dismissive or rude, I apologize if it >> > > > comes off that way, but we have worked quite hard to avoid inserting >> > > > unnecessary workarounds, as they are ultimately technical debt that can >> > > > be hard to manage over the long term. >> > > > >> > > > Cheers, >> > > > Nathan >> > > >> > > Thanks a lot Nathan >> > > >> > > It is definitely the clang version 11.0.x which is not updated in aosp >> > > Android 11 production tags >> > > >> > > I will use Nick's workaround which works since only lsl %rax, %rax is >> > > currently happening >> > > >> > > Many thanks, problem solved >> > >> > Hello, >> > I'm back again because I was assuming that Nick's workaround was working ok, >> > but I have found that ARCH=x86_64 i.e. 64bit built kernel is causing >> > an immediate hard reboot at initrd execution, >> > just after hitting [ENTER] at grub/efi menu. >> >> It looks like there was a follow up fix for that workaround, maybe that >> resolves this issue as well? >> >> https://android.googlesource.com/kernel/common/+/cc7f7a84191f5defc2ea4633eeea4acb4486b549 >> >> > ARCh=x86 i.e. 32bit kernel binary is not affected, but is Nick's >> > workaround targeting 32 bit kernel builds? >> >> No, the file that the build error originates from (entry_64.S) is only >> built on x86_64. >> >> > How do aosp android-mailine kernels avoid this instantaneous hard reboot issue? >> >> That hack was reverted once the toolchain was upgraded: >> >> https://android.googlesource.com/kernel/common/+/ff0216d09fd31802537f2d1702ec2f3e9be73aa3 >> https://android.googlesource.com/kernel/common/+/3c2c8d8f7f2639e319212d10cb8df5bd13098dae >> >> Cheers, >> Nathan > > > Hello, > > sorry i still have the issue when building with hack "ANDROID: x86: entry: work around LLVM_IAS=1 bug in LSL" > I'd just like to understand why I get instant reboot in 64bit kernel built with LLVM_IAS=1
As Nathan noted, I messed up the commit "ANDROID: x86: entry: work around LLVM_IAS=1 bug in LSL". Please see: https://android-review.googlesource.com/c/kernel/common/+/1521061 https://android-review.googlesource.com/c/kernel/common/+/1560152/
If you're using an older toolchain, you'll need just the first. If you're using a newer toolchain, you'll need BOTH (or none, including dropping "ANDROID: x86: entry: work around LLVM_IAS=1 bug in LSL").
> > I searched for the places where #include "calling.h" is used > > utente@utente-3TB:~/r-x86_kernel/kernel$ grep -r \#include\ \"calling > arch/x86/entry/thunk_64.S:#include "calling.h" > arch/x86/entry/entry_32.S:#include "calling.h" > arch/x86/entry/entry_64_compat.S:#include "calling.h" > arch/x86/entry/entry_64.S:#include "calling.h" > > Probably the hardcoding done in the hack is impacting some other asm target built in 64 bit kernel and causes a wrong X86 instruction , is there a way to refine the #if to avoid that problem while still building with LLVM_IAS=1 ? > > Thanks for the info > Mauro > >
-- Thanks, ~Nick Desaulniers
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