Pali Rohár <p...@kernel.org> writes: > On Saturday 23 July 2022 14:42:22 Christophe Leroy wrote: >> Le 22/07/2022 à 11:09, Pali Rohár a écrit : >> > Trying to boot mainline Linux kernel v5.15+, including current version >> > from master branch, on Freescale P2020 does not work. Kernel does not >> > print anything to serial console, seems that it does not work and after >> > timeout watchdog reset the board. >> >> Can you provide more information ? Which defconfig or .config, which >> version of gcc, etc ... ? > > I used default defconfig for mpc85xx with gcc 8, compilation for e500 > cores. > > If you need exact .config content I can send it during week. > >> > I run git bisect and it found following commit: >> > >> > 9401f4e46cf6965e23738f70e149172344a01eef is the first bad commit >> > commit 9401f4e46cf6965e23738f70e149172344a01eef >> > Author: Christophe Leroy <christophe.le...@csgroup.eu> >> > Date: Tue Mar 2 08:48:11 2021 +0000 >> > >> > powerpc: Use lwarx/ldarx directly instead of PPC_LWARX/LDARX macros >> > >> > Force the eh flag at 0 on PPC32. >> > >> > Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu> >> > Signed-off-by: Michael Ellerman <m...@ellerman.id.au> >> > Link: >> > https://lore.kernel.org/r/1fc81f07cabebb875b963e295408cc3dd38c8d85.1614674882.git.christophe.le...@csgroup.eu >> > >> > :040000 040000 fe6747e45736dfcba74914a9445e5f70f5120600 >> > 96358d08b65d3200928a973efb5b969b3d45f2b0 M arch >> > >> > >> > If I revert this commit then kernel boots correctly. It also boots fine >> > if I revert this commit on top of master branch. >> > >> > Freescale P2020 has two 32-bit e500 powerpc cores. >> > >> > Any idea why above commit is causing crash of the kernel? And why it is >> > needed? Could eh flag set to 0 cause deadlock? >> >> Setting the eh flag to 0 is not supposed to be a change introduced by >> that commit. Indeed that commit is not supposed to change anything at >> all in the generated code. > > My understanding of that commit is that it changed eh flag parameter > from 1 to 0 for 32-bit powerpc, including also p2020.
Can you compare the disassembly before and after and find a place where an instruction has changed? cheers
