Messages in this thread | | | From | Christophe Leroy <> | Subject | Re: Regression: Linux v5.15+ does not boot on Freescale P2020 | Date | Sat, 23 Jul 2022 14:42:22 +0000 |
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Hello,
Le 22/07/2022 à 11:09, Pali Rohár a écrit : > Hello! > > 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 run git bisect and it found following commit: > > 9401f4e46cf6965e23738f70e149172344a01eef is the first bad commit > commit 9401f4e46cf6965e23738f70e149172344a01eef > Author: Christophe Leroy <christophe.leroy@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.leroy@csgroup.eu> > Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> > Link: https://lore.kernel.org/r/1fc81f07cabebb875b963e295408cc3dd38c8d85.1614674882.git.christophe.leroy@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.
Christophe
> > I have looked into e500 Reference Manual for lwarx instruction (page 562) > https://www.nxp.com/files-static/32bit/doc/ref_manual/EREF_RM.pdf and > both 0 and 1 values for EH flag should be supported. | |