[Bug 215621] Warning: Unable to mark rodata read only on this CPU. (PPC970MP)
https://bugzilla.kernel.org/show_bug.cgi?id=215621 --- Comment #4 from Christophe Leroy (christophe.le...@csgroup.eu) --- It is up to you to unselect CONFIG_STRICT_KERNEL_RWX. The kernel is usually built to boot on any PPC64 processors, so we can't forbid the selection of CONFIG_STRICT_KERNEL_RWX. -- You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.
[Bug 215621] Warning: Unable to mark rodata read only on this CPU. (PPC970MP)
https://bugzilla.kernel.org/show_bug.cgi?id=215621 Erhard F. (erhar...@mailbox.org) changed: What|Removed |Added Status|NEW |RESOLVED Resolution|--- |INVALID --- Comment #3 from Erhard F. (erhar...@mailbox.org) --- Erm ok, so it seems I did not check this thoroughly... If MMU_FTRS_PPC970 doesn't provide MMU_FTR_KERNEL_RO then perhaps CONFIG_STRICT_KERNEL_RWX can be skipped in the .config so it can't be wrongly selected? Anyhow you are correct that this is not a bug. Thanks for the background! -- You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.
[Bug 215621] Warning: Unable to mark rodata read only on this CPU. (PPC970MP)
https://bugzilla.kernel.org/show_bug.cgi?id=215621
Christophe Leroy (christophe.le...@csgroup.eu) changed:
What|Removed |Added
CC||christophe.le...@csgroup.eu
--- Comment #2 from Christophe Leroy (christophe.le...@csgroup.eu) ---
Look at
https://elixir.bootlin.com/linux/v5.17-rc4/source/arch/powerpc/kernel/cputable.c#L196
at you'll see that your processor has .mmu_features = MMU_FTRS_PPC970
Then you see at
https://elixir.bootlin.com/linux/v5.17-rc4/source/arch/powerpc/include/asm/mmu.h#L135
that MMU_FTRS_PPC970 doesn't include MMU_FTR_KERNEL_RO.
MMU_FTR_KERNEL_RO is in POWER6.
In commit 984d7a1ec67c ("powerpc/mm: Fixup kernel read only mapping") you see
that this feature appears in ISA 2.04.
Previous version of ISA only has PP bits which only provides RW for kernel
pages.
So this bug is not a bug, it's a limitation of PPC970MP, and the warning in
dmesg is there to warn you that allthough you have select
CONFIG_STRICT_KERNEL_RWX, this CPU doesn't support it.
And for the same reason, CONFIG_STRICT_MODULE_RWX doesn't work either.
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[Bug 215621] Warning: Unable to mark rodata read only on this CPU. (PPC970MP)
https://bugzilla.kernel.org/show_bug.cgi?id=215621 --- Comment #1 from Erhard F. (erhar...@mailbox.org) --- Created attachment 300483 --> https://bugzilla.kernel.org/attachment.cgi?id=300483=edit kernel .config (5.17-rc4, PowerMac G5 11,2) -- You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.
