Re: [PATCH] powerpc: add support for folded p4d page tables

Michael Ellerman
2020-01-07T04:24:25Z

Mike Rapoport <rppt@kernel.org> writes:
> On Mon, Jan 06, 2020 at 02:31:41PM +1100, Michael Ellerman wrote:
>> Mike Rapoport <rppt@kernel.org> writes:
>> > Any updates on this?
>>
>> It's very ... big, and kind of intrusive.
>
> I've tried to split it to several smaller ones, but I couldn't find a way
> to do it without breaking bisectability.

Yeah I didn't necessarily mean splitting it, it's just a lot of churn.

It seems to break qemu mac99 booting pmac32 defconfig, haven't had time
to look any further:

Loading compiled-in X.509 certificates
rtc-generic rtc-generic: setting system clock to 2020-01-07T02:42:59 UTC (1578364979)
BUG: Unable to handle kernel unaligned access at 0xf10af004
Faulting instruction address: 0xc01cc6c4
Vector: 600 (Alignment) at [ef0b5de0]
pc: c01cc6c4: f_dupfd+0x6c/0xb8
lr: c01cc698: f_dupfd+0x40/0xb8
sp: ef0b5e98
msr: 9032
dar: f10af004
dsisr: 40000140
current = 0xef0b0000
pid = 1, comm = swapper
Linux version 5.5.0-rc2+ (michael@alpine1-p1) (gcc version 9.2.1 20191127 (Ubuntu 9.2.1-20ubuntu3)) #8 Tue Jan 7 13:38:04 AEDT 2020
enter ? for help
[ef0b5eb8] c000550c console_on_rootfs+0x44/0x90
[ef0b5ed8] c090d7c0 kernel_init_freeable+0x1a4/0x24c
[ef0b5f18] c0005770 kernel_init+0x18/0x108
[ef0b5f38] c0017274 ret_from_kernel_thread+0x14/0x1c
FAIL! Booting BE pmac32

cheers