Hi Ariel

Le 09/04/2022 à 15:47, Ariel Marcovitch a écrit :

quoted

Hi Christophe, did you get the chance to look at this?

I tested something this morning, it works for me, see below

quoted

On 23/03/2022 21:06, Mike Rapoport wrote:

quoted

Hi Catalin,

On Wed, Mar 23, 2022 at 05:22:38PM +0000, Catalin Marinas wrote:

quoted

Hi Ariel,

On Fri, Feb 18, 2022 at 09:45:51PM +0200, Ariel Marcovitch wrote:

quoted

I was running a powerpc 32bit kernel (built using
qemu_ppc_mpc8544ds_defconfig
buildroot config, with enabling DEBUGFS+KMEMLEAK+HIGHMEM in the kernel
config)

...

quoted

quoted

quoted

quoted

I don't suppose I can just shuffle the calls in setup_arch() around, 
so I
wanted to hear your opinions first

I think it's better if we change the logic than shuffling the calls.
IIUC MEMBLOCK_ALLOC_ACCESSIBLE means that __va() works on the phys
address return by memblock, so something like below (untested):

MEMBLOCK_ALLOC_ACCESSIBLE means "anywhere", see commit e63075a3c937
("memblock: Introduce default allocation limit and use it to replace
explicit ones"), so it won't help to detect high memory.

If I remember correctly, ppc initializes memblock *very* early, so 
setting
max_low_pfn along with lowmem_end_addr in
arch/powerpc/mm/init_32::MMU_init() makes sense to me.

Maybe ppc folks have other ideas...
I've added Christophe who works on ppc32 these days.

I think memblock is already available at the end of MMU_init() on PPC32 
and at the end of early_setup() on PPC64. It means it is ready when we 
enter setup_arch().

I tested the change below, it works for me, I don't get any kmemleak 
report anymore.

diff --git a/arch/powerpc/kernel/setup-common.c 

b/arch/powerpc/kernel/setup-common.c
index 518ae5aa9410..9f4e50b176c9 100644

--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c

@@ -840,6 +840,9 @@ void __init setup_arch(char **cmdline_p)
  	/* Set a half-reasonable default so udelay does something sensible */
  	loops_per_jiffy = 500000000 / HZ;

+	/* Parse memory topology */
+	mem_topology_setup();
+
  	/* Unflatten the device-tree passed by prom_init or kexec */
  	unflatten_device_tree();