[PATCH v2 4/4] mm, arch: add generic implementation of pfn_valid() for FLATMEM

[Guenter Roeck]

On 2/12/23 17:26, Mike Rapoport wrote:
> On Sun, Feb 12, 2023 at 08:13:20AM -0800, Guenter Roeck wrote:
>> On Sun, Jan 29, 2023 at 02:42:35PM +0200, Mike Rapoport wrote:
>>> From: "Mike Rapoport (IBM)" <rppt at kernel.org>
>>>
>>> Every architecture that supports FLATMEM memory model defines its own
>>> version of pfn_valid() that essentially compares a pfn to max_mapnr.
>>>
>>> Use mips/powerpc version implemented as static inline as a generic
>>> implementation of pfn_valid() and drop its per-architecture definitions.
>>>
>>
>> With this patch in the tree, sh4 and sh4eb qemu emulations no longer boot.
>> Reverting this patch fixes the problem.
> 
> This should be a better fix than a revert:
> 
> diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c
> index 506784702430..bf1b54055316 100644
> --- a/arch/sh/mm/init.c
> +++ b/arch/sh/mm/init.c
> @@ -301,6 +301,7 @@ void __init paging_init(void)
>   	 */
>   	max_low_pfn = max_pfn = memblock_end_of_DRAM() >> PAGE_SHIFT;
>   	min_low_pfn = __MEMORY_START >> PAGE_SHIFT;
> +	set_max_mapnr(max_low_pfn - min_low_pfn);
>   
>   	nodes_clear(node_online_map);
>   

Confirmed, this fixes the problem for me.

Thanks,
Guenter

>   
>> Guenter
>>
>> ---
>> # bad: [6ba8a227fd19d19779005fb66ad7562608e1df83] Add linux-next specific files for 20230210
>> # good: [4ec5183ec48656cec489c49f989c508b68b518e3] Linux 6.2-rc7
>> git bisect start 'HEAD' 'v6.2-rc7'
>> # good: [94613f0efc69ed41f9229ef5c294db3ec37145da] Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git
>> git bisect good 94613f0efc69ed41f9229ef5c294db3ec37145da
>> # good: [19e62c715fe70dae4582c2874ed3e66715d09af6] Merge branch 'rcu/next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
>> git bisect good 19e62c715fe70dae4582c2874ed3e66715d09af6
>> # good: [5d8b7ecef7f4a681b6e5538db59ff26c389c0ab6] Merge branch 'for-next' of https://gitlab.com/peda-linux/mux.git
>> git bisect good 5d8b7ecef7f4a681b6e5538db59ff26c389c0ab6
>> # good: [c349bf6ec83903b20fe570c5609b9a864a64e09c] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/krisman/unicode.git
>> git bisect good c349bf6ec83903b20fe570c5609b9a864a64e09c
>> # good: [5a06a9f17454df38f35672be522ff5eb9b4277d2] selftest: add testing unsharing and counting ksm zero page
>> git bisect good 5a06a9f17454df38f35672be522ff5eb9b4277d2
>> # bad: [f5d115a7b06e5661ed5218ffa9a2644c4ff1c135] Merge branch 'mm-nonmm-unstable' into mm-everything
>> git bisect bad f5d115a7b06e5661ed5218ffa9a2644c4ff1c135
>> # bad: [acb018d6ea0c055381fba7dddaef386ee28f8075] mm/vmalloc.c: allow vread() to read out vm_map_ram areas
>> git bisect bad acb018d6ea0c055381fba7dddaef386ee28f8075
>> # good: [1a5d9782ac969dc6e61c6786500b5160603188ea] mm/mmap: remove __vma_adjust()
>> git bisect good 1a5d9782ac969dc6e61c6786500b5160603188ea
>> # good: [4b32363697de957dcc890b6245bec3f58903639a] arm: include asm-generic/memory_model.h from page.h rather than memory.h
>> git bisect good 4b32363697de957dcc890b6245bec3f58903639a
>> # bad: [328cf3fa6682ce6a4de6f8bb8009c833dc33f3c8] mm/migrate: convert isolate_movable_page() to use folios
>> git bisect bad 328cf3fa6682ce6a4de6f8bb8009c833dc33f3c8
>> # bad: [b704c765b08cabe82adf76a4d1a74f3688eee410] mm/mempolicy: convert queue_pages_pmd() to queue_folios_pmd()
>> git bisect bad b704c765b08cabe82adf76a4d1a74f3688eee410
>> # bad: [e5734c8b0edfd2a053a5c256189586a3b1e9f63d] mm, arch: add generic implementation of pfn_valid() for FLATMEM
>> git bisect bad e5734c8b0edfd2a053a5c256189586a3b1e9f63d
>> # good: [ad8aecea034c591b9754bc5908da9719853aa7fa] mips: drop definition of pfn_valid() for DISCONTIGMEM
>> git bisect good ad8aecea034c591b9754bc5908da9719853aa7fa
>> # first bad commit: [e5734c8b0edfd2a053a5c256189586a3b1e9f63d] mm, arch: add generic implementation of pfn_valid() for FLATMEM
>