On 4/20/2021 9:10 AM, Ard Biesheuvel wrote:
On Tue, 20 Apr 2021 at 17:54, Rob Herring robh+dt@kernel.org wrote:
On Tue, Apr 20, 2021 at 10:12 AM Alexandre TORGUE alexandre.torgue@foss.st.com wrote:
On 4/20/21 4:45 PM, Rob Herring wrote:
On Tue, Apr 20, 2021 at 9:03 AM Alexandre TORGUE alexandre.torgue@foss.st.com wrote:
Hi,
Greg or Sasha won't know what to do with this. Not sure who follows the stable list either. Quentin sent the patch, but is not the author. Given the patch in question is about consistency between EFI memory map boot and DT memory map boot, copying EFI knowledgeable folks would help (Ard B for starters).
Ok thanks for the tips. I add Ard in the loop.
Sigh. If it was only Ard I was suggesting I would have done that myself. Now everyone on the patch in question and relevant lists are Cc'ed.
Thanks for the cc.
Ard, let me know if other people have to be directly added or if I have to resend to another mailing list.
thanks alex
Since v5.4.102 I observe a regression on stm32mp1 platform: "no-map" reserved-memory regions are no more "reserved" and make part of the kernel System RAM. This causes allocation failure for devices which try to take a reserved-memory region.
It has been introduced by the following path:
"fdt: Properly handle "no-map" field in the memory region [ Upstream commit 86588296acbfb1591e92ba60221e95677ecadb43 ]" which replace memblock_remove by memblock_mark_nomap in no-map case.
Why was this backported? It doesn't look like a bugfix to me.
Reverting this patch it's fine.
I add part of my DT (something is maybe wrong inside):
memory@c0000000 { reg = <0xc0000000 0x20000000>; };
reserved-memory { #address-cells = <1>; #size-cells = <1>; ranges;
gpu_reserved: gpu@d4000000 { reg = <0xd4000000 0x4000000>; no-map; };};
Sorry if this issue has already been raised and discussed.
Could you explain why it fails? The region is clearly part of system memory, and tagged as no-map, so the patch in itself is not unreasonable. However, we obviously have code that relies on how the region is represented in /proc/iomem, so it would be helpful to get some insight into why this is the case.
I do wonder as well, we have a 32MB "no-map" reserved memory region on our platforms located at 0xfe000000. Without the offending commit, /proc/iomem looks like this:
40000000-fdffefff : System RAM 40008000-40ffffff : Kernel code 41e00000-41ef1d77 : Kernel data 100000000-13fffffff : System RAM
and with the patch applied, we have this:
40000000-fdffefff : System RAM 40008000-40ffffff : Kernel code 41e00000-41ef3db7 : Kernel data fdfff000-ffffffff : System RAM 100000000-13fffffff : System RAM
so we can now see that the region 0xfe000000 - 0xfffffff is also cobbled up with the preceding region which is a mailbox between Linux and the secure monitor at 0xfdfff000 and of size 4KB. It seems like there is
The memblock=debug outputs is also different:
[ 0.000000] MEMBLOCK configuration: [ 0.000000] memory size = 0xfdfff000 reserved size = 0x7ce4d20d [ 0.000000] memory.cnt = 0x2 [ 0.000000] memory[0x0] [0x00000040000000-0x000000fdffefff], 0xbdfff000 bytes flags: 0x0 [ 0.000000] memory[0x1] [0x00000100000000-0x0000013fffffff], 0x40000000 bytes flags: 0x0 [ 0.000000] reserved.cnt = 0x6 [ 0.000000] reserved[0x0] [0x00000040003000-0x0000004000e494], 0xb495 bytes flags: 0x0 [ 0.000000] reserved[0x1] [0x00000040200000-0x00000041ef1d77], 0x1cf1d78 bytes flags: 0x0 [ 0.000000] reserved[0x2] [0x00000045000000-0x000000450fffff], 0x100000 bytes flags: 0x0 [ 0.000000] reserved[0x3] [0x00000047000000-0x0000004704ffff], 0x50000 bytes flags: 0x0 [ 0.000000] reserved[0x4] [0x000000c2c00000-0x000000fdbfffff], 0x3b000000 bytes flags: 0x0 [ 0.000000] reserved[0x5] [0x00000100000000-0x0000013fffffff], 0x40000000 bytes flags: 0x0
[ 0.000000] MEMBLOCK configuration: [ 0.000000] memory size = 0x100000000 reserved size = 0x7ca4f24d [ 0.000000] memory.cnt = 0x3 [ 0.000000] memory[0x0] [0x00000040000000-0x000000fdffefff], 0xbdfff000 bytes flags: 0x0 [ 0.000000] memory[0x1] [0x000000fdfff000-0x000000ffffffff], 0x2001000 bytes flags: 0x4 [ 0.000000] memory[0x2] [0x00000100000000-0x0000013fffffff], 0x40000000 bytes flags: 0x0 [ 0.000000] reserved.cnt = 0x6 [ 0.000000] reserved[0x0] [0x00000040003000-0x0000004000e494], 0xb495 bytes flags: 0x0 [ 0.000000] reserved[0x1] [0x00000040200000-0x00000041ef3db7], 0x1cf3db8 bytes flags: 0x0 [ 0.000000] reserved[0x2] [0x00000045000000-0x000000450fffff], 0x100000 bytes flags: 0x0 [ 0.000000] reserved[0x3] [0x00000047000000-0x0000004704ffff], 0x50000 bytes flags: 0x0 [ 0.000000] reserved[0x4] [0x000000c3000000-0x000000fdbfffff], 0x3ac00000 bytes flags: 0x0 [ 0.000000] reserved[0x5] [0x00000100000000-0x0000013fffffff], 0x40000000 bytes flags: 0x0
in the second case we can clearly see that the 32MB no-map region is now considered as usable RAM.
Hope this helps.
In any case, the mere fact that this causes a regression should be sufficient justification to revert/withdraw it from v5.4, as I don't see a reason why it was merged there in the first place. (It has no fixes tag or cc:stable)
Agreed, however that means we still need to find out whether a more recent kernel is also broken, I should be able to tell you that a little later.