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Message-ID: <20240703210707.1986816-1-scott@os.amperecomputing.com>
Date: Wed, 3 Jul 2024 14:07:07 -0700
From: D Scott Phillips <scott@...amperecomputing.com>
To: linux-arm-kernel@...ts.infradead.org,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
linux-kernel@...r.kernel.org,
patches@...erecomputing.com
Subject: [PATCH] arm64: limit MAX_PHYSMEM_BITS based on vmemmap
Prior to the memory map adjustments in v6.9-rc1, the amdgpu driver could
trip over the warning of:
`WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END));`
in vmemmap_populate()[1]. After the adjustments, it becomes a translation
fault and panic.
The cause is that the amdgpu driver allocates some unused space from
iomem_resource and claims it as MEMORY_DEVICE_PRIVATE and
devm_memremap_pages() it. An address above those backed by the vmemmap is
used.
Adjust MAX_PHYSMEM_BITS so that addresses not backed by the vmemmap will
not be chosen as device private addresses.
[1]: Call trace:
vmemmap_populate+0x30/0x48
__populate_section_memmap+0x40/0x90
sparse_add_section+0xfc/0x3e8
__add_pages+0xb4/0x168
pagemap_range+0x300/0x410
memremap_pages+0x184/0x2d8
devm_memremap_pages+0x30/0x90
kgd2kfd_init_zone_device+0xe0/0x1f0 [amdgpu]
amdgpu_device_ip_init+0x674/0x888 [amdgpu]
amdgpu_device_init+0x7bc/0xed8 [amdgpu]
amdgpu_driver_load_kms+0x28/0x1c0 [amdgpu]
amdgpu_pci_probe+0x194/0x580 [amdgpu]
local_pci_probe+0x48/0xb8
work_for_cpu_fn+0x24/0x40
process_one_work+0x170/0x3e0
worker_thread+0x2ac/0x3e0
kthread+0xf4/0x108
ret_from_fork+0x10/0x20
Signed-off-by: D Scott Phillips <scott@...amperecomputing.com>
---
arch/arm64/include/asm/sparsemem.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/sparsemem.h b/arch/arm64/include/asm/sparsemem.h
index 8a8acc220371c..8387301f2e206 100644
--- a/arch/arm64/include/asm/sparsemem.h
+++ b/arch/arm64/include/asm/sparsemem.h
@@ -5,7 +5,7 @@
#ifndef __ASM_SPARSEMEM_H
#define __ASM_SPARSEMEM_H
-#define MAX_PHYSMEM_BITS CONFIG_ARM64_PA_BITS
+#define MAX_PHYSMEM_BITS ilog2(VMEMMAP_RANGE)
/*
* Section size must be at least 512MB for 64K base
--
2.45.2
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