From 3eb9cdffb39701743973382860f214026f4d7825 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Wed, 25 Aug 2021 11:10:07 +0100 Subject: [PATCH] Partially revert "arm64/mm: drop HAVE_ARCH_PFN_VALID" This partially reverts commit 16c9afc776608324ca71c0bc354987bab532f51d. Alex Bee reports a regression in 5.14 on their RK3328 SoC when configuring the PL330 DMA controller: | ------------[ cut here ]------------ | WARNING: CPU: 2 PID: 373 at kernel/dma/mapping.c:235 dma_map_resource+0x68/0xc0 | Modules linked in: spi_rockchip(+) fuse | CPU: 2 PID: 373 Comm: systemd-udevd Not tainted 5.14.0-rc7 #1 | Hardware name: Pine64 Rock64 (DT) | pstate: 80000005 (Nzcv daif -PAN -UAO -TCO BTYPE=--) | pc : dma_map_resource+0x68/0xc0 | lr : pl330_prep_slave_fifo+0x78/0xd0 This appears to be because dma_map_resource() is being called for a physical address which does not correspond to a memory address yet does have a valid 'struct page' due to the way in which the vmemmap is constructed. Prior to 16c9afc77660 ("arm64/mm: drop HAVE_ARCH_PFN_VALID"), the arm64 implementation of pfn_valid() called memblock_is_memory() to return 'false' for such regions and the DMA mapping request would proceed. However, now that we are using the generic implementation where only the presence of the memory map entry is considered, we return 'true' and erroneously fail with DMA_MAPPING_ERROR because we identify the region as DRAM. Although fixing this in the DMA mapping code is arguably the right fix, it is a risky, cross-architecture change at this stage in the cycle. So just revert arm64 back to its old pfn_valid() implementation for v5.14. The change to the generic pfn_valid() code is preserved from the original patch, so as to avoid impacting other architectures. Cc: Catalin Marinas Cc: Robin Murphy Cc: Mike Rapoport Cc: Anshuman Khandual Cc: Christoph Hellwig Reported-by: Alex Bee Link: https://lore.kernel.org/r/d3a3c828-b777-faf8-e901-904995688437@gmail.com Signed-off-by: Will Deacon --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/page.h | 1 + arch/arm64/mm/init.c | 37 +++++++++++++++++++++++++++++++++++++ 3 files changed, 39 insertions(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index fdcd54d..62c3c1d 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -156,6 +156,7 @@ config ARM64 select HAVE_ARCH_KGDB select HAVE_ARCH_MMAP_RND_BITS select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT + select HAVE_ARCH_PFN_VALID select HAVE_ARCH_PREL32_RELOCATIONS select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET select HAVE_ARCH_SECCOMP_FILTER diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h index 993a27e..f98c91b 100644 --- a/arch/arm64/include/asm/page.h +++ b/arch/arm64/include/asm/page.h @@ -41,6 +41,7 @@ void tag_clear_highpage(struct page *to); typedef struct page *pgtable_t; +int pfn_valid(unsigned long pfn); int pfn_is_map_memory(unsigned long pfn); #include diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 8490ed2..1fdb7bb 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -219,6 +219,43 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max) free_area_init(max_zone_pfns); } +int pfn_valid(unsigned long pfn) +{ + phys_addr_t addr = PFN_PHYS(pfn); + struct mem_section *ms; + + /* + * Ensure the upper PAGE_SHIFT bits are clear in the + * pfn. Else it might lead to false positives when + * some of the upper bits are set, but the lower bits + * match a valid pfn. + */ + if (PHYS_PFN(addr) != pfn) + return 0; + + if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) + return 0; + + ms = __pfn_to_section(pfn); + if (!valid_section(ms)) + return 0; + + /* + * ZONE_DEVICE memory does not have the memblock entries. + * memblock_is_map_memory() check for ZONE_DEVICE based + * addresses will always fail. Even the normal hotplugged + * memory will never have MEMBLOCK_NOMAP flag set in their + * memblock entries. Skip memblock search for all non early + * memory sections covering all of hotplug memory including + * both normal and ZONE_DEVICE based. + */ + if (!early_section(ms)) + return pfn_section_valid(ms, pfn); + + return memblock_is_memory(addr); +} +EXPORT_SYMBOL(pfn_valid); + int pfn_is_map_memory(unsigned long pfn) { phys_addr_t addr = PFN_PHYS(pfn); -- 2.7.4