Logan Gunthorpe <log...@deltatee.com> 於 2019年8月14日 週三 上午12:50寫道： > > On 2019-08-13 10:39 a.m., Paul Walmsley wrote: > > On Tue, 13 Aug 2019, Logan Gunthorpe wrote: > > > >> On 2019-08-13 12:04 a.m., Greentime Hu wrote: > >> > >>> Every architecture with mmu defines their own pfn_valid(). > >> > >> Not true. Arm64, for example just uses the generic implementation in > >> mmzone.h. > > > > arm64 seems to define their own: > > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/Kconfig#n899 > > Oh, yup. My mistake. > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/mm/init.c#n235 > > > > While there are many architectures which have their own pfn_valid(); > > oddly, almost none of them set HAVE_ARCH_PFN_VALID ? > > Yes, much of this is super confusing. Seems HAVE_ARCH_PFN_VALID only > matters if SPARSEMEM is set. So risc-v probably doesn't need to set it > and we just need a #ifdef !CONFIG_FLATMEM around the pfn_valid > definition like other arches. >
Maybe this commit explains why it used HAVE_ARCH_PFN_VALID instead of SPARSEMEM. https://github.com/torvalds/linux/commit/7b7bf499f79de3f6c85a340c8453a78789523f85 BTW, I found another issue here. #define FIXADDR_TOP (VMALLOC_START) #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) #define VMEMMAP_END (VMALLOC_START - 1) #define VMEMMAP_START (VMALLOC_START - VMEMMAP_SIZE) These 2 regions are overlapped. How about this fix? Not sure if it is good for everyone. diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 3f12b069af1d..3c4d394679d0 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -115,9 +115,6 @@ config PGTABLE_LEVELS default 3 if 64BIT default 2 -config HAVE_ARCH_PFN_VALID - def_bool y - menu "Platform type" choice diff --git a/arch/riscv/include/asm/fixmap.h b/arch/riscv/include/asm/fixmap.h index c207f6634b91..72e106b60bc5 100644 --- a/arch/riscv/include/asm/fixmap.h +++ b/arch/riscv/include/asm/fixmap.h @@ -26,7 +26,7 @@ enum fixed_addresses { }; #define FIXADDR_SIZE (__end_of_fixed_addresses * PAGE_SIZE) -#define FIXADDR_TOP (VMALLOC_START) +#define FIXADDR_TOP (VMEMMAP_START) #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) #define FIXMAP_PAGE_IO PAGE_KERNEL diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h index 8ddb6c7fedac..83830997dce6 100644 --- a/arch/riscv/include/asm/page.h +++ b/arch/riscv/include/asm/page.h @@ -100,8 +100,10 @@ extern unsigned long min_low_pfn; #define page_to_bus(page) (page_to_phys(page)) #define phys_to_page(paddr) (pfn_to_page(phys_to_pfn(paddr))) +#if defined(CONFIG_FLATMEM) #define pfn_valid(pfn) \ (((pfn) >= pfn_base) && (((pfn)-pfn_base) < max_mapnr)) +#endif #define ARCH_PFN_OFFSET (pfn_base)
