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Commit d95f1a54 authored by Logan Gunthorpe's avatar Logan Gunthorpe Committed by Paul Walmsley
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RISC-V: Implement sparsemem 



Implement sparsemem support for Risc-v which helps pave the
way for memory hotplug and eventually P2P support.

Introduce Kconfig options for virtual and physical address bits which
are used to calculate the size of the vmemmap and set the
MAX_PHYSMEM_BITS.

The vmemmap is located directly before the VMALLOC region and sized
such that we can allocate enough pages to populate all the virtual
address space in the system (similar to the way it's done in arm64).

During initialization, call memblocks_present() and sparse_init(),
and provide a stub for vmemmap_populate() (all of which is similar to
arm64).

[greentime.hu@sifive.com: fixed pfn_valid, FIXADDR_TOP and fixed a bug
 rebasing onto v5.3]
Signed-off-by: default avatarGreentime Hu <greentime.hu@sifive.com>
Signed-off-by: default avatarLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: default avatarPalmer Dabbelt <palmer@sifive.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Andrew Waterman <andrew@sifive.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Michael Clark <michaeljclark@mac.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Zong Li <zong@andestech.com>
Reviewed-by: default avatarMike Rapoport <rppt@linux.ibm.com>
[paul.walmsley@sifive.com: updated to apply; minor commit message
 reformat]
Signed-off-by: default avatarPaul Walmsley <paul.walmsley@sifive.com>
parent 4f3f9008

arch/riscv/Kconfig

+21 −0
Original line number Diff line number Diff line
@@ -55,6 +55,7 @@ config RISCV 
	select EDAC_SUPPORT

	select ARCH_HAS_GIGANTIC_PAGE

	select ARCH_WANT_HUGE_PMD_SHARE if 64BIT

	select SPARSEMEM_STATIC if 32BIT



config MMU

	def_bool y
@@ -63,12 +64,32 @@ config ZONE_DMA32 
	bool

	default y if 64BIT



config VA_BITS

	int

	default 32 if 32BIT

	default 39 if 64BIT



config PA_BITS

	int

	default 34 if 32BIT

	default 56 if 64BIT



config PAGE_OFFSET

	hex

	default 0xC0000000 if 32BIT && MAXPHYSMEM_2GB

	default 0xffffffff80000000 if 64BIT && MAXPHYSMEM_2GB

	default 0xffffffe000000000 if 64BIT && MAXPHYSMEM_128GB



config ARCH_FLATMEM_ENABLE

	def_bool y



config ARCH_SPARSEMEM_ENABLE

	def_bool y

	select SPARSEMEM_VMEMMAP_ENABLE



config ARCH_SELECT_MEMORY_MODEL

	def_bool ARCH_SPARSEMEM_ENABLE



config ARCH_WANT_GENERAL_HUGETLB

	def_bool y

arch/riscv/include/asm/page.h

+2 −0
Original line number Diff line number Diff line
@@ -110,8 +110,10 @@ 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)))



#ifdef CONFIG_FLATMEM

#define pfn_valid(pfn) \

	(((pfn) >= pfn_base) && (((pfn)-pfn_base) < max_mapnr))

#endif



#define ARCH_PFN_OFFSET		(pfn_base)

arch/riscv/include/asm/pgtable.h

+13 −0
Original line number Diff line number Diff line
@@ -83,6 +83,19 @@ extern pgd_t swapper_pg_dir[]; 
#define __S110	PAGE_SHARED_EXEC

#define __S111	PAGE_SHARED_EXEC



/*

 * Roughly size the vmemmap space to be large enough to fit enough

 * struct pages to map half the virtual address space. Then

 * position vmemmap directly below the VMALLOC region.

 */

#define VMEMMAP_SHIFT \

	(CONFIG_VA_BITS - PAGE_SHIFT - 1 + STRUCT_PAGE_MAX_SHIFT)

#define VMEMMAP_SIZE	BIT(VMEMMAP_SHIFT)

#define VMEMMAP_END	(VMALLOC_START - 1)

#define VMEMMAP_START	(VMALLOC_START - VMEMMAP_SIZE)



#define vmemmap		((struct page *)VMEMMAP_START)



/*

 * ZERO_PAGE is a global shared page that is always zero,

 * used for zero-mapped memory areas, etc.

arch/riscv/include/asm/sparsemem.h

0 → 100644
+11 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */



#ifndef __ASM_SPARSEMEM_H

#define __ASM_SPARSEMEM_H



#ifdef CONFIG_SPARSEMEM

#define MAX_PHYSMEM_BITS	CONFIG_PA_BITS

#define SECTION_SIZE_BITS	27

#endif /* CONFIG_SPARSEMEM */



#endif /* __ASM_SPARSEMEM_H */

arch/riscv/mm/init.c

+10 −0
Original line number Diff line number Diff line
@@ -442,6 +442,16 @@ static void __init setup_vm_final(void) 
void __init paging_init(void)

{

	setup_vm_final();

	memblocks_present();

	sparse_init();

	setup_zero_page();

	zone_sizes_init();

}



#ifdef CONFIG_SPARSEMEM

int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,

			       struct vmem_altmap *altmap)

{

	return vmemmap_populate_basepages(start, end, node);

}

#endif