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Commit d90d45d7 authored by Anup Patel's avatar Anup Patel Committed by Paul Walmsley
Browse files

RISC-V: Fix memory reservation in setup_bootmem() 



Currently, the setup_bootmem() reserves memory from RAM start to the
kernel end. This prevents us from exploring ways to use the RAM below
(or before) the kernel start hence this patch updates setup_bootmem()
to only reserve memory from the kernel start to the kernel end.

Suggested-by: default avatarMike Rapoport <rppt@linux.ibm.com>
Signed-off-by: default avatarAnup Patel <anup.patel@wdc.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarPaul Walmsley <paul.walmsley@sifive.com>
parent bbc5dc51

arch/riscv/mm/init.c

+7 −7
Original line number Diff line number Diff line
@@ -21,6 +21,8 @@ unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] 
							__page_aligned_bss;

EXPORT_SYMBOL(empty_zero_page);



extern char _start[];



static void __init zone_sizes_init(void)

{

	unsigned long max_zone_pfns[MAX_NR_ZONES] = { 0, };
@@ -95,18 +97,14 @@ void __init setup_bootmem(void) 
{

	struct memblock_region *reg;

	phys_addr_t mem_size = 0;

	phys_addr_t vmlinux_end = __pa(&_end);

	phys_addr_t vmlinux_start = __pa(&_start);



	/* Find the memory region containing the kernel */

	for_each_memblock(memory, reg) {

		phys_addr_t vmlinux_end = __pa(_end);

		phys_addr_t end = reg->base + reg->size;



		if (reg->base <= vmlinux_end && vmlinux_end <= end) {

			/*

			 * Reserve from the start of the region to the end of

			 * the kernel

			 */

			memblock_reserve(reg->base, vmlinux_end - reg->base);

			mem_size = min(reg->size, (phys_addr_t)-PAGE_OFFSET);



			/*
@@ -120,6 +118,9 @@ void __init setup_bootmem(void) 
	}

	BUG_ON(mem_size == 0);



	/* Reserve from the start of the kernel to the end of the kernel */

	memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);



	set_max_mapnr(PFN_DOWN(mem_size));

	max_low_pfn = PFN_DOWN(memblock_end_of_DRAM());
@@ -197,7 +198,6 @@ void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot) 


asmlinkage void __init setup_vm(void)

{

	extern char _start;

	uintptr_t i;

	uintptr_t pa = (uintptr_t) &_start;

	pgprot_t prot = __pgprot(pgprot_val(PAGE_KERNEL) | _PAGE_EXEC);