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riscv: Add mem kernel parameter support

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The memblock_enforce_memory_limit() could change the memblock
range, so move the dram_end assignment after it in bootmem_init(),
then support mem= cmdline.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
This commit is contained in:
Kefeng Wang 2021-06-02 16:55:17 +08:00 committed by Palmer Dabbelt
parent ce3aca0465
commit c9811e379b
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GPG Key ID: 2E1319F35FBB1889
1 changed files with 25 additions and 3 deletions
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28
arch/riscv/mm/init.c
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@ -123,19 +123,40 @@ void __init mem_init(void)
print_vm_layout();
}
/*
* The default maximal physical memory size is -PAGE_OFFSET,
* limit the memory size via mem.
*/
static phys_addr_t memory_limit = -PAGE_OFFSET;
static int __init early_mem(char *p)
{
u64 size;
if (!p)
return 1;
size = memparse(p, &p) & PAGE_MASK;
memory_limit = min_t(u64, size, memory_limit);
pr_notice("Memory limited to %lldMB\n", (u64)memory_limit >> 20);
return 0;
}
early_param("mem", early_mem);
static void __init setup_bootmem(void)
{
phys_addr_t vmlinux_end = __pa_symbol(&_end);
phys_addr_t vmlinux_start = __pa_symbol(&_start);
phys_addr_t dram_end = memblock_end_of_DRAM();
phys_addr_t max_mapped_addr = __pa(~(ulong)0);
phys_addr_t dram_end;
#ifdef CONFIG_XIP_KERNEL
vmlinux_start = __pa_symbol(&_sdata);
#endif
/* The maximal physical memory size is -PAGE_OFFSET. */
memblock_enforce_memory_limit(-PAGE_OFFSET);
memblock_enforce_memory_limit(memory_limit);
/*
* Reserve from the start of the kernel to the end of the kernel
@ -150,6 +171,7 @@ static void __init setup_bootmem(void)
#endif
memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
dram_end = memblock_end_of_DRAM();
/*
* memblock allocator is not aware of the fact that last 4K bytes of
* the addressable memory can not be mapped because of IS_ERR_VALUE