From 1a718d4caa1a0bed3cf3f37ac2815af8314002fb Mon Sep 17 00:00:00 2001 From: Jinyang He Date: Sat, 25 Jul 2020 13:56:38 +0800 Subject: [PATCH] MIPS: Fix unable to reserve memory for Crash kernel MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Upstream commit b1ce9716f3b5ed3b49badf1f003b9e34b7ead0f9 ] Use 0 as the align parameter in memblock_find_in_range() is incorrect when we reserve memory for Crash kernel. The environment as follows: [ 0.000000] MIPS: machine is loongson,loongson64c-4core-rs780e ... [ 1.951016] crashkernel=64M@128M The warning as follows: [ 0.000000] Invalid memory region reserved for crash kernel And the iomem as follows: 00200000-0effffff : System RAM 04000000-0484009f : Kernel code 048400a0-04ad7fff : Kernel data 04b40000-05c4c6bf : Kernel bss 1a000000-1bffffff : pci@1a000000 ... The align parameter may be finally used by round_down() or round_up(). Like the following call tree: mips-next: mm/memblock.c memblock_find_in_range └── memblock_find_in_range_node ├── __memblock_find_range_bottom_up │ └── round_up └── __memblock_find_range_top_down └── round_down \#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1) \#define round_down(x, y) ((x) & ~__round_mask(x, y)) \#define __round_mask(x, y) ((__typeof__(x))((y)-1)) The round_down(or round_up)'s second parameter must be a power of 2. If the second parameter is 0, it both will return 0. Use 1 as the parameter to fix the bug and the iomem as follows: 00200000-0effffff : System RAM 04000000-0484009f : Kernel code 048400a0-04ad7fff : Kernel data 04b40000-05c4c6bf : Kernel bss 08000000-0bffffff : Crash kernel 1a000000-1bffffff : pci@1a000000 ... Signed-off-by: Jinyang He Reviewed-by: Jiaxun Yang Signed-off-by: Thomas Bogendoerfer Signed-off-by: Sasha Levin --- arch/mips/kernel/setup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c index 7b06e6ee6817..b8884de89c81 100644 --- a/arch/mips/kernel/setup.c +++ b/arch/mips/kernel/setup.c @@ -494,7 +494,7 @@ static void __init mips_parse_crashkernel(void) if (ret != 0 || crash_size <= 0) return; - if (!memblock_find_in_range(crash_base, crash_base + crash_size, crash_size, 0)) { + if (!memblock_find_in_range(crash_base, crash_base + crash_size, crash_size, 1)) { pr_warn("Invalid memory region reserved for crash kernel\n"); return; }