On 01/24/22 at 04:47pm, Zhen Lei wrote:
> From: Chen Zhou <chenzhou10@xxxxxxxxxx>
......
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 6c653a2c7cff052..a5d43feac0d7d96 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -71,6 +71,30 @@ phys_addr_t arm64_dma_phys_limit __ro_after_init;
> #define CRASH_ADDR_LOW_MAX arm64_dma_phys_limit
> #define CRASH_ADDR_HIGH_MAX MEMBLOCK_ALLOC_ACCESSIBLE
>
> +static int __init reserve_crashkernel_low(unsigned long long low_size)
> +{
> + unsigned long long low_base;
> +
> + /* passed with crashkernel=0,low ? */
> + if (!low_size)
> + return 0;
> +
> + low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
> + if (!low_base) {
> + pr_err("cannot allocate crashkernel low memory (size:0x%llx).\n", low_size);
> + return -ENOMEM;
> + }
> +
> + pr_info("crashkernel low memory reserved: 0x%llx - 0x%llx (%lld MB)\n",
> + low_base, low_base + low_size, low_size >> 20);
> +
> + crashk_low_res.start = low_base;
> + crashk_low_res.end = low_base + low_size - 1;
> + insert_resource(&iomem_resource, &crashk_low_res);
> +
> + return 0;
> +}
> +
> /*
> * reserve_crashkernel() - reserves memory for crash kernel
> *
> @@ -81,29 +105,62 @@ phys_addr_t arm64_dma_phys_limit __ro_after_init;
> static void __init reserve_crashkernel(void)
> {
> unsigned long long crash_base, crash_size;
> + unsigned long long crash_low_size = SZ_256M;
> unsigned long long crash_max = CRASH_ADDR_LOW_MAX;
> int ret;
> + bool fixed_base;
> + char *cmdline = boot_command_line;
>
> - ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
> + /* crashkernel=X[@offset] */
> + ret = parse_crashkernel(cmdline, memblock_phys_mem_size(),
> &crash_size, &crash_base);
> - /* no crashkernel= or invalid value specified */
> - if (ret || !crash_size)
> - return;
> + if (ret || !crash_size) {
> + unsigned long long low_size;
>
> + /* crashkernel=X,high */
> + ret = parse_crashkernel_high(cmdline, 0, &crash_size, &crash_base);
> + if (ret || !crash_size)
> + return;
> +
> + /* crashkernel=X,low */
> + ret = parse_crashkernel_low(cmdline, 0, &low_size, &crash_base);
> + if (!ret)
> + crash_low_size = low_size;
Here, the error case is not checked and handled. But it still gets
expeced result which is the default SZ_256M. Is this designed on
purpose?
> +
> + crash_max = CRASH_ADDR_HIGH_MAX;
> + }
> +
> + fixed_base = !!crash_base;
> crash_size = PAGE_ALIGN(crash_size);
>
> /* User specifies base address explicitly. */
> if (crash_base)
> crash_max = crash_base + crash_size;
>
> +retry:
> crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
> crash_base, crash_max);
> if (!crash_base) {
> + /*
> + * Attempt to fully allocate low memory failed, fall back
> + * to high memory, the minimum required low memory will be
> + * reserved later.
> + */
> + if (!fixed_base && (crash_max == CRASH_ADDR_LOW_MAX)) {
> + crash_max = CRASH_ADDR_HIGH_MAX;
> + goto retry;
> + }
> +
> pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
> crash_size);
> return;
> }
>
> + if (crash_base >= SZ_4G && reserve_crashkernel_low(crash_low_size)) {
> + memblock_phys_free(crash_base, crash_size);
> + return;
> + }
> +
> pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
> crash_base, crash_base + crash_size, crash_size >> 20);
>
> @@ -112,6 +169,9 @@ static void __init reserve_crashkernel(void)
> * map. Inform kmemleak so that it won't try to access it.
> */
> kmemleak_ignore_phys(crash_base);
> + if (crashk_low_res.end)
> + kmemleak_ignore_phys(crashk_low_res.start);
> +
> crashk_res.start = crash_base;
> crashk_res.end = crash_base + crash_size - 1;
> insert_resource(&iomem_resource, &crashk_res);
> --
> 2.25.1
>
