From: Dave Kleikamp <dave.kleikamp@oracle.com>
To: Zhen Lei <thunder.leizhen@huawei.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org, Dave Young <dyoung@redhat.com>,
Baoquan He <bhe@redhat.com>, Vivek Goyal <vgoyal@redhat.com>,
Eric Biederman <ebiederm@xmission.com>,
kexec@lists.infradead.org,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org,
Rob Herring <robh+dt@kernel.org>,
Frank Rowand <frowand.list@gmail.com>,
devicetree@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>,
linux-doc@vger.kernel.org
Cc: Randy Dunlap <rdunlap@infradead.org>,
Feng Zhou <zhoufeng.zf@bytedance.com>,
Kefeng Wang <wangkefeng.wang@huawei.com>,
Chen Zhou <dingguo.cz@antgroup.com>,
John Donnelly <John.p.donnelly@oracle.com>
Subject: Re: [PATCH v19 11/13] arm64: kdump: reimplement crashkernel=X
Date: Wed, 12 Jan 2022 08:45:15 -0600 [thread overview]
Message-ID: <e48ac849-cc3d-3c0b-e159-7408af61eece@oracle.com> (raw)
In-Reply-To: <20211228132612.1860-12-thunder.leizhen@huawei.com>
On 12/28/21 7:26AM, Zhen Lei wrote:
> From: Chen Zhou <chenzhou10@huawei.com>
>
> There are following issues in arm64 kdump:
> 1. We use crashkernel=X to reserve crashkernel below 4G, which
> will fail when there is no enough low memory.
> 2. If reserving crashkernel above 4G, in this case, crash dump
> kernel will boot failure because there is no low memory available
> for allocation.
>
> To solve these issues, change the behavior of crashkernel=X and
> introduce crashkernel=X,[high,low]. crashkernel=X tries low allocation
> in DMA zone, and fall back to high allocation if it fails.
> We can also use "crashkernel=X,high" to select a region above DMA zone,
> which also tries to allocate at least 256M in DMA zone automatically.
> "crashkernel=Y,low" can be used to allocate specified size low memory.
>
> Another minor change, there may be two regions reserved for crash
> dump kernel, in order to distinct from the high region and make no
> effect to the use of existing kexec-tools, rename the low region as
> "Crash kernel (low)".
>
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> Co-developed-by: Zhen Lei <thunder.leizhen@huawei.com>
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> ---
> arch/arm64/kernel/machine_kexec.c | 5 +++-
> arch/arm64/kernel/machine_kexec_file.c | 12 ++++++--
> arch/arm64/kernel/setup.c | 13 +++++++-
> arch/arm64/mm/init.c | 41 ++++++++++----------------
> 4 files changed, 42 insertions(+), 29 deletions(-)
>
> diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
> index 6fb31c117ebe08c..6665bf31f6b6a19 100644
> --- a/arch/arm64/kernel/machine_kexec.c
> +++ b/arch/arm64/kernel/machine_kexec.c
> @@ -327,7 +327,10 @@ bool crash_is_nosave(unsigned long pfn)
>
> /* in reserved memory? */
> addr = __pfn_to_phys(pfn);
> - if ((addr < crashk_res.start) || (crashk_res.end < addr))
> + if (((addr < crashk_res.start) || (crashk_res.end < addr)) && !crashk_low_res.end)
> + return false;
> +
> + if ((addr < crashk_low_res.start) || (crashk_low_res.end < addr))
> return false;
>
> if (!kexec_crash_image)
> diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
> index 59c648d51848886..889951291cc0f9c 100644
> --- a/arch/arm64/kernel/machine_kexec_file.c
> +++ b/arch/arm64/kernel/machine_kexec_file.c
> @@ -65,10 +65,18 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
>
> /* Exclude crashkernel region */
> ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
> + if (ret)
> + goto out;
> +
> + if (crashk_low_res.end) {
> + ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
> + if (ret)
> + goto out;
> + }
>
> - if (!ret)
> - ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
> + ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
>
> +out:
> kfree(cmem);
> return ret;
> }
> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index be5f85b0a24de69..4bb2e55366be64d 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -248,7 +248,18 @@ static void __init request_standard_resources(void)
> kernel_data.end <= res->end)
> request_resource(res, &kernel_data);
> #ifdef CONFIG_KEXEC_CORE
> - /* Userspace will find "Crash kernel" region in /proc/iomem. */
> + /*
> + * Userspace will find "Crash kernel" or "Crash kernel (low)"
> + * region in /proc/iomem.
> + * In order to distinct from the high region and make no effect
> + * to the use of existing kexec-tools, rename the low region as
> + * "Crash kernel (low)".
> + */
> + if (crashk_low_res.end && crashk_low_res.start >= res->start &&
> + crashk_low_res.end <= res->end) {
> + crashk_low_res.name = "Crash kernel (low)";
> + request_resource(res, &crashk_low_res);
> + }
> if (crashk_res.end && crashk_res.start >= res->start &&
> crashk_res.end <= res->end)
> request_resource(res, &crashk_res);
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index be4595dc7459115..91b8038a1529068 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -74,41 +74,32 @@ 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_max = CRASH_ADDR_LOW_MAX;
> + unsigned long long crash_size, crash_base, total_mem, low_size;
low_size needs to be initialized to -1.
If parse_crashkernel() succeeds, then an uninitialized low_size will be
passed to reserve_crashkernel_mem().
> + bool high = false;
> int ret;
>
> - ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
> - &crash_size, &crash_base);
> - /* no crashkernel= or invalid value specified */
> - if (ret || !crash_size)
> - return;
> -
> - crash_size = PAGE_ALIGN(crash_size);
> -
> - /* User specifies base address explicitly. */
> - if (crash_base)
> - crash_max = crash_base + crash_size;
> + total_mem = memblock_phys_mem_size();
>
> - /* Current arm64 boot protocol requires 2MB alignment */
> - crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
> - crash_base, crash_max);
> - if (!crash_base) {
> - pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
> - crash_size);
> - return;
> + ret = parse_crashkernel(boot_command_line, total_mem, &crash_size, &crash_base);
> + if (ret != 0 || crash_size <= 0) {
> + /* crashkernel=X,high and possible crashkernel=Y,low */
> + ret = parse_crashkernel_high_low(boot_command_line, &crash_size, &low_size);
> + if (ret)
> + return;
> + high = true;
> }
>
> - pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
> - crash_base, crash_base + crash_size, crash_size >> 20);
> + ret = reserve_crashkernel_mem(total_mem, crash_size, crash_base, low_size, high);
> + if (ret)
> + return;
>
> /*
> * The crashkernel memory will be removed from the kernel linear
> * map. Inform kmemleak so that it won't try to access it.
> */
> - kmemleak_ignore_phys(crash_base);
> - crashk_res.start = crash_base;
> - crashk_res.end = crash_base + crash_size - 1;
> + kmemleak_ignore_phys(crashk_res.start);
> + if (crashk_low_res.end)
> + kmemleak_ignore_phys(crashk_low_res.start);
> }
> #else
> static void __init reserve_crashkernel(void)
next prev parent reply other threads:[~2022-01-12 14:46 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-28 13:25 [PATCH v19 00/13] support reserving crashkernel above 4G on arm64 kdump Zhen Lei
2021-12-28 13:26 ` [PATCH v19 01/13] kdump: add helper parse_crashkernel_high_low() Zhen Lei
2021-12-30 10:14 ` Leizhen (ThunderTown)
2021-12-30 10:40 ` Borislav Petkov
2021-12-30 11:08 ` Leizhen (ThunderTown)
2021-12-31 9:22 ` Leizhen (ThunderTown)
2021-12-31 12:29 ` Leizhen (ThunderTown)
2022-01-11 15:03 ` john.p.donnelly
2021-12-28 13:26 ` [PATCH v19 02/13] x86/setup: Use parse_crashkernel_high_low() to simplify code Zhen Lei
2021-12-28 16:13 ` Borislav Petkov
2021-12-29 2:27 ` Leizhen (ThunderTown)
2021-12-29 7:27 ` Dave Young
2021-12-29 7:45 ` Dave Young
2021-12-29 10:11 ` Borislav Petkov
2021-12-29 10:38 ` Dave Young
2021-12-29 11:11 ` Borislav Petkov
2021-12-29 14:13 ` Leizhen (ThunderTown)
2021-12-29 10:03 ` Borislav Petkov
2021-12-29 10:46 ` Dave Young
2021-12-29 15:04 ` Leizhen (ThunderTown)
2021-12-29 16:51 ` Borislav Petkov
2021-12-30 2:39 ` Leizhen (ThunderTown)
2021-12-30 8:56 ` Leizhen (ThunderTown)
2021-12-29 12:19 ` Leizhen (ThunderTown)
2022-01-11 15:04 ` john.p.donnelly
2021-12-28 13:26 ` [PATCH v19 03/13] kdump: make parse_crashkernel_{high|low}() static Zhen Lei
2022-01-11 15:04 ` john.p.donnelly
2021-12-28 13:26 ` [PATCH v19 04/13] kdump: reduce unnecessary parameters of parse_crashkernel_{high|low}() Zhen Lei
2022-01-11 15:05 ` john.p.donnelly
2021-12-28 13:26 ` [PATCH v19 05/13] x86/setup: Add and use CRASH_BASE_ALIGN Zhen Lei
2022-01-11 15:06 ` john.p.donnelly
2021-12-28 13:26 ` [PATCH v19 06/13] kexec: move crashk[_low]_res to crash_core module Zhen Lei
2022-01-11 15:06 ` john.p.donnelly
2021-12-28 13:26 ` [PATCH v19 07/13] kdump: Add helper reserve_crashkernel_mem[_low]() Zhen Lei
2021-12-28 13:26 ` [PATCH v19 08/13] x86/setup: Move CRASH[_BASE]_ALIGN and CRASH_ADDR_{LOW|HIGH}_MAX to asm/kexec.h Zhen Lei
2021-12-28 13:26 ` [PATCH v19 09/13] x86/setup: Use generic reserve_crashkernel_mem[_low]() Zhen Lei
2021-12-28 13:26 ` [PATCH v19 10/13] arm64: kdump: introduce some macros for crash kernel reservation Zhen Lei
2021-12-28 13:26 ` [PATCH v19 11/13] arm64: kdump: reimplement crashkernel=X Zhen Lei
2022-01-12 14:45 ` Dave Kleikamp [this message]
2022-01-13 1:17 ` Leizhen (ThunderTown)
2021-12-28 13:26 ` [PATCH v19 12/13] of: fdt: Add memory for devices by DT property "linux,usable-memory-range" Zhen Lei
2021-12-28 13:26 ` [PATCH v19 13/13] kdump: update Documentation about crashkernel Zhen Lei
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