From: Zhen Lei <thunder.leizhen@huawei.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
<x86@kernel.org>, "H . Peter Anvin" <hpa@zytor.com>,
Eric Biederman <ebiederm@xmission.com>,
Rob Herring <robh+dt@kernel.org>,
Frank Rowand <frowand.list@gmail.com>,
<devicetree@vger.kernel.org>, Dave Young <dyoung@redhat.com>,
Baoquan He <bhe@redhat.com>, Vivek Goyal <vgoyal@redhat.com>,
<kexec@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
Jonathan Corbet <corbet@lwn.net>, <linux-doc@vger.kernel.org>
Cc: Zhen Lei <thunder.leizhen@huawei.com>,
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>,
Dave Kleikamp <dave.kleikamp@oracle.com>
Subject: [PATCH] arm64: kdump: Provide default size when crashkernel=Y,low is not specified
Date: Thu, 9 Jun 2022 21:50:29 +0800 [thread overview]
Message-ID: <20220609135029.607-1-thunder.leizhen@huawei.com> (raw)
To be consistent with the implementation of x86 and improve cross-platform
user experience. Try to allocate at least 256 MiB low memory automatically
when crashkernel=Y,low is not specified.
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
Documentation/admin-guide/kernel-parameters.txt | 10 +++-------
arch/arm64/mm/init.c | 12 +++++++++++-
2 files changed, 14 insertions(+), 8 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 8090130b544b070..9560f5af248e0d6 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -843,7 +843,9 @@
available.
It will be ignored if crashkernel=X is specified.
crashkernel=size[KMG],low
- [KNL, X86-64] range under 4G. When crashkernel=X,high
+ [KNL, X86-64, ARM64] range under 4G(For some platforms,
+ not all low 4G memory can be directly accessed by devices,
+ use the DMA zones instead). When crashkernel=X,high
is passed, kernel could allocate physical memory region
above 4G, that cause second kernel crash on system
that require some amount of low memory, e.g. swiotlb
@@ -857,12 +859,6 @@
It will be ignored when crashkernel=X,high is not used
or memory reserved is below 4G.
- [KNL, ARM64] range in low memory.
- This one lets the user specify a low range in the
- DMA zone for the crash dump kernel.
- It will be ignored when crashkernel=X,high is not used
- or memory reserved is located in the DMA zones.
-
cryptomgr.notests
[KNL] Disable crypto self-tests
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 339ee84e5a61a0b..5390f361208ccf7 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -96,6 +96,14 @@ phys_addr_t __ro_after_init arm64_dma_phys_limit = PHYS_MASK + 1;
#define CRASH_ADDR_LOW_MAX arm64_dma_phys_limit
#define CRASH_ADDR_HIGH_MAX (PHYS_MASK + 1)
+/*
+ * This is an empirical value in x86_64 and taken here directly. Please
+ * refer to the code comment in reserve_crashkernel_low() of x86_64 for more
+ * details.
+ */
+#define DEFAULT_CRASH_KERNEL_LOW_SIZE \
+ max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20)
+
static int __init reserve_crashkernel_low(unsigned long long low_size)
{
unsigned long long low_base;
@@ -147,7 +155,9 @@ static void __init reserve_crashkernel(void)
* is not allowed.
*/
ret = parse_crashkernel_low(cmdline, 0, &crash_low_size, &crash_base);
- if (ret && (ret != -ENOENT))
+ if (ret == -ENOENT)
+ crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
+ else if (ret)
return;
crash_max = CRASH_ADDR_HIGH_MAX;
--
2.25.1
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next reply other threads:[~2022-06-09 13:55 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-09 13:50 Zhen Lei [this message]
2022-06-13 8:29 ` [PATCH] arm64: kdump: Provide default size when crashkernel=Y,low is not specified Leizhen (ThunderTown)
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