From: "Suzuki K. Poulose" <suzuki@in.ibm.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: mahesh@linux.vnet.ibm.com, benh@kernel.crashing.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v2 2/2] [powerpc] Export memory limit via device tree
Date: Tue, 21 Aug 2012 17:12:43 +0530 [thread overview]
Message-ID: <20120821114240.29282.44213.stgit@suzukikp.in.ibm.com> (raw)
In-Reply-To: <20120821113815.29282.4000.stgit@suzukikp.in.ibm.com>
The powerpc kernel doesn't export the memory limit enforced by 'mem='
kernel parameter. This is required for building the ELF header in
kexec-tools to limit the vmcore to capture only the used memory. On
powerpc the kexec-tools depends on the device-tree for memory related
information, unlike /proc/iomem on the x86.
Without this information, the kexec-tools assumes the entire System
RAM and vmcore creates an unnecessarily larger dump.
This patch exports the memory limit, if present, via
chosen/linux,memory-limit
property, so that the vmcore can be limited to the memory limit.
The prom_init seems to export this value in the same node. But doesn't
really
appear there. Also the memory_limit gets adjusted with the processing of
crashkernel= parameter. This patch makes sure we get the actual limit.
The kexec-tools will use the value to limit the 'end' of the memory
regions.
Tested this patch on ppc64 and ppc32(ppc440) with a kexec-tools
patch by Mahesh.
Signed-off-by: Suzuki K. Poulose <suzuki@in.ibm.com>
Tested-by: Mahesh J. Salgaonkar <mahesh@linux.vnet.ibm.com>
---
arch/powerpc/kernel/machine_kexec.c | 12 ++++++++++++
1 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c
index 4074eff..fa9f6c7 100644
--- a/arch/powerpc/kernel/machine_kexec.c
+++ b/arch/powerpc/kernel/machine_kexec.c
@@ -204,6 +204,12 @@ static struct property crashk_size_prop = {
.value = &crashk_size,
};
+static struct property memory_limit_prop = {
+ .name = "linux,memory-limit",
+ .length = sizeof(unsigned long long),
+ .value = &memory_limit,
+};
+
static void __init export_crashk_values(struct device_node *node)
{
struct property *prop;
@@ -223,6 +229,12 @@ static void __init export_crashk_values(struct device_node *node)
crashk_size = resource_size(&crashk_res);
prom_add_property(node, &crashk_size_prop);
}
+
+ /*
+ * memory_limit is required by the kexec-tools to limit the
+ * crash regions to the actual memory used.
+ */
+ prom_update_property(node, &memory_limit_prop);
}
static int __init kexec_setup(void)
prev parent reply other threads:[~2012-08-21 11:43 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-21 11:42 [PATCH v2 0/2][powerpc] Export memory_limit via device tree Suzuki K. Poulose
2012-08-21 11:42 ` [PATCH v2 1/2] [powerpc] Change memory_limit from phys_addr_t to unsigned long long Suzuki K. Poulose
2012-09-07 1:35 ` Benjamin Herrenschmidt
2012-09-07 10:01 ` Suzuki K. Poulose
2012-08-21 11:42 ` Suzuki K. Poulose [this message]
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