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| author | Suzuki Poulose <suzuki@in.ibm.com> | 2012-08-21 03:42:43 +0200 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2012-09-07 03:44:33 +0200 |
| commit | 4bc77a5ed215b4ec9cc39d5f55323b2e68000055 (patch) | |
| tree | e1735aea84fe497b4f9359a391e2cc2f842243c1 | |
| parent | powerpc: Change memory_limit from phys_addr_t to unsigned long long (diff) | |
| download | linux-4bc77a5ed215b4ec9cc39d5f55323b2e68000055.tar.xz linux-4bc77a5ed215b4ec9cc39d5f55323b2e68000055.zip | |
powerpc: Export memory limit via device tree
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>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
| -rw-r--r-- | 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 4074eff1e744..fa9f6c72f557 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) |