[RFC][patch 2/2] s390: Add architecture code for unmapping crashkernel memory

Michael Holzheu
2011-09-08T13:27:04Z

[-- Attachment #1: s390-kdump-arch-crash_map_pages.patch --]
[-- Type: text/plain, Size: 3075 bytes --]

From: Michael Holzheu <holzheu@linux.vnet.ibm.com>

This patch implements the crash_map_pages() function for s390.
KEXEC_CRASH_MEM_ALIGN is set to HPAGE_SIZE, in order to support
kernel mappings that use large pages.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
---
arch/s390/include/asm/kexec.h | 3 +++
arch/s390/kernel/machine_kexec.c | 15 +++++++++++++++
arch/s390/kernel/setup.c | 10 ++++++----
3 files changed, 24 insertions(+), 4 deletions(-)

--- a/arch/s390/include/asm/kexec.h
+++ b/arch/s390/include/asm/kexec.h
@@ -36,6 +36,9 @@
/* Allocate one page for the pdp and the second for the code */
#define KEXEC_CONTROL_PAGE_SIZE 4096

+/* Alignment of crashkernel memory */
+#define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE
+
/* The native architecture */
#define KEXEC_ARCH KEXEC_ARCH_S390

--- a/arch/s390/kernel/machine_kexec.c
+++ b/arch/s390/kernel/machine_kexec.c
@@ -243,6 +243,21 @@ static void __machine_kdump(void *image)
#endif

/*
+ * Map or unmap crashkernel memory
+ */
+void crash_map_pages(int enable)
+{
+ unsigned long size = crashk_res.end - crashk_res.start + 1;
+
+ BUG_ON(crashk_res.start % KEXEC_CRASH_MEM_ALIGN ||
+ size % KEXEC_CRASH_MEM_ALIGN);
+ if (enable)
+ vmem_add_mapping(crashk_res.start, size);
+ else
+ vmem_remove_mapping(crashk_res.start, size);
+}
+
+/*
* Give back memory to hypervisor before new kdump is loaded
*/
static int machine_kexec_prepare_kdump(void)
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -446,6 +446,7 @@ static void __init setup_resources(void)
res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
switch (memory_chunk[i].type) {
case CHUNK_READ_WRITE:
+ case CHUNK_CRASHK:
res->name = "System RAM";
break;
case CHUNK_READ_ONLY:
@@ -706,8 +707,8 @@ static void __init reserve_crashkernel(v
&crash_base);
if (rc || crash_size == 0)
return;
- crash_base = PAGE_ALIGN(crash_base);
- crash_size = PAGE_ALIGN(crash_size);
+ crash_base = ALIGN(crash_base, KEXEC_CRASH_MEM_ALIGN);
+ crash_size = ALIGN(crash_size, KEXEC_CRASH_MEM_ALIGN);
if (register_memory_notifier(&kdump_mem_nb))
return;
if (!crash_base)
@@ -727,7 +728,7 @@ static void __init reserve_crashkernel(v
crashk_res.start = crash_base;
crashk_res.end = crash_base + crash_size - 1;
insert_resource(&iomem_resource, &crashk_res);
- reserve_kdump_bootmem(crash_base, crash_size, CHUNK_READ_WRITE);
+ reserve_kdump_bootmem(crash_base, crash_size, CHUNK_CRASHK);
pr_info("Reserving %lluMB of memory at %lluMB "
"for crashkernel (System RAM: %luMB)\n",
crash_size >> 20, crash_base >> 20, memory_end >> 20);
@@ -802,7 +803,8 @@ setup_memory(void)
for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
unsigned long start_chunk, end_chunk, pfn;

- if (memory_chunk[i].type != CHUNK_READ_WRITE)
+ if (memory_chunk[i].type != CHUNK_READ_WRITE &&
+ memory_chunk[i].type != CHUNK_CRASHK)
continue;
start_chunk = PFN_DOWN(memory_chunk[i].addr);
end_chunk = start_chunk + PFN_DOWN(memory_chunk[i].size);