Some kexec/kdump implementations (e.g. Xen PVOPS) could not use default
functions or require some changes in behavior of kexec/kdump generic code.
To cope with that problem kexec_ops struct was introduced. It allows
a developer to replace all or some functions and control some
functionality of kexec/kdump generic code.
Default behavior of kexec/kdump generic code is not changed.
v2 - suggestions/fixes:
- add comment for kexec_ops.crash_alloc_temp_store member
(suggested by Konrad Rzeszutek Wilk),
- simplify kexec_ops usage
(suggested by Konrad Rzeszutek Wilk).
Signed-off-by: Daniel Kiper <daniel.kiper at oracle.com>
---
include/linux/kexec.h | 26 ++++++++++
kernel/kexec.c | 131 +++++++++++++++++++++++++++++++++++++------------
2 files changed, 125 insertions(+), 32 deletions(-)
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index d0b8458..c8d0b35 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -116,7 +116,33 @@ struct kimage {
#endif
};
+struct kexec_ops {
+ /*
+ * Some kdump implementations (e.g. Xen PVOPS dom0) could not access
+ * directly crash kernel memory area. In this situation they must
+ * allocate memory outside of it and later move contents from temporary
+ * storage to final resting places (usualy done by relocate_kernel()).
+ * Such behavior could be enforced by setting
+ * crash_alloc_temp_store member to true.
+ */
+ bool crash_alloc_temp_store;
+ struct page *(*kimage_alloc_pages)(gfp_t gfp_mask,
+ unsigned int order,
+ unsigned long limit);
+ void (*kimage_free_pages)(struct page *page);
+ unsigned long (*page_to_pfn)(struct page *page);
+ struct page *(*pfn_to_page)(unsigned long pfn);
+ unsigned long (*virt_to_phys)(volatile void *address);
+ void *(*phys_to_virt)(unsigned long address);
+ int (*machine_kexec_prepare)(struct kimage *image);
+ int (*machine_kexec_load)(struct kimage *image);
+ void (*machine_kexec_cleanup)(struct kimage *image);
+ void (*machine_kexec_unload)(struct kimage *image);
+ void (*machine_kexec_shutdown)(void);
+ void (*machine_kexec)(struct kimage *image);
+};
+extern struct kexec_ops kexec_ops;
/* kexec interface functions */
extern void machine_kexec(struct kimage *image);
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 5e4bd78..a5f7324 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -55,6 +55,56 @@ struct resource crashk_res = {
.flags = IORESOURCE_BUSY | IORESOURCE_MEM
};
+static struct page *kimage_alloc_pages(gfp_t gfp_mask,
+ unsigned int order,
+ unsigned long limit);
+static void kimage_free_pages(struct page *page);
+
+static unsigned long generic_page_to_pfn(struct page *page)
+{
+ return page_to_pfn(page);
+}
+
+static struct page *generic_pfn_to_page(unsigned long pfn)
+{
+ return pfn_to_page(pfn);
+}
+
+static unsigned long generic_virt_to_phys(volatile void *address)
+{
+ return virt_to_phys(address);
+}
+
+static void *generic_phys_to_virt(unsigned long address)
+{
+ return phys_to_virt(address);
+}
+
+static int generic_kexec_load(struct kimage *image)
+{
+ return 0;
+}
+
+static void generic_kexec_unload(struct kimage *image)
+{
+}
+
+struct kexec_ops kexec_ops = {
+ .crash_alloc_temp_store = false,
+ .kimage_alloc_pages = kimage_alloc_pages,
+ .kimage_free_pages = kimage_free_pages,
+ .page_to_pfn = generic_page_to_pfn,
+ .pfn_to_page = generic_pfn_to_page,
+ .virt_to_phys = generic_virt_to_phys,
+ .phys_to_virt = generic_phys_to_virt,
+ .machine_kexec_prepare = machine_kexec_prepare,
+ .machine_kexec_load = generic_kexec_load,
+ .machine_kexec_cleanup = machine_kexec_cleanup,
+ .machine_kexec_unload = generic_kexec_unload,
+ .machine_kexec_shutdown = machine_shutdown,
+ .machine_kexec = machine_kexec
+};
+
int kexec_should_crash(struct task_struct *p)
{
if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops)
@@ -354,7 +404,9 @@ static int kimage_is_destination_range(struct kimage *image,
return 0;
}
-static struct page *kimage_alloc_pages(gfp_t gfp_mask, unsigned int order)
+static struct page *kimage_alloc_pages(gfp_t gfp_mask,
+ unsigned int order,
+ unsigned long limit)
{
struct page *pages;
@@ -391,7 +443,7 @@ static void kimage_free_page_list(struct list_head *list)
page = list_entry(pos, struct page, lru);
list_del(&page->lru);
- kimage_free_pages(page);
+ (*kexec_ops.kimage_free_pages)(page);
}
}
@@ -424,10 +476,11 @@ static struct page *kimage_alloc_normal_control_pages(struct kimage *image,
do {
unsigned long pfn, epfn, addr, eaddr;
- pages = kimage_alloc_pages(GFP_KERNEL, order);
+ pages = (*kexec_ops.kimage_alloc_pages)(GFP_KERNEL, order,
+ KEXEC_CONTROL_MEMORY_LIMIT);
if (!pages)
break;
- pfn = page_to_pfn(pages);
+ pfn = (*kexec_ops.page_to_pfn)(pages);
epfn = pfn + count;
addr = pfn << PAGE_SHIFT;
eaddr = epfn << PAGE_SHIFT;
@@ -514,7 +567,7 @@ static struct page *kimage_alloc_crash_control_pages(struct kimage *image,
}
/* If I don't overlap any segments I have found my hole! */
if (i == image->nr_segments) {
- pages = pfn_to_page(hole_start >> PAGE_SHIFT);
+ pages = (*kexec_ops.pfn_to_page)(hole_start >> PAGE_SHIFT);
break;
}
}
@@ -531,12 +584,13 @@ struct page *kimage_alloc_control_pages(struct kimage *image,
struct page *pages = NULL;
switch (image->type) {
+ case KEXEC_TYPE_CRASH:
+ if (!kexec_ops.crash_alloc_temp_store) {
+ pages = kimage_alloc_crash_control_pages(image, order);
+ break;
+ }
case KEXEC_TYPE_DEFAULT:
pages = kimage_alloc_normal_control_pages(image, order);
- break;
- case KEXEC_TYPE_CRASH:
- pages = kimage_alloc_crash_control_pages(image, order);
- break;
}
return pages;
@@ -556,7 +610,7 @@ static int kimage_add_entry(struct kimage *image, kimage_entry_t entry)
return -ENOMEM;
ind_page = page_address(page);
- *image->entry = virt_to_phys(ind_page) | IND_INDIRECTION;
+ *image->entry = (*kexec_ops.virt_to_phys)(ind_page) | IND_INDIRECTION;
image->entry = ind_page;
image->last_entry = ind_page +
((PAGE_SIZE/sizeof(kimage_entry_t)) - 1);
@@ -615,14 +669,14 @@ static void kimage_terminate(struct kimage *image)
#define for_each_kimage_entry(image, ptr, entry) \
for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); \
ptr = (entry & IND_INDIRECTION)? \
- phys_to_virt((entry & PAGE_MASK)): ptr +1)
+ (*kexec_ops.phys_to_virt)((entry & PAGE_MASK)): ptr +1)
static void kimage_free_entry(kimage_entry_t entry)
{
struct page *page;
- page = pfn_to_page(entry >> PAGE_SHIFT);
- kimage_free_pages(page);
+ page = (*kexec_ops.pfn_to_page)(entry >> PAGE_SHIFT);
+ (*kexec_ops.kimage_free_pages)(page);
}
static void kimage_free(struct kimage *image)
@@ -652,7 +706,7 @@ static void kimage_free(struct kimage *image)
kimage_free_entry(ind);
/* Handle any machine specific cleanup */
- machine_kexec_cleanup(image);
+ (*kexec_ops.machine_kexec_cleanup)(image);
/* Free the kexec control pages... */
kimage_free_page_list(&image->control_pages);
@@ -708,7 +762,7 @@ static struct page *kimage_alloc_page(struct kimage *image,
* have a match.
*/
list_for_each_entry(page, &image->dest_pages, lru) {
- addr = page_to_pfn(page) << PAGE_SHIFT;
+ addr = (*kexec_ops.page_to_pfn)(page) << PAGE_SHIFT;
if (addr == destination) {
list_del(&page->lru);
return page;
@@ -719,16 +773,17 @@ static struct page *kimage_alloc_page(struct kimage *image,
kimage_entry_t *old;
/* Allocate a page, if we run out of memory give up */
- page = kimage_alloc_pages(gfp_mask, 0);
+ page = (*kexec_ops.kimage_alloc_pages)(gfp_mask, 0,
+ KEXEC_SOURCE_MEMORY_LIMIT);
if (!page)
return NULL;
/* If the page cannot be used file it away */
- if (page_to_pfn(page) >
+ if ((*kexec_ops.page_to_pfn)(page) >
(KEXEC_SOURCE_MEMORY_LIMIT >> PAGE_SHIFT)) {
list_add(&page->lru, &image->unuseable_pages);
continue;
}
- addr = page_to_pfn(page) << PAGE_SHIFT;
+ addr = (*kexec_ops.page_to_pfn)(page) << PAGE_SHIFT;
/* If it is the destination page we want use it */
if (addr == destination)
@@ -751,7 +806,7 @@ static struct page *kimage_alloc_page(struct kimage *image,
struct page *old_page;
old_addr = *old & PAGE_MASK;
- old_page = pfn_to_page(old_addr >> PAGE_SHIFT);
+ old_page = (*kexec_ops.pfn_to_page)(old_addr >> PAGE_SHIFT);
copy_highpage(page, old_page);
*old = addr | (*old & ~PAGE_MASK);
@@ -761,7 +816,7 @@ static struct page *kimage_alloc_page(struct kimage *image,
*/
if (!(gfp_mask & __GFP_HIGHMEM) &&
PageHighMem(old_page)) {
- kimage_free_pages(old_page);
+ (*kexec_ops.kimage_free_pages)(old_page);
continue;
}
addr = old_addr;
@@ -807,7 +862,7 @@ static int kimage_load_normal_segment(struct kimage *image,
result = -ENOMEM;
goto out;
}
- result = kimage_add_page(image, page_to_pfn(page)
+ result = kimage_add_page(image, (*kexec_ops.page_to_pfn)(page)
<< PAGE_SHIFT);
if (result < 0)
goto out;
@@ -861,7 +916,7 @@ static int kimage_load_crash_segment(struct kimage *image,
char *ptr;
size_t uchunk, mchunk;
- page = pfn_to_page(maddr >> PAGE_SHIFT);
+ page = (*kexec_ops.pfn_to_page)(maddr >> PAGE_SHIFT);
if (!page) {
result = -ENOMEM;
goto out;
@@ -900,12 +955,13 @@ static int kimage_load_segment(struct kimage *image,
int result = -ENOMEM;
switch (image->type) {
+ case KEXEC_TYPE_CRASH:
+ if (!kexec_ops.crash_alloc_temp_store) {
+ result = kimage_load_crash_segment(image, segment);
+ break;
+ }
case KEXEC_TYPE_DEFAULT:
result = kimage_load_normal_segment(image, segment);
- break;
- case KEXEC_TYPE_CRASH:
- result = kimage_load_crash_segment(image, segment);
- break;
}
return result;
@@ -993,6 +1049,7 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
/* Free any current crash dump kernel before
* we corrupt it.
*/
+ (*kexec_ops.machine_kexec_unload)(image);
kimage_free(xchg(&kexec_crash_image, NULL));
result = kimage_crash_alloc(&image, entry,
nr_segments, segments);
@@ -1003,7 +1060,7 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
if (flags & KEXEC_PRESERVE_CONTEXT)
image->preserve_context = 1;
- result = machine_kexec_prepare(image);
+ result = (*kexec_ops.machine_kexec_prepare)(image);
if (result)
goto out;
@@ -1016,11 +1073,21 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
if (flags & KEXEC_ON_CRASH)
crash_unmap_reserved_pages();
}
+
+ result = (*kexec_ops.machine_kexec_load)(image);
+
+ if (result)
+ goto out;
+
/* Install the new kernel, and Uninstall the old */
image = xchg(dest_image, image);
out:
mutex_unlock(&kexec_mutex);
+
+ if (kexec_ops.machine_kexec_unload)
+ (*kexec_ops.machine_kexec_unload)(image);
+
kimage_free(image);
return result;
@@ -1094,7 +1161,7 @@ void crash_kexec(struct pt_regs *regs)
crash_setup_regs(&fixed_regs, regs);
crash_save_vmcoreinfo();
machine_crash_shutdown(&fixed_regs);
- machine_kexec(kexec_crash_image);
+ (*kexec_ops.machine_kexec)(kexec_crash_image);
}
mutex_unlock(&kexec_mutex);
}
@@ -1116,8 +1183,8 @@ void __weak crash_free_reserved_phys_range(unsigned long begin,
unsigned long addr;
for (addr = begin; addr < end; addr += PAGE_SIZE) {
- ClearPageReserved(pfn_to_page(addr >> PAGE_SHIFT));
- init_page_count(pfn_to_page(addr >> PAGE_SHIFT));
+ ClearPageReserved((*kexec_ops.pfn_to_page)(addr >> PAGE_SHIFT));
+ init_page_count((*kexec_ops.pfn_to_page)(addr >> PAGE_SHIFT));
free_page((unsigned long)__va(addr));
totalram_pages++;
}
@@ -1571,10 +1638,10 @@ int kernel_kexec(void)
{
kernel_restart_prepare(NULL);
printk(KERN_EMERG "Starting new kernel\n");
- machine_shutdown();
+ (*kexec_ops.machine_kexec_shutdown)();
}
- machine_kexec(kexec_image);
+ (*kexec_ops.machine_kexec)(kexec_image);
#ifdef CONFIG_KEXEC_JUMP
if (kexec_image->preserve_context) {
--
1.5.6.5
