kexec: allocate the kexec control page with KEXEC_CONTROL_MEMORY_GFP

[ Upstream commit 7e01b5acd88b3f3108d8c4ce44e3205d67437202 ]

Introduce KEXEC_CONTROL_MEMORY_GFP to allow the architecture code
to override the gfp flags of the allocation for the kexec control
page. The loop in kimage_alloc_normal_control_pages allocates pages
with GFP_KERNEL until a page is found that happens to have an
address smaller than the KEXEC_CONTROL_MEMORY_LIMIT. On systems
with a large memory size but a small KEXEC_CONTROL_MEMORY_LIMIT
the loop will keep allocating memory until the oom killer steps in.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

diff --git a/arch/s390/include/asm/kexec.h b/arch/s390/include/asm/kexec.h
index 694bcd6bd927bff60bf76ceede7a222877e02999..2f924bc30e358542201bdde082ab6d0289f3403c 100644 (file)
--- a/arch/s390/include/asm/kexec.h
+++ b/arch/s390/include/asm/kexec.h
@@ -26,6 +26,9 @@
 /* Not more than 2GB */
 #define KEXEC_CONTROL_MEMORY_LIMIT (1UL<<31)
 
+/* Allocate control page with GFP_DMA */
+#define KEXEC_CONTROL_MEMORY_GFP GFP_DMA
+
 /* Maximum address we can use for the crash control pages */
 #define KEXEC_CRASH_CONTROL_MEMORY_LIMIT (-1UL)
 

diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 9d957b7ae095ed7f2980db140a9c21a6aae70084..9739607a6dfbe8b530691f77b135466489facfdd 100644 (file)
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -27,6 +27,10 @@
 #error KEXEC_CONTROL_MEMORY_LIMIT not defined
 #endif
 
+#ifndef KEXEC_CONTROL_MEMORY_GFP
+#define KEXEC_CONTROL_MEMORY_GFP GFP_KERNEL
+#endif
+
 #ifndef KEXEC_CONTROL_PAGE_SIZE
 #error KEXEC_CONTROL_PAGE_SIZE not defined
 #endif

diff --git a/kernel/kexec.c b/kernel/kexec.c
index 2abf9f6e9a61866302c858e408c8dd7b5ec93dd5..04eae03efe1e3c7790559c9cb0415b32f8ad8b5a 100644 (file)
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -707,7 +707,7 @@ 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 = kimage_alloc_pages(KEXEC_CONTROL_MEMORY_GFP, order);
                if (!pages)
                        break;
                pfn   = page_to_pfn(pages);