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authorAlexander Gordeev <agordeev@linux.ibm.com>2023-09-26 15:58:51 +0200
committerAlexander Gordeev <agordeev@linux.ibm.com>2024-04-17 13:38:02 +0200
commit54f2ecc3188f78723267826f634e0747169f8685 (patch)
tree8359599359b4c4730842f3f1dd5ef33e87cb55fa /arch/s390/include/asm/page.h
parentc98d2ecae08f02bd2dccd24e7e485e9f0211db65 (diff)
s390: Map kernel at fixed location when KASLR is disabled
Since kernel virtual and physical address spaces are uncoupled the kernel is mapped at the top of the virtual address space in case KASLR is disabled. That does not pose any issue with regard to the kernel booting and operation, but makes it difficult to use a generated vmlinux with some debugging tools (e.g. gdb), because the exact location of the kernel image in virtual memory is unknown. Make that location known and introduce CONFIG_KERNEL_IMAGE_BASE configuration option. A custom CONFIG_KERNEL_IMAGE_BASE value that would break the virtual memory layout leads to a build error. The kernel image size is defined by KERNEL_IMAGE_SIZE macro and set to 512 MB, by analogy with x86. Suggested-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Diffstat (limited to 'arch/s390/include/asm/page.h')
-rw-r--r--arch/s390/include/asm/page.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index b39d724ab6f6..e1b6355ddbef 100644
--- a/arch/s390/include/asm/page.h
+++ b/arch/s390/include/asm/page.h
@@ -273,4 +273,8 @@ static inline unsigned long virt_to_pfn(const void *kaddr)
#include <asm-generic/memory_model.h>
#include <asm-generic/getorder.h>
+#define KERNEL_IMAGE_SIZE (512 * 1024 * 1024)
+#define __NO_KASLR_START_KERNEL CONFIG_KERNEL_IMAGE_BASE
+#define __NO_KASLR_END_KERNEL (__NO_KASLR_START_KERNEL + KERNEL_IMAGE_SIZE)
+
#endif /* _S390_PAGE_H */