[Makedumpfile PATCH] book3s/ppc64: Lower the max real address to 53 bits for kernels >= v4.11

[Atsushi Kumagai]

Hello Bhupesh,

>Kernel commit 2f18d533757da3899f4bedab0b2c051b080079dc lowered the
>max real address on ppc64 to 53 bits.
>
>Make similar changes in makedumpfile (on basis of the underlying kernel
>version), without which the makedumpfile will fail to create a dumpfile
>and instead throw a SEGV fault as shown below on kernels >= v4.11:
>
> # makedumpfile --split -d 31 -x vmlinux vmcore dumpfile_{1,2,3} 2>&1
>
> The kernel version is not supported.
> The makedumpfile operation may be incomplete.
> [ 1196.252094] makedumpfile[2367]: unhandled signal 11 at
> 00000100f7011ca8 nip 000000001001eecc lr 000000001001f3c0 code 30001
> Segmentation fault
>
>Signed-off-by: Bhupesh Sharma <bhsharma at redhat.com>
>---
> makedumpfile.h | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
>diff --git a/makedumpfile.h b/makedumpfile.h
>index 7d81bbcf2234..142753d84e8d 100644
>--- a/makedumpfile.h
>+++ b/makedumpfile.h
>@@ -684,8 +684,9 @@ unsigned long get_kvbase_arm64(void);
> #define PMD_MASKED_BITS_64K_4_6  0xc0000000000000ffUL
>
> #define PTE_RPN_MASK_DEFAULT  0xffffffffffffffffUL
>-#define PTE_RPN_SIZE_L4_4_6   (info->page_size == 65536 ? 41 : 45)
>-#define PTE_RPN_MASK_L4_4_6   (((1UL << PTE_RPN_SIZE_L4_4_6) - 1) << info->page_shift)
>+#define PAGE_PA_MAX_L4_4_6    (info->kernel_version >= KERNEL_VERSION(4,11,0) ? 53 : 57)
>+#define PTE_RPN_MASK_L4_4_6   \
>+	(((1UL << PAGE_PA_MAX_L4_4_6) - 1) & ~((1UL << info->page_shift) - 1))

This fix is a bit complicated, please introduce *_L4_4_11 simply.

Thanks
Atsushi Kumagai

> #define PTE_RPN_SHIFT_L4_4_6  info->page_shift
>
> #define PGD_MASKED_BITS_4_7  0xc0000000000000ffUL
>--
>2.7.4
>