Hi Tachibana, As part of the s390 patch to add support for > 4TB system memory (present in linux-next tree), the newer s390 kernel will bump the MAX_PHYSMEM_BITS from 42 to 46. Once that patch makes into umpstream kernel, this change will need to go into makedumpfile. For now, I am posting this patch for a review. Reference: http://git.kernel.org/?p=linux/kernel/git/next/linux-next.git;a=commit;h=8980036860565a6d2a4f95bb097927e832fa3d1a Thanks, -Mahesh. From: Mahesh Salgaonkar <mahesh@xxxxxxxxxxxxxxxxxx> So far s390x kernel was using 42 bits for MAX_PHYSMEM_BITS that use to support maximum of 4TB of memory. In order to support bigger systems, the newer s390x kernel will now use 46 bits for MAX_PHYSMEM_BITS to support maximum of 64TB of memory. This patch auto-detects the correct value to use for MAX_PHYSMEM_BITS by examining the mem_section array size from the vmcore being analyzed. Signed-off-by: Mahesh Salgaonkar <mahesh at linux.vnet.ibm.com> --- arch/s390x.c | 27 ++++++++++++++++++++++++++- makedumpfile.h | 3 ++- 2 files changed, 28 insertions(+), 2 deletions(-) diff --git a/arch/s390x.c b/arch/s390x.c index 9237eaa..c73220a 100644 --- a/arch/s390x.c +++ b/arch/s390x.c @@ -60,6 +60,28 @@ #define pte_offset(x) (pte_index(x) * sizeof(unsigned long)) int +set_s390x_max_physmem_bits(void) +{ + long array_len = ARRAY_LENGTH(mem_section); + /* + * The older s390x kernels uses _MAX_PHYSMEM_BITS as 42 and the + * newer kernels uses 46 bits. + */ + + info->max_physmem_bits = _MAX_PHYSMEM_BITS_OLD; + if ((array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT_EXTREME())) + || (array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT()))) + return TRUE; + + info->max_physmem_bits = _MAX_PHYSMEM_BITS_NEW; + if ((array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT_EXTREME())) + || (array_len == (NR_MEM_SECTIONS() / _SECTIONS_PER_ROOT()))) + return TRUE; + + return FALSE; +} + +int get_machdep_info_s390x(void) { unsigned long vmalloc_start; @@ -70,7 +92,10 @@ get_machdep_info_s390x(void) flag_ignore_r_char = 1; info->section_size_bits = _SECTION_SIZE_BITS; - info->max_physmem_bits = _MAX_PHYSMEM_BITS; + if (!set_s390x_max_physmem_bits()) { + ERRMSG("Can't detect max_physmem_bits.\n"); + return FALSE; + } info->page_offset = __PAGE_OFFSET; if (SYMBOL(_stext) == NOT_FOUND_SYMBOL) { diff --git a/makedumpfile.h b/makedumpfile.h index b3de521..a95d132 100644 --- a/makedumpfile.h +++ b/makedumpfile.h @@ -531,7 +531,8 @@ do { \ #define KERNELBASE (0) #define KVBASE KERNELBASE #define _SECTION_SIZE_BITS (28) -#define _MAX_PHYSMEM_BITS (42) +#define _MAX_PHYSMEM_BITS_OLD (42) +#define _MAX_PHYSMEM_BITS_NEW (46) /* Bits in the segment/region table address-space-control-element */ #define _ASCE_TYPE_MASK 0x0c
