diff options
| author | Vasily Gorbik <gor@linux.ibm.com> | 2020-10-19 11:01:33 +0200 |
|---|---|---|
| committer | Heiko Carstens <hca@linux.ibm.com> | 2020-11-20 19:19:10 +0100 |
| commit | 73045a08cf5549cc7dee14463431fbeb2134dd67 (patch) | |
| tree | e332a31ea39cbc7748b6b42349544d24db806203 /arch/s390/mm | |
| parent | 1e632eaa0f4b7f65a81301205ca122024991e1d3 (diff) | |
s390: unify identity mapping limits handling
Currently we have to consider too many different values which
in the end only affect identity mapping size. These are:
1. max_physmem_end - end of physical memory online or standby.
Always <= end of the last online memory block (get_mem_detect_end()).
2. CONFIG_MAX_PHYSMEM_BITS - the maximum size of physical memory the
kernel is able to support.
3. "mem=" kernel command line option which limits physical memory usage.
4. OLDMEM_BASE which is a kdump memory limit when the kernel is executed as
crash kernel.
5. "hsa" size which is a memory limit when the kernel is executed during
zfcp/nvme dump.
Through out kernel startup and run we juggle all those values at once
but that does not bring any amusement, only confusion and complexity.
Unify all those values to a single one we should really care, that is
our identity mapping size.
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Diffstat (limited to 'arch/s390/mm')
| -rw-r--r-- | arch/s390/mm/dump_pagetables.c | 2 | ||||
| -rw-r--r-- | arch/s390/mm/kasan_init.c | 21 |
2 files changed, 15 insertions, 8 deletions
diff --git a/arch/s390/mm/dump_pagetables.c b/arch/s390/mm/dump_pagetables.c index 8f9ff7e7187d..e40a30647d99 100644 --- a/arch/s390/mm/dump_pagetables.c +++ b/arch/s390/mm/dump_pagetables.c @@ -255,7 +255,7 @@ static int pt_dump_init(void) */ max_addr = (S390_lowcore.kernel_asce & _REGION_ENTRY_TYPE_MASK) >> 2; max_addr = 1UL << (max_addr * 11 + 31); - address_markers[IDENTITY_AFTER_END_NR].start_address = memory_end; + address_markers[IDENTITY_AFTER_END_NR].start_address = ident_map_size; address_markers[MODULES_NR].start_address = MODULES_VADDR; address_markers[MODULES_END_NR].start_address = MODULES_END; address_markers[VMEMMAP_NR].start_address = (unsigned long) vmemmap; diff --git a/arch/s390/mm/kasan_init.c b/arch/s390/mm/kasan_init.c index a9f561491110..db4d303aaaa9 100644 --- a/arch/s390/mm/kasan_init.c +++ b/arch/s390/mm/kasan_init.c @@ -289,12 +289,19 @@ void __init kasan_early_init(void) memsize = get_mem_detect_end(); if (!memsize) kasan_early_panic("cannot detect physical memory size\n"); - /* respect mem= cmdline parameter */ - if (memory_end_set && memsize > memory_end) - memsize = memory_end; - if (IS_ENABLED(CONFIG_CRASH_DUMP) && OLDMEM_BASE) - memsize = min(memsize, OLDMEM_SIZE); - memsize = min(memsize, KASAN_SHADOW_START); + /* + * Kasan currently supports standby memory but only if it follows + * online memory (default allocation), i.e. no memory holes. + * - memsize represents end of online memory + * - ident_map_size represents online + standby and memory limits + * accounted. + * Kasan maps "memsize" right away. + * [0, memsize] - as identity mapping + * [__sha(0), __sha(memsize)] - shadow memory for identity mapping + * The rest [memsize, ident_map_size] if memsize < ident_map_size + * could be mapped/unmapped dynamically later during memory hotplug. + */ + memsize = min(memsize, ident_map_size); BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, P4D_SIZE)); BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, P4D_SIZE)); @@ -377,7 +384,7 @@ void __init kasan_early_init(void) POPULATE_SHALLOW); } /* populate kasan shadow for untracked memory */ - kasan_early_pgtable_populate(__sha(max_physmem_end), __sha(untracked_mem_end), + kasan_early_pgtable_populate(__sha(ident_map_size), __sha(untracked_mem_end), POPULATE_ZERO_SHADOW); kasan_early_pgtable_populate(__sha(kasan_vmax), __sha(vmax_unlimited), POPULATE_ZERO_SHADOW); |