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authorVasily Gorbik <gor@linux.ibm.com>2018-04-11 19:15:24 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2018-10-09 11:21:12 +0200
commit54c57795e848100a2502b7a39b12b784292f4576 (patch)
treeae93ff66373017b80bbeecd2bc74aa5e04746246 /arch/s390/boot
parentcd45c995610420755c5fe0d09afee3106c586e26 (diff)
downloadlinux-54c57795e848100a2502b7a39b12b784292f4576.tar.bz2
s390/mem_detect: replace tprot loop with binary search
In a situation when other memory detection methods are not available (no SCLP and no z/VM diag260), continuous online memory is assumed. Replacing tprot loop with faster binary search, as only online memory end has to be found. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/boot')
-rw-r--r--arch/s390/boot/mem_detect.c49
1 files changed, 17 insertions, 32 deletions
diff --git a/arch/s390/boot/mem_detect.c b/arch/s390/boot/mem_detect.c
index 3becf6bbe4c7..65ae3c926042 100644
--- a/arch/s390/boot/mem_detect.c
+++ b/arch/s390/boot/mem_detect.c
@@ -3,12 +3,10 @@
#include <asm/sclp.h>
#include <asm/sections.h>
#include <asm/mem_detect.h>
+#include <asm/sparsemem.h>
#include "compressed/decompressor.h"
#include "boot.h"
-#define CHUNK_READ_WRITE 0
-#define CHUNK_READ_ONLY 1
-
unsigned long __bootdata(max_physmem_end);
struct mem_detect_info __bootdata(mem_detect);
@@ -141,38 +139,25 @@ static int tprot(unsigned long addr)
return rc;
}
-static void scan_memory(unsigned long rzm)
+static void search_mem_end(void)
{
- unsigned long addr, size;
- int type;
-
- if (!rzm)
- rzm = 1UL << 20;
-
- addr = 0;
- do {
- size = 0;
- /* assume lowcore is writable */
- type = addr ? tprot(addr) : CHUNK_READ_WRITE;
- do {
- size += rzm;
- if (max_physmem_end && addr + size >= max_physmem_end)
- break;
- } while (type == tprot(addr + size));
- if (type == CHUNK_READ_WRITE || type == CHUNK_READ_ONLY) {
- if (max_physmem_end && (addr + size > max_physmem_end))
- size = max_physmem_end - addr;
- add_mem_detect_block(addr, addr + size);
- }
- addr += size;
- } while (addr < max_physmem_end);
+ unsigned long range = 1 << (MAX_PHYSMEM_BITS - 20); /* in 1MB blocks */
+ unsigned long offset = 0;
+ unsigned long pivot;
+
+ while (range > 1) {
+ range >>= 1;
+ pivot = offset + range;
+ if (!tprot(pivot << 20))
+ offset = pivot;
+ }
+
+ add_mem_detect_block(0, (offset + 1) << 20);
}
void detect_memory(void)
{
- unsigned long rzm;
-
- sclp_early_get_meminfo(&max_physmem_end, &rzm);
+ sclp_early_get_memsize(&max_physmem_end);
if (!sclp_early_read_storage_info()) {
mem_detect.info_source = MEM_DETECT_SCLP_STOR_INFO;
@@ -190,7 +175,7 @@ void detect_memory(void)
return;
}
- scan_memory(rzm);
- mem_detect.info_source = MEM_DETECT_TPROT_LOOP;
+ search_mem_end();
+ mem_detect.info_source = MEM_DETECT_BIN_SEARCH;
max_physmem_end = get_mem_detect_end();
}