From 54c57795e848100a2502b7a39b12b784292f4576 Mon Sep 17 00:00:00 2001 From: Vasily Gorbik Date: Wed, 11 Apr 2018 19:15:24 +0200 Subject: [PATCH] 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 Reviewed-by: Martin Schwidefsky Signed-off-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky --- arch/s390/boot/mem_detect.c | 49 ++++++++++------------------- arch/s390/include/asm/mem_detect.h | 2 +- arch/s390/include/asm/sclp.h | 2 +- drivers/s390/char/sclp_early_core.c | 3 +- 4 files changed, 20 insertions(+), 36 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 #include #include +#include #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(); } diff --git a/arch/s390/include/asm/mem_detect.h b/arch/s390/include/asm/mem_detect.h index 153c3542fa8a..6114b92ab667 100644 --- a/arch/s390/include/asm/mem_detect.h +++ b/arch/s390/include/asm/mem_detect.h @@ -9,7 +9,7 @@ enum mem_info_source { MEM_DETECT_SCLP_STOR_INFO, MEM_DETECT_DIAG260, MEM_DETECT_SCLP_READ_INFO, - MEM_DETECT_TPROT_LOOP + MEM_DETECT_BIN_SEARCH }; struct mem_detect_block { diff --git a/arch/s390/include/asm/sclp.h b/arch/s390/include/asm/sclp.h index e0da13c0ef79..32b683f6992f 100644 --- a/arch/s390/include/asm/sclp.h +++ b/arch/s390/include/asm/sclp.h @@ -114,7 +114,7 @@ void sclp_early_printk(const char *s); void sclp_early_printk_force(const char *s); void __sclp_early_printk(const char *s, unsigned int len, unsigned int force); -int sclp_early_get_meminfo(unsigned long *mem, unsigned long *rzm); +int sclp_early_get_memsize(unsigned long *mem); int _sclp_get_core_info(struct sclp_core_info *info); int sclp_core_configure(u8 core); int sclp_core_deconfigure(u8 core); diff --git a/drivers/s390/char/sclp_early_core.c b/drivers/s390/char/sclp_early_core.c index 0df08dcb9fe8..acfe09313852 100644 --- a/drivers/s390/char/sclp_early_core.c +++ b/drivers/s390/char/sclp_early_core.c @@ -272,7 +272,7 @@ int __init sclp_early_get_info(struct read_info_sccb *info) return 0; } -int __init sclp_early_get_meminfo(unsigned long *mem, unsigned long *rzm) +int __init sclp_early_get_memsize(unsigned long *mem) { unsigned long rnmax; unsigned long rnsize; @@ -285,7 +285,6 @@ int __init sclp_early_get_meminfo(unsigned long *mem, unsigned long *rzm) rnsize = sccb->rnsize ? sccb->rnsize : sccb->rnsize2; rnsize <<= 20; *mem = rnsize * rnmax; - *rzm = rnsize; return 0; } -- 2.25.1