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Commit 54c57795 authored by Vasily Gorbik's avatar Vasily Gorbik Committed by Martin Schwidefsky
Browse files

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: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent cd45c995

arch/s390/boot/mem_detect.c

+17 −32
Original line number Diff line number Diff line
@@ -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);

	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;

	}

		addr += size;

	} while (addr < max_physmem_end);



	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();

}

arch/s390/include/asm/mem_detect.h

+1 −1
Original line number Diff line number Diff line
@@ -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 {

arch/s390/include/asm/sclp.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

drivers/s390/char/sclp_early_core.c

+1 −2
Original line number Diff line number Diff line
@@ -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;

}