s390/mem_detect: do not truncate online memory ranges info

Commit bf64f0517e5d ("s390/mem_detect: handle online memory limit
just once") introduced truncation of mem_detect online ranges
based on identity mapping size. For kdump case however the full
set of online memory ranges has to be feed into memblock_physmem_add
so that crashed system memory could be extracted.

Instead of truncating introduce a "usable limit" which is respected by
mem_detect api. Also add extra online memory ranges iterator which still
provides full set of online memory ranges disregarding the "usable limit".

Fixes: bf64f0517e5d ("s390/mem_detect: handle online memory limit just once")
Reported-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Tested-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

5 files changed, 14 insertions, 14 deletions

diff --git a/arch/s390/boot/boot.h b/arch/s390/boot/boot.h
index ed85b144119a..58ce701d6110 100644
--- a/arch/s390/boot/boot.h
+++ b/arch/s390/boot/boot.h
@@ -34,7 +34,7 @@ struct vmlinux_info {
 
 void startup_kernel(void);
 unsigned long detect_memory(unsigned long *safe_addr);
-void mem_detect_truncate(unsigned long limit);
+void mem_detect_set_usable_limit(unsigned long limit);
 bool is_ipl_block_dump(void);
 void store_ipl_parmblock(void);
 unsigned long read_ipl_report(unsigned long safe_addr);
diff --git a/arch/s390/boot/kaslr.c b/arch/s390/boot/kaslr.c
index 70ff68dd1fee..3e3d846400b4 100644
--- a/arch/s390/boot/kaslr.c
+++ b/arch/s390/boot/kaslr.c
@@ -132,7 +132,7 @@ static unsigned long count_valid_kernel_positions(unsigned long kernel_size,
 	unsigned long start, end, pos = 0;
 	int i;
 
-	for_each_mem_detect_block(i, &start, &end) {
+	for_each_mem_detect_usable_block(i, &start, &end) {
 		if (_min >= end)
 			continue;
 		if (start >= _max)
@@ -153,7 +153,7 @@ static unsigned long position_to_address(unsigned long pos, unsigned long kernel
 	unsigned long start, end;
 	int i;
 
-	for_each_mem_detect_block(i, &start, &end) {
+	for_each_mem_detect_usable_block(i, &start, &end) {
 		if (_min >= end)
 			continue;
 		if (start >= _max)
@@ -172,7 +172,7 @@ static unsigned long position_to_address(unsigned long pos, unsigned long kernel
 
 unsigned long get_random_base(unsigned long safe_addr)
 {
-	unsigned long online_mem_total = get_mem_detect_online_total();
+	unsigned long usable_total = get_mem_detect_usable_total();
 	unsigned long memory_limit = get_mem_detect_end();
 	unsigned long base_pos, max_pos, kernel_size;
 	int i;
@@ -182,8 +182,8 @@ unsigned long get_random_base(unsigned long safe_addr)
 	 * which vmem and kasan code will use for shadow memory and
 	 * pgtable mapping allocations.
 	 */
-	memory_limit -= kasan_estimate_memory_needs(online_mem_total);
-	memory_limit -= vmem_estimate_memory_needs(online_mem_total);
+	memory_limit -= kasan_estimate_memory_needs(usable_total);
+	memory_limit -= vmem_estimate_memory_needs(usable_total);
 
 	safe_addr = ALIGN(safe_addr, THREAD_SIZE);
 	kernel_size = vmlinux.image_size + vmlinux.bss_size;
diff --git a/arch/s390/boot/mem_detect.c b/arch/s390/boot/mem_detect.c
index 3058d397a9da..35f4ba11f7fd 100644
--- a/arch/s390/boot/mem_detect.c
+++ b/arch/s390/boot/mem_detect.c
@@ -172,20 +172,20 @@ unsigned long detect_memory(unsigned long *safe_addr)
 	return max_physmem_end;
 }
 
-void mem_detect_truncate(unsigned long limit)
+void mem_detect_set_usable_limit(unsigned long limit)
 {
 	struct mem_detect_block *block;
 	int i;
 
+	/* make sure mem_detect.usable ends up within online memory block */
 	for (i = 0; i < mem_detect.count; i++) {
 		block = __get_mem_detect_block_ptr(i);
-		if (block->start >= limit) {
-			mem_detect.count = i;
+		if (block->start >= limit)
 			break;
-		} else if (block->end > limit) {
-			block->end = (u64)limit;
-			mem_detect.count = i + 1;
+		if (block->end >= limit) {
+			mem_detect.usable = limit;
 			break;
 		}
+		mem_detect.usable = block->end;
 	}
 }
diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c
index f5a7545d3c13..11413f0baabc 100644
--- a/arch/s390/boot/startup.c
+++ b/arch/s390/boot/startup.c
@@ -304,7 +304,7 @@ void startup_kernel(void)
 	setup_ident_map_size(max_physmem_end);
 	setup_vmalloc_size();
 	asce_limit = setup_kernel_memory_layout();
-	mem_detect_truncate(ident_map_size);
+	mem_detect_set_usable_limit(ident_map_size);
 
 	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_enabled) {
 		random_lma = get_random_base(safe_addr);
diff --git a/arch/s390/boot/vmem.c b/arch/s390/boot/vmem.c
index 4e54357ccd00..4d1d0d8e99cb 100644
--- a/arch/s390/boot/vmem.c
+++ b/arch/s390/boot/vmem.c
@@ -252,7 +252,7 @@ void setup_vmem(unsigned long asce_limit)
 	 */
 	pgtable_populate_init();
 	pgtable_populate(0, sizeof(struct lowcore), POPULATE_ONE2ONE);
-	for_each_mem_detect_block(i, &start, &end)
+	for_each_mem_detect_usable_block(i, &start, &end)
 		pgtable_populate(start, end, POPULATE_ONE2ONE);
 	pgtable_populate(__abs_lowcore, __abs_lowcore + sizeof(struct lowcore),
 			 POPULATE_ABS_LOWCORE);