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>

diff --git a/arch/s390/boot/boot.h b/arch/s390/boot/boot.h
index ed85b144119a03df82f91902b2e2ef1a349fe1f2..58ce701d6110427e39748d6899eb2b179ed591b1 100644 (file)
--- 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 70ff68dd1feec1cb1253817cb7f73b8d6c348cf6..3e3d846400b4e85d5b0edc34cfe422f0736a2d6a 100644 (file)
--- 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 3058d397a9da40ed636f190a6dda88772b68c4c8..35f4ba11f7fd47ba226c4d8e8ecb126e5a2ba1d2 100644 (file)
--- 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 f5a7545d3c13db091f1f87f42c7c289d2d9941d4..11413f0baabcbc5ebd587d32c0354f575c73b50b 100644 (file)
--- 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 4e54357ccd00e319b6a0bf651f84457f75ad1718..4d1d0d8e99cb2ee25bd90b153181b583e1d1734e 100644 (file)
--- 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);

diff --git a/arch/s390/include/asm/mem_detect.h b/arch/s390/include/asm/mem_detect.h
index decd8c4cb799d68c909c80baa9232db4d08db5aa..f9e7354036d235c4bd94293729df7942201015cf 100644 (file)
--- a/arch/s390/include/asm/mem_detect.h
+++ b/arch/s390/include/asm/mem_detect.h
@@ -30,6 +30,7 @@ struct mem_detect_block {
 struct mem_detect_info {
        u32 count;
        u8 info_source;
+       unsigned long usable;
        struct mem_detect_block entries[MEM_INLINED_ENTRIES];
        struct mem_detect_block *entries_extended;
 };
@@ -38,7 +39,7 @@ extern struct mem_detect_info mem_detect;
 void add_mem_detect_block(u64 start, u64 end);
 
 static inline int __get_mem_detect_block(u32 n, unsigned long *start,
-                                        unsigned long *end)
+                                        unsigned long *end, bool respect_usable_limit)
 {
        if (n >= mem_detect.count) {
                *start = 0;
@@ -53,28 +54,37 @@ static inline int __get_mem_detect_block(u32 n, unsigned long *start,
                *start = (unsigned long)mem_detect.entries_extended[n - MEM_INLINED_ENTRIES].start;
                *end = (unsigned long)mem_detect.entries_extended[n - MEM_INLINED_ENTRIES].end;
        }
+
+       if (respect_usable_limit && mem_detect.usable) {
+               if (*start >= mem_detect.usable)
+                       return -1;
+               if (*end > mem_detect.usable)
+                       *end = mem_detect.usable;
+       }
        return 0;
 }
 
 /**
- * for_each_mem_detect_block - early online memory range iterator
+ * for_each_mem_detect_usable_block - early online memory range iterator
  * @i: an integer used as loop variable
  * @p_start: ptr to unsigned long for start address of the range
  * @p_end: ptr to unsigned long for end address of the range
  *
- * Walks over detected online memory ranges.
+ * Walks over detected online memory ranges below usable limit.
  */
-#define for_each_mem_detect_block(i, p_start, p_end)                   \
-       for (i = 0, __get_mem_detect_block(i, p_start, p_end);          \
-            i < mem_detect.count;                                      \
-            i++, __get_mem_detect_block(i, p_start, p_end))
+#define for_each_mem_detect_usable_block(i, p_start, p_end)            \
+       for (i = 0; !__get_mem_detect_block(i, p_start, p_end, true); i++)
+
+/* Walks over all detected online memory ranges disregarding usable limit. */
+#define for_each_mem_detect_block(i, p_start, p_end)           \
+       for (i = 0; !__get_mem_detect_block(i, p_start, p_end, false); i++)
 
-static inline unsigned long get_mem_detect_online_total(void)
+static inline unsigned long get_mem_detect_usable_total(void)
 {
        unsigned long start, end, total = 0;
        int i;
 
-       for_each_mem_detect_block(i, &start, &end)
+       for_each_mem_detect_usable_block(i, &start, &end)
                total += end - start;
 
        return total;
@@ -95,8 +105,10 @@ static inline unsigned long get_mem_detect_end(void)
        unsigned long start;
        unsigned long end;
 
+       if (mem_detect.usable)
+               return mem_detect.usable;
        if (mem_detect.count) {
-               __get_mem_detect_block(mem_detect.count - 1, &start, &end);
+               __get_mem_detect_block(mem_detect.count - 1, &start, &end, false);
                return end;
        }
        return 0;

diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index d8f41ccfe54e62680c22750f00004a34904cdcff..8ec5cdf9dadc77d029dc45866f258f80101fc7be 100644 (file)
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -772,10 +772,10 @@ static void __init memblock_add_mem_detect_info(void)
                 get_mem_info_source(), mem_detect.info_source);
        /* keep memblock lists close to the kernel */
        memblock_set_bottom_up(true);
-       for_each_mem_detect_block(i, &start, &end) {
+       for_each_mem_detect_usable_block(i, &start, &end)
                memblock_add(start, end - start);
+       for_each_mem_detect_block(i, &start, &end)
                memblock_physmem_add(start, end - start);
-       }
        memblock_set_bottom_up(false);
        memblock_set_node(0, ULONG_MAX, &memblock.memory, 0);
 }

diff --git a/arch/s390/mm/kasan_init.c b/arch/s390/mm/kasan_init.c
index 4f6678282726dfcf7e9f0973f8a310c918c15016..ef89a5f26853de96d238ed524750987170f1f5f5 100644 (file)
--- a/arch/s390/mm/kasan_init.c
+++ b/arch/s390/mm/kasan_init.c
@@ -244,7 +244,7 @@ void __init kasan_early_init(void)
        memset64((u64 *)kasan_early_shadow_pte, pte_val(pte_z), PTRS_PER_PTE);
 
        if (has_edat) {
-               shadow_alloc_size = get_mem_detect_online_total() >> KASAN_SHADOW_SCALE_SHIFT;
+               shadow_alloc_size = get_mem_detect_usable_total() >> KASAN_SHADOW_SCALE_SHIFT;
                segment_pos = round_down(pgalloc_pos, _SEGMENT_SIZE);
                segment_low = segment_pos - shadow_alloc_size;
                segment_low = round_down(segment_low, _SEGMENT_SIZE);
@@ -282,7 +282,7 @@ void __init kasan_early_init(void)
         * +- shadow end ----+---------+- shadow end ---+
         */
        /* populate kasan shadow (for identity mapping and zero page mapping) */
-       for_each_mem_detect_block(i, &start, &end)
+       for_each_mem_detect_usable_block(i, &start, &end)
                kasan_early_pgtable_populate(__sha(start), __sha(end), POPULATE_MAP);
        if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) {
                untracked_end = VMALLOC_START;