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| author | Vasily Gorbik <gor@linux.ibm.com> | 2023-01-23 17:24:17 +0300 |
|---|---|---|
| committer | Heiko Carstens <hca@linux.ibm.com> | 2023-01-31 20:56:36 +0300 |
| commit | e966ccf836e8964edf984adc4b4af5f3a3e07de6 (patch) | |
| tree | 613f16e8b7a85f316477180a7303c0f96316bf5c /arch/s390/boot/vmem.c | |
| parent | 2213d44e140f979f4b60c3c0f8dd56d151cc8692 (diff) | |
| download | linux-e966ccf836e8964edf984adc4b4af5f3a3e07de6.tar.xz | |
s390/boot: avoid mapping standby memory
Commit bb1520d581a3 ("s390/mm: start kernel with DAT enabled")
doesn't consider online memory holes due to potential memory offlining
and erroneously creates pgtables for stand-by memory, which bear RW+X
attribute and trigger a warning:
RANGE SIZE STATE REMOVABLE BLOCK
0x0000000000000000-0x0000000c3fffffff 49G online yes 0-48
0x0000000c40000000-0x0000000c7fffffff 1G offline 49
0x0000000c80000000-0x0000000fffffffff 14G online yes 50-63
0x0000001000000000-0x00000013ffffffff 16G offline 64-79
s390/mm: Found insecure W+X mapping at address 0xc40000000
WARNING: CPU: 14 PID: 1 at arch/s390/mm/dump_pagetables.c:142 note_page+0x2cc/0x2d8
Map only online memory ranges which fit within identity mapping limit.
Fixes: bb1520d581a3 ("s390/mm: start kernel with DAT enabled")
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>
Diffstat (limited to 'arch/s390/boot/vmem.c')
| -rw-r--r-- | arch/s390/boot/vmem.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/arch/s390/boot/vmem.c b/arch/s390/boot/vmem.c index 3bcef4fcea80..edcad545b949 100644 --- a/arch/s390/boot/vmem.c +++ b/arch/s390/boot/vmem.c @@ -39,7 +39,7 @@ static void boot_check_oom(void) error("out of memory on boot\n"); } -static void pgtable_populate_begin(unsigned long online_end) +static void pgtable_populate_begin(unsigned long ident_map_size) { unsigned long initrd_end; unsigned long kernel_end; @@ -51,7 +51,7 @@ static void pgtable_populate_begin(unsigned long online_end) pgalloc_low = max(pgalloc_low, initrd_end); } - pgalloc_end = round_down(online_end, PAGE_SIZE); + pgalloc_end = round_down(min(ident_map_size, get_mem_detect_end()), PAGE_SIZE); pgalloc_pos = pgalloc_end; boot_check_oom(); @@ -247,10 +247,12 @@ static void pgtable_populate_end(void) } while (pgalloc_pos < pgalloc_pos_prev); } -void setup_vmem(unsigned long online_end, unsigned long asce_limit) +void setup_vmem(unsigned long ident_map_size, unsigned long asce_limit) { + unsigned long start, end; unsigned long asce_type; unsigned long asce_bits; + int i; if (asce_limit == _REGION1_SIZE) { asce_type = _REGION2_ENTRY_EMPTY; @@ -272,9 +274,13 @@ void setup_vmem(unsigned long online_end, unsigned long asce_limit) * No further pgtable_populate() calls are allowed after the value * of pgalloc_pos finalized with a call to pgtable_populate_end(). */ - pgtable_populate_begin(online_end); + pgtable_populate_begin(ident_map_size); pgtable_populate(0, sizeof(struct lowcore), POPULATE_ONE2ONE); - pgtable_populate(0, online_end, POPULATE_ONE2ONE); + for_each_mem_detect_block(i, &start, &end) { + if (start >= ident_map_size) + break; + pgtable_populate(start, min(end, ident_map_size), POPULATE_ONE2ONE); + } pgtable_populate(__abs_lowcore, __abs_lowcore + sizeof(struct lowcore), POPULATE_ABS_LOWCORE); pgtable_populate(__memcpy_real_area, __memcpy_real_area + PAGE_SIZE, |