diff options
| author | Heiko Carstens | 2020-11-16 08:06:41 +0100 |
|---|---|---|
| committer | Heiko Carstens | 2020-11-23 12:01:12 +0100 |
| commit | 0290c9e328e04052e317171953feb18177a34aed (patch) | |
| tree | 9ba70533fc8727ef2d664542b62f90180d44819c /arch/s390/kernel | |
| parent | 87d5986345219a7e4f204726d9085ea87f3e22d0 (diff) | |
s390/mm: use invalid asce instead of kernel asce
Create a region 3 page table which contains only invalid entries, and
use that via "s390_invalid_asce" instead of the kernel ASCE whenever
there is either
- no user address space available, e.g. during early startup
- as an intermediate ASCE when address spaces are switched
This makes sure that user space accesses in such situations are
guaranteed to fail.
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Diffstat (limited to 'arch/s390/kernel')
| -rw-r--r-- | arch/s390/kernel/smp.c | 2 | ||||
| -rw-r--r-- | arch/s390/kernel/vmlinux.lds.S | 3 |
2 files changed, 3 insertions, 2 deletions
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index cac96f240dd8..7f7d81f19292 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -259,7 +259,7 @@ static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu) lc->spinlock_index = 0; lc->percpu_offset = __per_cpu_offset[cpu]; lc->kernel_asce = S390_lowcore.kernel_asce; - lc->user_asce = S390_lowcore.kernel_asce; + lc->user_asce = s390_invalid_asce; lc->machine_flags = S390_lowcore.machine_flags; lc->user_timer = lc->system_timer = lc->steal_timer = lc->avg_steal_timer = 0; diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S index 177ccfbda40a..4c0e19145cc6 100644 --- a/arch/s390/kernel/vmlinux.lds.S +++ b/arch/s390/kernel/vmlinux.lds.S @@ -10,7 +10,8 @@ * Put .bss..swapper_pg_dir as the first thing in .bss. This will * make sure it has 16k alignment. */ -#define BSS_FIRST_SECTIONS *(.bss..swapper_pg_dir) +#define BSS_FIRST_SECTIONS *(.bss..swapper_pg_dir) \ + *(.bss..invalid_pg_dir) /* Handle ro_after_init data on our own. */ #define RO_AFTER_INIT_DATA |