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| author | Heiko Carstens <hca@linux.ibm.com> | 2020-11-16 08:06:41 +0100 |
|---|---|---|
| committer | Heiko Carstens <hca@linux.ibm.com> | 2020-11-23 12:01:12 +0100 |
| commit | 062e527956d05fae02f143c0d5ff9e8525c6799f (patch) | |
| tree | 8e070371d94d41cd6f6eb7eeb8801442ad73bdf2 /arch/s390/lib | |
| parent | 0290c9e328e04052e317171953feb18177a34aed (diff) | |
s390/mm: add debug user asce support
Verify on exit to user space that always
- the primary ASCE (cr1) is set to kernel ASCE
- the secondary ASCE (cr7) is set to user ASCE
If this is not the case: panic since something went terribly wrong.
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Diffstat (limited to 'arch/s390/lib')
| -rw-r--r-- | arch/s390/lib/uaccess.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/s390/lib/uaccess.c b/arch/s390/lib/uaccess.c index 0ffbe1fad72a..e8f642446fed 100644 --- a/arch/s390/lib/uaccess.c +++ b/arch/s390/lib/uaccess.c @@ -16,6 +16,22 @@ #include <asm/mmu_context.h> #include <asm/facility.h> +#ifdef CONFIG_DEBUG_USER_ASCE +void debug_user_asce(void) +{ + unsigned long cr1, cr7; + + __ctl_store(cr1, 1, 1); + __ctl_store(cr7, 7, 7); + if (cr1 == S390_lowcore.kernel_asce && cr7 == S390_lowcore.user_asce) + return; + panic("incorrect ASCE on kernel exit\n" + "cr1: %016lx cr7: %016lx\n" + "kernel: %016llx user: %016llx\n", + cr1, cr7, S390_lowcore.kernel_asce, S390_lowcore.user_asce); +} +#endif /*CONFIG_DEBUG_USER_ASCE */ + #ifndef CONFIG_HAVE_MARCH_Z10_FEATURES static DEFINE_STATIC_KEY_FALSE(have_mvcos); |