Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
s390/mm: Change comment and die() message if teid.b61 is zero
The comments in do_protection() give the impression that a TEID, where bit
61 is zero, indicates a low address protection exception. This is not
necessarily true, and it depends on the type of Suppression-on-Protection
facility of the machine (see Princples of Operation) what this means.
Rework the comments and the die() message to reflect this. This may also
help to avoid confusion.
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
+4
-9
+4
-9
arch/s390/mm/fault.c
+4
-9
arch/s390/mm/fault.c
···
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if (!(regs->int_code & 0x200))
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regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16);
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/*
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-
* Check for low-address protection. This needs to be treated
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* as a special case because the translation exception code
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* field is not guaranteed to contain valid data in this case.
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+
* If bit 61 if the TEID is not set, the remainder of the
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+
* TEID is unpredictable. Special handling is required.
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*/
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if (unlikely(!teid.b61)) {
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if (user_mode(regs)) {
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-
/* Low-address protection in user mode: cannot happen */
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dump_fault_info(regs);
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-
die(regs, "Low-address protection");
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+
die(regs, "Unexpected TEID");
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}
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-
/*
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* Low-address protection in kernel mode means
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* NULL pointer write access in kernel mode.
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-
*/
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+
/* Assume low-address protection in kernel mode. */
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return handle_fault_error_nolock(regs, 0);
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}
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if (unlikely(cpu_has_nx() && teid.b56)) {