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powerpc/64s: fix hash page fault interrupt handler 

The early bad fault or key fault test in do_hash_fault() ends up calling
into ___do_page_fault without having gone through an interrupt handler
wrapper (except the initial _RAW one). This can end up calling local irq
functions while the interrupt has not been reconciled, which will likely
cause crashes and it trips up on a later patch that adds more assertions.

pkey_exec_prot from selftests causes this path to be executed.

There is no real reason to run the in_nmi() test should be performed
before the key fault check. In fact if a perf interrupt in the hash
fault code did a stack walk that was made to take a key fault somehow
then running ___do_page_fault could possibly cause another hash fault
causing problems. Move the in_nmi() test first, and then do everything
else inside the regular interrupt handler function.

Fixes: 3a96570ffc ("powerpc: convert interrupt handlers to use wrappers")
Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210630074621.2109197-2-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2021-06-30 17:46:13 +10:00 committed by Michael Ellerman
parent fc4999864b
commit 5567b1ee29
1 changed files with 11 additions and 13 deletions
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24
arch/powerpc/mm/book3s64/hash_utils.c
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@ -1522,8 +1522,8 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap,
} }
EXPORT_SYMBOL_GPL(hash_page); EXPORT_SYMBOL_GPL(hash_page);
DECLARE_INTERRUPT_HANDLER_RET(__do_hash_fault); DECLARE_INTERRUPT_HANDLER(__do_hash_fault);
DEFINE_INTERRUPT_HANDLER_RET(__do_hash_fault) DEFINE_INTERRUPT_HANDLER(__do_hash_fault)
{ {
unsigned long ea = regs->dar; unsigned long ea = regs->dar;
unsigned long dsisr = regs->dsisr; unsigned long dsisr = regs->dsisr;
@ -1533,6 +1533,11 @@ DEFINE_INTERRUPT_HANDLER_RET(__do_hash_fault)
unsigned int region_id; unsigned int region_id;
long err; long err;
if (unlikely(dsisr & (DSISR_BAD_FAULT_64S | DSISR_KEYFAULT))) {
hash__do_page_fault(regs);
return;
}
region_id = get_region_id(ea); region_id = get_region_id(ea);
if ((region_id == VMALLOC_REGION_ID) || (region_id == IO_REGION_ID)) if ((region_id == VMALLOC_REGION_ID) || (region_id == IO_REGION_ID))
mm = &init_mm; mm = &init_mm;
@ -1571,9 +1576,10 @@ DEFINE_INTERRUPT_HANDLER_RET(__do_hash_fault)
bad_page_fault(regs, SIGBUS); bad_page_fault(regs, SIGBUS);
} }
err = 0; err = 0;
}
return err; } else if (err) {
hash__do_page_fault(regs);
}
} }
/* /*
@ -1582,13 +1588,6 @@ DEFINE_INTERRUPT_HANDLER_RET(__do_hash_fault)
*/ */
DEFINE_INTERRUPT_HANDLER_RAW(do_hash_fault) DEFINE_INTERRUPT_HANDLER_RAW(do_hash_fault)
{ {
unsigned long dsisr = regs->dsisr;
if (unlikely(dsisr & (DSISR_BAD_FAULT_64S | DSISR_KEYFAULT))) {
hash__do_page_fault(regs);
return 0;
}
/* /*
* If we are in an "NMI" (e.g., an interrupt when soft-disabled), then * If we are in an "NMI" (e.g., an interrupt when soft-disabled), then
* don't call hash_page, just fail the fault. This is required to * don't call hash_page, just fail the fault. This is required to
@ -1607,8 +1606,7 @@ DEFINE_INTERRUPT_HANDLER_RAW(do_hash_fault)
return 0; return 0;
} }
if (__do_hash_fault(regs)) __do_hash_fault(regs);
hash__do_page_fault(regs);
return 0; return 0;
} }