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| author |   Nicholas Piggin <npiggin@gmail.com> | 2021-01-30 23:08:41 +1000 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2021-02-09 00:02:12 +1100 |
| commit | a008f8f9fd67ffb13d906ef4ea6235a3d62dfdb6 (patch) | |
| tree | b46363cdf1768c3aad470434f58a5ed9f29b7983 /arch/powerpc/mm/book3s64 | |
| parent | powerpc/64: context tracking remove _TIF_NOHZ (diff) | |
| download | linux-dev-a008f8f9fd67ffb13d906ef4ea6235a3d62dfdb6.tar.xz linux-dev-a008f8f9fd67ffb13d906ef4ea6235a3d62dfdb6.zip | |
powerpc/64s/hash: improve context tracking of hash faults
This moves the 64s/hash context tracking from hash_page_mm() to
__do_hash_fault(), so it's no longer called by OCXL / SPU
accelerators, which was certainly the wrong thing to be doing,
because those callers are not low level interrupt handlers, so
should have entered a kernel context tracking already.
Then remain in kernel context for the duration of the fault,
rather than enter/exit for the hash fault then enter/exit for
the page fault, which is pointless.
Even still, calling exception_enter/exit in __do_hash_fault seems
questionable because that's touching per-cpu variables, tracing,
etc., which might have been interrupted by this hash fault or
themselves cause hash faults. But maybe I miss something because
hash_page_mm very deliberately calls trace_hash_fault too, for
example. So for now go with it, it's no worse than before, in this
regard.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-32-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/mm/book3s64')
| -rw-r--r-- | arch/powerpc/mm/book3s64/hash_utils.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c index cf167f6d825d..d681dc5a7b1c 100644 --- a/arch/powerpc/mm/book3s64/hash_utils.c +++ b/arch/powerpc/mm/book3s64/hash_utils.c @@ -1289,7 +1289,6 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea, unsigned long flags) { bool is_thp; - enum ctx_state prev_state = exception_enter(); pgd_t *pgdir; unsigned long vsid; pte_t *ptep; @@ -1491,7 +1490,6 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea, DBG_LOW(" -> rc=%d\n", rc); bail: - exception_exit(prev_state); return rc; } EXPORT_SYMBOL_GPL(hash_page_mm); @@ -1516,6 +1514,7 @@ EXPORT_SYMBOL_GPL(hash_page); DECLARE_INTERRUPT_HANDLER_RET(__do_hash_fault); DEFINE_INTERRUPT_HANDLER_RET(__do_hash_fault) { + enum ctx_state prev_state = exception_enter(); unsigned long ea = regs->dar; unsigned long dsisr = regs->dsisr; unsigned long access = _PAGE_PRESENT | _PAGE_READ; @@ -1564,6 +1563,8 @@ DEFINE_INTERRUPT_HANDLER_RET(__do_hash_fault) err = 0; } + exception_exit(prev_state); + return err; } @@ -1600,7 +1601,7 @@ DEFINE_INTERRUPT_HANDLER_RAW(do_hash_fault) err = __do_hash_fault(regs); if (err) { page_fault: - err = do_page_fault(regs); + err = hash__do_page_fault(regs); } return err; |