From: Oliver O'Halloran oohall@gmail.com
[ Upstream commit 33439620680be5225c1b8806579a291e0d761ca0 ]
In commit 4a7b06c157a2 ("powerpc/eeh: Handle hugepages in ioremap space") support for using hugepages in the vmalloc and ioremap areas was enabled for radix. Unfortunately this broke EEH MMIO error checking.
Detection works by inserting a hook which checks the results of the ioreadXX() set of functions. When a read returns a 0xFFs response we need to check for an error which we do by mapping the (virtual) MMIO address back to a physical address, then mapping physical address to a PCI device via an interval tree.
When translating virt -> phys we currently assume the ioremap space is only populated by PAGE_SIZE mappings. If a hugepage mapping is found we emit a WARN_ON(), but otherwise handles the check as though a normal page was found. In pathalogical cases such as copying a buffer containing a lot of 0xFFs from BAR memory this can result in the system not booting because it's too busy printing WARN_ON()s.
There's no real reason to assume huge pages can't be present and we're prefectly capable of handling them, so do that.
Fixes: 4a7b06c157a2 ("powerpc/eeh: Handle hugepages in ioremap space") Reported-by: Sachin Sant sachinp@linux.vnet.ibm.com Signed-off-by: Oliver O'Halloran oohall@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/20190710150517.27114-1-oohall@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/kernel/eeh.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c index 45322b37669a..d2ba7936d0d3 100644 --- a/arch/powerpc/kernel/eeh.c +++ b/arch/powerpc/kernel/eeh.c @@ -361,10 +361,19 @@ static inline unsigned long eeh_token_to_phys(unsigned long token) ptep = find_init_mm_pte(token, &hugepage_shift); if (!ptep) return token; - WARN_ON(hugepage_shift); - pa = pte_pfn(*ptep) << PAGE_SHIFT;
- return pa | (token & (PAGE_SIZE-1)); + pa = pte_pfn(*ptep); + + /* On radix we can do hugepage mappings for io, so handle that */ + if (hugepage_shift) { + pa <<= hugepage_shift; + pa |= token & ((1ul << hugepage_shift) - 1); + } else { + pa <<= PAGE_SHIFT; + pa |= token & (PAGE_SIZE - 1); + } + + return pa; }
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