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| author | Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz> | 2020-08-06 07:14:55 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-15 15:14:50 +0300 |
| commit | b09700574652d0e9cf0b3b35e48ca542e9830255 (patch) | |
| tree | 65e6833120600594a16e6ba716965af12a99b79b | |
| parent | 60dd1082322966f192f42fe2a6605dfa08eef41f (diff) | |
| download | linux-b09700574652d0e9cf0b3b35e48ca542e9830255.tar.xz | |
PCI: Reduce warnings on possible RW1C corruption
[ Upstream commit 92c45b63ce22c8898aa41806e8d6692bcd577510 ]
For hardware that only supports 32-bit writes to PCI there is the
possibility of clearing RW1C (write-one-to-clear) bits. A rate-limited
messages was introduced by fb2659230120, but rate-limiting is not the best
choice here. Some devices may not show the warnings they should if another
device has just produced a bunch of warnings. Also, the number of messages
can be a nuisance on devices which are otherwise working fine.
Change the ratelimit to a single warning per bus. This ensures no bus is
'starved' of emitting a warning and also that there isn't a continuous
stream of warnings. It would be preferable to have a warning per device,
but the pci_dev structure is not available here, and a lookup from devfn
would be far too slow.
Suggested-by: Bjorn Helgaas <helgaas@kernel.org>
Fixes: fb2659230120 ("PCI: Warn on possible RW1C corruption for sub-32 bit config writes")
Link: https://lore.kernel.org/r/20200806041455.11070-1-mark.tomlinson@alliedtelesis.co.nz
Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/pci/access.c | 9 | ||||
| -rw-r--r-- | include/linux/pci.h | 1 |
2 files changed, 7 insertions, 3 deletions
diff --git a/drivers/pci/access.c b/drivers/pci/access.c index 3c8ffd62dc00..98ee5f05fc0f 100644 --- a/drivers/pci/access.c +++ b/drivers/pci/access.c @@ -160,9 +160,12 @@ int pci_generic_config_write32(struct pci_bus *bus, unsigned int devfn, * write happen to have any RW1C (write-one-to-clear) bits set, we * just inadvertently cleared something we shouldn't have. */ - dev_warn_ratelimited(&bus->dev, "%d-byte config write to %04x:%02x:%02x.%d offset %#x may corrupt adjacent RW1C bits\n", - size, pci_domain_nr(bus), bus->number, - PCI_SLOT(devfn), PCI_FUNC(devfn), where); + if (!bus->unsafe_warn) { + dev_warn(&bus->dev, "%d-byte config write to %04x:%02x:%02x.%d offset %#x may corrupt adjacent RW1C bits\n", + size, pci_domain_nr(bus), bus->number, + PCI_SLOT(devfn), PCI_FUNC(devfn), where); + bus->unsafe_warn = 1; + } mask = ~(((1 << (size * 8)) - 1) << ((where & 0x3) * 8)); tmp = readl(addr) & mask; diff --git a/include/linux/pci.h b/include/linux/pci.h index a4bbce871e08..3e06e9790c25 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -581,6 +581,7 @@ struct pci_bus { struct bin_attribute *legacy_io; /* Legacy I/O for this bus */ struct bin_attribute *legacy_mem; /* Legacy mem */ unsigned int is_added:1; + unsigned int unsafe_warn:1; /* warned about RW1C config write */ }; #define to_pci_bus(n) container_of(n, struct pci_bus, dev) |