| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.4 098/355] PCI: pci-bridge-emul: Fix emulation of W1C bits | Date | Mon, 15 Nov 2021 18:00:22 +0100 |
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From: Marek Behún <kabel@kernel.org>
commit 7a41ae80bdcb17e14dd7d83239b8a0cf368f18be upstream.
The pci_bridge_emul_conf_write() function correctly clears W1C bits in cfgspace cache, but it does not inform the underlying implementation about the clear request: the .write_op() method is given the value with these bits cleared.
This is wrong if the .write_op() needs to know which bits were requested to be cleared.
Fix the value to be passed into the .write_op() method to have requested W1C bits set, so that it can clear them.
Both pci-bridge-emul users (mvebu and aardvark) are compatible with this change.
Link: https://lore.kernel.org/r/20211028185659.20329-2-kabel@kernel.org Fixes: 23a5fba4d941 ("PCI: Introduce PCI bridge emulated config space common logic") Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Marek Behún <kabel@kernel.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: stable@vger.kernel.org Cc: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/pci/pci-bridge-emul.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)
--- a/drivers/pci/pci-bridge-emul.c +++ b/drivers/pci/pci-bridge-emul.c @@ -432,8 +432,21 @@ int pci_bridge_emul_conf_write(struct pc /* Clear the W1C bits */ new &= ~((value << shift) & (behavior[reg / 4].w1c & mask)); + /* Save the new value with the cleared W1C bits into the cfgspace */ cfgspace[reg / 4] = cpu_to_le32(new); + /* + * Clear the W1C bits not specified by the write mask, so that the + * write_op() does not clear them. + */ + new &= ~(behavior[reg / 4].w1c & ~mask); + + /* + * Set the W1C bits specified by the write mask, so that write_op() + * knows about that they are to be cleared. + */ + new |= (value << shift) & (behavior[reg / 4].w1c & mask); + if (write_op) write_op(bridge, reg, old, new, mask);
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