This is a note to let you know that I've just added the patch titled
PCI: pci-bridge-emul: Fix emulation of W1C bits
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
pci-pci-bridge-emul-fix-emulation-of-w1c-bits.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 7a41ae80bdcb17e14dd7d83239b8a0cf368f18be Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Beh=C3=BAn?= <kabel@xxxxxxxxxx>
Date: Thu, 28 Oct 2021 20:56:53 +0200
Subject: PCI: pci-bridge-emul: Fix emulation of W1C bits
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From: Marek Behún <kabel@xxxxxxxxxx>
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@xxxxxxxxxx
Fixes: 23a5fba4d941 ("PCI: Introduce PCI bridge emulated config space common logic")
Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
Signed-off-by: Marek Behún <kabel@xxxxxxxxxx>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Cc: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);
Patches currently in stable-queue which might be from kabel@xxxxxxxxxx are
queue-5.4/pci-aardvark-fix-reporting-data-link-layer-link-active.patch
queue-5.4/pci-pci-bridge-emul-fix-emulation-of-w1c-bits.patch
queue-5.4/pci-aardvark-fix-checking-for-link-up-via-ltssm-state.patch
queue-5.4/pci-aardvark-fix-return-value-of-msi-domain-.alloc-method.patch
queue-5.4/pci-aardvark-read-all-16-bits-from-pcie_msi_payload_reg.patch
queue-5.4/pci-aardvark-do-not-unmask-unused-interrupts.patch
queue-5.4/pci-aardvark-do-not-clear-status-bits-of-masked-interrupts.patch
