Fork of alistair23 Linux kernel for reMarkable from https://github.com/alistair23/linux
424ca4c551
For paged accesses to be truely safe, we need to hold the bus lock to prevent anyone else gaining access to the registers while we modify them. The phydev->lock mutex does not do this: userspace via the MII ioctl can still sneak in and read or write any register while we are on a different page, and the suspend/resume methods can be called by a thread different to the thread polling the phy status. Races have been observed with mvneta on SolidRun Clearfog with phylink, particularly between the phylib worker reading the PHYs status, and the thread resuming mvneta, calling phy_start() which then calls through to m88e1121_config_aneg_rgmii_delays(), which tries to read-modify-write the MSCR register: CPU0 CPU1 marvell_read_status_page() marvell_set_page(phydev, MII_MARVELL_FIBER_PAGE) ... m88e1121_config_aneg_rgmii_delays() set_page(MII_MARVELL_MSCR_PAGE) phy_read(phydev, MII_88E1121_PHY_MSCR_REG) marvell_set_page(phydev, MII_MARVELL_COPPER_PAGE); ... phy_write(phydev, MII_88E1121_PHY_MSCR_REG) The result of this is we end up writing the copper page register 21, which causes the copper PHY to be disabled, and the link partner sees the link immediately go down. Solve this by taking the bus lock instead of the PHY lock, thereby preventing other accesses to the PHY while we are accessing other PHY pages. Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: David S. Miller <davem@davemloft.net> |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.