| Message ID | 20200124132957.15769-1-geert+renesas@glider.be (mailing list archive) |
|---|---|
| Headers | show |
| Series | Fix debugfs register access while suspended | expand |
Hi Geert, Thanks for your series. On 2020-01-24 14:29:55 +0100, Geert Uytterhoeven wrote: > Hi all, > > While comparing register values read from debugfs files under > /sys/kernel/debug/ccree/, I noticed some oddities. > Apparently there is no guarantee these registers are read from the > device while it is resumed. This may lead to bogus values, or crashes > and lock-ups. > > This patch series: > 1. Allows debugfs_create_regset32() to be used for devices whose > registers must be accessed when resumed, > 2. Fixes the CCREE driver to make use of this. > > I have identified several other drivers that may be affected (i.e. > using debugfs_create_regset32() and pm_runtime_*()): > - drivers/gpu/drm/msm/disp/dpu1 > - drivers/usb/dwc3 > - drivers/usb/host/ehci-omap.c > - drivers/usb/host/ehci-tegra.c > - drivers/usb/host/ohci-platform.c > - drivers/usb/host/xhci.c > - drivers/usb/host/xhci-dbgcap.c > - drivers/usb/host/xhci-histb.c > - drivers/usb/host/xhci-hub.c > - drivers/usb/host/xhci-mtk.c > - drivers/usb/host/xhci-pci.c > - drivers/usb/host/xhci-plat.c > - drivers/usb/host/xhci-tegra.c > - drivers/usb/mtu3 > - drivers/usb/musb > > Some of these call pm_runtime_forbid(), but given the comment "users > should enable runtime pm using power/control in sysfs", this can be > overridden from userspace, so these are unsafe, too? > > Thanks for your comments! Looks good to me, Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se> > > Geert Uytterhoeven (2): > debugfs: regset32: Add Runtime PM support > crypto: ccree - fix debugfs register access while suspended > > drivers/crypto/ccree/cc_debugfs.c | 2 ++ > fs/debugfs/file.c | 8 ++++++++ > include/linux/debugfs.h | 1 + > 3 files changed, 11 insertions(+) > > -- > 2.17.1 > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds
Hi all, While comparing register values read from debugfs files under /sys/kernel/debug/ccree/, I noticed some oddities. Apparently there is no guarantee these registers are read from the device while it is resumed. This may lead to bogus values, or crashes and lock-ups. This patch series: 1. Allows debugfs_create_regset32() to be used for devices whose registers must be accessed when resumed, 2. Fixes the CCREE driver to make use of this. I have identified several other drivers that may be affected (i.e. using debugfs_create_regset32() and pm_runtime_*()): - drivers/gpu/drm/msm/disp/dpu1 - drivers/usb/dwc3 - drivers/usb/host/ehci-omap.c - drivers/usb/host/ehci-tegra.c - drivers/usb/host/ohci-platform.c - drivers/usb/host/xhci.c - drivers/usb/host/xhci-dbgcap.c - drivers/usb/host/xhci-histb.c - drivers/usb/host/xhci-hub.c - drivers/usb/host/xhci-mtk.c - drivers/usb/host/xhci-pci.c - drivers/usb/host/xhci-plat.c - drivers/usb/host/xhci-tegra.c - drivers/usb/mtu3 - drivers/usb/musb Some of these call pm_runtime_forbid(), but given the comment "users should enable runtime pm using power/control in sysfs", this can be overridden from userspace, so these are unsafe, too? Thanks for your comments! Geert Uytterhoeven (2): debugfs: regset32: Add Runtime PM support crypto: ccree - fix debugfs register access while suspended drivers/crypto/ccree/cc_debugfs.c | 2 ++ fs/debugfs/file.c | 8 ++++++++ include/linux/debugfs.h | 1 + 3 files changed, 11 insertions(+)