Am Freitag, dem 28.01.2022 um 09:29 +0100 schrieb Francesco Dolcini: > From: Jason Liu <jason.hui.liu@xxxxxxx> > > The driver install one hook to handle the external abort, but issue > is that if the abort introduced from user space code, the following > code unsigned long instr = *(unsigned long *)pc; which will created > another data-abort(page domain fault) if CONFIG_CPU_SW_DOMAIN_PAN. > > The patch does not intent to use copy_from_user and then do the hack > due to the security consideration. In fact, we can just return and > report the external abort to user-space. > I'm not sure how userspace would be able to trigger this abort. Maybe invalid access to a device cfg space via sysfs? However the patch seems to do the right thing in that case. Acked-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx> > Signed-off-by: Jason Liu <jason.hui.liu@xxxxxxx> > Reviewed-by: Richard Zhu <hongxing.zhu@xxxxxxx> > Signed-off-by: Francesco Dolcini <francesco.dolcini@xxxxxxxxxxx> > --- > We have this patch from NXP downstream kernel [1] in our kernel branch [2] > since a long time, to me it would make sense to upstream it. Any concern? > > [1] https://source.codeaurora.org/external/imxsupport/linux-imx/commit/?id=62dfb2fb953463dd1b6710567c9e174672a98f24 > [2] https://git.toradex.com/cgit/linux-toradex.git/commit/?id=2b42547cf659f979be2defdff6a99f921b33d0f1 > --- > drivers/pci/controller/dwc/pci-imx6.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c > index 6974bd5aa116..6b178a29e253 100644 > --- a/drivers/pci/controller/dwc/pci-imx6.c > +++ b/drivers/pci/controller/dwc/pci-imx6.c > @@ -27,6 +27,7 @@ > #include <linux/resource.h> > #include <linux/signal.h> > #include <linux/types.h> > +#include <linux/uaccess.h> > #include <linux/interrupt.h> > #include <linux/reset.h> > #include <linux/phy/phy.h> > @@ -297,8 +298,15 @@ static int imx6q_pcie_abort_handler(unsigned long addr, > unsigned int fsr, struct pt_regs *regs) > { > unsigned long pc = instruction_pointer(regs); > - unsigned long instr = *(unsigned long *)pc; > - int reg = (instr >> 12) & 15; > + unsigned long instr; > + int reg; > + > + /* if the abort from user-space, just return and report it */ > + if (user_mode(regs)) > + return 1; > + > + instr = *(unsigned long *)pc; > + reg = (instr >> 12) & 15; > > /* > * If the instruction being executed was a read,
