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. 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, -- 2.25.1
