On Mon, Sep 27, 2021 at 5:38 AM Arnd Bergmann <arnd@xxxxxxxxxx> wrote: > > From: Arnd Bergmann <arnd@xxxxxxxx> > > clang does not understand the "mrc%?" syntax: > > drivers/usb/gadget/udc/pxa25x_udc.c:2330:11: error: invalid % escape in inline assembly string > > I don't understand it either, but removing the %? here gets it to build. > This is probably wrong and someone else should do a proper patch. > > Any suggestions? https://gcc.gnu.org/onlinedocs/gccint/Output-Template.html says: >> ‘%’ followed by a punctuation character specifies a substitution that does not use an operand. Only one case is standard: ‘%%’ outputs a ‘%’ into the assembler code. I don't think the intention was to have `mrc?` in the emitted assembler (is that even valid?), so it's not clear to me what this point of `%?` was. Patch LGTM. > > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> > --- > drivers/usb/gadget/udc/pxa25x_udc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/usb/gadget/udc/pxa25x_udc.c b/drivers/usb/gadget/udc/pxa25x_udc.c > index a09ec1d826b2..52cdfd8212d6 100644 > --- a/drivers/usb/gadget/udc/pxa25x_udc.c > +++ b/drivers/usb/gadget/udc/pxa25x_udc.c > @@ -2325,7 +2325,7 @@ static int pxa25x_udc_probe(struct platform_device *pdev) > pr_info("%s: version %s\n", driver_name, DRIVER_VERSION); > > /* insist on Intel/ARM/XScale */ > - asm("mrc%? p15, 0, %0, c0, c0" : "=r" (chiprev)); > + asm("mrc p15, 0, %0, c0, c0" : "=r" (chiprev)); > if ((chiprev & CP15R0_VENDOR_MASK) != CP15R0_XSCALE_VALUE) { > pr_err("%s: not XScale!\n", driver_name); > return -ENODEV; > -- > 2.29.2 > -- Thanks, ~Nick Desaulniers
