| Message ID | 20210927123830.1278953-1-arnd@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | e27bea459d5eaa485ba091e0e051bf4575614d4f |
| Headers | show |
| Series | [RFC] usb: gadget: avoid unusual inline assembly | expand |
On Mon, Sep 27, 2021 at 02:38:20PM +0200, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@arndb.de> > > 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? > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > 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 > Given that no one had any objections, I'll queue this up and see what breaks :) thanks, greg k-h
On Mon, Sep 27, 2021 at 5:38 AM Arnd Bergmann <arnd@kernel.org> wrote: > > From: Arnd Bergmann <arnd@arndb.de> > > 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@arndb.de> > --- > 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 >
On 9/27/21 5:38 AM, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@arndb.de> > > 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? > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > 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)); You could consider using read_cpuid() from arch/arm/include/asm/cputype.h as this driver really does not seem to have portability in mind. > if ((chiprev & CP15R0_VENDOR_MASK) != CP15R0_XSCALE_VALUE) { > pr_err("%s: not XScale!\n", driver_name); > return -ENODEV; >
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;