[PATCH 2/2] speakup: only build serialio when ISA is enabled

[PATCH 2/2] speakup: only build serialio when ISA is enabled

[Samuel Thibault]

Drivers using serialio are already made available in Kconfig only under
the ISA condition.

This solves warnings in inb/outb macros on platform that do not have 
support for ISA.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

Index: linux-2.6/drivers/accessibility/speakup/Makefile
===================================================================
--- linux-2.6.orig/drivers/accessibility/speakup/Makefile
+++ linux-2.6/drivers/accessibility/speakup/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_SPEAKUP_SYNTH_TXPRT) += spe
 obj-$(CONFIG_SPEAKUP_SYNTH_DUMMY) += speakup_dummy.o
 
 obj-$(CONFIG_SPEAKUP) += speakup.o
+obj-$(CONFIG_ISA) += serialio.o
 speakup-y := \
 	buffers.o \
 	devsynth.o \
@@ -25,7 +26,6 @@ speakup-y := \
 	keyhelp.o \
 	kobjects.o \
 	selection.o \
-	serialio.o \
 	spk_ttyio.o \
 	synth.o \
 	thread.o \

Re: [PATCH 2/2] speakup: only build serialio when ISA is enabled

[Samuel Thibault]

Greg KH, le mar. 04 août 2020 13:34:13 +0200, a ecrit:
> On Tue, Aug 04, 2020 at 01:13:32PM +0200, Samuel Thibault wrote:
> > Drivers using serialio are already made available in Kconfig only under
> > the ISA condition.
> > 
> > This solves warnings in inb/outb macros on platform that do not have 
> > support for ISA.
> > 
> > Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
> > 
> > Index: linux-2.6/drivers/accessibility/speakup/Makefile
> > ===================================================================
> > --- linux-2.6.orig/drivers/accessibility/speakup/Makefile
> > +++ linux-2.6/drivers/accessibility/speakup/Makefile
> > @@ -16,6 +16,7 @@ obj-$(CONFIG_SPEAKUP_SYNTH_TXPRT) += spe
> >  obj-$(CONFIG_SPEAKUP_SYNTH_DUMMY) += speakup_dummy.o
> >  
> >  obj-$(CONFIG_SPEAKUP) += speakup.o
> > +obj-$(CONFIG_ISA) += serialio.o
> >  speakup-y := \
> >  	buffers.o \
> >  	devsynth.o \
> > @@ -25,7 +26,6 @@ speakup-y := \
> >  	keyhelp.o \
> >  	kobjects.o \
> >  	selection.o \
> > -	serialio.o \
> >  	spk_ttyio.o \
> >  	synth.o \
> >  	thread.o \
> 
> Oops, no, I get the following build errors with this patch:
> 
> ERROR: modpost: "spk_wait_for_xmitr" [drivers/accessibility/speakup/speakup.ko] undefined!

Yes, it depends on the first of the queue.

Samuel

Re: [PATCH 2/2] speakup: only build serialio when ISA is enabled

[Samuel Thibault]

Greg KH, le mar. 04 août 2020 13:58:17 +0200, a ecrit:
> 	ERROR: modpost: "spk_serial_io_ops" [drivers/accessibility/speakup/speakup_keypc.ko] undefined!
> 	ERROR: modpost: "spk_stop_serial_interrupt" [drivers/accessibility/speakup/speakup_keypc.ko] undefined!

Oh, indeed, these are not covered by the first patch.

I realize that KEYPC depends on ISA, but with COMPILE_TEST as
alternative. We can build serialio in the COMPILE_TEST case too, I'll
update the patches.

But then we'll still have:

> the riscv build issues.

Actually I was surprised by the riscv build issue: the issue is within
riscv's inb() implementation, serialio.c is only calling it.
arch/riscv/include/asm/io.h says:

#define PCI_IOBASE		((void __iomem *)PCI_IO_START)
[...]
#define inb(c)		({ u8  __v; __io_pbr(); __v = readb_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; })

and thus yes it's arithmetic over a (void*) pointer, the caller cannot
do anything about it.

8250_port.c itself uses inb(), doesn't it get a warning as well? Or is
it getting compiled-out on riscv because of some Kconfig condition?  I
see that the whole drivers/tty/serial is under HAS_IOMEM, and that's the
only condition I can see for 8250_port.c (except SERIAL_8250 of course),
is that it, or is SERIAL_8250 just not enabled in the riscv bot?

Actually the warning seems new, when looking at the Debian build log:

https://buildd.debian.org/status/fetch.php?pkg=linux&arch=riscv64&ver=5.7.10-1&stamp=1595803499&raw=0

and looking for serialio.c, I do not see a warning, and its code hasn't
changed. Is the build bot compiler just more talkative?

Samuel

Re: [PATCH 2/2] speakup: only build serialio when ISA is enabled

[Samuel Thibault]

Greg KH, le mar. 04 août 2020 17:49:52 +0200, a ecrit:
> > #define inb(c)		({ u8  __v; __io_pbr(); __v = readb_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; })
> > 
> > and thus yes it's arithmetic over a (void*) pointer, the caller cannot
> > do anything about it.
> 
> And that's fine, math with pointers, even void ones, is ok.

C++ doesn't like it, but in general compilers provide some semantic for
it, yes.

> I wonder why riscv was complaining about that.  It's not nice, but it is
> valid C.

Strictly C speaking, no, but GNU C yes.

> Let's see if any of their developers care about it :)

Ok :) In the meanwhile I sent a v2 series that should fix the different
link cases, just not the particular riscv warning.

Samuel