Re: [PATCH 3/3 v2] sh: fix READ/WRITE redefinition warnings

) Hi Adrian,

On Wed, Jun 30, 2021 at 9:36 PM John Paul Adrian Glaubitz
[off-list ref] wrote:

On 6/30/21 9:33 PM, Randy Dunlap wrote:

quoted

On 6/30/21 2:36 AM, John Paul Adrian Glaubitz wrote:

quoted

On 6/28/21 12:05 AM, Randy Dunlap wrote:

quoted

kernel.h defines READ and WRITE, so rename the SH math-emu macros
to MREAD and MWRITE.

Fixes these warnings:

../arch/sh/math-emu/math.c:54: warning: "WRITE" redefined
   54 | #define WRITE(d,a) ({if(put_user(d, (typeof (d) __user *)a)) return -EFAULT;})
In file included from ../arch/sh/math-emu/math.c:10:
../include/linux/kernel.h:37: note: this is the location of the previous definition
   37 | #define WRITE   1
../arch/sh/math-emu/math.c:55: warning: "READ" redefined
   55 | #define READ(d,a) ({if(get_user(d, (typeof (d) __user *)a)) return -EFAULT;})
In file included from ../arch/sh/math-emu/math.c:10:
../include/linux/kernel.h:36: note: this is the location of the previous definition
   36 | #define READ   0

Fixes: 4b565680d163 ("sh: math-emu support")
Signed-off-by: Randy Dunlap <redacted>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: linux-sh@vger.kernel.org
Cc: Takashi YOSHII <redacted>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
---
v2: renumber patches, otherwise no change;

 arch/sh/math-emu/math.c |   44 +++++++++++++++++++-------------------
 1 file changed, 22 insertions(+), 22 deletions(-)

quoted

quoted

This one no longer applies to Linus' tree:

glaubitz@node54:/data/home/glaubitz/linux> git am ../sh-patches-2021/\[PATCH\ 3_3\ v2\]\ sh\:\ fix\ READ_WRITE\ redefinition\ warnings.eml
Applying: sh: fix READ/WRITE redefinition warnings
error: patch failed: arch/sh/math-emu/math.c:51
error: arch/sh/math-emu/math.c: patch does not apply
Patch failed at 0001 sh: fix READ/WRITE redefinition warnings
hint: Use 'git am --show-current-patch=diff' to see the failed patch
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".
glaubitz@node54:/data/home/glaubitz/linux>

OK. Thanks for all of the testing.

I'll report back with the other patch applied that Geert mentioned from linux-next before this one.

FTR, I booted all three successfully on qemu/rts7751r2d and on physical landisk.

FWIW, there are some warnings when building the SH-7785LCR configuration:

In file included from ./arch/sh/include/asm/hw_irq.h:6,
                 from ./include/linux/irq.h:591,
                 from ./include/asm-generic/hardirq.h:17,
                 from ./arch/sh/include/asm/hardirq.h:9,
                 from ./include/linux/hardirq.h:11,
                 from ./include/linux/interrupt.h:11,
                 from ./include/linux/serial_core.h:13,
                 from ./include/linux/serial_sci.h:6,
                 from arch/sh/kernel/cpu/sh4a/setup-sh7785.c:10:
./include/linux/sh_intc.h:100:63: warning: division 'sizeof (void *) / sizeof (void)' does not compute the number of array elements [-Wsizeof-pointer-div]
  100 | #define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a)
      |                                                               ^
./include/linux/sh_intc.h:107:9: note: in expansion of macro '_INTC_ARRAY'
  107 |         _INTC_ARRAY(sense_regs), _INTC_ARRAY(ack_regs), \
      |         ^~~~~~~~~~~
./include/linux/sh_intc.h:124:15: note: in expansion of macro 'INTC_HW_DESC'
  124 |         .hw = INTC_HW_DESC(vectors, groups, mask_regs,                  \
      |               ^~~~~~~~~~~~
arch/sh/kernel/cpu/sh4a/setup-sh7785.c:478:8: note: in expansion of macro 'DECLARE_INTC_DESC'
  478 | static DECLARE_INTC_DESC(intc_desc, "sh7785", vectors, groups,
      |        ^~~~~~~~~~~~~~~~~

A while ago, I had a look into fixing them, but it was non-trivial.
The issue is that the macros are sometimes used with NULL pointer arrays.
The __same_type() check in

    #define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a)

is supposed to catch that, but modern compilers seem to evaluate the
non-taken branch, too, leading to the warning.

Anyone with a suggestion? (CCing the multi-compiler guru)

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds