Hi Yamada-san,
On Tue, Jan 8, 2019 at 12:41 AM Masahiro Yamada
<yamada.masahiro@xxxxxxxxxxxxx> wrote:
Most architectures do not export shmparam.h to user-space.
$ find arch -name shmparam.h | sort
arch/alpha/include/asm/shmparam.h
arch/arc/include/asm/shmparam.h
arch/arm64/include/asm/shmparam.h
arch/arm/include/asm/shmparam.h
arch/csky/include/asm/shmparam.h
arch/ia64/include/asm/shmparam.h
arch/mips/include/asm/shmparam.h
arch/nds32/include/asm/shmparam.h
arch/nios2/include/asm/shmparam.h
arch/parisc/include/asm/shmparam.h
arch/powerpc/include/asm/shmparam.h
arch/s390/include/asm/shmparam.h
arch/sh/include/asm/shmparam.h
arch/sparc/include/asm/shmparam.h
arch/x86/include/asm/shmparam.h
arch/xtensa/include/asm/shmparam.h
Strangely, some users of the asm-generic wrapper export shmparam.h
$ git grep 'generic-y += shmparam.h'
arch/c6x/include/uapi/asm/Kbuild:generic-y += shmparam.h
arch/h8300/include/uapi/asm/Kbuild:generic-y += shmparam.h
arch/hexagon/include/uapi/asm/Kbuild:generic-y += shmparam.h
arch/m68k/include/uapi/asm/Kbuild:generic-y += shmparam.h
arch/microblaze/include/uapi/asm/Kbuild:generic-y += shmparam.h
arch/openrisc/include/uapi/asm/Kbuild:generic-y += shmparam.h
arch/riscv/include/asm/Kbuild:generic-y += shmparam.h
arch/unicore32/include/uapi/asm/Kbuild:generic-y += shmparam.h
The newly added riscv correctly creates the asm-generic wrapper
in the kernel space, but the others (c6x, h8300, hexagon, m68k,
microblaze, openrisc, unicore32) create the one in the uapi directory.
Digging into the git history, now I guess fcc8487d477a ("uapi:
export all headers under uapi directories") was the misconversion.
Prior to that commit, no architecture exported to shmparam.h
As its commit description said, that commit exported shmparam.h
for c6x, h8300, hexagon, m68k, openrisc, unicore32.
83f0124ad81e ("microblaze: remove asm-generic wrapper headers")
accidentally exported shmparam.h for microblaze.
This commit unexports shmparam.h for those architectures.
There is no more reason to export include/uapi/asm-generic/shmparam.h,
so it has been moved to include/asm-generic/shmparam.h
Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Thanks for your patch!
include/uapi/asm-generic/shmparam.h contains a single definition:
#define SHMLBA PAGE_SIZE /* attach addr a multiple of this */
So this definition is not used by userspace?
Note that it is refered to by include/uapi/linux/shm.h, albeit in a comment:
#define SHM_RND 020000 /* round attach address to SHMLBA
boundary */
Glibc provides its own definition in /usr/include/x86_64-linux-gnu/bits/shm.h
#define SHMLBA (__getpagesize ())
So probably this is safe.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
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
