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SubjectRe: [PATCH 2/4] Add NR_syscalls for x86_64

On Tue, 25 Aug 2009, Jason Baron wrote:

> On Tue, Aug 25, 2009 at 09:40:05AM -0400, Jason Baron wrote:
> >
> > right, for x86_64, unistd.h is included to generate __NR_syscall_max
> > which is then used for NR_syscalls. So I did initially try it there, but
> > there were dependency problems. I'll see what I can come up with...
> >
> > thanks,
> >
> > -Jason
>
> ok, since unistd_64.h is used to generate offsets.c, which eventually
> generates, asm/asm-offsets.h, which defines, __NR_syscall_max, we can't
> just put #define of NR_syscalls in unistd_64.h. However, it seems the

Why not? A define is not a problem until it is used. Is something in
asm-offsets.c using NR_syscalls?

> only point in time that unistd_64.h can not depend upon __NR_syscall_max,
> is before asm/asm-offsets.h is defined. Thus, the patch below passes in
> a '-DCREATE_OFFSETS' during the creation of asm/asm-offsets.h, so that
> we do not include it before it exists. The patch is hacky but works.
> thoughts?
>
> Signed-off-by: Jason Baron <jbaron@redhat.com>
>
> ---
>
> Kbuild | 2 +-
> arch/x86/include/asm/unistd_64.h | 6 ++++++
> scripts/Makefile.build | 4 ++++
> 3 files changed, 11 insertions(+), 1 deletions(-)
>
>
> diff --git a/Kbuild b/Kbuild
> index f056b4f..5f43d4d 100644
> --- a/Kbuild
> +++ b/Kbuild
> @@ -78,7 +78,7 @@ endef
> arch/$(SRCARCH)/kernel/asm-offsets.s: arch/$(SRCARCH)/kernel/asm-offsets.c \
> $(obj)/$(bounds-file) FORCE
> $(Q)mkdir -p $(dir $@)
> - $(call if_changed_dep,cc_s_c)
> + $(call if_changed_dep,cc_s_c_define_offset)
>
> $(obj)/$(offsets-file): arch/$(SRCARCH)/kernel/asm-offsets.s Kbuild
> $(call cmd,offsets)
> diff --git a/arch/x86/include/asm/unistd_64.h b/arch/x86/include/asm/unistd_64.h
> index 900e161..70c0c3d 100644
> --- a/arch/x86/include/asm/unistd_64.h
> +++ b/arch/x86/include/asm/unistd_64.h
> @@ -688,6 +688,12 @@ __SYSCALL(__NR_perf_counter_open, sys_perf_counter_open)
> #endif /* __NO_STUBS */
>
> #ifdef __KERNEL__
> +
> +#ifndef CREATE_OFFSETS
> +#include <asm/asm-offsets.h>
> +#define NR_syscalls (__NR_syscall_max + 1)
> +#endif
> +
> /*
> * "Conditional" syscalls
> *
> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> index 5c4b7a4..4177858 100644
> --- a/scripts/Makefile.build
> +++ b/scripts/Makefile.build
> @@ -145,6 +145,10 @@ $(multi-objs-y:.o=.lst) : modname = $(modname-multi)
> quiet_cmd_cc_s_c = CC $(quiet_modtag) $@
> cmd_cc_s_c = $(CC) $(c_flags) -fverbose-asm -S -o $@ $<
>
> +quiet_cmd_cc_s_c_define_offset = CC $(quiet_modtag) $@
> +cmd_cc_s_c_define_offset = $(CC) $(c_flags) -DCREATE_OFFSETS \
> + -fverbose-asm -S -o $@ $<
> +
> $(obj)/%.s: $(src)/%.c FORCE
> $(call if_changed_dep,cc_s_c)


Ug, yuck yuck yuck. Sometimes "it works" is not good enough ;-)

How about just adding in asm/unistd.h

#ifdef __KERNEL__
# ifdef CONFIG_X86_32
# include "unistd_32.h"
# else
# include "unistd_64.h"
+# define NR_syscalls (__NR_syscall_max + 1)
# endif
#else
# ifdef __i386__
# include "unistd_32.h"
# else
# include "unistd_64.h"
# endif
#endif

And if this is a problem because asm-offset_64.c includes asm/unistd.h,
then make it just include unistd_64.h.

Or am I missing something?

-- Steve




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