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authorRich Felker <dalias@aerifal.cx>2019-07-30 13:07:55 -0400
committerRich Felker <dalias@aerifal.cx>2019-07-30 14:23:56 -0400
commitf56d57f8a7aa536d40014933841a8b22f9c10328 (patch)
treef34e16245f19c8b1fcf739c9a8e9526d44bbba5d /arch/x32
parent722a1ae3351a03ab25010dbebd492eced664853b (diff)
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move IPC_64 from public bits/ipc.h to syscall_arch.h
the definition of the IPC_64 macro controls the interface between libc
and the kernel through syscalls; it's not a public API. the meaning is
rather obscure. long ago, Linux's sysvipc *id_ds structures used
16-bit uids/gids and wrong types for a few other fields. this was in
the libc5 era, before glibc. the IPC_64 flag (64 is a misnomer; it's
more like 32) tells the kernel to use the modern[-ish] versions of the
structures.

the definition of IPC_64 has nothing to do with whether the arch is
32- or 64-bit. rather, due to either historical accident or
intentional obnoxiousness, the kernel only accepts and masks off the
0x100 IPC_64 flag conditional on CONFIG_ARCH_WANT_IPC_PARSE_VERSION,
i.e. for archs that want to provide, or that accidentally provided,
both. for archs which don't define this option, no masking is
performed and commands with the 0x100 bit set will fail as invalid. so
ultimately, the definition is just a matter of matching an arbitrary
switch defined per-arch in the kernel.
Diffstat (limited to 'arch/x32')
-rw-r--r--arch/x32/bits/ipc.h2
-rw-r--r--arch/x32/syscall_arch.h2
2 files changed, 2 insertions, 2 deletions
diff --git a/arch/x32/bits/ipc.h b/arch/x32/bits/ipc.h
index 55d2e41a..a12380f6 100644
--- a/arch/x32/bits/ipc.h
+++ b/arch/x32/bits/ipc.h
@@ -9,5 +9,3 @@ struct ipc_perm {
 	long long __pad1;
 	long long __pad2;
 };
-
-#define IPC_64 0
diff --git a/arch/x32/syscall_arch.h b/arch/x32/syscall_arch.h
index 81d1d0df..e0a22160 100644
--- a/arch/x32/syscall_arch.h
+++ b/arch/x32/syscall_arch.h
@@ -87,3 +87,5 @@ static __inline long __syscall6(long long n, long long a1, long long a2, long lo
 #define SYS_rt_sigtimedwait_time64 SYS_rt_sigtimedwait
 #define SYS_futex_time64 SYS_futex
 #define SYS_sched_rr_get_interval_time64 SYS_sched_rr_get_interval
+
+#define IPC_64 0