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author | Arnd Bergmann <arnd@arndb.de> | 2018-12-31 22:22:40 +0100 |
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committer | Arnd Bergmann <arnd@arndb.de> | 2019-01-25 17:22:50 +0100 |
commit | 275f22148e8720e84b180d9e0cdf8abfd69bac5b (patch) | |
tree | f7cb9810f8415904589d73a8d8f3c15b0bc70246 /README | |
parent | 73a66023c937ef258f2aa340cdb53ae7d8b1d47c (diff) | |
download | lwn-275f22148e8720e84b180d9e0cdf8abfd69bac5b.tar.gz lwn-275f22148e8720e84b180d9e0cdf8abfd69bac5b.zip |
ipc: rename old-style shmctl/semctl/msgctl syscalls
The behavior of these system calls is slightly different between
architectures, as determined by the CONFIG_ARCH_WANT_IPC_PARSE_VERSION
symbol. Most architectures that implement the split IPC syscalls don't set
that symbol and only get the modern version, but alpha, arm, microblaze,
mips-n32, mips-n64 and xtensa expect the caller to pass the IPC_64 flag.
For the architectures that so far only implement sys_ipc(), i.e. m68k,
mips-o32, powerpc, s390, sh, sparc, and x86-32, we want the new behavior
when adding the split syscalls, so we need to distinguish between the
two groups of architectures.
The method I picked for this distinction is to have a separate system call
entry point: sys_old_*ctl() now uses ipc_parse_version, while sys_*ctl()
does not. The system call tables of the five architectures are changed
accordingly.
As an additional benefit, we no longer need the configuration specific
definition for ipc_parse_version(), it always does the same thing now,
but simply won't get called on architectures with the modern interface.
A small downside is that on architectures that do set
ARCH_WANT_IPC_PARSE_VERSION, we now have an extra set of entry points
that are never called. They only add a few bytes of bloat, so it seems
better to keep them compared to adding yet another Kconfig symbol.
I considered adding new syscall numbers for the IPC_64 variants for
consistency, but decided against that for now.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'README')
0 files changed, 0 insertions, 0 deletions