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authorArnd Bergmann <arnd@arndb.de>2018-12-31 22:22:40 +0100
committerArnd Bergmann <arnd@arndb.de>2019-01-25 17:22:50 +0100
commit275f22148e8720e84b180d9e0cdf8abfd69bac5b (patch)
treef7cb9810f8415904589d73a8d8f3c15b0bc70246 /README
parent73a66023c937ef258f2aa340cdb53ae7d8b1d47c (diff)
downloadlwn-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>
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