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| author | Arnd Bergmann <arnd@arndb.de> | 2021-08-11 08:30:22 +0100 |
|---|---|---|
| committer | Russell King (Oracle) <rmk+kernel@armlinux.org.uk> | 2021-08-20 11:39:26 +0100 |
| commit | 249dbe74d3c4b568a623fb55c56cddf19fdf0b89 (patch) | |
| tree | fd5589c73ebae8ca985846b0cf07508d5a82ca9a /arch/arm/tools | |
| parent | 4e57a4ddf6b0d9cce1cf2ffd153df1ad3c2c9cc2 (diff) | |
| download | linux-stable-249dbe74d3c4b568a623fb55c56cddf19fdf0b89.tar.gz linux-stable-249dbe74d3c4b568a623fb55c56cddf19fdf0b89.tar.bz2 linux-stable-249dbe74d3c4b568a623fb55c56cddf19fdf0b89.zip | |
ARM: 9108/1: oabi-compat: rework epoll_wait/epoll_pwait emulation
The epoll_wait() system call wrapper is one of the remaining users of
the set_fs() infrasturcture for Arm. Changing it to not require set_fs()
is rather complex unfortunately.
The approach I'm taking here is to allow architectures to override
the code that copies the output to user space, and let the oabi-compat
implementation check whether it is getting called from an EABI or OABI
system call based on the thread_info->syscall value.
The in_oabi_syscall() check here mirrors the in_compat_syscall() and
in_x32_syscall() helpers for 32-bit compat implementations on other
architectures.
Overall, the amount of code goes down, at least with the newly added
sys_oabi_epoll_pwait() helper getting removed again. The downside
is added complexity in the source code for the native implementation.
There should be no difference in runtime performance except for Arm
kernels with CONFIG_OABI_COMPAT enabled that now have to go through
an external function call to check which of the two variants to use.
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm/tools')
| -rw-r--r-- | arch/arm/tools/syscall.tbl | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl index 11d0b960b2c2..344424a9611f 100644 --- a/arch/arm/tools/syscall.tbl +++ b/arch/arm/tools/syscall.tbl @@ -266,7 +266,7 @@ 249 common lookup_dcookie sys_lookup_dcookie 250 common epoll_create sys_epoll_create 251 common epoll_ctl sys_epoll_ctl sys_oabi_epoll_ctl -252 common epoll_wait sys_epoll_wait sys_oabi_epoll_wait +252 common epoll_wait sys_epoll_wait 253 common remap_file_pages sys_remap_file_pages # 254 for set_thread_area # 255 for get_thread_area @@ -360,7 +360,7 @@ 343 common vmsplice sys_vmsplice 344 common move_pages sys_move_pages 345 common getcpu sys_getcpu -346 common epoll_pwait sys_epoll_pwait sys_oabi_epoll_pwait +346 common epoll_pwait sys_epoll_pwait 347 common kexec_load sys_kexec_load 348 common utimensat sys_utimensat_time32 349 common signalfd sys_signalfd |