summaryrefslogtreecommitdiff
path: root/Documentation/process/adding-syscalls.rst
diff options
context:
space:
mode:
authorDominik Brodowski <linux@dominikbrodowski.net>2018-04-09 12:51:43 +0200
committerIngo Molnar <mingo@kernel.org>2018-04-09 16:47:28 +0200
commit5ac9efa3c50d7caff9f3933bb8a3ad1139d92d92 (patch)
tree8911252894d4f412bf6e2f1f1b4378a9f366d966 /Documentation/process/adding-syscalls.rst
parente145242ea0df6b7d28fd7186e61d6840fa4bb06e (diff)
syscalls/core, syscalls/x86: Clean up compat syscall stub naming convention
Tidy the naming convention for compat syscall subs. Hints which describe the purpose of the stub go in front and receive a double underscore to denote that they are generated on-the-fly by the COMPAT_SYSCALL_DEFINEx() macro. For the generic case, this means: t kernel_waitid # common C function (see kernel/exit.c) __do_compat_sys_waitid # inlined helper doing the actual work # (takes original parameters as declared) T __se_compat_sys_waitid # sign-extending C function calling inlined # helper (takes parameters of type long, # casts them to unsigned long and then to # the declared type) T compat_sys_waitid # alias to __se_compat_sys_waitid() # (taking parameters as declared), to # be included in syscall table For x86, the naming is as follows: t kernel_waitid # common C function (see kernel/exit.c) __do_compat_sys_waitid # inlined helper doing the actual work # (takes original parameters as declared) t __se_compat_sys_waitid # sign-extending C function calling inlined # helper (takes parameters of type long, # casts them to unsigned long and then to # the declared type) T __ia32_compat_sys_waitid # IA32_EMULATION 32-bit-ptregs -> C stub, # calls __se_compat_sys_waitid(); to be # included in syscall table T __x32_compat_sys_waitid # x32 64-bit-ptregs -> C stub, calls # __se_compat_sys_waitid(); to be included # in syscall table If only one of IA32_EMULATION and x32 is enabled, __se_compat_sys_waitid() may be inlined into the stub __{ia32,x32}_compat_sys_waitid(). Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180409105145.5364-3-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'Documentation/process/adding-syscalls.rst')
-rw-r--r--Documentation/process/adding-syscalls.rst4
1 files changed, 2 insertions, 2 deletions
diff --git a/Documentation/process/adding-syscalls.rst b/Documentation/process/adding-syscalls.rst
index 314c8bf6f2a2..0d4f29bc798b 100644
--- a/Documentation/process/adding-syscalls.rst
+++ b/Documentation/process/adding-syscalls.rst
@@ -360,7 +360,7 @@ First, the entry in ``arch/x86/entry/syscalls/syscall_32.tbl`` gets an extra
column to indicate that a 32-bit userspace program running on a 64-bit kernel
should hit the compat entry point::
- 380 i386 xyzzy sys_xyzzy compat_sys_xyzzy
+ 380 i386 xyzzy sys_xyzzy __ia32_compat_sys_xyzzy
Second, you need to figure out what should happen for the x32 ABI version of
the new system call. There's a choice here: the layout of the arguments
@@ -373,7 +373,7 @@ the compatibility wrapper::
333 64 xyzzy sys_xyzzy
...
- 555 x32 xyzzy compat_sys_xyzzy
+ 555 x32 xyzzy __x32_compat_sys_xyzzy
If no pointers are involved, then it is preferable to re-use the 64-bit system
call for the x32 ABI (and consequently the entry in