x86/compat: Adjust in_compat_syscall() to generic code under !COMPAT

The result of in_compat_syscall() can be pictured as:

x86 platform:
    ---------------------------------------------------
    |  Arch\syscall  |  64-bit  |   ia32   |   x32    |
    |-------------------------------------------------|
    |     x86_64     |  false   |   true   |   true   |
    |-------------------------------------------------|
    |      i686      |          |  <true>  |          |
    ---------------------------------------------------

Other platforms:
    -------------------------------------------
    |  Arch\syscall  |  64-bit  |   compat    |
    |-----------------------------------------|
    |     64-bit     |  false   |    true     |
    |-----------------------------------------|
    |    32-bit(?)   |          |   <false>   |
    -------------------------------------------

As seen, the result of in_compat_syscall() on generic 32-bit platform
differs from i686.

There is no reason for in_compat_syscall() == true on native i686.  It also
easy to misread code if the result on native 32-bit platform differs
between arches.

Because of that non arch-specific code has many places with:
    if (IS_ENABLED(CONFIG_COMPAT) && in_compat_syscall())
in different variations.

It looks-like the only non-x86 code which uses in_compat_syscall() not
under CONFIG_COMPAT guard is in amd/amdkfd. But according to the commit
a18069c132cb ("amdkfd: Disable support for 32-bit user processes"), it
actually should be disabled on native i686.

Rename in_compat_syscall() to in_32bit_syscall() for x86-specific code
and make in_compat_syscall() false under !CONFIG_COMPAT.

A follow on patch will clean up generic users which were forced to check
IS_ENABLED(CONFIG_COMPAT) with in_compat_syscall().

Signed-off-by: Dmitry Safonov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Andy Lutomirski <[email protected]>
Cc: Dmitry Safonov <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: John Stultz <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Steffen Klassert <[email protected]>
Cc: Stephen Boyd <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]

0 files changed, 0 insertions, 0 deletions