• Rohan McLure's avatar
    powerpc: Adopt SYSCALL_DEFINE for arch-specific syscall handlers · dec20c50
    Rohan McLure authored
    Arch-specific implementations of syscall handlers are currently used
    over generic implementations for the following reasons:
    
    1. Semantics unique to powerpc
    2. Compatibility syscalls require 'argument padding' to comply with
       64-bit argument convention in ELF32 abi.
    3. Parameter types or order is different in other architectures.
    
    These syscall handlers have been defined prior to this patch series
    without invoking the SYSCALL_DEFINE or COMPAT_SYSCALL_DEFINE macros with
    custom input and output types. We remove every such direct definition in
    favour of the aforementioned macros.
    
    Also update syscalls.tbl in order to refer to the symbol names generated
    by each of these macros. Since ppc64_personality can be called by both
    64 bit and 32 bit binaries through compatibility, we must generate both
    both compat_sys_ and sys_ symbols for this handler.
    
    As an aside:
    A number of architectures including arm and powerpc agree on an
    alternative argument order and numbering for most of these arch-specific
    handlers. A future patch series may allow for asm/unistd.h to signal
    through its defines that a generic implementation of these syscall
    handlers with the correct calling convention be emitted, through the
    __ARCH_WANT_COMPAT_SYS_... convention.
    Signed-off-by: default avatarRohan McLure <rmclure@linux.ibm.com>
    Reviewed-by: default avatarNicholas Piggin <npiggin@gmail.com>
    Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
    Link: https://lore.kernel.org/r/20220921065605.1051927-16-rmclure@linux.ibm.com
    dec20c50
syscalls.h 2.14 KB