On Mon, Jun 18, 2018 at 01:02:58PM +0100, Mark Rutland wrote: > The arm64 sigreturn* syscall handlers are non-standard. Rather than > taking a number of user parameters in registers as per the AAPCS, > they expect the pt_regs as their sole argument. > > To make this work, we override the syscall definitions to invoke > wrappers written in assembly, which mov the SP into x0, and branch to > their respective C functions. > > On other architectures (such as x86), the sigreturn* functions take no > argument and instead use current_pt_regs() to acquire the user > registers. This requires less boilerplate code, and allows for other > features such as interposing C code in this path. > > This patch takes the same approach for arm64. > > Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx> > Tentatively-reviewed-by: Dave Martin <dave.martin@xxxxxxx> > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > Cc: Will Deacon <will.deacon@xxxxxxx> Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
