On Mon, 22 Feb 2021 03:57:52 -0500 Janosch Frank <frankja@xxxxxxxxxxxxx> wrote: > The ELF ABI dictates that we need to allocate 160 bytes of stack space > for the C functions we're calling. Since we would need to do that for > every interruption handler which, combined with the new stack argument > being saved in GR2, makes cstart64.S look a bit messy. > > So let's introduce the CALL_INT_HANDLER macro that handles all of > that, calls the C interrupt handler and handles cleanup afterwards. > > Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx> > Reviewed-by: Thomas Huth <thuth@xxxxxxxxxx> Reviewed-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx> > --- > s390x/cstart64.S | 28 +++++----------------------- > s390x/macros.S | 17 +++++++++++++++++ > 2 files changed, 22 insertions(+), 23 deletions(-) > > diff --git a/s390x/cstart64.S b/s390x/cstart64.S > index 35d20293..666a9567 100644 > --- a/s390x/cstart64.S > +++ b/s390x/cstart64.S > @@ -92,37 +92,19 @@ memsetxc: > > .section .text > pgm_int: > - SAVE_REGS_STACK > - lgr %r2, %r15 > - brasl %r14, handle_pgm_int > - RESTORE_REGS_STACK > - lpswe GEN_LC_PGM_OLD_PSW > + CALL_INT_HANDLER handle_pgm_int, GEN_LC_PGM_OLD_PSW > > ext_int: > - SAVE_REGS_STACK > - lgr %r2, %r15 > - brasl %r14, handle_ext_int > - RESTORE_REGS_STACK > - lpswe GEN_LC_EXT_OLD_PSW > + CALL_INT_HANDLER handle_ext_int, GEN_LC_EXT_OLD_PSW > > mcck_int: > - SAVE_REGS_STACK > - brasl %r14, handle_mcck_int > - RESTORE_REGS_STACK > - lpswe GEN_LC_MCCK_OLD_PSW > + CALL_INT_HANDLER handle_mcck_int, GEN_LC_MCCK_OLD_PSW > > io_int: > - SAVE_REGS_STACK > - lgr %r2, %r15 > - brasl %r14, handle_io_int > - RESTORE_REGS_STACK > - lpswe GEN_LC_IO_OLD_PSW > + CALL_INT_HANDLER handle_io_int, GEN_LC_IO_OLD_PSW > > svc_int: > - SAVE_REGS_STACK > - brasl %r14, handle_svc_int > - RESTORE_REGS_STACK > - lpswe GEN_LC_SVC_OLD_PSW > + CALL_INT_HANDLER handle_svc_int, GEN_LC_SVC_OLD_PSW > > .align 8 > initial_psw: > diff --git a/s390x/macros.S b/s390x/macros.S > index a7d62c6f..11f4397a 100644 > --- a/s390x/macros.S > +++ b/s390x/macros.S > @@ -11,6 +11,23 @@ > * David Hildenbrand <david@xxxxxxxxxx> > */ > #include <asm/asm-offsets.h> > +/* > + * Exception handler macro that saves registers on the stack, > + * allocates stack space and calls the C handler function. Afterwards > + * we re-load the registers and load the old PSW. > + */ > + .macro CALL_INT_HANDLER c_func, old_psw > + SAVE_REGS_STACK > + /* Save the stack address in GR2 which is the first function > argument */ > + lgr %r2, %r15 > + /* Allocate stack space for called C function, as specified > in s390 ELF ABI */ > + slgfi %r15, 160 > + brasl %r14, \c_func > + algfi %r15, 160 > + RESTORE_REGS_STACK > + lpswe \old_psw > + .endm > + > .macro SAVE_REGS > /* save grs 0-15 */ > stmg %r0, %r15, GEN_LC_SW_INT_GRS
