| Message ID | 1589818051-20549-2-git-send-email-pmorel@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | s390x: Testing the Channel Subsystem I/O | expand |
On 5/18/20 6:07 PM, Pierre Morel wrote: > If we use multiple source of interrupts, for example, using SCLP > console to print information while using I/O interrupts, we need > to have a re-entrant register saving interruption handling. > > Instead of saving at a static memory address, let's save the base > registers, the floating point registers and the floating point > control register on the stack in case of I/O interrupts > > Note that we keep the static register saving to recover from the > RESET tests. > > Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> Some nits below Acked-by: Janosch Frank <frankja@linux.ibm.com> > --- > s390x/cstart64.S | 41 +++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 39 insertions(+), 2 deletions(-) > > diff --git a/s390x/cstart64.S b/s390x/cstart64.S > index 9af6bb3..3c7d8a9 100644 > --- a/s390x/cstart64.S > +++ b/s390x/cstart64.S > @@ -118,6 +118,43 @@ memsetxc: > lmg %r0, %r15, GEN_LC_SW_INT_GRS > .endm > > +/* Save registers on the stack (r15), so we can have stacked interrupts. */ > + .macro SAVE_REGS_STACK > + /* Allocate a stack frame for 15 general registers */ > + slgfi %r15, 15 * 8 > + /* Store all registers from r0 to r14 on the stack */ /* Store registers r0 to r14 on the stack */ > + stmg %r0, %r14, 0(%r15) > + /* Allocate a stack frame for 16 floating point registers */ > + /* The size of a FP register is the size of an double word */ > + slgfi %r15, 16 * 8 > + /* Save fp register on stack: offset to SP is multiple of reg number */ > + .irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 > + std \i, \i * 8(%r15) > + .endr > + /* Save fpc, but keep stack aligned on 64bits */ > + slgfi %r15, 8 > + efpc %r0 > + stg %r0, 0(%r15) > + .endm > + > +/* Restore the register in reverse order */ > + .macro RESTORE_REGS_STACK > + /* Restore fpc */ > + lfpc 0(%r15) > + algfi %r15, 8 > + /* Restore fp register from stack: SP still where it was left */ > + /* and offset to SP is a multile of reg number */ multile? Multiple? > + .irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 > + ld \i, \i * 8(%r15) > + .endr > + /* Now it is done, rewind the stack pointer by 16 double word */ Now that we're done, rewind the stack pointer by 16 double words > + algfi %r15, 16 * 8 > + /* Load the registers from stack */ > + lmg %r0, %r14, 0(%r15) > + /* Rewind the stack by 15 double word */ > + algfi %r15, 15 * 8 > + .endm > + > .section .text > /* > * load_reset calling convention: > @@ -182,9 +219,9 @@ mcck_int: > lpswe GEN_LC_MCCK_OLD_PSW > > io_int: > - SAVE_REGS > + SAVE_REGS_STACK > brasl %r14, handle_io_int > - RESTORE_REGS > + RESTORE_REGS_STACK > lpswe GEN_LC_IO_OLD_PSW > > svc_int: >
On 2020-05-26 12:30, Janosch Frank wrote: > On 5/18/20 6:07 PM, Pierre Morel wrote: >> If we use multiple source of interrupts, for example, using SCLP >> console to print information while using I/O interrupts, we need >> to have a re-entrant register saving interruption handling. >> >> Instead of saving at a static memory address, let's save the base >> registers, the floating point registers and the floating point >> control register on the stack in case of I/O interrupts >> >> Note that we keep the static register saving to recover from the >> RESET tests. >> >> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> > > Some nits below > > Acked-by: Janosch Frank <frankja@linux.ibm.com> > > Thanks, I will modify the nits as you proposed. regards, Pierre
diff --git a/s390x/cstart64.S b/s390x/cstart64.S index 9af6bb3..3c7d8a9 100644 --- a/s390x/cstart64.S +++ b/s390x/cstart64.S @@ -118,6 +118,43 @@ memsetxc: lmg %r0, %r15, GEN_LC_SW_INT_GRS .endm +/* Save registers on the stack (r15), so we can have stacked interrupts. */ + .macro SAVE_REGS_STACK + /* Allocate a stack frame for 15 general registers */ + slgfi %r15, 15 * 8 + /* Store all registers from r0 to r14 on the stack */ + stmg %r0, %r14, 0(%r15) + /* Allocate a stack frame for 16 floating point registers */ + /* The size of a FP register is the size of an double word */ + slgfi %r15, 16 * 8 + /* Save fp register on stack: offset to SP is multiple of reg number */ + .irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 + std \i, \i * 8(%r15) + .endr + /* Save fpc, but keep stack aligned on 64bits */ + slgfi %r15, 8 + efpc %r0 + stg %r0, 0(%r15) + .endm + +/* Restore the register in reverse order */ + .macro RESTORE_REGS_STACK + /* Restore fpc */ + lfpc 0(%r15) + algfi %r15, 8 + /* Restore fp register from stack: SP still where it was left */ + /* and offset to SP is a multile of reg number */ + .irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 + ld \i, \i * 8(%r15) + .endr + /* Now it is done, rewind the stack pointer by 16 double word */ + algfi %r15, 16 * 8 + /* Load the registers from stack */ + lmg %r0, %r14, 0(%r15) + /* Rewind the stack by 15 double word */ + algfi %r15, 15 * 8 + .endm + .section .text /* * load_reset calling convention: @@ -182,9 +219,9 @@ mcck_int: lpswe GEN_LC_MCCK_OLD_PSW io_int: - SAVE_REGS + SAVE_REGS_STACK brasl %r14, handle_io_int - RESTORE_REGS + RESTORE_REGS_STACK lpswe GEN_LC_IO_OLD_PSW svc_int:
If we use multiple source of interrupts, for example, using SCLP console to print information while using I/O interrupts, we need to have a re-entrant register saving interruption handling. Instead of saving at a static memory address, let's save the base registers, the floating point registers and the floating point control register on the stack in case of I/O interrupts Note that we keep the static register saving to recover from the RESET tests. Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> --- s390x/cstart64.S | 41 +++++++++++++++++++++++++++++++++++++++-- 1 file changed, 39 insertions(+), 2 deletions(-)