2017-08-17 22:07 GMT+02:00 Gedare Bloom <ged...@rtems.org>: > On Thu, Aug 17, 2017 at 1:48 PM, Denis Obrezkov <denisobrez...@gmail.com> > wrote: > > 2017-08-17 17:25 GMT+02:00 Gedare Bloom <ged...@rtems.org>: > >> > >> On Wed, Aug 16, 2017 at 11:13 AM, Denis Obrezkov > >> <denisobrez...@gmail.com> wrote: > >> > --- > >> > cpukit/score/cpu/riscv32/riscv-context-switch.S | 12 ++++++++++-- > >> > 1 file changed, 10 insertions(+), 2 deletions(-) > >> > > >> > diff --git a/cpukit/score/cpu/riscv32/riscv-context-switch.S > >> > b/cpukit/score/cpu/riscv32/riscv-context-switch.S > >> > index a199596..bcdfe0e 100644 > >> > --- a/cpukit/score/cpu/riscv32/riscv-context-switch.S > >> > +++ b/cpukit/score/cpu/riscv32/riscv-context-switch.S > >> > @@ -46,6 +46,7 @@ PUBLIC(restore) > >> > > >> > SYM(_CPU_Context_switch): > >> > /* Disable interrupts and store all registers */ > >> > + csrci mstatus, 0x8 > >> Why is this necessary? > >> > >> > SREG x1, 4(a0) > >> > SREG x2, 8(a0) > >> > SREG x3, 12(a0) > >> > @@ -78,8 +79,9 @@ SYM(_CPU_Context_switch): > >> > SREG x30, 120(a0) > >> > SREG x31, 124(a0) > >> > > >> > -SYM(restore): > >> > > >> > +SYM(restore): > >> > + > >> > LREG x1, 4(a1) > >> > LREG x2, 8(a1) > >> > LREG x3, 12(a1) > >> > @@ -111,9 +113,15 @@ SYM(restore): > >> > LREG x29, 116(a1) > >> > LREG x30, 120(a1) > >> > LREG x31, 124(a1) > >> > - ret > >> > + > >> > + > >> > + csrsi mstatus, 0x8 > >> > + nop > >> > + nop > >> Why the nops? > >> > >> > + ret > >> > > >> > SYM(_CPU_Context_restore): > >> > + csrci mstatus, 0x8 > >> > mv a1, a0 > >> > j restore > >> > nop > >> > -- > >> > 2.1.4 > >> > > >> > _______________________________________________ > >> > devel mailing list > >> > devel@rtems.org > >> > http://lists.rtems.org/mailman/listinfo/devel > > > > So, don't we turn off interrupts during the context switch? > > Nope, and turning them back on unconditionally is wrong too. > > > Yes, nops are unnecessary. > > > > > > -- > > Regards, Denis Obrezkov > Ok, I was confused by this obsolete comment: /* Disable interrupts and store all registers */ Will remove all that enabling/disabling.
Is the same true for start.S file with interrupted task's stack saving? -- Regards, Denis Obrezkov
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