/* * This file contains the basic algorithms for all assembly code used * in an specific CPU port of RTEMS. These algorithms must be implemented * in assembly language. * * COPYRIGHT (c) 1989-2011. * On-Line Applications Research Corporation (OAR). * * Copyright (c) 2014, 2017 embedded brains GmbH * * The license and distribution terms for this file may be * found in the file LICENSE in this distribution or at * http://www.rtems.org/license/LICENSE. * * Ported to ERC32 implementation of the SPARC by On-Line Applications * Research Corporation (OAR) under contract to the European Space * Agency (ESA). * * ERC32 modifications of respective RTEMS file: COPYRIGHT (c) 1995. * European Space Agency. */ #include #include #include /* * void _ISR_Handler() * * This routine provides the RTEMS interrupt management. * * We enter this handler from the 4 instructions in the trap table with * the following registers assumed to be set as shown: * * l0 = PSR * l1 = PC * l2 = nPC * l3 = trap type * * NOTE: By an executive defined convention, trap type is between 0 and 255 if * it is an asynchonous trap and 256 and 511 if it is synchronous. */ .align 4 PUBLIC(_ISR_Handler) SYM(_ISR_Handler): /* * Fix the return address for synchronous traps. */ andcc %l3, SPARC_SYNCHRONOUS_TRAP_BIT_MASK, %g0 ! Is this a synchronous trap? be,a win_ovflow ! No, then skip the adjustment nop ! DELAY mov %l1, %l6 ! save trapped pc for debug info mov %l2, %l1 ! do not return to the instruction add %l2, 4, %l2 ! indicated win_ovflow: /* * Save the globals this block uses. * * These registers are not restored from the locals. Their contents * are saved directly from the locals into the ISF below. */ mov %g4, %l4 ! save the globals this block uses mov %g5, %l5 /* * When at a "window overflow" trap, (wim == (1 << cwp)). * If we get here like that, then process a window overflow. */ rd %wim, %g4 srl %g4, %l0, %g5 ! g5 = win >> cwp ; shift count and CWP ! are LS 5 bits ; how convenient :) cmp %g5, 1 ! Is this an invalid window? bne dont_do_the_window ! No, then skip all this stuff ! we are using the delay slot /* * The following is same as a 1 position right rotate of WIM */ srl %g4, 1, %g5 ! g5 = WIM >> 1 sll %g4, SPARC_NUMBER_OF_REGISTER_WINDOWS-1 , %g4 ! g4 = WIM << (Number Windows - 1) or %g4, %g5, %g4 ! g4 = (WIM >> 1) | ! (WIM << (Number Windows - 1)) /* * At this point: * * g4 = the new WIM * g5 is free */ /* * Since we are tinkering with the register windows, we need to * make sure that all the required information is in global registers. */ save ! Save into the window wr %g4, 0, %wim ! WIM = new WIM nop ! delay slots nop nop /* * Now save the window just as if we overflowed to it. */ std %l0, [%sp + CPU_STACK_FRAME_L0_OFFSET] SPARC_LEON3FT_B2BST_NOP std %l2, [%sp + CPU_STACK_FRAME_L2_OFFSET] SPARC_LEON3FT_B2BST_NOP std %l4, [%sp + CPU_STACK_FRAME_L4_OFFSET] SPARC_LEON3FT_B2BST_NOP std %l6, [%sp + CPU_STACK_FRAME_L6_OFFSET] SPARC_LEON3FT_B2BST_NOP std %i0, [%sp + CPU_STACK_FRAME_I0_OFFSET] SPARC_LEON3FT_B2BST_NOP std %i2, [%sp + CPU_STACK_FRAME_I2_OFFSET] SPARC_LEON3FT_B2BST_NOP std %i4, [%sp + CPU_STACK_FRAME_I4_OFFSET] SPARC_LEON3FT_B2BST_NOP std %i6, [%sp + CPU_STACK_FRAME_I6_FP_OFFSET] restore nop dont_do_the_window: /* * Global registers %g4 and %g5 are saved directly from %l4 and * %l5 directly into the ISF below. */ /* * Save the state of the interrupted task -- especially the global * registers -- in the Interrupt Stack Frame. Note that the ISF * includes a regular minimum stack frame which will be used if * needed by register window overflow and underflow handlers. * * REGISTERS SAME AS AT _ISR_Handler */ sub %fp, CPU_INTERRUPT_FRAME_SIZE, %sp ! make space for ISF std %l0, [%sp + ISF_PSR_OFFSET] ! save psr, PC SPARC_LEON3FT_B2BST_NOP st %l2, [%sp + ISF_NPC_OFFSET] ! save nPC st %g1, [%sp + ISF_G1_OFFSET] ! save g1 std %g2, [%sp + ISF_G2_OFFSET] ! save g2, g3 SPARC_LEON3FT_B2BST_NOP std %l4, [%sp + ISF_G4_OFFSET] ! save g4, g5 -- see above SPARC_LEON3FT_B2BST_NOP st %g7, [%sp + ISF_G7_OFFSET] ! save g7 std %i0, [%sp + ISF_I0_OFFSET] ! save i0, i1 SPARC_LEON3FT_B2BST_NOP std %i2, [%sp + ISF_I2_OFFSET] ! save i2, i3 SPARC_LEON3FT_B2BST_NOP std %i4, [%sp + ISF_I4_OFFSET] ! save i4, i5 SPARC_LEON3FT_B2BST_NOP std %i6, [%sp + ISF_I6_FP_OFFSET] ! save i6/fp, i7 rd %y, %g1 st %g1, [%sp + ISF_Y_OFFSET] ! save y st %l6, [%sp + ISF_TPC_OFFSET] ! save real trapped pc mov %sp, %o1 ! 2nd arg to ISR Handler /* * Increment ISR nest level and Thread dispatch disable level. * * Register usage for this section: * * l6 = _Thread_Dispatch_disable_level value * l7 = _ISR_Nest_level value * * NOTE: It is assumed that l6 - l7 will be preserved until the ISR * nest and thread dispatch disable levels are unnested. */ ld [%g6 + PER_CPU_ISR_NEST_LEVEL], %l7 ld [%g6 + PER_CPU_THREAD_DISPATCH_DISABLE_LEVEL], %l6 add %l7, 1, %l7 st %l7, [%g6 + PER_CPU_ISR_NEST_LEVEL] SPARC_LEON3FT_B2BST_NOP add %l6, 1, %l6 st %l6, [%g6 + PER_CPU_THREAD_DISPATCH_DISABLE_LEVEL] #if SPARC_HAS_FPU == 1 /* * We cannot use an intermediate value for operations with the PSR[EF] * bit since they use a 13-bit sign extension and PSR[EF] is bit 12. */ sethi %hi(SPARC_PSR_EF_MASK), %l5 #endif /* * If ISR nest level was zero (now 1), then switch stack. */ mov %sp, %fp subcc %l7, 1, %l7 ! outermost interrupt handler? bnz dont_switch_stacks ! No, then do not switch stacks #if defined(RTEMS_PROFILING) sethi %hi(_SPARC_Counter), %o5 ld [%o5 + %lo(_SPARC_Counter)], %l4 call %l4 nop mov %o0, %o5 #else nop #endif ld [%g6 + PER_CPU_INTERRUPT_STACK_HIGH], %sp #if SPARC_HAS_FPU == 1 /* * Test if the interrupted thread uses the floating point unit * (PSR[EF] == 1). In case it uses the floating point unit, then store * the floating point status register. This has the side-effect that * all pending floating point operations complete before the store * completes. The PSR[EF] bit is restored after the call to the * interrupt handler. Thus post-switch actions (e.g. signal handlers) * and context switch extensions may still corrupt the floating point * context. */ andcc %l0, %l5, %g0 beq dont_switch_stacks nop st %fsr, [%g6 + SPARC_PER_CPU_FSR_OFFSET] #endif dont_switch_stacks: /* * Make sure we have a place on the stack for the window overflow * trap handler to write into. At this point it is safe to * enable traps again. */ sub %sp, SPARC_MINIMUM_STACK_FRAME_SIZE, %sp /* * Check if we have an external interrupt (trap 0x11 - 0x1f). If so, * set the PIL in the %psr to mask off interrupts with lower priority. * The original %psr in %l0 is not modified since it will be restored * when the interrupt handler returns. */ mov %l0, %g5 and %l3, 0x0ff, %g4 subcc %g4, 0x11, %g0 bl dont_fix_pil subcc %g4, 0x1f, %g0 bg dont_fix_pil sll %g4, 8, %g4 and %g4, SPARC_PSR_PIL_MASK, %g4 andn %l0, SPARC_PSR_PIL_MASK, %g5 ba pil_fixed or %g4, %g5, %g5 dont_fix_pil: or %g5, SPARC_PSR_PIL_MASK, %g5 pil_fixed: #if SPARC_HAS_FPU == 1 /* * Clear the PSR[EF] bit of the interrupted context to ensure that * interrupt service routines cannot corrupt the floating point context. */ andn %g5, %l5, %g5 #endif wr %g5, SPARC_PSR_ET_MASK, %psr ! **** ENABLE TRAPS **** /* * Vector to user's handler. * * NOTE: TBR may no longer have vector number in it since * we just enabled traps. It is definitely in l3. */ sethi %hi(SYM(_ISR_Vector_table)), %g4 or %g4, %lo(SYM(_ISR_Vector_table)), %g4 and %l3, 0xFF, %g5 ! remove synchronous trap indicator sll %g5, 2, %g5 ! g5 = offset into table ld [%g4 + %g5], %g4 ! g4 = _ISR_Vector_table[ vector ] ! o1 = 2nd arg = address of the ISF ! WAS LOADED WHEN ISF WAS SAVED!!! mov %l3, %o0 ! o0 = 1st arg = vector number call %g4 #if defined(RTEMS_PROFILING) mov %o5, %l3 ! save interrupt entry instant #else nop ! delay slot #endif #if defined(SPARC_USE_SYNCHRONOUS_FP_SWITCH) mov %l0, %g1 ! PSR[EF] value of interrupted context ta SPARC_SWTRAP_IRQDIS_FP ! **** DISABLE INTERRUPTS **** #else ta SPARC_SWTRAP_IRQDIS ! **** DISABLE INTERRUPTS **** #endif #if defined(RTEMS_PROFILING) cmp %l7, 0 bne profiling_not_outer_most_exit nop call %l4 ! Call _SPARC_Counter.counter_read mov %g1, %l4 ! Save previous interrupt status mov %o0, %o2 ! o2 = 3rd arg = interrupt exit instant mov %l3, %o1 ! o1 = 2nd arg = interrupt entry instant call SYM(_Profiling_Outer_most_interrupt_entry_and_exit) mov %g6, %o0 ! o0 = 1st arg = per-CPU control profiling_not_outer_most_exit: #endif /* * Decrement ISR nest level and Thread dispatch disable level. * * Register usage for this section: * * o2 = g6->dispatch_necessary value * o3 = g6->isr_dispatch_disable value * l6 = g6->thread_dispatch_disable_level value * l7 = g6->isr_nest_level value */ ldub [%g6 + PER_CPU_DISPATCH_NEEDED], %o2 ld [%g6 + PER_CPU_ISR_DISPATCH_DISABLE], %o3 st %l7, [%g6 + PER_CPU_ISR_NEST_LEVEL] SPARC_LEON3FT_B2BST_NOP sub %l6, 1, %l6 st %l6, [%g6 + PER_CPU_THREAD_DISPATCH_DISABLE_LEVEL] /* * Thread dispatching is necessary and allowed if and only if * g6->dispatch_necessary == 1 and * g6->isr_dispatch_disable == 0 and * g6->thread_dispatch_disable_level == 0. * * Otherwise, continue with the simple return. */ xor %o2, 1, %o2 or %o2, %l6, %o2 orcc %o2, %o3, %o2 bnz simple_return /* * Switch back on the interrupted tasks stack and add enough room to * invoke the dispatcher. Doing this in the delay slot causes no harm, * since the stack pointer (%sp) is not used in the simple return path. */ sub %fp, SPARC_MINIMUM_STACK_FRAME_SIZE, %sp isr_dispatch: /* Set ISR dispatch disable and thread dispatch disable level to one */ mov 1, %l6 st %l6, [%g6 + PER_CPU_THREAD_DISPATCH_DISABLE_LEVEL] st %l6, [%g6 + PER_CPU_ISR_DISPATCH_DISABLE] /* Call _Thread_Do_dispatch(), this function will enable interrupts */ mov 0, %o1 ! ISR level for _Thread_Do_dispatch() #if defined(SPARC_USE_LAZY_FP_SWITCH) /* Test if we interrupted a floating point thread (PSR[EF] == 1) */ andcc %l0, %l5, %g0 be .Lnon_fp_thread_dispatch ld [%g6 + PER_CPU_OFFSET_EXECUTING], %l6 /* Set new floating point unit owner to executing thread */ st %l6, [%g6 + SPARC_PER_CPU_FP_OWNER_OFFSET] call SYM(_Thread_Do_dispatch) mov %g6, %o0 /* * If we are still the floating point unit owner, then reset the * floating point unit owner to NULL, otherwise clear PSR[EF] in the * interrupt frame and let the FP disabled system call do the floating * point context save/restore. */ ld [%g6 + SPARC_PER_CPU_FP_OWNER_OFFSET], %l7 cmp %l6, %l7 bne,a .Ldisable_fp andn %l0, %l5, %l0 st %g0, [%g6 + SPARC_PER_CPU_FP_OWNER_OFFSET] ba .Lthread_dispatch_done nop .Ldisable_fp: st %l0, [%fp + ISF_PSR_OFFSET] ba .Lthread_dispatch_done nop .Lnon_fp_thread_dispatch: #elif defined(SPARC_USE_SYNCHRONOUS_FP_SWITCH) /* Test if we interrupted a floating point thread (PSR[EF] == 1) */ andcc %l0, %l5, %g0 be .Lnon_fp_thread_dispatch nop /* * Yes, this is a floating point thread, then save the floating point * context to a new stack frame. Then do the thread dispatch. * Post-switch actions (e.g. signal handlers) and context switch * extensions may safely use the floating point unit. */ sub %sp, SPARC_FP_FRAME_SIZE, %sp std %f0, [%sp + SPARC_FP_FRAME_OFFSET_FO_F1] SPARC_LEON3FT_B2BST_NOP std %f2, [%sp + SPARC_FP_FRAME_OFFSET_F2_F3] SPARC_LEON3FT_B2BST_NOP std %f4, [%sp + SPARC_FP_FRAME_OFFSET_F4_F5] SPARC_LEON3FT_B2BST_NOP std %f6, [%sp + SPARC_FP_FRAME_OFFSET_F6_F7] SPARC_LEON3FT_B2BST_NOP std %f8, [%sp + SPARC_FP_FRAME_OFFSET_F8_F9] SPARC_LEON3FT_B2BST_NOP std %f10, [%sp + SPARC_FP_FRAME_OFFSET_F1O_F11] SPARC_LEON3FT_B2BST_NOP std %f12, [%sp + SPARC_FP_FRAME_OFFSET_F12_F13] SPARC_LEON3FT_B2BST_NOP std %f14, [%sp + SPARC_FP_FRAME_OFFSET_F14_F15] SPARC_LEON3FT_B2BST_NOP std %f16, [%sp + SPARC_FP_FRAME_OFFSET_F16_F17] SPARC_LEON3FT_B2BST_NOP std %f18, [%sp + SPARC_FP_FRAME_OFFSET_F18_F19] SPARC_LEON3FT_B2BST_NOP std %f20, [%sp + SPARC_FP_FRAME_OFFSET_F2O_F21] SPARC_LEON3FT_B2BST_NOP std %f22, [%sp + SPARC_FP_FRAME_OFFSET_F22_F23] SPARC_LEON3FT_B2BST_NOP std %f24, [%sp + SPARC_FP_FRAME_OFFSET_F24_F25] SPARC_LEON3FT_B2BST_NOP std %f26, [%sp + SPARC_FP_FRAME_OFFSET_F26_F27] SPARC_LEON3FT_B2BST_NOP std %f28, [%sp + SPARC_FP_FRAME_OFFSET_F28_F29] SPARC_LEON3FT_B2BST_NOP std %f30, [%sp + SPARC_FP_FRAME_OFFSET_F3O_F31] SPARC_LEON3FT_B2BST_NOP st %fsr, [%sp + SPARC_FP_FRAME_OFFSET_FSR] call SYM(_Thread_Do_dispatch) mov %g6, %o0 /* * Restore the floating point context from stack frame and release the * stack frame. */ ldd [%sp + SPARC_FP_FRAME_OFFSET_FO_F1], %f0 ldd [%sp + SPARC_FP_FRAME_OFFSET_F2_F3], %f2 ldd [%sp + SPARC_FP_FRAME_OFFSET_F4_F5], %f4 ldd [%sp + SPARC_FP_FRAME_OFFSET_F6_F7], %f6 ldd [%sp + SPARC_FP_FRAME_OFFSET_F8_F9], %f8 ldd [%sp + SPARC_FP_FRAME_OFFSET_F1O_F11], %f10 ldd [%sp + SPARC_FP_FRAME_OFFSET_F12_F13], %f12 ldd [%sp + SPARC_FP_FRAME_OFFSET_F14_F15], %f14 ldd [%sp + SPARC_FP_FRAME_OFFSET_F16_F17], %f16 ldd [%sp + SPARC_FP_FRAME_OFFSET_F18_F19], %f18 ldd [%sp + SPARC_FP_FRAME_OFFSET_F2O_F21], %f20 ldd [%sp + SPARC_FP_FRAME_OFFSET_F22_F23], %f22 ldd [%sp + SPARC_FP_FRAME_OFFSET_F24_F25], %f24 ldd [%sp + SPARC_FP_FRAME_OFFSET_F26_F27], %f26 ldd [%sp + SPARC_FP_FRAME_OFFSET_F28_F29], %f28 ldd [%sp + SPARC_FP_FRAME_OFFSET_F3O_F31], %f30 ld [%sp + SPARC_FP_FRAME_OFFSET_FSR], %fsr ba .Lthread_dispatch_done add %sp, SPARC_FP_FRAME_SIZE, %sp .Lnon_fp_thread_dispatch: #endif call SYM(_Thread_Do_dispatch) mov %g6, %o0 #if SPARC_HAS_FPU == 1 .Lthread_dispatch_done: #endif ta SPARC_SWTRAP_IRQDIS ! **** DISABLE INTERRUPTS **** /* * While we had ISR dispatching disabled in this thread, * did we miss anything? If so, then we need to do another * _Thread_Do_dispatch() before leaving this ISR dispatch context. */ ldub [%g6 + PER_CPU_DISPATCH_NEEDED], %l7 orcc %l7, %g0, %g0 ! Is a thread dispatch necessary? bne isr_dispatch ! Yes, then invoke the dispatcher again. mov 0, %o1 ! ISR level for _Thread_Do_dispatch() /* * No, then set the ISR dispatch disable flag to zero and continue with * the simple return. */ st %g0, [%g6 + PER_CPU_ISR_DISPATCH_DISABLE] /* * The CWP in place at this point may be different from * that which was in effect at the beginning of the ISR if we * have been context switched between the beginning of this invocation * of _ISR_Handler and this point. Thus the CWP and WIM should * not be changed back to their values at ISR entry time. Any * changes to the PSR must preserve the CWP. */ simple_return: ld [%fp + ISF_Y_OFFSET], %l5 ! restore y wr %l5, 0, %y ldd [%fp + ISF_PSR_OFFSET], %l0 ! restore psr, PC ld [%fp + ISF_NPC_OFFSET], %l2 ! restore nPC rd %psr, %l3 and %l3, SPARC_PSR_CWP_MASK, %l3 ! want "current" CWP andn %l0, SPARC_PSR_CWP_MASK, %l0 ! want rest from task or %l3, %l0, %l0 ! install it later... andn %l0, SPARC_PSR_ET_MASK, %l0 /* * Restore tasks global and out registers */ mov %fp, %g1 ! g1 is restored later ldd [%fp + ISF_G2_OFFSET], %g2 ! restore g2, g3 ldd [%fp + ISF_G4_OFFSET], %g4 ! restore g4, g5 ld [%fp + ISF_G7_OFFSET], %g7 ! restore g7 ldd [%fp + ISF_I0_OFFSET], %i0 ! restore i0, i1 ldd [%fp + ISF_I2_OFFSET], %i2 ! restore i2, i3 ldd [%fp + ISF_I4_OFFSET], %i4 ! restore i4, i5 ldd [%fp + ISF_I6_FP_OFFSET], %i6 ! restore i6/fp, i7 /* * Registers: * * ALL global registers EXCEPT G1 and the input registers have * already been restored and thuse off limits. * * The following is the contents of the local registers: * * l0 = original psr * l1 = return address (i.e. PC) * l2 = nPC * l3 = CWP */ /* * if (CWP + 1) is an invalid window then we need to reload it. * * WARNING: Traps should now be disabled */ mov %l0, %psr ! **** DISABLE TRAPS **** nop nop nop rd %wim, %l4 add %l0, 1, %l6 ! l6 = cwp + 1 and %l6, SPARC_PSR_CWP_MASK, %l6 ! do the modulo on it srl %l4, %l6, %l5 ! l5 = win >> cwp + 1 ; shift count ! and CWP are conveniently LS 5 bits cmp %l5, 1 ! Is tasks window invalid? bne good_task_window /* * The following code is the same as a 1 position left rotate of WIM. */ sll %l4, 1, %l5 ! l5 = WIM << 1 srl %l4, SPARC_NUMBER_OF_REGISTER_WINDOWS-1 , %l4 ! l4 = WIM >> (Number Windows - 1) or %l4, %l5, %l4 ! l4 = (WIM << 1) | ! (WIM >> (Number Windows - 1)) /* * Now restore the window just as if we underflowed to it. */ wr %l4, 0, %wim ! WIM = new WIM nop ! must delay after writing WIM nop nop restore ! now into the tasks window ldd [%g1 + CPU_STACK_FRAME_L0_OFFSET], %l0 ldd [%g1 + CPU_STACK_FRAME_L2_OFFSET], %l2 ldd [%g1 + CPU_STACK_FRAME_L4_OFFSET], %l4 ldd [%g1 + CPU_STACK_FRAME_L6_OFFSET], %l6 ldd [%g1 + CPU_STACK_FRAME_I0_OFFSET], %i0 ldd [%g1 + CPU_STACK_FRAME_I2_OFFSET], %i2 ldd [%g1 + CPU_STACK_FRAME_I4_OFFSET], %i4 ldd [%g1 + CPU_STACK_FRAME_I6_FP_OFFSET], %i6 ! reload of sp clobbers ISF save ! Back to ISR dispatch window good_task_window: TN0018_WAIT_IFLUSH %l3,%l4 ! GRLIB-TN-0018 work around macro mov %l0, %psr ! **** DISABLE TRAPS **** nop; nop; nop ! and restore condition codes. ld [%g1 + ISF_G1_OFFSET], %g1 ! restore g1 TN0018_FIX %l3,%l4 ! GRLIB-TN-0018 work around macro jmp %l1 ! transfer control and rett %l2 ! go back to tasks window /* end of file */