ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/arch/arc/kernel/entry-compact.S b/marvell/linux/arch/arc/kernel/entry-compact.S
new file mode 100644
index 0000000..5cb0cd7
--- /dev/null
+++ b/marvell/linux/arch/arc/kernel/entry-compact.S
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+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Low Level Interrupts/Traps/Exceptions(non-TLB) Handling for ARCompact ISA
+ *
+ * Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com)
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * vineetg: May 2011
+ * -Userspace unaligned access emulation
+ *
+ * vineetg: Feb 2011 (ptrace low level code fixes)
+ * -traced syscall return code (r0) was not saved into pt_regs for restoring
+ * into user reg-file when traded task rets to user space.
+ * -syscalls needing arch-wrappers (mainly for passing sp as pt_regs)
+ * were not invoking post-syscall trace hook (jumping directly into
+ * ret_from_system_call)
+ *
+ * vineetg: Nov 2010:
+ * -Vector table jumps (@8 bytes) converted into branches (@4 bytes)
+ * -To maintain the slot size of 8 bytes/vector, added nop, which is
+ * not executed at runtime.
+ *
+ * vineetg: Nov 2009 (Everything needed for TIF_RESTORE_SIGMASK)
+ * -do_signal()invoked upon TIF_RESTORE_SIGMASK as well
+ * -Wrappers for sys_{,rt_}sigsuspend() no longer needed as they don't
+ * need ptregs anymore
+ *
+ * Vineetg: Oct 2009
+ * -In a rare scenario, Process gets a Priv-V exception and gets scheduled
+ * out. Since we don't do FAKE RTIE for Priv-V, CPU exception state remains
+ * active (AE bit enabled). This causes a double fault for a subseq valid
+ * exception. Thus FAKE RTIE needed in low level Priv-Violation handler.
+ * Instr Error could also cause similar scenario, so same there as well.
+ *
+ * Vineetg: March 2009 (Supporting 2 levels of Interrupts)
+ *
+ * Vineetg: Aug 28th 2008: Bug #94984
+ * -Zero Overhead Loop Context shd be cleared when entering IRQ/EXcp/Trap
+ * Normally CPU does this automatically, however when doing FAKE rtie,
+ * we need to explicitly do this. The problem in macros
+ * FAKE_RET_FROM_EXCPN and FAKE_RET_FROM_EXCPN_LOCK_IRQ was that this bit
+ * was being "CLEARED" rather then "SET". Since it is Loop INHIBIT Bit,
+ * setting it and not clearing it clears ZOL context
+ *
+ * Vineetg: May 16th, 2008
+ * - r25 now contains the Current Task when in kernel
+ *
+ * Vineetg: Dec 22, 2007
+ * Minor Surgery of Low Level ISR to make it SMP safe
+ * - MMU_SCRATCH0 Reg used for freeing up r9 in Level 1 ISR
+ * - _current_task is made an array of NR_CPUS
+ * - Access of _current_task wrapped inside a macro so that if hardware
+ * team agrees for a dedicated reg, no other code is touched
+ *
+ * Amit Bhor, Rahul Trivedi, Kanika Nema, Sameer Dhavale : Codito Tech 2004
+ */
+
+#include <linux/errno.h>
+#include <linux/linkage.h> /* {ENTRY,EXIT} */
+#include <asm/entry.h>
+#include <asm/irqflags.h>
+
+ .cpu A7
+
+;############################ Vector Table #################################
+
+.macro VECTOR lbl
+#if 1 /* Just in case, build breaks */
+ j \lbl
+#else
+ b \lbl
+ nop
+#endif
+.endm
+
+ .section .vector, "ax",@progbits
+ .align 4
+
+/* Each entry in the vector table must occupy 2 words. Since it is a jump
+ * across sections (.vector to .text) we are guaranteed that 'j somewhere'
+ * will use the 'j limm' form of the instruction as long as somewhere is in
+ * a section other than .vector.
+ */
+
+; ********* Critical System Events **********************
+VECTOR res_service ; 0x0, Reset Vector (0x0)
+VECTOR mem_service ; 0x8, Mem exception (0x1)
+VECTOR instr_service ; 0x10, Instrn Error (0x2)
+
+; ******************** Device ISRs **********************
+#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
+VECTOR handle_interrupt_level2
+#else
+VECTOR handle_interrupt_level1
+#endif
+
+.rept 28
+VECTOR handle_interrupt_level1 ; Other devices
+.endr
+
+/* FOR ARC600: timer = 0x3, uart = 0x8, emac = 0x10 */
+
+; ******************** Exceptions **********************
+VECTOR EV_MachineCheck ; 0x100, Fatal Machine check (0x20)
+VECTOR EV_TLBMissI ; 0x108, Instruction TLB miss (0x21)
+VECTOR EV_TLBMissD ; 0x110, Data TLB miss (0x22)
+VECTOR EV_TLBProtV ; 0x118, Protection Violation (0x23)
+ ; or Misaligned Access
+VECTOR EV_PrivilegeV ; 0x120, Privilege Violation (0x24)
+VECTOR EV_Trap ; 0x128, Trap exception (0x25)
+VECTOR EV_Extension ; 0x130, Extn Instruction Excp (0x26)
+
+.rept 24
+VECTOR reserved ; Reserved Exceptions
+.endr
+
+
+;##################### Scratch Mem for IRQ stack switching #############
+
+ARCFP_DATA int1_saved_reg
+ .align 32
+ .type int1_saved_reg, @object
+ .size int1_saved_reg, 4
+int1_saved_reg:
+ .zero 4
+
+/* Each Interrupt level needs its own scratch */
+ARCFP_DATA int2_saved_reg
+ .type int2_saved_reg, @object
+ .size int2_saved_reg, 4
+int2_saved_reg:
+ .zero 4
+
+; ---------------------------------------------
+ .section .text, "ax",@progbits
+
+
+reserved:
+ flag 1 ; Unexpected event, halt
+
+;##################### Interrupt Handling ##############################
+
+#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
+; ---------------------------------------------
+; Level 2 ISR: Can interrupt a Level 1 ISR
+; ---------------------------------------------
+ENTRY(handle_interrupt_level2)
+
+ INTERRUPT_PROLOGUE 2
+
+ ;------------------------------------------------------
+ ; if L2 IRQ interrupted a L1 ISR, disable preemption
+ ;
+ ; This is to avoid a potential L1-L2-L1 scenario
+ ; -L1 IRQ taken
+ ; -L2 interrupts L1 (before L1 ISR could run)
+ ; -preemption off IRQ, user task in syscall picked to run
+ ; -RTIE to userspace
+ ; Returns from L2 context fine
+ ; But both L1 and L2 re-enabled, so another L1 can be taken
+ ; while prev L1 is still unserviced
+ ;
+ ;------------------------------------------------------
+
+ ; L2 interrupting L1 implies both L2 and L1 active
+ ; However both A2 and A1 are NOT set in STATUS32, thus
+ ; need to check STATUS32_L2 to determine if L1 was active
+
+ ld r9, [sp, PT_status32] ; get statu32_l2 (saved in pt_regs)
+ bbit0 r9, STATUS_A1_BIT, 1f ; L1 not active when L2 IRQ, so normal
+
+ ; bump thread_info->preempt_count (Disable preemption)
+ GET_CURR_THR_INFO_FROM_SP r10
+ ld r9, [r10, THREAD_INFO_PREEMPT_COUNT]
+ add r9, r9, 1
+ st r9, [r10, THREAD_INFO_PREEMPT_COUNT]
+
+1:
+ ;------------------------------------------------------
+ ; setup params for Linux common ISR and invoke it
+ ;------------------------------------------------------
+ lr r0, [icause2]
+ and r0, r0, 0x1f
+
+ bl.d @arch_do_IRQ
+ mov r1, sp
+
+ mov r8,0x2
+ sr r8, [AUX_IRQ_LV12] ; clear bit in Sticky Status Reg
+
+ b ret_from_exception
+
+END(handle_interrupt_level2)
+
+#endif
+
+; ---------------------------------------------
+; User Mode Memory Bus Error Interrupt Handler
+; (Kernel mode memory errors handled via separate exception vectors)
+; ---------------------------------------------
+ENTRY(mem_service)
+
+ INTERRUPT_PROLOGUE 2
+
+ mov r0, ilink2
+ mov r1, sp
+
+ ; User process needs to be killed with SIGBUS, but first need to get
+ ; out of the L2 interrupt context (drop to pure kernel mode) and jump
+ ; off to "C" code where SIGBUS in enqueued
+ lr r3, [status32]
+ bclr r3, r3, STATUS_A2_BIT
+ or r3, r3, (STATUS_E1_MASK|STATUS_E2_MASK)
+ sr r3, [status32_l2]
+ mov ilink2, 1f
+ rtie
+1:
+ bl do_memory_error
+ b ret_from_exception
+END(mem_service)
+
+; ---------------------------------------------
+; Level 1 ISR
+; ---------------------------------------------
+ENTRY(handle_interrupt_level1)
+
+ INTERRUPT_PROLOGUE 1
+
+ lr r0, [icause1]
+ and r0, r0, 0x1f
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+ ; icause1 needs to be read early, before calling tracing, which
+ ; can clobber scratch regs, hence use of stack to stash it
+ push r0
+ TRACE_ASM_IRQ_DISABLE
+ pop r0
+#endif
+
+ bl.d @arch_do_IRQ
+ mov r1, sp
+
+ mov r8,0x1
+ sr r8, [AUX_IRQ_LV12] ; clear bit in Sticky Status Reg
+
+ b ret_from_exception
+END(handle_interrupt_level1)
+
+;################### Non TLB Exception Handling #############################
+
+; ---------------------------------------------
+; Protection Violation Exception Handler
+; ---------------------------------------------
+
+ENTRY(EV_TLBProtV)
+
+ EXCEPTION_PROLOGUE
+
+ mov r2, r10 ; ECR set into r10 already
+ lr r0, [efa] ; Faulting Data address (not part of pt_regs saved above)
+
+ ; Exception auto-disables further Intr/exceptions.
+ ; Re-enable them by pretending to return from exception
+ ; (so rest of handler executes in pure K mode)
+
+ FAKE_RET_FROM_EXCPN
+
+ mov r1, sp ; Handle to pt_regs
+
+ ;------ (5) Type of Protection Violation? ----------
+ ;
+ ; ProtV Hardware Exception is triggered for Access Faults of 2 types
+ ; -Access Violation : 00_23_(00|01|02|03)_00
+ ; x r w r+w
+ ; -Unaligned Access : 00_23_04_00
+ ;
+ bbit1 r2, ECR_C_BIT_PROTV_MISALIG_DATA, 4f
+
+ ;========= (6a) Access Violation Processing ========
+ bl do_page_fault
+ b ret_from_exception
+
+ ;========== (6b) Non aligned access ============
+4:
+
+ SAVE_CALLEE_SAVED_USER
+ mov r2, sp ; callee_regs
+
+ bl do_misaligned_access
+
+ ; TBD: optimize - do this only if a callee reg was involved
+ ; either a dst of emulated LD/ST or src with address-writeback
+ RESTORE_CALLEE_SAVED_USER
+
+ b ret_from_exception
+
+END(EV_TLBProtV)
+
+; Wrapper for Linux page fault handler called from EV_TLBMiss*
+; Very similar to ProtV handler case (6a) above, but avoids the extra checks
+; for Misaligned access
+;
+ENTRY(call_do_page_fault)
+
+ EXCEPTION_PROLOGUE
+ lr r0, [efa] ; Faulting Data address
+ mov r1, sp
+ FAKE_RET_FROM_EXCPN
+
+ mov blink, ret_from_exception
+ b do_page_fault
+
+END(call_do_page_fault)
+
+;############# Common Handlers for ARCompact and ARCv2 ##############
+
+#include "entry.S"
+
+;############# Return from Intr/Excp/Trap (ARC Specifics) ##############
+;
+; Restore the saved sys context (common exit-path for EXCPN/IRQ/Trap)
+; IRQ shd definitely not happen between now and rtie
+; All 2 entry points to here already disable interrupts
+
+.Lrestore_regs:
+
+ # Interrupts are actually disabled from this point on, but will get
+ # reenabled after we return from interrupt/exception.
+ # But irq tracer needs to be told now...
+ TRACE_ASM_IRQ_ENABLE
+
+ lr r10, [status32]
+
+ ; Restore REG File. In case multiple Events outstanding,
+ ; use the same priority as rtie: EXCPN, L2 IRQ, L1 IRQ, None
+ ; Note that we use realtime STATUS32 (not pt_regs->status32) to
+ ; decide that.
+
+ and.f 0, r10, (STATUS_A1_MASK|STATUS_A2_MASK)
+ bz .Lexcep_or_pure_K_ret
+
+ ; Returning from Interrupts (Level 1 or 2)
+
+#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
+
+ ; Level 2 interrupt return Path - from hardware standpoint
+ bbit0 r10, STATUS_A2_BIT, not_level2_interrupt
+
+ ;------------------------------------------------------------------
+ ; However the context returning might not have taken L2 intr itself
+ ; e.g. Task'A' user-code -> L2 intr -> schedule -> 'B' user-code ret
+ ; Special considerations needed for the context which took L2 intr
+
+ ld r9, [sp, PT_event] ; Ensure this is L2 intr context
+ brne r9, event_IRQ2, 149f
+
+ ;------------------------------------------------------------------
+ ; if L2 IRQ interrupted an L1 ISR, we'd disabled preemption earlier
+ ; so that sched doesn't move to new task, causing L1 to be delayed
+ ; undeterministically. Now that we've achieved that, let's reset
+ ; things to what they were, before returning from L2 context
+ ;----------------------------------------------------------------
+
+ ld r9, [sp, PT_status32] ; get statu32_l2 (saved in pt_regs)
+ bbit0 r9, STATUS_A1_BIT, 149f ; L1 not active when L2 IRQ, so normal
+
+ ; decrement thread_info->preempt_count (re-enable preemption)
+ GET_CURR_THR_INFO_FROM_SP r10
+ ld r9, [r10, THREAD_INFO_PREEMPT_COUNT]
+
+ ; paranoid check, given A1 was active when A2 happened, preempt count
+ ; must not be 0 because we would have incremented it.
+ ; If this does happen we simply HALT as it means a BUG !!!
+ cmp r9, 0
+ bnz 2f
+ flag 1
+
+2:
+ sub r9, r9, 1
+ st r9, [r10, THREAD_INFO_PREEMPT_COUNT]
+
+149:
+ INTERRUPT_EPILOGUE 2 ; return from level 2 interrupt
+debug_marker_l2:
+ rtie
+
+not_level2_interrupt:
+
+#endif
+
+ INTERRUPT_EPILOGUE 1 ; return from level 1 interrupt
+debug_marker_l1:
+ rtie
+
+.Lexcep_or_pure_K_ret:
+
+ ;this case is for syscalls or Exceptions or pure kernel mode
+
+ EXCEPTION_EPILOGUE
+debug_marker_syscall:
+ rtie
+
+END(ret_from_exception)