ARC: mm: remove tlb paranoid code
This was used back in arc700 days when ASID allocator was fragile. Not needed in last 5 years Signed-off-by: Vineet Gupta <vgupta@kernel.org>
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Vineet Gupta
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6128df5be4
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12e7804c26
@ -537,9 +537,6 @@ config ARC_DW2_UNWIND
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If you don't debug the kernel, you can say N, but we may not be able
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to solve problems without frame unwind information
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config ARC_DBG_TLB_PARANOIA
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bool "Paranoia Checks in Low Level TLB Handlers"
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config ARC_DBG_JUMP_LABEL
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bool "Paranoid checks in Static Keys (jump labels) code"
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depends on JUMP_LABEL
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@ -64,12 +64,6 @@ typedef struct {
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unsigned long asid[NR_CPUS]; /* 8 bit MMU PID + Generation cycle */
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} mm_context_t;
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#ifdef CONFIG_ARC_DBG_TLB_PARANOIA
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void tlb_paranoid_check(unsigned int mm_asid, unsigned long address);
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#else
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#define tlb_paranoid_check(a, b)
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#endif
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void arc_mmu_init(void);
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extern char *arc_mmu_mumbojumbo(int cpu_id, char *buf, int len);
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void read_decode_mmu_bcr(void);
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@ -400,7 +400,6 @@ void create_tlb(struct vm_area_struct *vma, unsigned long vaddr, pte_t *ptep)
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*
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* Removing the assumption involves
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* -Using vma->mm->context{ASID,SASID}, as opposed to MMU reg.
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* -Fix the TLB paranoid debug code to not trigger false negatives.
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* -More importantly it makes this handler inconsistent with fast-path
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* TLB Refill handler which always deals with "current"
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*
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@ -423,8 +422,6 @@ void create_tlb(struct vm_area_struct *vma, unsigned long vaddr, pte_t *ptep)
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local_irq_save(flags);
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tlb_paranoid_check(asid_mm(vma->vm_mm, smp_processor_id()), vaddr);
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vaddr &= PAGE_MASK;
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/* update this PTE credentials */
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@ -818,40 +815,3 @@ void do_tlb_overlap_fault(unsigned long cause, unsigned long address,
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local_irq_restore(flags);
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}
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/***********************************************************************
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* Diagnostic Routines
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* -Called from Low Level TLB Handlers if things don;t look good
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**********************************************************************/
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#ifdef CONFIG_ARC_DBG_TLB_PARANOIA
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/*
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* Low Level ASM TLB handler calls this if it finds that HW and SW ASIDS
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* don't match
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*/
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void print_asid_mismatch(int mm_asid, int mmu_asid, int is_fast_path)
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{
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pr_emerg("ASID Mismatch in %s Path Handler: sw-pid=0x%x hw-pid=0x%x\n",
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is_fast_path ? "Fast" : "Slow", mm_asid, mmu_asid);
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__asm__ __volatile__("flag 1");
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}
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void tlb_paranoid_check(unsigned int mm_asid, unsigned long addr)
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{
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unsigned int mmu_asid;
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mmu_asid = read_aux_reg(ARC_REG_PID) & 0xff;
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/*
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* At the time of a TLB miss/installation
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* - HW version needs to match SW version
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* - SW needs to have a valid ASID
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*/
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if (addr < 0x70000000 &&
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((mm_asid == MM_CTXT_NO_ASID) ||
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(mmu_asid != (mm_asid & MM_CTXT_ASID_MASK))))
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print_asid_mismatch(mm_asid, mmu_asid, 0);
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}
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#endif
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@ -93,11 +93,6 @@ ex_saved_reg1:
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st_s r1, [r0, 4]
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st_s r2, [r0, 8]
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st_s r3, [r0, 12]
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; VERIFY if the ASID in MMU-PID Reg is same as
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; one in Linux data structures
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tlb_paranoid_check_asm
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.endm
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.macro TLBMISS_RESTORE_REGS
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@ -146,51 +141,6 @@ ex_saved_reg1:
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#endif
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;============================================================================
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; Troubleshooting Stuff
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;============================================================================
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; Linux keeps ASID (Address Space ID) in task->active_mm->context.asid
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; When Creating TLB Entries, instead of doing 3 dependent loads from memory,
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; we use the MMU PID Reg to get current ASID.
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; In bizzare scenrios SW and HW ASID can get out-of-sync which is trouble.
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; So we try to detect this in TLB Mis shandler
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.macro tlb_paranoid_check_asm
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#ifdef CONFIG_ARC_DBG_TLB_PARANOIA
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GET_CURR_TASK_ON_CPU r3
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ld r0, [r3, TASK_ACT_MM]
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ld r0, [r0, MM_CTXT+MM_CTXT_ASID]
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breq r0, 0, 55f ; Error if no ASID allocated
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lr r1, [ARC_REG_PID]
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and r1, r1, 0xFF
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and r2, r0, 0xFF ; MMU PID bits only for comparison
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breq r1, r2, 5f
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55:
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; Error if H/w and S/w ASID don't match, but NOT if in kernel mode
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lr r2, [erstatus]
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bbit0 r2, STATUS_U_BIT, 5f
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; We sure are in troubled waters, Flag the error, but to do so
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; need to switch to kernel mode stack to call error routine
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GET_TSK_STACK_BASE r3, sp
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; Call printk to shoutout aloud
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mov r2, 1
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j print_asid_mismatch
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5: ; ASIDs match so proceed normally
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nop
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#endif
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.endm
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;============================================================================
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;TLB Miss handling Code
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;============================================================================
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