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>

diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index 53d143f..56aad10 100644 (file)
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -537,9 +537,6 @@ config ARC_DW2_UNWIND
          If you don't debug the kernel, you can say N, but we may not be able
          to solve problems without frame unwind information
 
          If you don't debug the kernel, you can say N, but we may not be able
          to solve problems without frame unwind information
 

-config ARC_DBG_TLB_PARANOIA
-       bool "Paranoia Checks in Low Level TLB Handlers"
-

 config ARC_DBG_JUMP_LABEL
        bool "Paranoid checks in Static Keys (jump labels) code"
        depends on JUMP_LABEL
 config ARC_DBG_JUMP_LABEL
        bool "Paranoid checks in Static Keys (jump labels) code"
        depends on JUMP_LABEL

diff --git a/arch/arc/include/asm/mmu.h b/arch/arc/include/asm/mmu.h
index 4065335..38a0365 100644 (file)
--- a/arch/arc/include/asm/mmu.h
+++ b/arch/arc/include/asm/mmu.h
@@ -64,12 +64,6 @@ typedef struct {
        unsigned long asid[NR_CPUS];    /* 8 bit MMU PID + Generation cycle */
 } mm_context_t;
 
        unsigned long asid[NR_CPUS];    /* 8 bit MMU PID + Generation cycle */
 } mm_context_t;
 

-#ifdef CONFIG_ARC_DBG_TLB_PARANOIA
-void tlb_paranoid_check(unsigned int mm_asid, unsigned long address);
-#else
-#define tlb_paranoid_check(a, b)
-#endif
-

 void arc_mmu_init(void);
 extern char *arc_mmu_mumbojumbo(int cpu_id, char *buf, int len);
 void read_decode_mmu_bcr(void);
 void arc_mmu_init(void);
 extern char *arc_mmu_mumbojumbo(int cpu_id, char *buf, int len);
 void read_decode_mmu_bcr(void);

diff --git a/arch/arc/mm/tlb.c b/arch/arc/mm/tlb.c
index 349fb7a..6079dfd 100644 (file)
--- a/arch/arc/mm/tlb.c
+++ b/arch/arc/mm/tlb.c
@@ -400,7 +400,6 @@ void create_tlb(struct vm_area_struct *vma, unsigned long vaddr, pte_t *ptep)
         *
         * Removing the assumption involves
         * -Using vma->mm->context{ASID,SASID}, as opposed to MMU reg.
         *
         * Removing the assumption involves
         * -Using vma->mm->context{ASID,SASID}, as opposed to MMU reg.

-        * -Fix the TLB paranoid debug code to not trigger false negatives.

         * -More importantly it makes this handler inconsistent with fast-path
         *  TLB Refill handler which always deals with "current"
         *
         * -More importantly it makes this handler inconsistent with fast-path
         *  TLB Refill handler which always deals with "current"
         *


@@ -423,8 +422,6 @@ void create_tlb(struct vm_area_struct *vma, unsigned long vaddr, pte_t *ptep)
 
        local_irq_save(flags);
 
 
        local_irq_save(flags);
 

-       tlb_paranoid_check(asid_mm(vma->vm_mm, smp_processor_id()), vaddr);
-

        vaddr &= PAGE_MASK;
 
        /* update this PTE credentials */
        vaddr &= PAGE_MASK;
 
        /* update this PTE credentials */


@@ -818,40 +815,3 @@ void do_tlb_overlap_fault(unsigned long cause, unsigned long address,
 
        local_irq_restore(flags);
 }
 
        local_irq_restore(flags);
 }

-
-/***********************************************************************
- * Diagnostic Routines
- *  -Called from Low Level TLB Handlers if things don;t look good
- **********************************************************************/
-
-#ifdef CONFIG_ARC_DBG_TLB_PARANOIA
-
-/*
- * Low Level ASM TLB handler calls this if it finds that HW and SW ASIDS
- * don't match
- */
-void print_asid_mismatch(int mm_asid, int mmu_asid, int is_fast_path)
-{
-       pr_emerg("ASID Mismatch in %s Path Handler: sw-pid=0x%x hw-pid=0x%x\n",
-              is_fast_path ? "Fast" : "Slow", mm_asid, mmu_asid);
-
-       __asm__ __volatile__("flag 1");
-}
-
-void tlb_paranoid_check(unsigned int mm_asid, unsigned long addr)
-{
-       unsigned int mmu_asid;
-
-       mmu_asid = read_aux_reg(ARC_REG_PID) & 0xff;
-
-       /*
-        * At the time of a TLB miss/installation
-        *   - HW version needs to match SW version
-        *   - SW needs to have a valid ASID
-        */
-       if (addr < 0x70000000 &&
-           ((mm_asid == MM_CTXT_NO_ASID) ||
-             (mmu_asid != (mm_asid & MM_CTXT_ASID_MASK))))
-               print_asid_mismatch(mm_asid, mmu_asid, 0);
-}
-#endif

diff --git a/arch/arc/mm/tlbex.S b/arch/arc/mm/tlbex.S
index bcd2909..0b4bb62 100644 (file)
--- a/arch/arc/mm/tlbex.S
+++ b/arch/arc/mm/tlbex.S
@@ -93,11 +93,6 @@ ex_saved_reg1:
        st_s  r1, [r0, 4]
        st_s  r2, [r0, 8]
        st_s  r3, [r0, 12]
        st_s  r1, [r0, 4]
        st_s  r2, [r0, 8]
        st_s  r3, [r0, 12]

-
-       ; VERIFY if the ASID in MMU-PID Reg is same as
-       ; one in Linux data structures
-
-       tlb_paranoid_check_asm

 .endm
 
 .macro TLBMISS_RESTORE_REGS
 .endm
 
 .macro TLBMISS_RESTORE_REGS


@@ -146,51 +141,6 @@ ex_saved_reg1:
 
 #endif
 
 
 #endif
 

-;============================================================================
-;  Troubleshooting Stuff
-;============================================================================
-
-; Linux keeps ASID (Address Space ID) in task->active_mm->context.asid
-; When Creating TLB Entries, instead of doing 3 dependent loads from memory,
-; we use the MMU PID Reg to get current ASID.
-; In bizzare scenrios SW and HW ASID can get out-of-sync which is trouble.
-; So we try to detect this in TLB Mis shandler
-
-.macro tlb_paranoid_check_asm
-
-#ifdef CONFIG_ARC_DBG_TLB_PARANOIA
-
-       GET_CURR_TASK_ON_CPU  r3
-       ld r0, [r3, TASK_ACT_MM]
-       ld r0, [r0, MM_CTXT+MM_CTXT_ASID]
-       breq r0, 0, 55f ; Error if no ASID allocated
-
-       lr r1, [ARC_REG_PID]
-       and r1, r1, 0xFF
-
-       and r2, r0, 0xFF        ; MMU PID bits only for comparison
-       breq r1, r2, 5f
-
-55:
-       ; Error if H/w and S/w ASID don't match, but NOT if in kernel mode
-       lr  r2, [erstatus]
-       bbit0 r2, STATUS_U_BIT, 5f
-
-       ; We sure are in troubled waters, Flag the error, but to do so
-       ; need to switch to kernel mode stack to call error routine
-       GET_TSK_STACK_BASE   r3, sp
-
-       ; Call printk to shoutout aloud
-       mov r2, 1
-       j print_asid_mismatch
-
-5:     ; ASIDs match so proceed normally
-       nop
-
-#endif
-
-.endm
-

 ;============================================================================
 ;TLB Miss handling Code
 ;============================================================================
 ;============================================================================
 ;TLB Miss handling Code
 ;============================================================================