From 12e7804c264143c63d1cae7e3a62d21fbed06f59 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Mon, 9 Sep 2019 16:59:59 -0700 Subject: [PATCH] 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 --- arch/arc/Kconfig | 3 --- arch/arc/include/asm/mmu.h | 6 ----- arch/arc/mm/tlb.c | 40 ------------------------------ arch/arc/mm/tlbex.S | 50 -------------------------------------- 4 files changed, 99 deletions(-) diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig index 53d143fc42fe..56aad105ad13 100644 --- 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 -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 diff --git a/arch/arc/include/asm/mmu.h b/arch/arc/include/asm/mmu.h index 4065335a7922..38a036508699 100644 --- 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; -#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); diff --git a/arch/arc/mm/tlb.c b/arch/arc/mm/tlb.c index 349fb7a75d1d..6079dfd129b9 100644 --- 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. - * -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" * @@ -423,8 +422,6 @@ void create_tlb(struct vm_area_struct *vma, unsigned long vaddr, pte_t *ptep) local_irq_save(flags); - tlb_paranoid_check(asid_mm(vma->vm_mm, smp_processor_id()), vaddr); - 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); } - -/*********************************************************************** - * 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 bcd2909c691f..0b4bb62fa0ab 100644 --- 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] - - ; 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 @@ -146,51 +141,6 @@ ex_saved_reg1: #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 ;============================================================================ -- 2.20.1