MIPS: MT: Remove SMTC support

Nobody is maintaining SMTC anymore and there also seems to be no userbase.
Which is a pity - the SMTC technology primarily developed by Kevin D.
Kissell <kevink@paralogos.com> is an ingenious demonstration for the MT
ASE's power and elegance.

Based on Markos Chandras <Markos.Chandras@imgtec.com> patch
https://patchwork.linux-mips.org/patch/6719/ which while very similar did
no longer apply cleanly when I tried to merge it plus some additional
post-SMTC cleanup - SMTC was a feature as tricky to remove as it was to
merge once upon a time.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 0 insertions, 107 deletions

diff --git a/arch/mips/include/asm/mmu_context.h b/arch/mips/include/asm/mmu_context.h
index e277bbad2871..0f75aaca201b 100644
--- a/arch/mips/include/asm/mmu_context.h
+++ b/arch/mips/include/asm/mmu_context.h
@@ -18,10 +18,6 @@
 #include <asm/cacheflush.h>
 #include <asm/hazards.h>
 #include <asm/tlbflush.h>
-#ifdef CONFIG_MIPS_MT_SMTC
-#include <asm/mipsmtregs.h>
-#include <asm/smtc.h>
-#endif /* SMTC */
 #include <asm-generic/mm_hooks.h>
 
 #define TLBMISS_HANDLER_SETUP_PGD(pgd)					\
@@ -63,13 +59,6 @@ extern unsigned long pgd_current[];
 #define ASID_INC	0x10
 #define ASID_MASK	0xff0
 
-#elif defined(CONFIG_MIPS_MT_SMTC)
-
-#define ASID_INC	0x1
-extern unsigned long smtc_asid_mask;
-#define ASID_MASK	(smtc_asid_mask)
-#define HW_ASID_MASK	0xff
-/* End SMTC/34K debug hack */
 #else /* FIXME: not correct for R6000 */
 
 #define ASID_INC	0x1
@@ -92,7 +81,6 @@ static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
 #define ASID_VERSION_MASK  ((unsigned long)~(ASID_MASK|(ASID_MASK-1)))
 #define ASID_FIRST_VERSION ((unsigned long)(~ASID_VERSION_MASK) + 1)
 
-#ifndef CONFIG_MIPS_MT_SMTC
 /* Normal, classic MIPS get_new_mmu_context */
 static inline void
 get_new_mmu_context(struct mm_struct *mm, unsigned long cpu)
@@ -115,12 +103,6 @@ get_new_mmu_context(struct mm_struct *mm, unsigned long cpu)
 	cpu_context(cpu, mm) = asid_cache(cpu) = asid;
 }
 
-#else /* CONFIG_MIPS_MT_SMTC */
-
-#define get_new_mmu_context(mm, cpu) smtc_get_new_mmu_context((mm), (cpu))
-
-#endif /* CONFIG_MIPS_MT_SMTC */
-
 /*
  * Initialize the context related info for a new mm_struct
  * instance.
@@ -141,46 +123,12 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
 {
 	unsigned int cpu = smp_processor_id();
 	unsigned long flags;
-#ifdef CONFIG_MIPS_MT_SMTC
-	unsigned long oldasid;
-	unsigned long mtflags;
-	int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id;
-	local_irq_save(flags);
-	mtflags = dvpe();
-#else /* Not SMTC */
 	local_irq_save(flags);
-#endif /* CONFIG_MIPS_MT_SMTC */
 
 	/* Check if our ASID is of an older version and thus invalid */
 	if ((cpu_context(cpu, next) ^ asid_cache(cpu)) & ASID_VERSION_MASK)
 		get_new_mmu_context(next, cpu);
-#ifdef CONFIG_MIPS_MT_SMTC
-	/*
-	 * If the EntryHi ASID being replaced happens to be
-	 * the value flagged at ASID recycling time as having
-	 * an extended life, clear the bit showing it being
-	 * in use by this "CPU", and if that's the last bit,
-	 * free up the ASID value for use and flush any old
-	 * instances of it from the TLB.
-	 */
-	oldasid = (read_c0_entryhi() & ASID_MASK);
-	if(smtc_live_asid[mytlb][oldasid]) {
-		smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu);
-		if(smtc_live_asid[mytlb][oldasid] == 0)
-			smtc_flush_tlb_asid(oldasid);
-	}
-	/*
-	 * Tread softly on EntryHi, and so long as we support
-	 * having ASID_MASK smaller than the hardware maximum,
-	 * make sure no "soft" bits become "hard"...
-	 */
-	write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK) |
-			 cpu_asid(cpu, next));
-	ehb(); /* Make sure it propagates to TCStatus */
-	evpe(mtflags);
-#else
 	write_c0_entryhi(cpu_asid(cpu, next));
-#endif /* CONFIG_MIPS_MT_SMTC */
 	TLBMISS_HANDLER_SETUP_PGD(next->pgd);
 
 	/*
@@ -213,34 +161,12 @@ activate_mm(struct mm_struct *prev, struct mm_struct *next)
 	unsigned long flags;
 	unsigned int cpu = smp_processor_id();
 
-#ifdef CONFIG_MIPS_MT_SMTC
-	unsigned long oldasid;
-	unsigned long mtflags;
-	int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id;
-#endif /* CONFIG_MIPS_MT_SMTC */
-
 	local_irq_save(flags);
 
 	/* Unconditionally get a new ASID.  */
 	get_new_mmu_context(next, cpu);
 
-#ifdef CONFIG_MIPS_MT_SMTC
-	/* See comments for similar code above */
-	mtflags = dvpe();
-	oldasid = read_c0_entryhi() & ASID_MASK;
-	if(smtc_live_asid[mytlb][oldasid]) {
-		smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu);
-		if(smtc_live_asid[mytlb][oldasid] == 0)
-			 smtc_flush_tlb_asid(oldasid);
-	}
-	/* See comments for similar code above */
-	write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK) |
-			 cpu_asid(cpu, next));
-	ehb(); /* Make sure it propagates to TCStatus */
-	evpe(mtflags);
-#else
 	write_c0_entryhi(cpu_asid(cpu, next));
-#endif /* CONFIG_MIPS_MT_SMTC */
 	TLBMISS_HANDLER_SETUP_PGD(next->pgd);
 
 	/* mark mmu ownership change */
@@ -258,48 +184,15 @@ static inline void
 drop_mmu_context(struct mm_struct *mm, unsigned cpu)
 {
 	unsigned long flags;
-#ifdef CONFIG_MIPS_MT_SMTC
-	unsigned long oldasid;
-	/* Can't use spinlock because called from TLB flush within DVPE */
-	unsigned int prevvpe;
-	int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id;
-#endif /* CONFIG_MIPS_MT_SMTC */
 
 	local_irq_save(flags);
 
 	if (cpumask_test_cpu(cpu, mm_cpumask(mm)))  {
 		get_new_mmu_context(mm, cpu);
-#ifdef CONFIG_MIPS_MT_SMTC
-		/* See comments for similar code above */
-		prevvpe = dvpe();
-		oldasid = (read_c0_entryhi() & ASID_MASK);
-		if (smtc_live_asid[mytlb][oldasid]) {
-			smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu);
-			if(smtc_live_asid[mytlb][oldasid] == 0)
-				smtc_flush_tlb_asid(oldasid);
-		}
-		/* See comments for similar code above */
-		write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK)
-				| cpu_asid(cpu, mm));
-		ehb(); /* Make sure it propagates to TCStatus */
-		evpe(prevvpe);
-#else /* not CONFIG_MIPS_MT_SMTC */
 		write_c0_entryhi(cpu_asid(cpu, mm));
-#endif /* CONFIG_MIPS_MT_SMTC */
 	} else {
 		/* will get a new context next time */
-#ifndef CONFIG_MIPS_MT_SMTC
 		cpu_context(cpu, mm) = 0;
-#else /* SMTC */
-		int i;
-
-		/* SMTC shares the TLB (and ASIDs) across VPEs */
-		for_each_online_cpu(i) {
-		    if((smtc_status & SMTC_TLB_SHARED)
-		    || (cpu_data[i].vpe_id == cpu_data[cpu].vpe_id))
-			cpu_context(i, mm) = 0;
-		}
-#endif /* CONFIG_MIPS_MT_SMTC */
 	}
 	local_irq_restore(flags);
 }