4 files changed, 110 insertions, 7 deletions

diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index 95b18a194f53..d5e335e6846a 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -872,10 +872,19 @@ static inline unsigned int decode_config4(struct cpuinfo_mips *c)
 
 static inline unsigned int decode_config5(struct cpuinfo_mips *c)
 {
-	unsigned int config5;
+	unsigned int config5, max_mmid_width;
+	unsigned long asid_mask;
 
 	config5 = read_c0_config5();
 	config5 &= ~(MIPS_CONF5_UFR | MIPS_CONF5_UFE);
+
+	if (cpu_has_mips_r6) {
+		if (!__builtin_constant_p(cpu_has_mmid) || cpu_has_mmid)
+			config5 |= MIPS_CONF5_MI;
+		else
+			config5 &= ~MIPS_CONF5_MI;
+	}
+
 	write_c0_config5(config5);
 
 	if (config5 & MIPS_CONF5_EVA)
@@ -894,6 +903,50 @@ static inline unsigned int decode_config5(struct cpuinfo_mips *c)
 	if (config5 & MIPS_CONF5_CRCP)
 		elf_hwcap |= HWCAP_MIPS_CRC32;
 
+	if (cpu_has_mips_r6) {
+		/* Ensure the write to config5 above takes effect */
+		back_to_back_c0_hazard();
+
+		/* Check whether we successfully enabled MMID support */
+		config5 = read_c0_config5();
+		if (config5 & MIPS_CONF5_MI)
+			c->options |= MIPS_CPU_MMID;
+
+		/*
+		 * Warn if we've hardcoded cpu_has_mmid to a value unsuitable
+		 * for the CPU we're running on, or if CPUs in an SMP system
+		 * have inconsistent MMID support.
+		 */
+		WARN_ON(!!cpu_has_mmid != !!(config5 & MIPS_CONF5_MI));
+
+		if (cpu_has_mmid) {
+			write_c0_memorymapid(~0ul);
+			back_to_back_c0_hazard();
+			asid_mask = read_c0_memorymapid();
+
+			/*
+			 * We maintain a bitmap to track MMID allocation, and
+			 * need a sensible upper bound on the size of that
+			 * bitmap. The initial CPU with MMID support (I6500)
+			 * supports 16 bit MMIDs, which gives us an 8KiB
+			 * bitmap. The architecture recommends that hardware
+			 * support 32 bit MMIDs, which would give us a 512MiB
+			 * bitmap - that's too big in most cases.
+			 *
+			 * Cap MMID width at 16 bits for now & we can revisit
+			 * this if & when hardware supports anything wider.
+			 */
+			max_mmid_width = 16;
+			if (asid_mask > GENMASK(max_mmid_width - 1, 0)) {
+				pr_info("Capping MMID width at %d bits",
+					max_mmid_width);
+				asid_mask = GENMASK(max_mmid_width - 1, 0);
+			}
+
+			set_cpu_asid_mask(c, asid_mask);
+		}
+	}
+
 	return config5 & MIPS_CONF_M;
 }
 
diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index f9dbd95e1d68..6fd9e94fc87e 100644
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -39,6 +39,7 @@
 
 #include <linux/atomic.h>
 #include <asm/cpu.h>
+#include <asm/ginvt.h>
 #include <asm/processor.h>
 #include <asm/idle.h>
 #include <asm/r4k-timer.h>
@@ -482,6 +483,15 @@ static void flush_tlb_all_ipi(void *info)
 
 void flush_tlb_all(void)
 {
+	if (cpu_has_mmid) {
+		htw_stop();
+		ginvt_full();
+		sync_ginv();
+		instruction_hazard();
+		htw_start();
+		return;
+	}
+
 	on_each_cpu(flush_tlb_all_ipi, NULL, 1);
 }
 
@@ -530,7 +540,12 @@ void flush_tlb_mm(struct mm_struct *mm)
 {
 	preempt_disable();
 
-	if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {
+	if (cpu_has_mmid) {
+		/*
+		 * No need to worry about other CPUs - the ginvt in
+		 * drop_mmu_context() will be globalized.
+		 */
+	} else if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {
 		smp_on_other_tlbs(flush_tlb_mm_ipi, mm);
 	} else {
 		unsigned int cpu;
@@ -561,9 +576,26 @@ static void flush_tlb_range_ipi(void *info)
 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
 {
 	struct mm_struct *mm = vma->vm_mm;
+	unsigned long addr;
+	u32 old_mmid;
 
 	preempt_disable();
-	if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {
+	if (cpu_has_mmid) {
+		htw_stop();
+		old_mmid = read_c0_memorymapid();
+		write_c0_memorymapid(cpu_asid(0, mm));
+		mtc0_tlbw_hazard();
+		addr = round_down(start, PAGE_SIZE * 2);
+		end = round_up(end, PAGE_SIZE * 2);
+		do {
+			ginvt_va_mmid(addr);
+			sync_ginv();
+			addr += PAGE_SIZE * 2;
+		} while (addr < end);
+		write_c0_memorymapid(old_mmid);
+		instruction_hazard();
+		htw_start();
+	} else if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {
 		struct flush_tlb_data fd = {
 			.vma = vma,
 			.addr1 = start,
@@ -571,6 +603,7 @@ void flush_tlb_range(struct vm_area_struct *vma, unsigned long start, unsigned l
 		};
 
 		smp_on_other_tlbs(flush_tlb_range_ipi, &fd);
+		local_flush_tlb_range(vma, start, end);
 	} else {
 		unsigned int cpu;
 		int exec = vma->vm_flags & VM_EXEC;
@@ -585,8 +618,8 @@ void flush_tlb_range(struct vm_area_struct *vma, unsigned long start, unsigned l
 			if (cpu != smp_processor_id() && cpu_context(cpu, mm))
 				set_cpu_context(cpu, mm, !exec);
 		}
+		local_flush_tlb_range(vma, start, end);
 	}
-	local_flush_tlb_range(vma, start, end);
 	preempt_enable();
 }
 
@@ -616,14 +649,28 @@ static void flush_tlb_page_ipi(void *info)
 
 void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 {
+	u32 old_mmid;
+
 	preempt_disable();
-	if ((atomic_read(&vma->vm_mm->mm_users) != 1) || (current->mm != vma->vm_mm)) {
+	if (cpu_has_mmid) {
+		htw_stop();
+		old_mmid = read_c0_memorymapid();
+		write_c0_memorymapid(cpu_asid(0, vma->vm_mm));
+		mtc0_tlbw_hazard();
+		ginvt_va_mmid(page);
+		sync_ginv();
+		write_c0_memorymapid(old_mmid);
+		instruction_hazard();
+		htw_start();
+	} else if ((atomic_read(&vma->vm_mm->mm_users) != 1) ||
+		   (current->mm != vma->vm_mm)) {
 		struct flush_tlb_data fd = {
 			.vma = vma,
 			.addr1 = page,
 		};
 
 		smp_on_other_tlbs(flush_tlb_page_ipi, &fd);
+		local_flush_tlb_page(vma, page);
 	} else {
 		unsigned int cpu;
 
@@ -637,8 +684,8 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 			if (cpu != smp_processor_id() && cpu_context(cpu, vma->vm_mm))
 				set_cpu_context(cpu, vma->vm_mm, 1);
 		}
+		local_flush_tlb_page(vma, page);
 	}
-	local_flush_tlb_page(vma, page);
 	preempt_enable();
 }
 
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index c91097f7b32f..995249be64f1 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -2223,7 +2223,9 @@ void per_cpu_trap_init(bool is_boot_cpu)
 		cp0_fdc_irq = -1;
 	}
 
-	if (!cpu_data[cpu].asid_cache)
+	if (cpu_has_mmid)
+		cpu_data[cpu].asid_cache = 0;
+	else if (!cpu_data[cpu].asid_cache)
 		cpu_data[cpu].asid_cache = asid_first_version(cpu);
 
 	mmgrab(&init_mm);
diff --git a/arch/mips/kernel/unaligned.c b/arch/mips/kernel/unaligned.c
index 0ed20a64b285..76e33f940971 100644
--- a/arch/mips/kernel/unaligned.c
+++ b/arch/mips/kernel/unaligned.c
@@ -89,6 +89,7 @@
 #include <asm/fpu.h>
 #include <asm/fpu_emulator.h>
 #include <asm/inst.h>
+#include <asm/mmu_context.h>
 #include <linux/uaccess.h>
 
 #define STR(x)	__STR(x)