blob: 9c7c6824728963bb5ecee80d2c24da89de691787 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* TLB Management (flush/create/diagnostics) for ARC700
*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*
* vineetg: Aug 2011
* -Reintroduce duplicate PD fixup - some customer chips still have the issue
*
* vineetg: May 2011
* -No need to flush_cache_page( ) for each call to update_mmu_cache()
* some of the LMBench tests improved amazingly
* = page-fault thrice as fast (75 usec to 28 usec)
* = mmap twice as fast (9.6 msec to 4.6 msec),
* = fork (5.3 msec to 3.7 msec)
*
* vineetg: April 2011 :
* -MMU v3: PD{0,1} bits layout changed: They don't overlap anymore,
* helps avoid a shift when preparing PD0 from PTE
*
* vineetg: April 2011 : Preparing for MMU V3
* -MMU v2/v3 BCRs decoded differently
* -Remove TLB_SIZE hardcoding as it's variable now: 256 or 512
* -tlb_entry_erase( ) can be void
* -local_flush_tlb_range( ):
* = need not "ceil" @end
* = walks MMU only if range spans < 32 entries, as opposed to 256
*
* Vineetg: Sept 10th 2008
* -Changes related to MMU v2 (Rel 4.8)
*
* Vineetg: Aug 29th 2008
* -In TLB Flush operations (Metal Fix MMU) there is a explicit command to
* flush Micro-TLBS. If TLB Index Reg is invalid prior to TLBIVUTLB cmd,
* it fails. Thus need to load it with ANY valid value before invoking
* TLBIVUTLB cmd
*
* Vineetg: Aug 21th 2008:
* -Reduced the duration of IRQ lockouts in TLB Flush routines
* -Multiple copies of TLB erase code separated into a "single" function
* -In TLB Flush routines, interrupt disabling moved UP to retrieve ASID
* in interrupt-safe region.
*
* Vineetg: April 23rd Bug #93131
* Problem: tlb_flush_kernel_range() doesn't do anything if the range to
* flush is more than the size of TLB itself.
*
* Rahul Trivedi : Codito Technologies 2004
*/
#include <linux/module.h>
#include <linux/bug.h>
#include <linux/mm_types.h>
#include <asm/arcregs.h>
#include <asm/setup.h>
#include <asm/mmu_context.h>
#include <asm/mmu.h>
/* Need for ARC MMU v2
*
* ARC700 MMU-v1 had a Joint-TLB for Code and Data and is 2 way set-assoc.
* For a memcpy operation with 3 players (src/dst/code) such that all 3 pages
* map into same set, there would be contention for the 2 ways causing severe
* Thrashing.
*
* Although J-TLB is 2 way set assoc, ARC700 caches J-TLB into uTLBS which has
* much higher associativity. u-D-TLB is 8 ways, u-I-TLB is 4 ways.
* Given this, the thrashing problem should never happen because once the 3
* J-TLB entries are created (even though 3rd will knock out one of the prev
* two), the u-D-TLB and u-I-TLB will have what is required to accomplish memcpy
*
* Yet we still see the Thrashing because a J-TLB Write cause flush of u-TLBs.
* This is a simple design for keeping them in sync. So what do we do?
* The solution which James came up was pretty neat. It utilised the assoc
* of uTLBs by not invalidating always but only when absolutely necessary.
*
* - Existing TLB commands work as before
* - New command (TLBWriteNI) for TLB write without clearing uTLBs
* - New command (TLBIVUTLB) to invalidate uTLBs.
*
* The uTLBs need only be invalidated when pages are being removed from the
* OS page table. If a 'victim' TLB entry is being overwritten in the main TLB
* as a result of a miss, the removed entry is still allowed to exist in the
* uTLBs as it is still valid and present in the OS page table. This allows the
* full associativity of the uTLBs to hide the limited associativity of the main
* TLB.
*
* During a miss handler, the new "TLBWriteNI" command is used to load
* entries without clearing the uTLBs.
*
* When the OS page table is updated, TLB entries that may be associated with a
* removed page are removed (flushed) from the TLB using TLBWrite. In this
* circumstance, the uTLBs must also be cleared. This is done by using the
* existing TLBWrite command. An explicit IVUTLB is also required for those
* corner cases when TLBWrite was not executed at all because the corresp
* J-TLB entry got evicted/replaced.
*/
/* A copy of the ASID from the PID reg is kept in asid_cache */
DEFINE_PER_CPU(unsigned int, asid_cache) = MM_CTXT_FIRST_CYCLE;
static int __read_mostly pae_exists;
/*
* Utility Routine to erase a J-TLB entry
* Caller needs to setup Index Reg (manually or via getIndex)
*/
static inline void __tlb_entry_erase(void)
{
write_aux_reg(ARC_REG_TLBPD1, 0);
if (is_pae40_enabled())
write_aux_reg(ARC_REG_TLBPD1HI, 0);
write_aux_reg(ARC_REG_TLBPD0, 0);
write_aux_reg(ARC_REG_TLBCOMMAND, TLBWrite);
}
static void utlb_invalidate(void)
{
#if (CONFIG_ARC_MMU_VER >= 2)
#if (CONFIG_ARC_MMU_VER == 2)
/* MMU v2 introduced the uTLB Flush command.
* There was however an obscure hardware bug, where uTLB flush would
* fail when a prior probe for J-TLB (both totally unrelated) would
* return lkup err - because the entry didn't exist in MMU.
* The Workaround was to set Index reg with some valid value, prior to
* flush. This was fixed in MMU v3
*/
unsigned int idx;
/* make sure INDEX Reg is valid */
idx = read_aux_reg(ARC_REG_TLBINDEX);
/* If not write some dummy val */
if (unlikely(idx & TLB_LKUP_ERR))
write_aux_reg(ARC_REG_TLBINDEX, 0xa);
#endif
write_aux_reg(ARC_REG_TLBCOMMAND, TLBIVUTLB);
#endif
}
#if (CONFIG_ARC_MMU_VER < 4)
static inline unsigned int tlb_entry_lkup(unsigned long vaddr_n_asid)
{
unsigned int idx;
write_aux_reg(ARC_REG_TLBPD0, vaddr_n_asid);
write_aux_reg(ARC_REG_TLBCOMMAND, TLBProbe);
idx = read_aux_reg(ARC_REG_TLBINDEX);
return idx;
}
static void tlb_entry_erase(unsigned int vaddr_n_asid)
{
unsigned int idx;
/* Locate the TLB entry for this vaddr + ASID */
idx = tlb_entry_lkup(vaddr_n_asid);
/* No error means entry found, zero it out */
if (likely(!(idx & TLB_LKUP_ERR))) {
__tlb_entry_erase();
} else {
/* Duplicate entry error */
WARN(idx == TLB_DUP_ERR, "Probe returned Dup PD for %x\n",
vaddr_n_asid);
}
}
static void tlb_entry_insert(unsigned int pd0, pte_t pd1)
{
unsigned int idx;
/*
* First verify if entry for this vaddr+ASID already exists
* This also sets up PD0 (vaddr, ASID..) for final commit
*/
idx = tlb_entry_lkup(pd0);
/*
* If Not already present get a free slot from MMU.
* Otherwise, Probe would have located the entry and set INDEX Reg
* with existing location. This will cause Write CMD to over-write
* existing entry with new PD0 and PD1
*/
if (likely(idx & TLB_LKUP_ERR))
write_aux_reg(ARC_REG_TLBCOMMAND, TLBGetIndex);
/* setup the other half of TLB entry (pfn, rwx..) */
write_aux_reg(ARC_REG_TLBPD1, pd1);
/*
* Commit the Entry to MMU
* It doesn't sound safe to use the TLBWriteNI cmd here
* which doesn't flush uTLBs. I'd rather be safe than sorry.
*/
write_aux_reg(ARC_REG_TLBCOMMAND, TLBWrite);
}
#else /* CONFIG_ARC_MMU_VER >= 4) */
static void tlb_entry_erase(unsigned int vaddr_n_asid)
{
write_aux_reg(ARC_REG_TLBPD0, vaddr_n_asid | _PAGE_PRESENT);
write_aux_reg(ARC_REG_TLBCOMMAND, TLBDeleteEntry);
}
static void tlb_entry_insert(unsigned int pd0, pte_t pd1)
{
write_aux_reg(ARC_REG_TLBPD0, pd0);
write_aux_reg(ARC_REG_TLBPD1, pd1);
if (is_pae40_enabled())
write_aux_reg(ARC_REG_TLBPD1HI, (u64)pd1 >> 32);
write_aux_reg(ARC_REG_TLBCOMMAND, TLBInsertEntry);
}
#endif
/*
* Un-conditionally (without lookup) erase the entire MMU contents
*/
noinline void local_flush_tlb_all(void)
{
struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
unsigned long flags;
unsigned int entry;
int num_tlb = mmu->sets * mmu->ways;
local_irq_save(flags);
/* Load PD0 and PD1 with template for a Blank Entry */
write_aux_reg(ARC_REG_TLBPD1, 0);
if (is_pae40_enabled())
write_aux_reg(ARC_REG_TLBPD1HI, 0);
write_aux_reg(ARC_REG_TLBPD0, 0);
for (entry = 0; entry < num_tlb; entry++) {
/* write this entry to the TLB */
write_aux_reg(ARC_REG_TLBINDEX, entry);
write_aux_reg(ARC_REG_TLBCOMMAND, TLBWriteNI);
}
if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
const int stlb_idx = 0x800;
/* Blank sTLB entry */
write_aux_reg(ARC_REG_TLBPD0, _PAGE_HW_SZ);
for (entry = stlb_idx; entry < stlb_idx + 16; entry++) {
write_aux_reg(ARC_REG_TLBINDEX, entry);
write_aux_reg(ARC_REG_TLBCOMMAND, TLBWriteNI);
}
}
utlb_invalidate();
local_irq_restore(flags);
}
/*
* Flush the entire MM for userland. The fastest way is to move to Next ASID
*/
noinline void local_flush_tlb_mm(struct mm_struct *mm)
{
/*
* Small optimisation courtesy IA64
* flush_mm called during fork,exit,munmap etc, multiple times as well.
* Only for fork( ) do we need to move parent to a new MMU ctxt,
* all other cases are NOPs, hence this check.
*/
if (atomic_read(&mm->mm_users) == 0)
return;
/*
* - Move to a new ASID, but only if the mm is still wired in
* (Android Binder ended up calling this for vma->mm != tsk->mm,
* causing h/w - s/w ASID to get out of sync)
* - Also get_new_mmu_context() new implementation allocates a new
* ASID only if it is not allocated already - so unallocate first
*/
destroy_context(mm);
if (current->mm == mm)
get_new_mmu_context(mm);
}
/*
* Flush a Range of TLB entries for userland.
* @start is inclusive, while @end is exclusive
* Difference between this and Kernel Range Flush is
* -Here the fastest way (if range is too large) is to move to next ASID
* without doing any explicit Shootdown
* -In case of kernel Flush, entry has to be shot down explicitly
*/
void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end)
{
const unsigned int cpu = smp_processor_id();
unsigned long flags;
/* If range @start to @end is more than 32 TLB entries deep,
* its better to move to a new ASID rather than searching for
* individual entries and then shooting them down
*
* The calc above is rough, doesn't account for unaligned parts,
* since this is heuristics based anyways
*/
if (unlikely((end - start) >= PAGE_SIZE * 32)) {
local_flush_tlb_mm(vma->vm_mm);
return;
}
/*
* @start moved to page start: this alone suffices for checking
* loop end condition below, w/o need for aligning @end to end
* e.g. 2000 to 4001 will anyhow loop twice
*/
start &= PAGE_MASK;
local_irq_save(flags);
if (asid_mm(vma->vm_mm, cpu) != MM_CTXT_NO_ASID) {
while (start < end) {
tlb_entry_erase(start | hw_pid(vma->vm_mm, cpu));
start += PAGE_SIZE;
}
}
local_irq_restore(flags);
}
/* Flush the kernel TLB entries - vmalloc/modules (Global from MMU perspective)
* @start, @end interpreted as kvaddr
* Interestingly, shared TLB entries can also be flushed using just
* @start,@end alone (interpreted as user vaddr), although technically SASID
* is also needed. However our smart TLbProbe lookup takes care of that.
*/
void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
unsigned long flags;
/* exactly same as above, except for TLB entry not taking ASID */
if (unlikely((end - start) >= PAGE_SIZE * 32)) {
local_flush_tlb_all();
return;
}
start &= PAGE_MASK;
local_irq_save(flags);
while (start < end) {
tlb_entry_erase(start);
start += PAGE_SIZE;
}
local_irq_restore(flags);
}
/*
* Delete TLB entry in MMU for a given page (??? address)
* NOTE One TLB entry contains translation for single PAGE
*/
void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
{
const unsigned int cpu = smp_processor_id();
unsigned long flags;
/* Note that it is critical that interrupts are DISABLED between
* checking the ASID and using it flush the TLB entry
*/
local_irq_save(flags);
if (asid_mm(vma->vm_mm, cpu) != MM_CTXT_NO_ASID) {
tlb_entry_erase((page & PAGE_MASK) | hw_pid(vma->vm_mm, cpu));
}
local_irq_restore(flags);
}
#ifdef CONFIG_SMP
struct tlb_args {
struct vm_area_struct *ta_vma;
unsigned long ta_start;
unsigned long ta_end;
};
static inline void ipi_flush_tlb_page(void *arg)
{
struct tlb_args *ta = arg;
local_flush_tlb_page(ta->ta_vma, ta->ta_start);
}
static inline void ipi_flush_tlb_range(void *arg)
{
struct tlb_args *ta = arg;
local_flush_tlb_range(ta->ta_vma, ta->ta_start, ta->ta_end);
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static inline void ipi_flush_pmd_tlb_range(void *arg)
{
struct tlb_args *ta = arg;
local_flush_pmd_tlb_range(ta->ta_vma, ta->ta_start, ta->ta_end);
}
#endif
static inline void ipi_flush_tlb_kernel_range(void *arg)
{
struct tlb_args *ta = (struct tlb_args *)arg;
local_flush_tlb_kernel_range(ta->ta_start, ta->ta_end);
}
void flush_tlb_all(void)
{
on_each_cpu((smp_call_func_t)local_flush_tlb_all, NULL, 1);
}
void flush_tlb_mm(struct mm_struct *mm)
{
on_each_cpu_mask(mm_cpumask(mm), (smp_call_func_t)local_flush_tlb_mm,
mm, 1);
}
void flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
{
struct tlb_args ta = {
.ta_vma = vma,
.ta_start = uaddr
};
on_each_cpu_mask(mm_cpumask(vma->vm_mm), ipi_flush_tlb_page, &ta, 1);
}
void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end)
{
struct tlb_args ta = {
.ta_vma = vma,
.ta_start = start,
.ta_end = end
};
on_each_cpu_mask(mm_cpumask(vma->vm_mm), ipi_flush_tlb_range, &ta, 1);
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end)
{
struct tlb_args ta = {
.ta_vma = vma,
.ta_start = start,
.ta_end = end
};
on_each_cpu_mask(mm_cpumask(vma->vm_mm), ipi_flush_pmd_tlb_range, &ta, 1);
}
#endif
void flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
struct tlb_args ta = {
.ta_start = start,
.ta_end = end
};
on_each_cpu(ipi_flush_tlb_kernel_range, &ta, 1);
}
#endif
/*
* Routine to create a TLB entry
*/
void create_tlb(struct vm_area_struct *vma, unsigned long vaddr, pte_t *ptep)
{
unsigned long flags;
unsigned int asid_or_sasid, rwx;
unsigned long pd0;
pte_t pd1;
/*
* create_tlb() assumes that current->mm == vma->mm, since
* -it ASID for TLB entry is fetched from MMU ASID reg (valid for curr)
* -completes the lazy write to SASID reg (again valid for curr tsk)
*
* 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"
*
* Lets see the use cases when current->mm != vma->mm and we land here
* 1. execve->copy_strings()->__get_user_pages->handle_mm_fault
* Here VM wants to pre-install a TLB entry for user stack while
* current->mm still points to pre-execve mm (hence the condition).
* However the stack vaddr is soon relocated (randomization) and
* move_page_tables() tries to undo that TLB entry.
* Thus not creating TLB entry is not any worse.
*
* 2. ptrace(POKETEXT) causes a CoW - debugger(current) inserting a
* breakpoint in debugged task. Not creating a TLB now is not
* performance critical.
*
* Both the cases above are not good enough for code churn.
*/
if (current->active_mm != vma->vm_mm)
return;
local_irq_save(flags);
tlb_paranoid_check(asid_mm(vma->vm_mm, smp_processor_id()), vaddr);
vaddr &= PAGE_MASK;
/* update this PTE credentials */
pte_val(*ptep) |= (_PAGE_PRESENT | _PAGE_ACCESSED);
/* Create HW TLB(PD0,PD1) from PTE */
/* ASID for this task */
asid_or_sasid = read_aux_reg(ARC_REG_PID) & 0xff;
pd0 = vaddr | asid_or_sasid | (pte_val(*ptep) & PTE_BITS_IN_PD0);
/*
* ARC MMU provides fully orthogonal access bits for K/U mode,
* however Linux only saves 1 set to save PTE real-estate
* Here we convert 3 PTE bits into 6 MMU bits:
* -Kernel only entries have Kr Kw Kx 0 0 0
* -User entries have mirrored K and U bits
*/
rwx = pte_val(*ptep) & PTE_BITS_RWX;
if (pte_val(*ptep) & _PAGE_GLOBAL)
rwx <<= 3; /* r w x => Kr Kw Kx 0 0 0 */
else
rwx |= (rwx << 3); /* r w x => Kr Kw Kx Ur Uw Ux */
pd1 = rwx | (pte_val(*ptep) & PTE_BITS_NON_RWX_IN_PD1);
tlb_entry_insert(pd0, pd1);
local_irq_restore(flags);
}
/*
* Called at the end of pagefault, for a userspace mapped page
* -pre-install the corresponding TLB entry into MMU
* -Finalize the delayed D-cache flush of kernel mapping of page due to
* flush_dcache_page(), copy_user_page()
*
* Note that flush (when done) involves both WBACK - so physical page is
* in sync as well as INV - so any non-congruent aliases don't remain
*/
void update_mmu_cache(struct vm_area_struct *vma, unsigned long vaddr_unaligned,
pte_t *ptep)
{
unsigned long vaddr = vaddr_unaligned & PAGE_MASK;
phys_addr_t paddr = pte_val(*ptep) & PAGE_MASK_PHYS;
struct page *page = pfn_to_page(pte_pfn(*ptep));
create_tlb(vma, vaddr, ptep);
if (page == ZERO_PAGE(0)) {
return;
}
/*
* Exec page : Independent of aliasing/page-color considerations,
* since icache doesn't snoop dcache on ARC, any dirty
* K-mapping of a code page needs to be wback+inv so that
* icache fetch by userspace sees code correctly.
* !EXEC page: If K-mapping is NOT congruent to U-mapping, flush it
* so userspace sees the right data.
* (Avoids the flush for Non-exec + congruent mapping case)
*/
if ((vma->vm_flags & VM_EXEC) ||
addr_not_cache_congruent(paddr, vaddr)) {
int dirty = !test_and_set_bit(PG_dc_clean, &page->flags);
if (dirty) {
/* wback + inv dcache lines (K-mapping) */
__flush_dcache_page(paddr, paddr);
/* invalidate any existing icache lines (U-mapping) */
if (vma->vm_flags & VM_EXEC)
__inv_icache_page(paddr, vaddr);
}
}
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
/*
* MMUv4 in HS38x cores supports Super Pages which are basis for Linux THP
* support.
*
* Normal and Super pages can co-exist (ofcourse not overlap) in TLB with a
* new bit "SZ" in TLB page descriptor to distinguish between them.
* Super Page size is configurable in hardware (4K to 16M), but fixed once
* RTL builds.
*
* The exact THP size a Linux configuration will support is a function of:
* - MMU page size (typical 8K, RTL fixed)
* - software page walker address split between PGD:PTE:PFN (typical
* 11:8:13, but can be changed with 1 line)
* So for above default, THP size supported is 8K * (2^8) = 2M
*
* Default Page Walker is 2 levels, PGD:PTE:PFN, which in THP regime
* reduces to 1 level (as PTE is folded into PGD and canonically referred
* to as PMD).
* Thus THP PMD accessors are implemented in terms of PTE (just like sparc)
*/
void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr,
pmd_t *pmd)
{
pte_t pte = __pte(pmd_val(*pmd));
update_mmu_cache(vma, addr, &pte);
}
void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
pgtable_t pgtable)
{
struct list_head *lh = (struct list_head *) pgtable;
assert_spin_locked(&mm->page_table_lock);
/* FIFO */
if (!pmd_huge_pte(mm, pmdp))
INIT_LIST_HEAD(lh);
else
list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
pmd_huge_pte(mm, pmdp) = pgtable;
}
pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
{
struct list_head *lh;
pgtable_t pgtable;
assert_spin_locked(&mm->page_table_lock);
pgtable = pmd_huge_pte(mm, pmdp);
lh = (struct list_head *) pgtable;
if (list_empty(lh))
pmd_huge_pte(mm, pmdp) = NULL;
else {
pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
list_del(lh);
}
pte_val(pgtable[0]) = 0;
pte_val(pgtable[1]) = 0;
return pgtable;
}
void local_flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end)
{
unsigned int cpu;
unsigned long flags;
local_irq_save(flags);
cpu = smp_processor_id();
if (likely(asid_mm(vma->vm_mm, cpu) != MM_CTXT_NO_ASID)) {
unsigned int asid = hw_pid(vma->vm_mm, cpu);
/* No need to loop here: this will always be for 1 Huge Page */
tlb_entry_erase(start | _PAGE_HW_SZ | asid);
}
local_irq_restore(flags);
}
#endif
/* Read the Cache Build Configuration Registers, Decode them and save into
* the cpuinfo structure for later use.
* No Validation is done here, simply read/convert the BCRs
*/
void read_decode_mmu_bcr(void)
{
struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
unsigned int tmp;
struct bcr_mmu_1_2 {
#ifdef CONFIG_CPU_BIG_ENDIAN
unsigned int ver:8, ways:4, sets:4, u_itlb:8, u_dtlb:8;
#else
unsigned int u_dtlb:8, u_itlb:8, sets:4, ways:4, ver:8;
#endif
} *mmu2;
struct bcr_mmu_3 {
#ifdef CONFIG_CPU_BIG_ENDIAN
unsigned int ver:8, ways:4, sets:4, res:3, sasid:1, pg_sz:4,
u_itlb:4, u_dtlb:4;
#else
unsigned int u_dtlb:4, u_itlb:4, pg_sz:4, sasid:1, res:3, sets:4,
ways:4, ver:8;
#endif
} *mmu3;
struct bcr_mmu_4 {
#ifdef CONFIG_CPU_BIG_ENDIAN
unsigned int ver:8, sasid:1, sz1:4, sz0:4, res:2, pae:1,
n_ways:2, n_entry:2, n_super:2, u_itlb:3, u_dtlb:3;
#else
/* DTLB ITLB JES JE JA */
unsigned int u_dtlb:3, u_itlb:3, n_super:2, n_entry:2, n_ways:2,
pae:1, res:2, sz0:4, sz1:4, sasid:1, ver:8;
#endif
} *mmu4;
tmp = read_aux_reg(ARC_REG_MMU_BCR);
mmu->ver = (tmp >> 24);
if (is_isa_arcompact()) {
if (mmu->ver <= 2) {
mmu2 = (struct bcr_mmu_1_2 *)&tmp;
mmu->pg_sz_k = TO_KB(0x2000);
mmu->sets = 1 << mmu2->sets;
mmu->ways = 1 << mmu2->ways;
mmu->u_dtlb = mmu2->u_dtlb;
mmu->u_itlb = mmu2->u_itlb;
} else {
mmu3 = (struct bcr_mmu_3 *)&tmp;
mmu->pg_sz_k = 1 << (mmu3->pg_sz - 1);
mmu->sets = 1 << mmu3->sets;
mmu->ways = 1 << mmu3->ways;
mmu->u_dtlb = mmu3->u_dtlb;
mmu->u_itlb = mmu3->u_itlb;
mmu->sasid = mmu3->sasid;
}
} else {
mmu4 = (struct bcr_mmu_4 *)&tmp;
mmu->pg_sz_k = 1 << (mmu4->sz0 - 1);
mmu->s_pg_sz_m = 1 << (mmu4->sz1 - 11);
mmu->sets = 64 << mmu4->n_entry;
mmu->ways = mmu4->n_ways * 2;
mmu->u_dtlb = mmu4->u_dtlb * 4;
mmu->u_itlb = mmu4->u_itlb * 4;
mmu->sasid = mmu4->sasid;
pae_exists = mmu->pae = mmu4->pae;
}
}
char *arc_mmu_mumbojumbo(int cpu_id, char *buf, int len)
{
int n = 0;
struct cpuinfo_arc_mmu *p_mmu = &cpuinfo_arc700[cpu_id].mmu;
char super_pg[64] = "";
if (p_mmu->s_pg_sz_m)
scnprintf(super_pg, 64, "%dM Super Page %s",
p_mmu->s_pg_sz_m,
IS_USED_CFG(CONFIG_TRANSPARENT_HUGEPAGE));
n += scnprintf(buf + n, len - n,
"MMU [v%x]\t: %dk PAGE, %sJTLB %d (%dx%d), uDTLB %d, uITLB %d%s%s\n",
p_mmu->ver, p_mmu->pg_sz_k, super_pg,
p_mmu->sets * p_mmu->ways, p_mmu->sets, p_mmu->ways,
p_mmu->u_dtlb, p_mmu->u_itlb,
IS_AVAIL2(p_mmu->pae, ", PAE40 ", CONFIG_ARC_HAS_PAE40));
return buf;
}
int pae40_exist_but_not_enab(void)
{
return pae_exists && !is_pae40_enabled();
}
void arc_mmu_init(void)
{
struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
char str[256];
int compat = 0;
pr_info("%s", arc_mmu_mumbojumbo(0, str, sizeof(str)));
/*
* Can't be done in processor.h due to header include dependencies
*/
BUILD_BUG_ON(!IS_ALIGNED((CONFIG_ARC_KVADDR_SIZE << 20), PMD_SIZE));
/*
* stack top size sanity check,
* Can't be done in processor.h due to header include dependencies
*/
BUILD_BUG_ON(!IS_ALIGNED(STACK_TOP, PMD_SIZE));
/*
* Ensure that MMU features assumed by kernel exist in hardware.
* For older ARC700 cpus, it has to be exact match, since the MMU
* revisions were not backwards compatible (MMUv3 TLB layout changed
* so even if kernel for v2 didn't use any new cmds of v3, it would
* still not work.
* For HS cpus, MMUv4 was baseline and v5 is backwards compatible
* (will run older software).
*/
if (is_isa_arcompact() && mmu->ver == CONFIG_ARC_MMU_VER)
compat = 1;
else if (is_isa_arcv2() && mmu->ver >= CONFIG_ARC_MMU_VER)
compat = 1;
if (!compat) {
panic("MMU ver %d doesn't match kernel built for %d...\n",
mmu->ver, CONFIG_ARC_MMU_VER);
}
if (mmu->pg_sz_k != TO_KB(PAGE_SIZE))
panic("MMU pg size != PAGE_SIZE (%luk)\n", TO_KB(PAGE_SIZE));
if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
mmu->s_pg_sz_m != TO_MB(HPAGE_PMD_SIZE))
panic("MMU Super pg size != Linux HPAGE_PMD_SIZE (%luM)\n",
(unsigned long)TO_MB(HPAGE_PMD_SIZE));
if (IS_ENABLED(CONFIG_ARC_HAS_PAE40) && !mmu->pae)
panic("Hardware doesn't support PAE40\n");
/* Enable the MMU */
write_aux_reg(ARC_REG_PID, MMU_ENABLE);
/* In smp we use this reg for interrupt 1 scratch */
#ifdef ARC_USE_SCRATCH_REG
/* swapper_pg_dir is the pgd for the kernel, used by vmalloc */
write_aux_reg(ARC_REG_SCRATCH_DATA0, swapper_pg_dir);
#endif
if (pae40_exist_but_not_enab())
write_aux_reg(ARC_REG_TLBPD1HI, 0);
}
/*
* TLB Programmer's Model uses Linear Indexes: 0 to {255, 511} for 128 x {2,4}
* The mapping is Column-first.
* --------------------- -----------
* |way0|way1|way2|way3| |way0|way1|
* --------------------- -----------
* [set0] | 0 | 1 | 2 | 3 | | 0 | 1 |
* [set1] | 4 | 5 | 6 | 7 | | 2 | 3 |
* ~ ~ ~ ~
* [set127] | 508| 509| 510| 511| | 254| 255|
* --------------------- -----------
* For normal operations we don't(must not) care how above works since
* MMU cmd getIndex(vaddr) abstracts that out.
* However for walking WAYS of a SET, we need to know this
*/
#define SET_WAY_TO_IDX(mmu, set, way) ((set) * mmu->ways + (way))
/* Handling of Duplicate PD (TLB entry) in MMU.
* -Could be due to buggy customer tapeouts or obscure kernel bugs
* -MMU complaints not at the time of duplicate PD installation, but at the
* time of lookup matching multiple ways.
* -Ideally these should never happen - but if they do - workaround by deleting
* the duplicate one.
* -Knob to be verbose abt it.(TODO: hook them up to debugfs)
*/
volatile int dup_pd_silent; /* Be silent abt it or complain (default) */
void do_tlb_overlap_fault(unsigned long cause, unsigned long address,
struct pt_regs *regs)
{
struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
unsigned long flags;
int set, n_ways = mmu->ways;
n_ways = min(n_ways, 4);
BUG_ON(mmu->ways > 4);
local_irq_save(flags);
/* loop thru all sets of TLB */
for (set = 0; set < mmu->sets; set++) {
int is_valid, way;
unsigned int pd0[4];
/* read out all the ways of current set */
for (way = 0, is_valid = 0; way < n_ways; way++) {
write_aux_reg(ARC_REG_TLBINDEX,
SET_WAY_TO_IDX(mmu, set, way));
write_aux_reg(ARC_REG_TLBCOMMAND, TLBRead);
pd0[way] = read_aux_reg(ARC_REG_TLBPD0);
is_valid |= pd0[way] & _PAGE_PRESENT;
pd0[way] &= PAGE_MASK;
}
/* If all the WAYS in SET are empty, skip to next SET */
if (!is_valid)
continue;
/* Scan the set for duplicate ways: needs a nested loop */
for (way = 0; way < n_ways - 1; way++) {
int n;
if (!pd0[way])
continue;
for (n = way + 1; n < n_ways; n++) {
if (pd0[way] != pd0[n])
continue;
if (!dup_pd_silent)
pr_info("Dup TLB PD0 %08x @ set %d ways %d,%d\n",
pd0[way], set, way, n);
/*
* clear entry @way and not @n.
* This is critical to our optimised loop
*/
pd0[way] = 0;
write_aux_reg(ARC_REG_TLBINDEX,
SET_WAY_TO_IDX(mmu, set, way));
__tlb_entry_erase();
}
}
}
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