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haukehauke
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kernel: Fix boot of realtek rtl838x
Revert two patches from upstream Linux: gregkh/linux@135713c gregkh/linux@231ac95 This fixes a boot hang on realtek rtl838x switches. This is the last printed message: Inode-cache hash table entries: 8192 (order: 3, 32768 bytes, linear) Thread on mips mailing list: https://lore.kernel.org/linux-mips/[email protected]/T/#u Link: openwrt/openwrt#21166 Signed-off-by: Hauke Mehrtens <[email protected]>
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‎target/linux/generic/pending-6.6/360-Revert-MIPS-mm-kmalloc-tlb_vpn-array-to-avoid-stack-.patch‎

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Hauke Mehrtens <[email protected]>
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Date: Mon, 15 Dec 2025 01:45:07 +0100
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Subject: Revert "MIPS: mm: kmalloc tlb_vpn array to avoid stack overflow"
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This reverts commit 231ac951fabae2aaed8b2c00b4a097107be49c8c.
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---
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arch/mips/mm/tlb-r4k.c | 18 ++----------------
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1 file changed, 2 insertions(+), 16 deletions(-)
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--- a/arch/mips/mm/tlb-r4k.c
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+++ b/arch/mips/mm/tlb-r4k.c
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@@ -12,7 +12,6 @@
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#include <linux/init.h>
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#include <linux/sched.h>
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#include <linux/smp.h>
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-#include <linux/memblock.h>
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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#include <linux/export.h>
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@@ -521,26 +520,17 @@ static int r4k_vpn_cmp(const void *a, co
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* Initialise all TLB entries with unique values that do not clash with
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* what we have been handed over and what we'll be using ourselves.
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*/
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-static void __ref r4k_tlb_uniquify(void)
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+static void r4k_tlb_uniquify(void)
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{
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+ unsigned long tlb_vpns[1 << MIPS_CONF1_TLBS_SIZE];
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int tlbsize = current_cpu_data.tlbsize;
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- bool use_slab = slab_is_available();
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int start = num_wired_entries();
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- phys_addr_t tlb_vpn_size;
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- unsigned long *tlb_vpns;
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unsigned long vpn_mask;
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int cnt, ent, idx, i;
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vpn_mask = GENMASK(cpu_vmbits - 1, 13);
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vpn_mask |= IS_ENABLED(CONFIG_64BIT) ? 3ULL << 62 : 1 << 31;
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- tlb_vpn_size = tlbsize * sizeof(*tlb_vpns);
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- tlb_vpns = (use_slab ?
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- kmalloc(tlb_vpn_size, GFP_KERNEL) :
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- memblock_alloc_raw(tlb_vpn_size, sizeof(*tlb_vpns)));
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- if (WARN_ON(!tlb_vpns))
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- return; /* Pray local_flush_tlb_all() is good enough. */
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-
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htw_stop();
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for (i = start, cnt = 0; i < tlbsize; i++, cnt++) {
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@@ -593,10 +583,6 @@ static void __ref r4k_tlb_uniquify(void)
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tlbw_use_hazard();
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htw_start();
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flush_micro_tlb();
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- if (use_slab)
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- kfree(tlb_vpns);
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- else
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- memblock_free(tlb_vpns, tlb_vpn_size);
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}
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/*

‎target/linux/generic/pending-6.6/361-Revert-MIPS-mm-Prevent-a-TLB-shutdown-on-initial-uni.patch‎

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Hauke Mehrtens <[email protected]>
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Date: Mon, 15 Dec 2025 01:45:20 +0100
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Subject: Revert "MIPS: mm: Prevent a TLB shutdown on initial uniquification"
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This reverts commit 135713cd0751bf296e515f5fdec234320f73bbd8.
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---
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arch/mips/mm/tlb-r4k.c | 100 +++++++++++++++--------------------------
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1 file changed, 37 insertions(+), 63 deletions(-)
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--- a/arch/mips/mm/tlb-r4k.c
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+++ b/arch/mips/mm/tlb-r4k.c
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@@ -15,7 +15,6 @@
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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#include <linux/export.h>
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-#include <linux/sort.h>
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#include <asm/cpu.h>
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#include <asm/cpu-type.h>
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@@ -507,79 +506,55 @@ static int __init set_ntlb(char *str)
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__setup("ntlb=", set_ntlb);
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-
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-/* Comparison function for EntryHi VPN fields. */
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-static int r4k_vpn_cmp(const void *a, const void *b)
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-{
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- long v = *(unsigned long *)a - *(unsigned long *)b;
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- int s = sizeof(long) > sizeof(int) ? sizeof(long) * 8 - 1: 0;
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- return s ? (v != 0) | v >> s : v;
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-}
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-
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-/*
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- * Initialise all TLB entries with unique values that do not clash with
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- * what we have been handed over and what we'll be using ourselves.
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- */
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+/* Initialise all TLB entries with unique values */
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static void r4k_tlb_uniquify(void)
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{
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- unsigned long tlb_vpns[1 << MIPS_CONF1_TLBS_SIZE];
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- int tlbsize = current_cpu_data.tlbsize;
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- int start = num_wired_entries();
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- unsigned long vpn_mask;
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- int cnt, ent, idx, i;
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-
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- vpn_mask = GENMASK(cpu_vmbits - 1, 13);
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- vpn_mask |= IS_ENABLED(CONFIG_64BIT) ? 3ULL << 62 : 1 << 31;
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+ int entry = num_wired_entries();
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htw_stop();
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+ write_c0_entrylo0(0);
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+ write_c0_entrylo1(0);
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- for (i = start, cnt = 0; i < tlbsize; i++, cnt++) {
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- unsigned long vpn;
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+ while (entry < current_cpu_data.tlbsize) {
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+ unsigned long asid_mask = cpu_asid_mask(&current_cpu_data);
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+ unsigned long asid = 0;
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+ int idx;
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- write_c0_index(i);
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- mtc0_tlbr_hazard();
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- tlb_read();
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- tlb_read_hazard();
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- vpn = read_c0_entryhi();
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- vpn &= vpn_mask & PAGE_MASK;
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- tlb_vpns[cnt] = vpn;
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+ /* Skip wired MMID to make ginvt_mmid work */
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+ if (cpu_has_mmid)
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+ asid = MMID_KERNEL_WIRED + 1;
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- /* Prevent any large pages from overlapping regular ones. */
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- write_c0_pagemask(read_c0_pagemask() & PM_DEFAULT_MASK);
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+ /* Check for match before using UNIQUE_ENTRYHI */
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+ do {
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+ if (cpu_has_mmid) {
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+ write_c0_memorymapid(asid);
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+ write_c0_entryhi(UNIQUE_ENTRYHI(entry));
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+ } else {
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+ write_c0_entryhi(UNIQUE_ENTRYHI(entry) | asid);
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+ }
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+ mtc0_tlbw_hazard();
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+ tlb_probe();
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+ tlb_probe_hazard();
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+ idx = read_c0_index();
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+ /* No match or match is on current entry */
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+ if (idx < 0 || idx == entry)
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+ break;
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+ /*
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+ * If we hit a match, we need to try again with
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+ * a different ASID.
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+ */
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+ asid++;
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+ } while (asid < asid_mask);
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+
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+ if (idx >= 0 && idx != entry)
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+ panic("Unable to uniquify TLB entry %d", idx);
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+
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+ write_c0_index(entry);
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mtc0_tlbw_hazard();
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tlb_write_indexed();
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- tlbw_use_hazard();
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+ entry++;
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}
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- sort(tlb_vpns, cnt, sizeof(tlb_vpns[0]), r4k_vpn_cmp, NULL);
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-
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- write_c0_pagemask(PM_DEFAULT_MASK);
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- write_c0_entrylo0(0);
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- write_c0_entrylo1(0);
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-
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- idx = 0;
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- ent = tlbsize;
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- for (i = start; i < tlbsize; i++)
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- while (1) {
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- unsigned long entryhi, vpn;
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-
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- entryhi = UNIQUE_ENTRYHI(ent);
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- vpn = entryhi & vpn_mask & PAGE_MASK;
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-
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- if (idx >= cnt || vpn < tlb_vpns[idx]) {
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- write_c0_entryhi(entryhi);
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- write_c0_index(i);
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- mtc0_tlbw_hazard();
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- tlb_write_indexed();
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- ent++;
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- break;
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- } else if (vpn == tlb_vpns[idx]) {
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- ent++;
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- } else {
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- idx++;
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- }
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- }
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-
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tlbw_use_hazard();
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htw_start();
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flush_micro_tlb();
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@@ -625,7 +600,6 @@ static void r4k_tlb_configure(void)
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/* From this point on the ARC firmware is dead. */
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r4k_tlb_uniquify();
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- local_flush_tlb_all();
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/* Did I tell you that ARC SUCKS? */
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}

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