From b22da3d8526a935aa31e086e63f60ff3246cb61c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Sat, 09 Dec 2023 07:24:11 +0000
Subject: [PATCH] add stmac read mac form eeprom
---
kernel/arch/arm64/mm/context.c | 225 ++++++++++++++++++++++++++++++++++++++++++++++---------
1 files changed, 187 insertions(+), 38 deletions(-)
diff --git a/kernel/arch/arm64/mm/context.c b/kernel/arch/arm64/mm/context.c
index c127f94..001737a 100644
--- a/kernel/arch/arm64/mm/context.c
+++ b/kernel/arch/arm64/mm/context.c
@@ -1,22 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* Based on arch/arm/mm/context.c
*
* Copyright (C) 2002-2003 Deep Blue Solutions Ltd, all rights reserved.
* Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/sched.h>
#include <linux/slab.h>
@@ -37,18 +27,16 @@
static DEFINE_PER_CPU(u64, reserved_asids);
static cpumask_t tlb_flush_pending;
+static unsigned long max_pinned_asids;
+static unsigned long nr_pinned_asids;
+static unsigned long *pinned_asid_map;
+
#define ASID_MASK (~GENMASK(asid_bits - 1, 0))
#define ASID_FIRST_VERSION (1UL << asid_bits)
-#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
-#define NUM_USER_ASIDS (ASID_FIRST_VERSION >> 1)
-#define asid2idx(asid) (((asid) & ~ASID_MASK) >> 1)
-#define idx2asid(idx) (((idx) << 1) & ~ASID_MASK)
-#else
-#define NUM_USER_ASIDS (ASID_FIRST_VERSION)
+#define NUM_USER_ASIDS ASID_FIRST_VERSION
#define asid2idx(asid) ((asid) & ~ASID_MASK)
#define idx2asid(idx) asid2idx(idx)
-#endif
/* Get the ASIDBits supported by the current CPU */
static u32 get_cpu_asid_bits(void)
@@ -61,7 +49,7 @@
default:
pr_warn("CPU%d: Unknown ASID size (%d); assuming 8-bit\n",
smp_processor_id(), fld);
- /* Fallthrough */
+ fallthrough;
case 0:
asid = 8;
break;
@@ -88,13 +76,38 @@
}
}
-static void flush_context(unsigned int cpu)
+static void set_kpti_asid_bits(unsigned long *map)
+{
+ unsigned int len = BITS_TO_LONGS(NUM_USER_ASIDS) * sizeof(unsigned long);
+ /*
+ * In case of KPTI kernel/user ASIDs are allocated in
+ * pairs, the bottom bit distinguishes the two: if it
+ * is set, then the ASID will map only userspace. Thus
+ * mark even as reserved for kernel.
+ */
+ memset(map, 0xaa, len);
+}
+
+static void set_reserved_asid_bits(void)
+{
+ if (pinned_asid_map)
+ bitmap_copy(asid_map, pinned_asid_map, NUM_USER_ASIDS);
+ else if (arm64_kernel_unmapped_at_el0())
+ set_kpti_asid_bits(asid_map);
+ else
+ bitmap_clear(asid_map, 0, NUM_USER_ASIDS);
+}
+
+#define asid_gen_match(asid) \
+ (!(((asid) ^ atomic64_read(&asid_generation)) >> asid_bits))
+
+static void flush_context(void)
{
int i;
u64 asid;
/* Update the list of reserved ASIDs and the ASID bitmap. */
- bitmap_clear(asid_map, 0, NUM_USER_ASIDS);
+ set_reserved_asid_bits();
for_each_possible_cpu(i) {
asid = atomic64_xchg_relaxed(&per_cpu(active_asids, i), 0);
@@ -142,7 +155,7 @@
return hit;
}
-static u64 new_context(struct mm_struct *mm, unsigned int cpu)
+static u64 new_context(struct mm_struct *mm)
{
static u32 cur_idx = 1;
u64 asid = atomic64_read(&mm->context.id);
@@ -156,6 +169,14 @@
* can continue to use it and this was just a false alarm.
*/
if (check_update_reserved_asid(asid, newasid))
+ return newasid;
+
+ /*
+ * If it is pinned, we can keep using it. Note that reserved
+ * takes priority, because even if it is also pinned, we need to
+ * update the generation into the reserved_asids.
+ */
+ if (refcount_read(&mm->context.pinned))
return newasid;
/*
@@ -180,7 +201,7 @@
/* We're out of ASIDs, so increment the global generation count */
generation = atomic64_add_return_relaxed(ASID_FIRST_VERSION,
&asid_generation);
- flush_context(cpu);
+ flush_context();
/* We have more ASIDs than CPUs, so this will always succeed */
asid = find_next_zero_bit(asid_map, NUM_USER_ASIDS, 1);
@@ -191,10 +212,14 @@
return idx2asid(asid) | generation;
}
-void check_and_switch_context(struct mm_struct *mm, unsigned int cpu)
+void check_and_switch_context(struct mm_struct *mm)
{
unsigned long flags;
+ unsigned int cpu;
u64 asid, old_active_asid;
+
+ if (system_supports_cnp())
+ cpu_set_reserved_ttbr0();
asid = atomic64_read(&mm->context.id);
@@ -212,25 +237,25 @@
* relaxed xchg in flush_context will treat us as reserved
* because atomic RmWs are totally ordered for a given location.
*/
- old_active_asid = atomic64_read(&per_cpu(active_asids, cpu));
- if (old_active_asid &&
- !((asid ^ atomic64_read(&asid_generation)) >> asid_bits) &&
- atomic64_cmpxchg_relaxed(&per_cpu(active_asids, cpu),
+ old_active_asid = atomic64_read(this_cpu_ptr(&active_asids));
+ if (old_active_asid && asid_gen_match(asid) &&
+ atomic64_cmpxchg_relaxed(this_cpu_ptr(&active_asids),
old_active_asid, asid))
goto switch_mm_fastpath;
raw_spin_lock_irqsave(&cpu_asid_lock, flags);
/* Check that our ASID belongs to the current generation. */
asid = atomic64_read(&mm->context.id);
- if ((asid ^ atomic64_read(&asid_generation)) >> asid_bits) {
- asid = new_context(mm, cpu);
+ if (!asid_gen_match(asid)) {
+ asid = new_context(mm);
atomic64_set(&mm->context.id, asid);
}
+ cpu = smp_processor_id();
if (cpumask_test_and_clear_cpu(cpu, &tlb_flush_pending))
local_flush_tlb_all();
- atomic64_set(&per_cpu(active_asids, cpu), asid);
+ atomic64_set(this_cpu_ptr(&active_asids), asid);
raw_spin_unlock_irqrestore(&cpu_asid_lock, flags);
switch_mm_fastpath:
@@ -245,23 +270,137 @@
cpu_switch_mm(mm->pgd, mm);
}
+unsigned long arm64_mm_context_get(struct mm_struct *mm)
+{
+ unsigned long flags;
+ u64 asid;
+
+ if (!pinned_asid_map)
+ return 0;
+
+ raw_spin_lock_irqsave(&cpu_asid_lock, flags);
+
+ asid = atomic64_read(&mm->context.id);
+
+ if (refcount_inc_not_zero(&mm->context.pinned))
+ goto out_unlock;
+
+ if (nr_pinned_asids >= max_pinned_asids) {
+ asid = 0;
+ goto out_unlock;
+ }
+
+ if (!asid_gen_match(asid)) {
+ /*
+ * We went through one or more rollover since that ASID was
+ * used. Ensure that it is still valid, or generate a new one.
+ */
+ asid = new_context(mm);
+ atomic64_set(&mm->context.id, asid);
+ }
+
+ nr_pinned_asids++;
+ __set_bit(asid2idx(asid), pinned_asid_map);
+ refcount_set(&mm->context.pinned, 1);
+
+out_unlock:
+ raw_spin_unlock_irqrestore(&cpu_asid_lock, flags);
+
+ asid &= ~ASID_MASK;
+
+ /* Set the equivalent of USER_ASID_BIT */
+ if (asid && arm64_kernel_unmapped_at_el0())
+ asid |= 1;
+
+ return asid;
+}
+EXPORT_SYMBOL_GPL(arm64_mm_context_get);
+
+void arm64_mm_context_put(struct mm_struct *mm)
+{
+ unsigned long flags;
+ u64 asid = atomic64_read(&mm->context.id);
+
+ if (!pinned_asid_map)
+ return;
+
+ raw_spin_lock_irqsave(&cpu_asid_lock, flags);
+
+ if (refcount_dec_and_test(&mm->context.pinned)) {
+ __clear_bit(asid2idx(asid), pinned_asid_map);
+ nr_pinned_asids--;
+ }
+
+ raw_spin_unlock_irqrestore(&cpu_asid_lock, flags);
+}
+EXPORT_SYMBOL_GPL(arm64_mm_context_put);
+
/* Errata workaround post TTBRx_EL1 update. */
asmlinkage void post_ttbr_update_workaround(void)
{
+ if (!IS_ENABLED(CONFIG_CAVIUM_ERRATUM_27456))
+ return;
+
asm(ALTERNATIVE("nop; nop; nop",
"ic iallu; dsb nsh; isb",
- ARM64_WORKAROUND_CAVIUM_27456,
- CONFIG_CAVIUM_ERRATUM_27456));
+ ARM64_WORKAROUND_CAVIUM_27456));
}
-static int asids_init(void)
+void cpu_do_switch_mm(phys_addr_t pgd_phys, struct mm_struct *mm)
{
- asid_bits = get_cpu_asid_bits();
+ unsigned long ttbr1 = read_sysreg(ttbr1_el1);
+ unsigned long asid = ASID(mm);
+ unsigned long ttbr0 = phys_to_ttbr(pgd_phys);
+
+ /* Skip CNP for the reserved ASID */
+ if (system_supports_cnp() && asid)
+ ttbr0 |= TTBR_CNP_BIT;
+
+ /* SW PAN needs a copy of the ASID in TTBR0 for entry */
+ if (IS_ENABLED(CONFIG_ARM64_SW_TTBR0_PAN))
+ ttbr0 |= FIELD_PREP(TTBR_ASID_MASK, asid);
+
+ /* Set ASID in TTBR1 since TCR.A1 is set */
+ ttbr1 &= ~TTBR_ASID_MASK;
+ ttbr1 |= FIELD_PREP(TTBR_ASID_MASK, asid);
+
+ write_sysreg(ttbr1, ttbr1_el1);
+ isb();
+ write_sysreg(ttbr0, ttbr0_el1);
+ isb();
+ post_ttbr_update_workaround();
+}
+
+static int asids_update_limit(void)
+{
+ unsigned long num_available_asids = NUM_USER_ASIDS;
+
+ if (arm64_kernel_unmapped_at_el0()) {
+ num_available_asids /= 2;
+ if (pinned_asid_map)
+ set_kpti_asid_bits(pinned_asid_map);
+ }
/*
* Expect allocation after rollover to fail if we don't have at least
* one more ASID than CPUs. ASID #0 is reserved for init_mm.
*/
- WARN_ON(NUM_USER_ASIDS - 1 <= num_possible_cpus());
+ WARN_ON(num_available_asids - 1 <= num_possible_cpus());
+ pr_info("ASID allocator initialised with %lu entries\n",
+ num_available_asids);
+
+ /*
+ * There must always be an ASID available after rollover. Ensure that,
+ * even if all CPUs have a reserved ASID and the maximum number of ASIDs
+ * are pinned, there still is at least one empty slot in the ASID map.
+ */
+ max_pinned_asids = num_available_asids - num_possible_cpus() - 2;
+ return 0;
+}
+arch_initcall(asids_update_limit);
+
+static int asids_init(void)
+{
+ asid_bits = get_cpu_asid_bits();
atomic64_set(&asid_generation, ASID_FIRST_VERSION);
asid_map = kcalloc(BITS_TO_LONGS(NUM_USER_ASIDS), sizeof(*asid_map),
GFP_KERNEL);
@@ -269,7 +408,17 @@
panic("Failed to allocate bitmap for %lu ASIDs\n",
NUM_USER_ASIDS);
- pr_info("ASID allocator initialised with %lu entries\n", NUM_USER_ASIDS);
+ pinned_asid_map = kcalloc(BITS_TO_LONGS(NUM_USER_ASIDS),
+ sizeof(*pinned_asid_map), GFP_KERNEL);
+ nr_pinned_asids = 0;
+
+ /*
+ * We cannot call set_reserved_asid_bits() here because CPU
+ * caps are not finalized yet, so it is safer to assume KPTI
+ * and reserve kernel ASID's from beginning.
+ */
+ if (IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0))
+ set_kpti_asid_bits(asid_map);
return 0;
}
early_initcall(asids_init);
--
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