Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
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linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2025 MIPS.
4 */
5
6#include <linux/memory.h>
7#include <linux/module.h>
8#include <asm/text-patching.h>
9#include <asm/alternative.h>
10#include <asm/errata_list.h>
11#include <asm/vendorid_list.h>
12#include <asm/vendor_extensions.h>
13#include <asm/vendor_extensions/mips.h>
14
15static inline bool errata_probe_pause(void)
16{
17 if (!IS_ENABLED(CONFIG_ERRATA_MIPS_P8700_PAUSE_OPCODE))
18 return false;
19
20 if (!riscv_isa_vendor_extension_available(MIPS_VENDOR_ID, XMIPSEXECTL))
21 return false;
22
23 return true;
24}
25
26static u32 mips_errata_probe(void)
27{
28 u32 cpu_req_errata = 0;
29
30 if (errata_probe_pause())
31 cpu_req_errata |= BIT(ERRATA_MIPS_P8700_PAUSE_OPCODE);
32
33 return cpu_req_errata;
34}
35
36void mips_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
37 unsigned long archid, unsigned long impid,
38 unsigned int stage)
39{
40 struct alt_entry *alt;
41 u32 cpu_req_errata = mips_errata_probe();
42 u32 tmp;
43
44 BUILD_BUG_ON(ERRATA_MIPS_NUMBER >= RISCV_VENDOR_EXT_ALTERNATIVES_BASE);
45
46 if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
47 return;
48
49 for (alt = begin; alt < end; alt++) {
50 if (alt->vendor_id != MIPS_VENDOR_ID)
51 continue;
52
53 if (alt->patch_id >= ERRATA_MIPS_NUMBER) {
54 WARN(1, "MIPS errata id:%d not in kernel errata list\n",
55 alt->patch_id);
56 continue;
57 }
58
59 tmp = (1U << alt->patch_id);
60 if (cpu_req_errata && tmp) {
61 mutex_lock(&text_mutex);
62 patch_text_nosync(ALT_OLD_PTR(alt), ALT_ALT_PTR(alt),
63 alt->alt_len);
64 mutex_unlock(&text_mutex);
65 }
66 }
67}