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4d2b036994
The condition checking whether a specific errata needs patching uses
logical AND (&&) instead of bitwise AND (&). Since logical AND only
checks that both operands are non-zero, this causes all errata patches
to be applied whenever any single errata is detected, rather than only
applying the matching one.
The SiFive errata implementation correctly uses bitwise AND for the same
check.
Fixes: 0b0ca959d2 ("riscv: errata: Fix the PAUSE Opcode for MIPS P8700")
Signed-off-by: Michael Neuling <mikey@neuling.org>
Assisted-by: Cursor:claude-4.6-opus-high-thinking
Link: https://patch.msgid.link/20260409091143.1348853-2-mikey@neuling.org
[pjw@kernel.org: fixed checkpatch warning]
Signed-off-by: Paul Walmsley <pjw@kernel.org>
68 lines
1.5 KiB
C
68 lines
1.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2025 MIPS.
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*/
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#include <linux/memory.h>
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#include <linux/module.h>
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#include <asm/text-patching.h>
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#include <asm/alternative.h>
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#include <asm/errata_list.h>
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#include <asm/vendorid_list.h>
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#include <asm/vendor_extensions.h>
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#include <asm/vendor_extensions/mips.h>
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static inline bool errata_probe_pause(void)
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{
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if (!IS_ENABLED(CONFIG_ERRATA_MIPS_P8700_PAUSE_OPCODE))
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return false;
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if (!riscv_isa_vendor_extension_available(MIPS_VENDOR_ID, XMIPSEXECTL))
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return false;
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return true;
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}
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static u32 mips_errata_probe(void)
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{
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u32 cpu_req_errata = 0;
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if (errata_probe_pause())
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cpu_req_errata |= BIT(ERRATA_MIPS_P8700_PAUSE_OPCODE);
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return cpu_req_errata;
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}
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void mips_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
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unsigned long archid, unsigned long impid,
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unsigned int stage)
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{
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struct alt_entry *alt;
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u32 cpu_req_errata = mips_errata_probe();
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u32 tmp;
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BUILD_BUG_ON(ERRATA_MIPS_NUMBER >= RISCV_VENDOR_EXT_ALTERNATIVES_BASE);
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if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
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return;
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for (alt = begin; alt < end; alt++) {
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if (alt->vendor_id != MIPS_VENDOR_ID)
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continue;
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if (alt->patch_id >= ERRATA_MIPS_NUMBER) {
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WARN(1, "MIPS errata id:%d not in kernel errata list\n",
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alt->patch_id);
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continue;
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}
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tmp = (1U << alt->patch_id);
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if (cpu_req_errata & tmp) {
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mutex_lock(&text_mutex);
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patch_text_nosync(ALT_OLD_PTR(alt), ALT_ALT_PTR(alt),
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alt->alt_len);
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mutex_unlock(&text_mutex);
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}
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}
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}
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