Merge tag 'riscv-for-linus-6.18-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Paul Walmsley

 - Replacement of __ASSEMBLY__ with __ASSEMBLER__ in header files (other
   architectures have already merged this type of cleanup)

 - The introduction of ioremap_wc() for RISC-V

 - Cleanup of the RISC-V kprobes code to use mostly-extant macros rather
   than open code

 - A RISC-V kprobes unit test

 - An architecture-specific endianness swap macro set implementation,
   leveraging some dedicated RISC-V instructions for this purpose if
   they are available

 - The ability to identity and communicate to userspace the presence
   of a MIPS P8700-specific ISA extension, and to leverage its
   MIPS-specific PAUSE implementation in cpu_relax()

 - Several other miscellaneous cleanups

* tag 'riscv-for-linus-6.18-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (39 commits)
  riscv: errata: Fix the PAUSE Opcode for MIPS P8700
  riscv: hwprobe: Document MIPS xmipsexectl vendor extension
  riscv: hwprobe: Add MIPS vendor extension probing
  riscv: Add xmipsexectl instructions
  riscv: Add xmipsexectl as a vendor extension
  dt-bindings: riscv: Add xmipsexectl ISA extension description
  riscv: cpufeature: add validation for zfa, zfh and zfhmin
  perf: riscv: skip empty batches in counter start
  selftests: riscv: Add README for RISC-V KSelfTest
  riscv: sbi: Switch to new sys-off handler API
  riscv: Move vendor errata definitions to new header
  RISC-V: ACPI: enable parsing the BGRT table
  riscv: Enable ARCH_HAVE_NMI_SAFE_CMPXCHG
  riscv: pi: use 'targets' instead of extra-y in Makefile
  riscv: introduce asm/swab.h
  riscv: mmap(): use unsigned offset type in riscv_sys_mmap
  drivers/perf: riscv: Remove redundant ternary operators
  riscv: mm: Use mmu-type from FDT to limit SATP mode
  riscv: mm: Return intended SATP mode for noXlvl options
  riscv: kprobes: Remove duplication of RV_EXTRACT_ITYPE_IMM
  ...

1 files changed, 67 insertions, 0 deletions

diff --git a/arch/riscv/errata/mips/errata.c b/arch/riscv/errata/mips/errata.c
new file mode 100644
index 000000000000..e984a8152208
--- /dev/null
+++ b/arch/riscv/errata/mips/errata.c
@@ -0,0 +1,67 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2025 MIPS.
+ */
+
+#include <linux/memory.h>
+#include <linux/module.h>
+#include <asm/text-patching.h>
+#include <asm/alternative.h>
+#include <asm/errata_list.h>
+#include <asm/vendorid_list.h>
+#include <asm/vendor_extensions.h>
+#include <asm/vendor_extensions/mips.h>
+
+static inline bool errata_probe_pause(void)
+{
+	if (!IS_ENABLED(CONFIG_ERRATA_MIPS_P8700_PAUSE_OPCODE))
+		return false;
+
+	if (!riscv_isa_vendor_extension_available(MIPS_VENDOR_ID, XMIPSEXECTL))
+		return false;
+
+	return true;
+}
+
+static u32 mips_errata_probe(void)
+{
+	u32 cpu_req_errata = 0;
+
+	if (errata_probe_pause())
+		cpu_req_errata |= BIT(ERRATA_MIPS_P8700_PAUSE_OPCODE);
+
+	return cpu_req_errata;
+}
+
+void mips_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
+			    unsigned long archid, unsigned long impid,
+			    unsigned int stage)
+{
+	struct alt_entry *alt;
+	u32 cpu_req_errata = mips_errata_probe();
+	u32 tmp;
+
+	BUILD_BUG_ON(ERRATA_MIPS_NUMBER >= RISCV_VENDOR_EXT_ALTERNATIVES_BASE);
+
+	if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
+		return;
+
+	for (alt = begin; alt < end; alt++) {
+		if (alt->vendor_id != MIPS_VENDOR_ID)
+			continue;
+
+		if (alt->patch_id >= ERRATA_MIPS_NUMBER) {
+			WARN(1, "MIPS errata id:%d not in kernel errata list\n",
+			     alt->patch_id);
+			continue;
+		}
+
+		tmp = (1U << alt->patch_id);
+		if (cpu_req_errata && tmp) {
+			mutex_lock(&text_mutex);
+			patch_text_nosync(ALT_OLD_PTR(alt), ALT_ALT_PTR(alt),
+					  alt->alt_len);
+			mutex_unlock(&text_mutex);
+		}
+	}
+}