MIPS: Add GINVT instruction helpers

Add a family of ginvt_* functions making it easy to emit a GINVT
instruction to globally invalidate TLB entries. We make use of the
_ASM_MACRO infrastructure to support emitting the instructions even if
the assembler isn't new enough to support them natively.

An associated STYPE_GINV definition & sync_ginv() function are added to
emit a sync instruction of type 0x14, which operates as a completion
barrier for these new GINVT (and GINVI) instructions.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org

arch/mips/Makefile

@@ -233,6 +233,8 @@ toolchain-crc				:= $(call cc-option-yn,$(mips-cflags) -Wa$(comma)-mcrc)
 cflags-$(toolchain-crc)			+= -DTOOLCHAIN_SUPPORTS_CRC
 toolchain-dsp				:= $(call cc-option-yn,$(mips-cflags) -Wa$(comma)-mdsp)
 cflags-$(toolchain-dsp)			+= -DTOOLCHAIN_SUPPORTS_DSP
+toolchain-ginv				:= $(call cc-option-yn,$(mips-cflags) -Wa$(comma)-mginv)
+cflags-$(toolchain-ginv)		+= -DTOOLCHAIN_SUPPORTS_GINV
 
 #
 # Firmware support

arch/mips/include/asm/barrier.h

@@ -105,6 +105,20 @@
  */
 #define STYPE_SYNC_MB 0x10
 
+/*
+ * stype 0x14 - A completion barrier specific to global invalidations
+ *
+ * When a sync instruction of this type completes any preceding GINVI or GINVT
+ * operation has been globalized & completed on all coherent CPUs. Anything
+ * that the GINV* instruction should invalidate will have been invalidated on
+ * all coherent CPUs when this instruction completes. It is implementation
+ * specific whether the GINV* instructions themselves will ensure completion,
+ * or this sync type will.
+ *
+ * In systems implementing global invalidates (ie. with Config5.GI == 2 or 3)
+ * this sync type also requires that previous SYNCI operations have completed.
+ */
+#define STYPE_GINV	0x14
 
 #ifdef CONFIG_CPU_HAS_SYNC
 #define __sync()				\
@@ -222,6 +236,11 @@
 #define __smp_mb__before_atomic()	__smp_mb__before_llsc()
 #define __smp_mb__after_atomic()	smp_llsc_mb()
 
+static inline void sync_ginv(void)
+{
+	asm volatile("sync\t%0" :: "i"(STYPE_GINV));
+}
+
 #include <asm-generic/barrier.h>
 
 #endif /* __ASM_BARRIER_H */

arch/mips/include/asm/ginvt.h

@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __MIPS_ASM_GINVT_H__
+#define __MIPS_ASM_GINVT_H__
+
+#include <asm/mipsregs.h>
+
+enum ginvt_type {
+	GINVT_FULL,
+	GINVT_VA,
+	GINVT_MMID,
+};
+
+#ifdef TOOLCHAIN_SUPPORTS_GINV
+# define _ASM_SET_GINV	".set	ginv\n"
+#else
+_ASM_MACRO_1R1I(ginvt, rs, type,
+		_ASM_INSN_IF_MIPS(0x7c0000bd | (__rs << 21) | (\\type << 8))
+		_ASM_INSN32_IF_MM(0x0000717c | (__rs << 16) | (\\type << 9)));
+# define _ASM_SET_GINV
+#endif
+
+static inline void ginvt(unsigned long addr, enum ginvt_type type)
+{
+	asm volatile(
+		".set	push\n"
+		_ASM_SET_GINV
+		"	ginvt	%0, %1\n"
+		".set	pop"
+		: /* no outputs */
+		: "r"(addr), "i"(type)
+		: "memory");
+}
+
+static inline void ginvt_full(void)
+{
+	ginvt(0, GINVT_FULL);
+}
+
+static inline void ginvt_va(unsigned long addr)
+{
+	addr &= PAGE_MASK << 1;
+	ginvt(addr, GINVT_VA);
+}
+
+static inline void ginvt_mmid(void)
+{
+	ginvt(0, GINVT_MMID);
+}
+
+static inline void ginvt_va_mmid(unsigned long addr)
+{
+	addr &= PAGE_MASK << 1;
+	ginvt(addr, GINVT_VA | GINVT_MMID);
+}
+
+#endif /* __MIPS_ASM_GINVT_H__ */

arch/mips/include/asm/mipsregs.h

@@ -1247,6 +1247,13 @@ __asm__(".macro	parse_r var r\n\t"
 		ENC							\
 		".endm")
 
+/* Instructions with 1 register operand & 1 immediate operand */
+#define _ASM_MACRO_1R1I(OP, R1, I2, ENC)				\
+	__asm__(".macro	" #OP " " #R1 ", " #I2 "\n\t"			\
+		"parse_r __" #R1 ", \\" #R1 "\n\t"			\
+		ENC							\
+		".endm")
+
 /* Instructions with 2 register operands */
 #define _ASM_MACRO_2R(OP, R1, R2, ENC)					\
 	__asm__(".macro	" #OP " " #R1 ", " #R2 "\n\t"			\