[RFC PATCH 1/3] riscv: errata: cmo: add CMO macro variant with both VA and PA

[Icenowy Zheng]

The standardized Zicbom extension supports only VA, however there's some
vendor extensions (e.g. XtheadCmo) that can handle cache management
operations on PA directly, bypassing the TLB lookup.

Add a CMO alternatives macro variant that come with both VA and PA
supplied, and the code can be patched to use either the VA or the PA at
runtime. In this case the codepath is now patched to use VA for Zicbom
and PA for XtheadCmo.

Signed-off-by: Icenowy Zheng <uwu at icenowy.me>
---
 arch/riscv/include/asm/errata_list.h | 30 ++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/arch/riscv/include/asm/errata_list.h b/arch/riscv/include/asm/errata_list.h
index 46adc1c9428f..bf80dd58145e 100644
--- a/arch/riscv/include/asm/errata_list.h
+++ b/arch/riscv/include/asm/errata_list.h
@@ -118,6 +118,9 @@ asm volatile(ALTERNATIVE(						\
 #define THEAD_clean_A0	".long 0x0255000b"
 #define THEAD_flush_A0	".long 0x0275000b"
 #define THEAD_SYNC_S	".long 0x0190000b"
+#define THEAD_inval_PA_A0	".long 0x02a5000b"
+#define THEAD_clean_PA_A0	".long 0x0295000b"
+#define THEAD_flush_PA_A0	".long 0x02b5000b"
 
 #define ALT_CMO_OP(_op, _start, _size, _cachesize)			\
 asm volatile(ALTERNATIVE_2(						\
@@ -144,6 +147,33 @@ asm volatile(ALTERNATIVE_2(						\
 	    "r"((unsigned long)(_start) + (_size))			\
 	: "a0")
 
+#define ALT_CMO_OP_VPA(_op, _vaddr, _paddr, _size, _cachesize)		\
+asm volatile(ALTERNATIVE_2(						\
+	__nops(6),							\
+	"mv a0, %1\n\t"							\
+	"j 2f\n\t"							\
+	"3:\n\t"							\
+	"cbo." __stringify(_op) " (a0)\n\t"				\
+	"add a0, a0, %0\n\t"						\
+	"2:\n\t"							\
+	"bltu a0, %2, 3b\n\t"						\
+	"nop", 0, CPUFEATURE_ZICBOM, CONFIG_RISCV_ISA_ZICBOM,		\
+	"mv a0, %3\n\t"							\
+	"j 2f\n\t"							\
+	"3:\n\t"							\
+	THEAD_##_op##_PA_A0 "\n\t"					\
+	"add a0, a0, %0\n\t"						\
+	"2:\n\t"							\
+	"bltu a0, %4, 3b\n\t"						\
+	THEAD_SYNC_S, THEAD_VENDOR_ID,					\
+			ERRATA_THEAD_CMO, CONFIG_ERRATA_THEAD_CMO)	\
+	: : "r"(_cachesize),						\
+	    "r"((unsigned long)(_vaddr) & ~((_cachesize) - 1UL)),	\
+	    "r"((unsigned long)(_vaddr) + (_size)),			\
+	    "r"((unsigned long)(_paddr) & ~((_cachesize) - 1UL)),	\
+	    "r"((unsigned long)(_paddr) + (_size))			\
+	: "a0")
+
 #define THEAD_C9XX_RV_IRQ_PMU			17
 #define THEAD_C9XX_CSR_SCOUNTEROF		0x5c5
 
-- 
2.38.1