riscv: Add cache information in AUX vector

There are no standard CSR registers to provide cache information, the
way for RISC-V is to get this information from DT. sysconf syscall
could use them to get information of cache through AUX vector.

The result of 'getconf -a|grep -i cache' as follows:
LEVEL1_ICACHE_SIZE                 32768
LEVEL1_ICACHE_ASSOC                2
LEVEL1_ICACHE_LINESIZE             64
LEVEL1_DCACHE_SIZE                 32768
LEVEL1_DCACHE_ASSOC                4
LEVEL1_DCACHE_LINESIZE             64
LEVEL2_CACHE_SIZE                  524288
LEVEL2_CACHE_ASSOC                 8
LEVEL2_CACHE_LINESIZE              64
LEVEL3_CACHE_SIZE                  4194304
LEVEL3_CACHE_ASSOC                 16
LEVEL3_CACHE_LINESIZE              64
LEVEL4_CACHE_SIZE                  0
LEVEL4_CACHE_ASSOC                 0
LEVEL4_CACHE_LINESIZE              0

Signed-off-by: Greentime Hu <greentime.hu@sifive.com>
Signed-off-by: Zong Li <zong.li@sifive.com>
Suggested-by: Zong Li <zong.li@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20220913061817.22564-8-zong.li@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/include/asm/elf.h

@@ -99,6 +99,10 @@ do {								\
 		get_cache_size(2, CACHE_TYPE_UNIFIED));		\
 	NEW_AUX_ENT(AT_L2_CACHEGEOMETRY,			\
 		get_cache_geometry(2, CACHE_TYPE_UNIFIED));	\
+	NEW_AUX_ENT(AT_L3_CACHESIZE,				\
+		get_cache_size(3, CACHE_TYPE_UNIFIED));		\
+	NEW_AUX_ENT(AT_L3_CACHEGEOMETRY,			\
+		get_cache_geometry(3, CACHE_TYPE_UNIFIED));	\
 } while (0)
 #define ARCH_HAS_SETUP_ADDITIONAL_PAGES
 struct linux_binprm;

arch/riscv/include/uapi/asm/auxvec.h

@@ -30,8 +30,10 @@
 #define AT_L1D_CACHEGEOMETRY	43
 #define AT_L2_CACHESIZE		44
 #define AT_L2_CACHEGEOMETRY	45
+#define AT_L3_CACHESIZE		46
+#define AT_L3_CACHEGEOMETRY	47
 
 /* entries in ARCH_DLINFO */
-#define AT_VECTOR_SIZE_ARCH	7
+#define AT_VECTOR_SIZE_ARCH	9
 
 #endif /* _UAPI_ASM_RISCV_AUXVEC_H */