MIPS: kernel: mips-r2-to-r6-emul: Add R2 emulator for MIPS R6

MIPS R6 removed quite a few R2 instructions. However, there is plenty of <R6 userland code so we add an in-kernel emulator so we can still be able to execute all R2 userland out there. The emulator comes with a handy debugfs under /mips/ directory (r2-emul-stats) to provide some basic statistics of the instructions that are being emulated. Below are some statistics from booting a minimal buildroot image: Instruction Total BDslot ------------------------------ movs 236969 0 hilo 56686 0 muls 55279 0 divs 10941 0 dsps 0 0 bops 1 0 traps 0 0 fpus 0 0 loads 214981 17 stores 103364 0 llsc 56898 0 dsemul 150418 0 jr 370158 bltzl 43 bgezl 1594 bltzll 0 bgezll 0 bltzal 39 bgezal 39 beql 14503 bnel 138741 blezl 0 bgtzl 3988 Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2014-12-03 15:47:03 +00:00
parent b55b9e2715
commit b0a668fb20
8 changed files with 2518 additions and 5 deletions
--- a/arch/mips/include/asm/mips-r2-to-r6-emul.h
+++ b/arch/mips/include/asm/mips-r2-to-r6-emul.h
@@ -0,0 +1,96 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 2014 Imagination Technologies Ltd.
+ * Author: Markos Chandras <markos.chandras@imgtec.com>
+ */
+
+#ifndef __ASM_MIPS_R2_TO_R6_EMUL_H
+#define __ASM_MIPS_R2_TO_R6_EMUL_H
+
+struct mips_r2_emulator_stats {
+	u64 movs;
+	u64 hilo;
+	u64 muls;
+	u64 divs;
+	u64 dsps;
+	u64 bops;
+	u64 traps;
+	u64 fpus;
+	u64 loads;
+	u64 stores;
+	u64 llsc;
+	u64 dsemul;
+};
+
+struct mips_r2br_emulator_stats {
+	u64 jrs;
+	u64 bltzl;
+	u64 bgezl;
+	u64 bltzll;
+	u64 bgezll;
+	u64 bltzall;
+	u64 bgezall;
+	u64 bltzal;
+	u64 bgezal;
+	u64 beql;
+	u64 bnel;
+	u64 blezl;
+	u64 bgtzl;
+};
+
+#ifdef CONFIG_DEBUG_FS
+
+#define MIPS_R2_STATS(M)						\
+do {									\
+	u32 nir;							\
+	int err;							\
+									\
+	preempt_disable();						\
+	__this_cpu_inc(mipsr2emustats.M);				\
+	err = __get_user(nir, (u32 __user *)regs->cp0_epc);		\
+	if (!err) {							\
+		if (nir == BREAK_MATH)					\
+			__this_cpu_inc(mipsr2bdemustats.M);		\
+	}								\
+	preempt_enable();						\
+} while (0)
+
+#define MIPS_R2BR_STATS(M)					\
+do {								\
+	preempt_disable();					\
+	__this_cpu_inc(mipsr2bremustats.M);			\
+	preempt_enable();					\
+} while (0)
+
+#else
+
+#define MIPS_R2_STATS(M)          do { } while (0)
+#define MIPS_R2BR_STATS(M)        do { } while (0)
+
+#endif /* CONFIG_DEBUG_FS */
+
+struct r2_decoder_table {
+	u32     mask;
+	u32     code;
+	int     (*func)(struct pt_regs *regs, u32 inst);
+};
+
+
+extern void do_trap_or_bp(struct pt_regs *regs, unsigned int code,
+			  const char *str);
+
+#ifndef CONFIG_MIPSR2_TO_R6_EMULATOR
+static int mipsr2_emulation;
+static __maybe_unused int mipsr2_decoder(struct pt_regs *regs, u32 inst) { return 0; };
+#else
+/* MIPS R2 Emulator ON/OFF */
+extern int mipsr2_emulation;
+extern int mipsr2_decoder(struct pt_regs *regs, u32 inst);
+#endif /* CONFIG_MIPSR2_TO_R6_EMULATOR */
+
+#define NO_R6EMU	(cpu_has_mips_r6 && !mipsr2_emulation)
+
+#endif /* __ASM_MIPS_R2_TO_R6_EMUL_H */