tlbrefill: Initial upload

tlbrefill/Makefile

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+EE_BIN= tlbrefill.elf
+EE_OBJS = tlbrefill.o tlbrefillhandler.o
+
+EE_CFLAGS = -Wall -O3
+
+all: $(EE_BIN)
+
+clean:
+	rm -f $(EE_OBJS) $(EE_BIN)
+
+run: $(EE_BIN)
+	ps2client execee host:$(EE_BIN)
+
+wsl: $(EE_BIN)
+	$(PCSX2) -elf "$(shell wslpath -w $(shell pwd))/$(EE_BIN)"
+
+emu: $(EE_BIN)
+	$(PCSX2) -elf "$(shell pwd)/$(EE_BIN)"
+
+reset:
+	ps2client reset
+	ps2client netdump
+
+include $(PS2SDK)/samples/Makefile.pref
+include $(PS2SDK)/samples/Makefile.eeglobal

tlbrefill/README.md

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+# TLBREFILL
+
+## Description
+Creates a TLB store refill handler and causes a miss. Logging the EPC and BadVAddr COP0 registers.
+
+In the future, it might be better to log the entire COP0 register states.
+
+## PCSX2 Behaviour
+The recompiler does not call the refill handlers and will continue emulation until a TLB exception messages threshold was met.
+
+The interpreter will call the proper refill handler.
+
+## Related PR(s) or Issue(s)
+n/a
+
+## Expected Results
+```
+TLB Refill handler test running
+
+TLB handler test completed
+ Expected EPC:    +-0x119ad0
+ Returned EPC:      0x119ad0
+ Expected BadVAddr: 0x123
+ Returned BadVAddr: 0x123
+
+TLB Refill handler test completed
+```

tlbrefill/tlbrefill.c

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+#include <debug.h>
+#include <kernel.h>
+#include <stdio.h>
+#include <sio.h>
+
+// Network based logging does not work for me
+// So I'll provide both network and ee-sio logs
+void dbgmsg(const char* fmt, ...)
+{
+	char buf[256];
+	va_list ap;
+	va_start(ap, fmt);
+	vsnprintf(buf, 256, fmt, ap);
+	vprintf(buf,ap);
+	va_end(ap);
+	sio_puts(buf);
+}
+
+void tlbRefillHandler();
+void* tlbRefillEPC = 0;
+void* tlbRefillBadVAddr = 0;
+
+__attribute__ ((__noinline__))
+void * get_pc () { return __builtin_return_address(0); }
+
+int main(void)
+{
+	dbgmsg("TLB Refill handler test running\n");
+	// Disable interrupts, don't risk having our handler called unintentionally
+	DIntr();
+
+	// Replace the existing TLB refill handler
+	// (3) -> Store
+	// (2) -> Load
+	void* prevVTLBRefillHandler = GetExceptionHandler(3);
+	SetVTLBRefillHandler(3, (void*)tlbRefillHandler);
+
+	// Cause a TLB store miss
+	asm("nop":::"memory");
+	volatile u8* badAddress = (volatile u8*)0x123;
+	void* exceptionPC = get_pc() + 8;
+	*badAddress = ~1;
+	asm("nop":::"memory");
+
+	// Restore the previous TLB refill handler
+	SetVTLBRefillHandler(3, prevVTLBRefillHandler);
+
+	EIntr();
+
+	dbgmsg(
+		"TLB handler test completed\n"
+		" Expected EPC:    +-%p\n"
+		" Returned EPC:      %p\n"
+		" Expected BadVAddr: %p\n"
+		" Returned BadVAddr: %p\n",
+		exceptionPC, tlbRefillEPC,
+		(void*)badAddress, tlbRefillBadVAddr
+		);
+
+	dbgmsg("TLB Refill handler test completed\n");
+	SleepThread();
+}

tlbrefill/tlbrefillhandler.S

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+
+.text
+.set noreorder
+
+.global tlbRefillHandler
+.global tlbRefillEPC
+.global tlbRefillBadVAddr
+
+.ent tlbRefillHandler
+tlbRefillHandler:
+	mfc0 $k0, $8 # Fetch BadVAddr
+	sync.p
+	sw $k0, tlbRefillBadVAddr
+
+	mfc0 $k0, $14 # Fetch EPC
+	sync.p
+	sw $k0, tlbRefillEPC
+
+	addi $k0, $k0, 4 # Skip to the instruction after our bad store
+	mtc0 $k0, $14    # Set EPC
+	sync.p
+	eret # Exit this handler
+	nop
+.end tlbRefillHandler