From f854810594658feb59b1e67c2d97e19553b4b34c Mon Sep 17 00:00:00 2001
From: Paul Cercueil <paul@crapouillou.net>
Date: Sat, 4 Jun 2022 21:12:14 +0100
Subject: [PATCH] lightrec: Enable code buffer support

Map a 8 MiB code buffer at (base + 0x80.0000), right after the emulated
RAM. In this code buffer, Lightrec will write the recompiled code for
the host machine.

In general, the code buffer support is very useful when the host
platform has only a small RW+X memory area available for JIT purposes,
like it's the case on the WiiU.

On Linux, this isn't a concern, but having a code buffer does still
bring a benefit: if both the start address and the end address of the
code buffer's address fit in 32 bits, then Lightrec's code LUT can be
shrunk in half (2.5 MiB instead of 5 MiB), as it only needs to store
32-bit pointers.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
---
 Makefile                           |  2 +-
 include/lightrec/lightrec-config.h |  3 +--
 libpcsxcore/lightrec/mem.c         | 17 +++++++++++++++++
 libpcsxcore/lightrec/mem.h         |  4 ++++
 libpcsxcore/lightrec/plugin.c      |  6 ++++++
 5 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index 0860c722..3aa06b7d 100644
--- a/Makefile
+++ b/Makefile
@@ -96,7 +96,7 @@ CFLAGS += -Ideps/lightning/include -Ideps/lightrec -Iinclude/lightning -Iinclude
 deps/lightning/lib/%.o: CFLAGS += -DHAVE_MMAP
 ifeq ($(LIGHTREC_CUSTOM_MAP),1)
 LDLIBS += -lrt
-OBJS += libpcsxcore/lightrec/mem.o
+OBJS += libpcsxcore/lightrec/mem.o deps/lightrec/tlsf/tlsf.o
 endif
 OBJS += libpcsxcore/lightrec/plugin.o
 OBJS += deps/lightning/lib/jit_disasm.o \
diff --git a/include/lightrec/lightrec-config.h b/include/lightrec/lightrec-config.h
index 34ac7a6e..2fa750f4 100644
--- a/include/lightrec/lightrec-config.h
+++ b/include/lightrec/lightrec-config.h
@@ -9,8 +9,7 @@
 #define ENABLE_THREADED_COMPILER 1
 #define ENABLE_FIRST_PASS 1
 #define ENABLE_DISASSEMBLER 0
-#define ENABLE_TINYMM 0
-#define ENABLE_CODE_BUFFER 0
+#define ENABLE_CODE_BUFFER 1
 
 #define HAS_DEFAULT_ELM 1
 
diff --git a/libpcsxcore/lightrec/mem.c b/libpcsxcore/lightrec/mem.c
index c3a1421e..ff67e3d0 100644
--- a/libpcsxcore/lightrec/mem.c
+++ b/libpcsxcore/lightrec/mem.c
@@ -31,6 +31,8 @@
 #define MFD_HUGETLB 0x0004
 #endif
 
+void *code_buffer;
+
 static const uintptr_t supported_io_bases[] = {
 	0x0,
 	0x10000000,
@@ -171,8 +173,22 @@ int lightrec_init_mmap(void)
 
 	psxH = (s8 *)map;
 
+	map = mmap_huge((void *)(base + 0x800000), CODE_BUFFER_SIZE,
+			PROT_EXEC | PROT_READ | PROT_WRITE,
+			MAP_PRIVATE | MAP_FIXED_NOREPLACE | MAP_ANONYMOUS,
+			0, 0);
+	if (map == MAP_FAILED) {
+		err = -EINVAL;
+		fprintf(stderr, "Unable to mmap code buffer\n");
+		goto err_unmap_scratch;
+	}
+
+	code_buffer = map;
+
 	return 0;
 
+err_unmap_scratch:
+	munmap(psxH, 0x10000);
 err_unmap_bios:
 	munmap(psxR, 0x80000);
 err_unmap_parallel:
@@ -187,6 +203,7 @@ void lightrec_free_mmap(void)
 {
 	unsigned int i;
 
+	munmap(code_buffer, CODE_BUFFER_SIZE);
 	munmap(psxH, 0x10000);
 	munmap(psxR, 0x80000);
 	munmap(psxP, 0x10000);
diff --git a/libpcsxcore/lightrec/mem.h b/libpcsxcore/lightrec/mem.h
index 7f04ce59..d747c174 100644
--- a/libpcsxcore/lightrec/mem.h
+++ b/libpcsxcore/lightrec/mem.h
@@ -6,6 +6,10 @@
 #ifndef __LIGHTREC_MEM_H__
 #define __LIGHTREC_MEM_H__
 
+#define CODE_BUFFER_SIZE (8 * 1024 * 1024)
+
+extern void *code_buffer;
+
 int lightrec_init_mmap(void);
 void lightrec_free_mmap(void);
 
diff --git a/libpcsxcore/lightrec/plugin.c b/libpcsxcore/lightrec/plugin.c
index 4b28c566..00d9c558 100644
--- a/libpcsxcore/lightrec/plugin.c
+++ b/libpcsxcore/lightrec/plugin.c
@@ -15,6 +15,8 @@
 
 #include "../frontend/main.h"
 
+#include "mem.h"
+
 #if (defined(__arm__) || defined(__aarch64__)) && !defined(ALLOW_LIGHTREC_ON_ARM)
 #error "Lightrec should not be used on ARM (please specify DYNAREC=ari64 to make)"
 #endif
@@ -289,6 +291,9 @@ static struct lightrec_mem_map lightrec_map[] = {
 		.length = 0x200000,
 		.mirror_of = &lightrec_map[PSX_MAP_KERNEL_USER_RAM],
 	},
+	[PSX_MAP_CODE_BUFFER] = {
+		.length = CODE_BUFFER_SIZE,
+	},
 };
 
 static void lightrec_enable_ram(struct lightrec_state *state, bool enable)
@@ -315,6 +320,7 @@ static int lightrec_plugin_init(void)
 		lightrec_map[PSX_MAP_MIRROR1].address = psxM + 0x200000;
 		lightrec_map[PSX_MAP_MIRROR2].address = psxM + 0x400000;
 		lightrec_map[PSX_MAP_MIRROR3].address = psxM + 0x600000;
+		lightrec_map[PSX_MAP_CODE_BUFFER].address = code_buffer;
 	}
 
 	lightrec_debug = !!getenv("LIGHTREC_DEBUG");
-- 
2.39.2