From c9c820840fd33b6722f00469d23dad740b981d9b Mon Sep 17 00:00:00 2001
From: Hojun-Cho <ghwns6743@gmail.com>
Date: Sun, 8 Dec 2024 23:14:32 +0900
Subject: [PATCH] add memprobe

NOTE: print "%llx" "%lld" not working now
---
 boot/Makefile |  2 +-
 boot/boot.c   |  5 +++-
 boot/dat.h    |  7 +++++
 boot/fn.h     |  8 ++++-
 boot/gdt.S    |  2 +-
 boot/mem.c    | 82 +++++++++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 102 insertions(+), 4 deletions(-)
 create mode 100644 boot/mem.c

diff --git a/boot/Makefile b/boot/Makefile
index 77041f0..fc930db 100644
--- a/boot/Makefile
+++ b/boot/Makefile
@@ -5,7 +5,7 @@ PROG = boot
 SRCS = srt0.S gdt.S boot.c
 OBJS = srt0.o gdt.o boot.o
 
-ESRCS = pccon.c sricon.c print.c a20.c time.c
+ESRCS = pccon.c sricon.c print.c a20.c time.c mem.c
 OBJS += $(ESRCS:.c=.o)
 
 include $(SDIR)/Makefile.inc
diff --git a/boot/boot.c b/boot/boot.c
index 1ea7e52..4a90533 100644
--- a/boot/boot.c
+++ b/boot/boot.c
@@ -6,7 +6,7 @@ static void coninit(void);
 static void machdep(void);
 
 void (*probe1[])(void) = {
-	a20up, coninit,
+	a20up, coninit, memprobe,
 };
 void (*probe2[])(void) = {
 };
@@ -31,7 +31,10 @@ ConDev contab[CON_END] = {
 		.init = cominit,
 	},
 };
+
 ConDev *con = &contab[0];
+BIOSmmap biosmmap[64];
+uint cnvmem, extmem;
 
 static void
 coninit(void)
diff --git a/boot/dat.h b/boot/dat.h
index 1166b5a..d71c07e 100644
--- a/boot/dat.h
+++ b/boot/dat.h
@@ -36,6 +36,11 @@ struct ConDev{
 	uint dev;
 	uchar pri; // the higher the better
 };
+typedef struct{
+	u64 addr;		/* Beginning of block */
+	u64 size;		/* Size of block */
+	u32 type;		/* Type of block */
+} __attribute__((packed)) BIOSmmap;
 
 // gdt.S
 extern volatile struct BIOSreg BIOSreg;
@@ -44,5 +49,7 @@ extern volatile struct BIOSreg BIOSreg;
 extern void (*probe1[])(void);
 extern void (*probe2[])(void);
 extern BootProbe probes[];
+extern BIOSmmap biosmmap[64];
 extern ConDev contab[CON_END];
 extern ConDev *con;
+extern uint cnvmem, extmem;
diff --git a/boot/fn.h b/boot/fn.h
index 4d1bb47..1231d2a 100644
--- a/boot/fn.h
+++ b/boot/fn.h
@@ -1,3 +1,6 @@
+#define MAX(x, y) ((x)>(y)?(x):(y))
+#define MIN(x, y) ((x)<(y)?(x):(y))
+
 // console.c
 void cominit(ConDev *d);
 void pcinit(ConDev *d);
@@ -16,7 +19,10 @@ void print(const char *fmt, ...);
 // a20.c
 void a20up(void);
 
-// long.c
+// mem.c
+void memprobe(void);
+
+// time.c
 long getsecs(void);
 
 static __inline int
diff --git a/boot/gdt.S b/boot/gdt.S
index 955f82c..f270930 100644
--- a/boot/gdt.S
+++ b/boot/gdt.S
@@ -78,7 +78,7 @@
 .globl	pmode_init	
 .globl	BIOSreg
 BIOSreg:
-	.space 64
+	.space 36, 0
 
 //	Table
 //	IDTR offset + 0 : entry 0
diff --git a/boot/mem.c b/boot/mem.c
new file mode 100644
index 0000000..e0a23fe
--- /dev/null
+++ b/boot/mem.c
@@ -0,0 +1,82 @@
+#include <u.h>
+#include "dat.h"
+#include "fn.h"
+
+#define IOMEM_BEGIN 0x0A0000
+#define IOMEM_END   0x100000
+
+enum{
+	MAP_END  = 0x00,
+	MAP_FREE = 0x01,
+	MAP_RES = 0x02,
+	MAP_ACPI_RECLAM = 0x03,
+	MAP_ACPI_NVS = 0x04,
+};
+
+static BIOSmmap*
+int15_E820(BIOSmmap *m)
+{
+	int rc, sig, off = 0;
+	do{
+		BIOSreg.es = ((uint)(m) >> 4);
+		__asm volatile("int $0x35; setc %b1"
+			: "=a" (sig), "=d" (rc), "=b" (off)
+			: "0" (0xE820), "1" (0x534d4150), "b" (off),
+			  "c" (sizeof(*m)), "D" (((uint)m) & 0xf)
+			: "cc", "memory");
+
+		off = BIOSreg.bx;
+		if(rc &0xff || sig !=0x534d4150){
+			break;
+		if(m->type == 0)
+			m->type = MAP_RES;
+		}
+		m++;
+	}while(off);
+	return m;
+}
+
+static void
+dumpmem(BIOSmmap *m)
+{
+	ulong tot = 0;
+
+	for(BIOSmmap *p=m; p->type != MAP_END; ++p){
+		print("MEM %u type %u size %lldKB at 0x%llx\n",
+			p-m, p->type, p->size/1024, p->addr);
+		if(p->type == MAP_FREE)
+			tot += p->size/1024;
+	}
+	print("RAM low:%dKB high:%dKB\n", cnvmem, extmem);	
+	print("Total free memory: %dKB\n", tot);
+}
+
+static int
+isa20done(void)
+{
+	register char *a = (char *)0x100000;
+	register char *b = (char *)0x000000;
+
+	return *a != *b;
+}
+
+void
+memprobe(void)
+{
+	BIOSmmap *m;
+
+	cnvmem = extmem = 0;
+	m = int15_E820(biosmmap);
+	m->type = MAP_END;
+	for(m = biosmmap; m->type != MAP_END; ++m){
+		if(m->type != MAP_FREE || m->size <= 0)
+			continue;	
+		if(m->addr < IOMEM_BEGIN)
+			cnvmem = MAX(cnvmem, m->addr + m->size)/1024;
+		if(m->addr >= IOMEM_END)
+			extmem += m->size/1024;
+	}
+	dumpmem(biosmmap);
+	print("A20:%d", isa20done());
+}
+