remove realmode and e820 code from kernel

sys/man/8/plan9.ini

@@ -642,13 +642,6 @@ hexadecimal 64-bit
 and
 .I end
 addresses of the usable memory areas.
-.SS \fL*norealmode=\fP
-The PC kernel switches the processor to 16-bit real mode
-to run BIOS interrupts, for example to find the memory map or to enable VESA.
-This variable disables such switches.
-.SS \fL*noe820scan=\fP
-When available, the PC kernel uses the BIOS E820 memory map
-to size memory.  This variable disables the scan.
 .SS \fL*maxmem=\fIvalue\fP
 This defines the maximum physical address that the system will scan when sizing memory.
 By default the PC operating system will scan up to 3.75 gigabytes

sys/src/9/pc/devarch.c

@@ -989,6 +989,39 @@ archctlwrite(Chan*, void *a, long n, vlong)
 	return n;
 }
 
+static long
+rmemrw(int isr, void *a, long n, vlong off)
+{
+	if(off < 0 || n < 0)
+		error("bad offset/count");
+	if(isr){
+		if(off >= MB)
+			return 0;
+		if(off+n >= MB)
+			n = MB - off;
+		memmove(a, KADDR((ulong)off), n);
+	}else{
+		/* allow vga framebuf's access */
+		if(off >= MB || off+n > MB ||
+		    (off < 0xA0000 || off+n > 0xB0000+0x10000))
+			error("bad offset/count in write");
+		memmove(KADDR((ulong)off), a, n);
+	}
+	return n;
+}
+
+static long
+rmemread(Chan*, void *a, long n, vlong off)
+{
+	return rmemrw(1, a, n, off);
+}
+
+static long
+rmemwrite(Chan*, void *a, long n, vlong off)
+{
+	return rmemrw(0, a, n, off);
+}
+
 void
 archinit(void)
 {
@@ -1037,6 +1070,7 @@ archinit(void)
 
 	addarchfile("cputype", 0444, cputyperead, nil);
 	addarchfile("archctl", 0664, archctlread, archctlwrite);
+	addarchfile("realmodemem", 0660, rmemread, rmemwrite);
 }
 
 /*

sys/src/9/pc/l.s

@@ -309,178 +309,6 @@ TEXT restoreregs(SB), $0
 	POPL	AX
 	RET
 
-/*
- * Assumed to be in protected mode at time of call.
- * Switch to real mode, execute an interrupt, and
- * then switch back to protected mode.  
- *
- * Assumes:
- *
- *	- no device interrupts are going to come in
- *	- 0-16MB is identity mapped in page tables
- *	- realmode() has copied us down from 0x100000 to 0x8000
- *	- can use code segment 0x0800 in real mode
- *		to get at l.s code
- *	- l.s code is less than 1 page
- */
-#define RELOC	(RMCODE-KTZERO)
-
-TEXT realmodeidtptr(SB), $0
-	WORD	$(4*256-1)
-	LONG	$0
-
-TEXT realmode0(SB), $0
-	CALL	saveregs(SB)
-
-	/* switch to low code address */
-	LEAL	physcode-KZERO(SB), AX
-	JMP *AX
-
-TEXT physcode(SB), $0
-
-	/* switch to low stack */
-	MOVL	SP, AX
-	MOVL	$0x7C00, SP
-	PUSHL	AX
-
-	/* change gdt to physical pointer */
-	MOVL	m0rgdtptr-KZERO(SB), GDTR
-
-	/* load IDT with real-mode version*/
-	MOVL	realmodeidtptr-KZERO(SB), IDTR
-
-	/* edit INT $0x00 instruction below */
-	MOVL	$(RMUADDR-KZERO+48), AX	/* &rmu.trap */
-	MOVL	(AX), AX
-	MOVB	AX, realmodeintrinst+(-KZERO+1+RELOC)(SB)
-
-	/* disable paging */
-	MOVL	CR0, AX
-	ANDL	$0x7FFFFFFF, AX
-	MOVL	AX, CR0
-	/* JMP .+2 to clear prefetch queue*/
-	BYTE $0xEB; BYTE $0x00
-
-	/* jump to 16-bit code segment */
-/*	JMPFAR	SELECTOR(KESEG16, SELGDT, 0):$again16bit(SB) /**/
-	 BYTE	$0xEA
-	 LONG	$again16bit-KZERO(SB)
-	 WORD	$SELECTOR(KESEG16, SELGDT, 0)
-
-TEXT again16bit(SB), $0
-	/*
-	 * Now in 16-bit compatibility mode.
-	 * These are 32-bit instructions being interpreted
-	 * as 16-bit instructions.  I'm being lazy and
-	 * not using the macros because I know when
-	 * the 16- and 32-bit instructions look the same
-	 * or close enough.
-	 */
-
-	/* disable protected mode and jump to real mode cs */
-	OPSIZE; MOVL CR0, AX
-	OPSIZE; XORL BX, BX
-	OPSIZE; INCL BX
-	OPSIZE; XORL BX, AX
-	OPSIZE; MOVL AX, CR0
-
-	/* JMPFAR 0x0800:now16real */
-	 BYTE $0xEA
-	 WORD	$now16real-KZERO(SB)
-	 WORD	$0x0800
-
-TEXT now16real(SB), $0
-	/* copy the registers for the bios call */
-	LWI(0x0000, rAX)
-	MOVW	AX,SS
-	LWI(RMUADDR, rBP)
-	
-	/* offsets are in Ureg */
-	LXW(44, xBP, rAX)
-	MOVW	AX, DS
-	LXW(40, xBP, rAX)
-	MOVW	AX, ES
-
-	OPSIZE; LXW(0, xBP, rDI)
-	OPSIZE; LXW(4, xBP, rSI)
-	OPSIZE; LXW(16, xBP, rBX)
-	OPSIZE; LXW(20, xBP, rDX)
-	OPSIZE; LXW(24, xBP, rCX)
-	OPSIZE; LXW(28, xBP, rAX)
-
-	CLC
-
-TEXT realmodeintrinst(SB), $0
-	INT $0x00
-
-	/* save the registers after the call */
-
-	LWI(0x7bfc, rSP)
-	OPSIZE; PUSHFL
-	OPSIZE; PUSHL AX
-
-	LWI(0, rAX)
-	MOVW	AX,SS
-	LWI(RMUADDR, rBP)
-	
-	OPSIZE; SXW(rDI, 0, xBP)
-	OPSIZE; SXW(rSI, 4, xBP)
-	OPSIZE; SXW(rBX, 16, xBP)
-	OPSIZE; SXW(rDX, 20, xBP)
-	OPSIZE; SXW(rCX, 24, xBP)
-	OPSIZE; POPL AX
-	OPSIZE; SXW(rAX, 28, xBP)
-
-	MOVW	DS, AX
-	OPSIZE; SXW(rAX, 44, xBP)
-	MOVW	ES, AX
-	OPSIZE; SXW(rAX, 40, xBP)
-
-	OPSIZE; POPL AX
-	OPSIZE; SXW(rAX, 64, xBP)	/* flags */
-
-	/* re-enter protected mode and jump to 32-bit code */
-	OPSIZE; MOVL $1, AX
-	OPSIZE; MOVL AX, CR0
-	
-/*	JMPFAR	SELECTOR(KESEG, SELGDT, 0):$again32bit(SB) /**/
-	 OPSIZE
-	 BYTE $0xEA
-	 LONG	$again32bit-KZERO(SB)
-	 WORD	$SELECTOR(KESEG, SELGDT, 0)
-
-TEXT again32bit(SB), $0
-	MOVW	$SELECTOR(KDSEG, SELGDT, 0),AX
-	MOVW	AX,DS
-	MOVW	AX,SS
-	MOVW	AX,ES
-	MOVW	AX,FS
-	MOVW	AX,GS
-
-	/* enable paging and jump to kzero-address code */
-	MOVL	CR0, AX
-	ORL	$0x80010000, AX	/* PG|WP */
-	MOVL	AX, CR0
-	LEAL	again32kzero(SB), AX
-	JMP*	AX
-
-TEXT again32kzero(SB), $0
-	/* breathe a sigh of relief - back in 32-bit protected mode */
-
-	/* switch to old stack */	
-	PUSHL	AX	/* match popl below for 8l */
-	MOVL	$0x7BFC, SP
-	POPL	SP
-
-	/* restore idt */
-	MOVL	m0idtptr(SB),IDTR
-
-	/* restore gdt */
-	MOVL	m0gdtptr(SB), GDTR
-
-	CALL	restoreregs(SB)
-	RET
-
 /*
  * BIOS32.
  */

sys/src/9/pc/mem.h

@@ -60,8 +60,6 @@
 #define	CONFADDR	(KZERO+0x1200)		/* info passed from boot loader */
 #define	TMPADDR		(KZERO+0x2000)		/* used for temporary mappings */
 #define	APBOOTSTRAP	(KZERO+0x3000)		/* AP bootstrap code */
-#define	RMUADDR		(KZERO+0x7C00)		/* real mode Ureg */
-#define	RMCODE		(KZERO+0x8000)		/* copy of first page of KTEXT */
 #define	RMBUF		(KZERO+0x9000)		/* buffer for user space - known to vga */
 #define	IDTADDR		(KZERO+0x10800)		/* idt */
 #define	REBOOTADDR	(0x11000)		/* reboot code - physical address */

sys/src/9/pc/memory.c

@@ -526,20 +526,10 @@ struct Emap
 {
 	uvlong base;
 	uvlong len;
-	ulong type;
 };
 static Emap emap[16];
 int nemap;
 
-static char *etypes[] =
-{
-	"type=0",
-	"memory",
-	"reserved",
-	"acpi reclaim",
-	"acpi nvs",
-};
-
 static int
 emapcmp(const void *va, const void *vb)
 {
@@ -551,11 +541,7 @@ emapcmp(const void *va, const void *vb)
 		return -1;
 	if(a->base > b->base)
 		return 1;
-	if(a->len < b->len)
+	return a->len - b->len;
-		return -1;
-	if(a->len > b->len)
-		return 1;
-	return a->type - b->type;
 }
 
 static void
@@ -668,66 +654,29 @@ map(ulong base, ulong len, int type)
 static int
 e820scan(void)
 {
-	int i;
+	ulong base, len;
-	Ureg u;
-	ulong cont, base, len;
 	uvlong last;
 	Emap *e;
 	char *s;
+	int i;
 
-	if((s = getconf("e820")) != nil){
+	/* passed by bootloader */
-		for(nemap = 0; nemap < nelem(emap); nemap++){
+	if((s = getconf("e820")) == nil)
-			if(*s == 0)
+		return -1;
-				break;
+	for(nemap = 0; nemap < nelem(emap); nemap++){
-			e = emap + nemap;
+		if(*s == 0)
-			e->base = strtoull(s, &s, 16);
+			break;
-			if(*s != ' ')
+		e = emap + nemap;
-				break;
+		e->base = strtoull(s, &s, 16);
-			e->len = strtoull(s, &s, 16) - e->base;
+		if(*s != ' ')
-			if(*s != ' ' && *s != 0 || e->len >= 1ull<<32 || e->len == 0)
+			break;
-				break;
+		e->len = strtoull(s, &s, 16) - e->base;
-			e->type = Ememory;
+		if(*s != ' ' && *s != 0 || e->len >= 1ull<<32 || e->len == 0)
-		}
+			break;
-	}else{
-		if(getconf("*norealmode") || getconf("*noe820scan"))
-			return -1;
-		cont = 0;
-		for(i=0; i<nelem(emap); i++){
-			memset(&u, 0, sizeof u);
-			u.ax = 0xE820;
-			u.bx = cont;
-			u.cx = 20;
-			u.dx = SMAP;
-			u.es = (PADDR(RMBUF)>>4)&0xF000;
-			u.di = PADDR(RMBUF)&0xFFFF;
-			u.trap = 0x15;
-			realmode(&u);
-			cont = u.bx;
-			if((u.flags&Carry) || u.ax != SMAP || u.cx != 20)
-				break;
-			e = &emap[nemap++];
-			*e = *(Emap*)RMBUF;
-			if(u.bx == 0)
-				break;
-		}
 	}
-
 	if(nemap == 0)
 		return -1;
-	
 	qsort(emap, nemap, sizeof emap[0], emapcmp);
-
-	if(s == nil && getconf("*noe820print") == nil){
-		for(i=0; i<nemap; i++){
-			e = &emap[i];
-			print("E820: %.8llux %.8llux ", e->base, e->base+e->len);
-			if(e->type < nelem(etypes))
-				print("%s\n", etypes[e->type]);
-			else
-				print("type=%lud\n", e->type);
-		}
-	}
-
 	last = 0;
 	for(i=0; i<nemap; i++){	
 		e = &emap[i];
@@ -747,10 +696,7 @@ e820scan(void)
 		if(last < e->base)
 			map(last, e->base-last, MemUPA);
 		last = base+len;
-		if(e->type == Ememory)
+		map(base, len, MemRAM);
-			map(base, len, MemRAM);
-		else
-			map(base, len, MemReserved);
 	}
 	if(last < (1LL<<32))
 		map(last, (u32int)-last, MemUPA);

sys/src/9/pc/pccpuf

@@ -38,7 +38,6 @@ dev
 
 link
 	segdesc
-	realmode
 	devpccard
 	devi82365
 	apm		apmjump

sys/src/9/pc/pcf

@@ -39,7 +39,6 @@ dev
 
 link
 	segdesc
-	realmode
 	devpccard
 	devi82365
 	apm		apmjump

sys/src/9/pc/realmode.c

@@ -1,140 +0,0 @@
-#include	"u.h"
-#include	"tos.h"
-#include	"../port/lib.h"
-#include	"mem.h"
-#include	"dat.h"
-#include	"fns.h"
-#include	"io.h"
-#include	"ureg.h"
-#include	"../port/error.h"
-
-/*
- * Back the processor into real mode to run a BIOS call,
- * then return.  This must be used carefully, since it 
- * completely disables hardware interrupts (e.g., the i8259)
- * while running.  It is *not* using VM86 mode. 
- * Maybe that's really the right answer, but real mode
- * is fine for now.  We don't expect to use this very much --
- * just for VGA and APM.
- */
-#define realmoderegs (*(Ureg*)RMUADDR)
-
-#define LORMBUF (RMBUF-KZERO)
-
-static Ureg rmu;
-static Lock rmlock;
-
-void
-realmode(Ureg *ureg)
-{
-	int s;
-	ulong cr3;
-	extern void realmode0(void);	/* in l.s */
-
-	if(getconf("*norealmode"))
-		return;
-
-	lock(&rmlock);
-	realmoderegs = *ureg;
-
-	/* copy l.s so that it can be run from 16-bit mode */
-	memmove((void*)RMCODE, (void*)KTZERO, 0x1000);
-
-	s = splhi();
-	m->pdb[PDX(0)] = m->pdb[PDX(KZERO)];	/* identity map low */
-	cr3 = getcr3();
-	putcr3(PADDR(m->pdb));
-	if (arch)
-		arch->introff();
-	else
-		i8259off();
-	realmode0();
-	if(m->tss){
-		/*
-		 * Called from memory.c before initialization of mmu.
-		 * Don't turn interrupts on before the kernel is ready!
-		 */
-		if (arch)
-			arch->intron();
-		else
-			i8259on();
-	}
-	m->pdb[PDX(0)] = 0;	/* remove low mapping */
-	putcr3(cr3);
-	splx(s);
-	*ureg = realmoderegs;
-	unlock(&rmlock);
-}
-
-static long
-rtrapread(Chan*, void *a, long n, vlong off)
-{
-	if(off < 0)
-		error("badarg");
-	if(n+off > sizeof rmu)
-		n = sizeof rmu - off;
-	if(n <= 0)
-		return 0;
-	memmove(a, (char*)&rmu+off, n);
-	return n;
-}
-
-static long
-rtrapwrite(Chan*, void *a, long n, vlong off)
-{
-	if(off || n != sizeof rmu)
-		error("write a Ureg");
-	memmove(&rmu, a, sizeof rmu);
-	/*
-	 * Sanity check
-	 */
-	if(rmu.trap == 0x10){	/* VBE */
-		rmu.es = (LORMBUF>>4)&0xF000;
-		rmu.di = LORMBUF&0xFFFF;
-	}else
-		error("invalid trap arguments");
-	realmode(&rmu);
-	return n;
-}
-
-static long
-rmemrw(int isr, void *a, long n, vlong off)
-{
-	if(off < 0 || n < 0)
-		error("bad offset/count");
-	if(isr){
-		if(off >= MB)
-			return 0;
-		if(off+n >= MB)
-			n = MB - off;
-		memmove(a, KADDR((ulong)off), n);
-	}else{
-		/* realmode buf page ok, allow vga framebuf's access */
-		if(off >= MB || off+n > MB ||
-		    (off < LORMBUF || off+n > LORMBUF+BY2PG) &&
-		    (off < 0xA0000 || off+n > 0xB0000+0x10000))
-			error("bad offset/count in write");
-		memmove(KADDR((ulong)off), a, n);
-	}
-	return n;
-}
-
-static long
-rmemread(Chan*, void *a, long n, vlong off)
-{
-	return rmemrw(1, a, n, off);
-}
-
-static long
-rmemwrite(Chan*, void *a, long n, vlong off)
-{
-	return rmemrw(0, a, n, off);
-}
-
-void
-realmodelink(void)
-{
-	addarchfile("realmode", 0660, rtrapread, rtrapwrite);
-	addarchfile("realmodemem", 0660, rmemread, rmemwrite);
-}
-