From: Joshua Wise <joshua@rebirth.joshuawise.com>
Date: Thu, 25 Sep 2008 22:12:28 +0000 (-0400)
Subject: Put BSS clearing in firstrun
X-Git-Url: http://git.joshuawise.com/netwatch.git/commitdiff_plain/f2b87dd63dc50a707ac102db7afb849b1f4f8db0?ds=sidebyside;hp=efea5b4edd5cc94b4ed0917ebca0efb6bb6a2f82

Put BSS clearing in firstrun
---

diff --git a/aseg/aseg.asm b/aseg/aseg.asm
index a6f71c2..7380dc0 100644
--- a/aseg/aseg.asm
+++ b/aseg/aseg.asm
@@ -22,18 +22,8 @@ continue:
 	mov gs, ax
 	mov ss, ax
 	mov esp, [dataptr]		; Load stack pointer.
-
-	mov al, [needclear]		; Has the aseg been run before?
-	cmp al, 0			; If so,
-	jz noclear			; don't clear BSS.
-	mov al, 0			; Otherwise, clear BSS.
-	mov edi, [dataptr+4]
-	mov ecx, [dataptr+8]
-	rep stosb
-	mov [needclear], al
 	
-noclear:
-	mov eax, [dataptr+12]		; Load target jump address
+	mov eax, [dataptr+4]		; Load target jump address
 	call eax			; then jump into C.
 
 	rsm				; and leave SMM
@@ -48,12 +38,7 @@ gdt:
 	db 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x93, 0xCF, 0x00	; data segment
 	db 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x9B, 0xCF, 0x00	; code segment
 
-needclear:
-	db 0x01
-
 dataptr:
 	; 4 bytes of stack top
-	; 4 bytes of BSS start
-	; 4 bytes of BSS length
 	; 4 bytes of C entry point
 	; These show up 
diff --git a/aseg/aseg.lds b/aseg/aseg.lds
index e969a54..83afbae 100644
--- a/aseg/aseg.lds
+++ b/aseg/aseg.lds
@@ -7,8 +7,6 @@ SECTIONS
 		_start = .;
 		aseg.o
 		LONG(_stacktop);
-		LONG(_bss);
-		LONG(_bssend - _bss);
 		LONG(smi_entry);
 		*(.text);
 		*(.data);
diff --git a/aseg/firstrun.c b/aseg/firstrun.c
index c6eab7b..9589a13 100644
--- a/aseg/firstrun.c
+++ b/aseg/firstrun.c
@@ -3,8 +3,20 @@
 #include <pci.h>
 #include <reg-82801b.h>
 #include "vga-overlay.h"
+#include <smram.h>
+
+extern int _bss, _bssend;
 
 void __firstrun_start() {
+	unsigned char *bp;
+	smram_state_t smram;
+	
+	smram = smram_save_state();
+	smram_tseg_set_state(SMRAM_TSEG_OPEN);
+	
+	for (bp = (void *)&_bss; (void *)bp < (void *)&_bssend; bp++)
+		*bp = 0;
+	
 	dologf("NetWatch running");
 
 	/* Try really hard to shut up USB_LEGKEY. */
@@ -17,5 +29,7 @@ void __firstrun_start() {
 	outb(0x830, inb(0x830) | ICH2_SMI_EN_SWSMI_TMR_EN);
 	outb(0x848, ICH2_DEVTRAP_EN_KBC_TRP_EN);
 	smi_enable();
+	
+	smram_restore_state(smram);
 }
 
diff --git a/grubload/multiboot_c.c b/grubload/multiboot_c.c
index 04f9b2f..17c1542 100644
--- a/grubload/multiboot_c.c
+++ b/grubload/multiboot_c.c
@@ -50,10 +50,10 @@ void c_start(unsigned int magic, struct mb_info *mbinfo)
 
 	if (mbinfo->mod_cnt != 1)
 		panic("Expected exactly one module; cannot continue.");
-
+	outputf("Current SMRAMC state is: %02x", pci_read8(0, 0, 0, 0x70));
 	outputf("Current USB state is: %04x %04x", pci_read16(0, 31, 2, 0xC0), pci_read16(0, 31, 4, 0xC0));
 	outputf("Current SMI state is: %08x", inl(0x830));
-	outputf("Current SMRAMC state is: %02x", pci_read8(0, 0, 0, 0x70));
+	
 	
 	smi_disable();
 	
@@ -80,6 +80,8 @@ void c_start(unsigned int magic, struct mb_info *mbinfo)
 
 	info->firstrun();
 	smram_restore_state(old_smramc);
+	
+	outputf("New SMRAMC state is: %02x", pci_read8(0, 0, 0, 0x70));
 
 	puts("Waiting for a bit before returning to real mode...");
 	for (i=0; i<0x500000; i++)
diff --git a/grubload/output.c b/grubload/output.c
index 6a6ffab..6abc72a 100644
--- a/grubload/output.c
+++ b/grubload/output.c
@@ -8,7 +8,7 @@
 
 static void safeputs(const char *s)
 {
-	unsigned long old = smram_save_state();
+	smram_state_t old = smram_save_state();
 	smram_aseg_set_state(SMRAM_ASEG_SMMONLY);
 	puts(s);
 	smram_restore_state(old);
diff --git a/ich2/smram-ich2.c b/ich2/smram-ich2.c
index d274c85..edf8ad5 100644
--- a/ich2/smram-ich2.c
+++ b/ich2/smram-ich2.c
@@ -127,3 +127,25 @@ int smram_aseg_set_state (int open) {
 
 	return 0;
 }
+
+int smram_tseg_set_state (int open) {
+	unsigned char smramc;
+
+	if (smram_locked())
+		return -1;
+		
+	smramc = pci_read8(0, 0, 0, SMRAMC);
+
+	switch (open)
+	{
+	case SMRAM_TSEG_OPEN:
+		smramc = (smramc & 0x8F) | 0x00;
+		break;
+	default:
+		return -1;
+	}
+
+	pci_write8(0, 0, 0, SMRAMC, smramc);
+
+	return 0;
+}
diff --git a/include/smram.h b/include/smram.h
index 6c4ac69..5509d09 100644
--- a/include/smram.h
+++ b/include/smram.h
@@ -6,11 +6,14 @@
 extern int smram_locked();
 extern smram_state_t smram_save_state();
 extern void smram_restore_state(smram_state_t state);
-extern int smram_aseg_set_state (int open);
+extern int smram_aseg_set_state(int open);
+extern int smram_tseg_set_state(int open);
 
 #define SMRAM_ASEG_CLOSED 0	/* SMRAM is not readable. */
 #define SMRAM_ASEG_OPEN 1	/* SMRAM is readable by everybody. */
 #define SMRAM_ASEG_SMMCODE 2	/* SMRAM is readable as SMM code only. */
 #define SMRAM_ASEG_SMMONLY 3	/* SMRAM is readable as SMM code and data only. */
 
+#define SMRAM_TSEG_OPEN 0
+
 #endif