From 29fe6716800e14c9a48951e6cec1b92896604192 Mon Sep 17 00:00:00 2001
From: Jan Kobler <eng1@koblersystems.de>
Date: Tue, 3 Jun 2014 15:51:55 +0200
Subject: [PATCH] arm: clear highly mapped kernel bss

	. added bss range values for the high (paged) kernel and
	  clear it in pre_init
	. this changes the meaning of the current _edata end _end in the
	  pre_init phase to mean: highly mapped bss; and the new symbols
	  _kern_unpaged_edata ... _kern_unpaged_edata to mean directly
	  mapped (pre_init) bss. This was previously _edata and _end.
	. added a sanity check in kmain (ben@)

The values can be verified by:

${CROSS_TOOLS}/arm-elf32-minix-objdump -xD ${OBJ}/kernel/kernel

Signed-off-by: Jan Kobler <eng1@koblersystems.de>
---
 kernel/arch/earm/kernel.lds | 8 +++++---
 kernel/arch/earm/pre_init.c | 6 ++++++
 kernel/main.c               | 5 +++++
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/kernel/arch/earm/kernel.lds b/kernel/arch/earm/kernel.lds
index c448dc140..9070b38bb 100644
--- a/kernel/arch/earm/kernel.lds
+++ b/kernel/arch/earm/kernel.lds
@@ -16,11 +16,10 @@ SECTIONS
 
 	.unpaged_text ALIGN(4096) : { unpaged_*.o(.text) }
 	.unpaged_data ALIGN(4096) : { unpaged_*.o(.data .rodata*) }
-	__k_unpaged__kern_unpaged__edata = .;
-	__k_unpaged__edata = .;
+	__k_unpaged__kern_unpaged_edata = .;
+
 	.unpaged_bss  ALIGN(4096) : { unpaged_*.o(.bss COMMON) }
 	__k_unpaged__kern_unpaged_end = .;
-	__k_unpaged__end = .;
 
 	. += _kern_offset;
 
@@ -34,12 +33,15 @@ SECTIONS
 	.data ALIGN(4096) : AT(ADDR(.data) - _kern_offset) { *(.data .rodata* ) }
 	. = ALIGN(4096);
 	_edata = .;
+	__k_unpaged__edata = . - _kern_offset;
 	.bss ALIGN(4096)  : AT(ADDR(.bss) - _kern_offset) { *(.bss* COMMON)
 		__k_unpaged__kern_size = . - _kern_vir_base;
 		_kern_size = __k_unpaged__kern_size;
+		
 		. += 4096;
 	}
 	_end = .;
+        __k_unpaged__end = . - _kern_offset;
 
       /DISCARD/ :
        {
diff --git a/kernel/arch/earm/pre_init.c b/kernel/arch/earm/pre_init.c
index 86b4e52aa..a7c757b8f 100644
--- a/kernel/arch/earm/pre_init.c
+++ b/kernel/arch/earm/pre_init.c
@@ -37,9 +37,14 @@ static void setup_mbi(multiboot_info_t *mbi, char *bootargs);
 /* Kernel may use memory */
 int kernel_may_alloc = 1;
 
+/* kernel bss */
 extern u32_t _edata;
 extern u32_t _end;
 
+/* kernel unpaged bss */
+extern char _kern_unpaged_edata;
+extern char _kern_unpaged_end;
+
 /**
  *
  * The following function combines a few things together
@@ -374,6 +379,7 @@ kinfo_t *pre_init(int argc, char **argv)
 	   
 	/* Clear BSS */
 	memset(&_edata, 0, (u32_t)&_end - (u32_t)&_edata);
+        memset(&_kern_unpaged_edata, 0, (u32_t)&_kern_unpaged_end - (u32_t)&_kern_unpaged_edata);
 
 	/* we get called in a c like fashion where the first arg
          * is the program name (load address) and the rest are
diff --git a/kernel/main.c b/kernel/main.c
index 8670ba530..cf59c09b0 100644
--- a/kernel/main.c
+++ b/kernel/main.c
@@ -123,6 +123,11 @@ void kmain(kinfo_t *local_cbi)
   struct boot_image *ip;	/* boot image pointer */
   register struct proc *rp;	/* process pointer */
   register int i, j;
+  static int bss_test;
+
+  /* bss sanity check */
+  assert(bss_test == 0);
+  bss_test = 1;
 
   /* save a global copy of the boot parameters */
   memcpy(&kinfo, local_cbi, sizeof(kinfo));