r760 - in coreboot-v3: arch/x86 include include/arch/x86 lib

Author: hailfinger
Date: 2008-08-14 11:25:58 +0200 (Thu, 14 Aug 2008)
New Revision: 760

Modified:
   coreboot-v3/arch/x86/stage1.c
   coreboot-v3/include/arch/x86/cpu.h
   coreboot-v3/include/console.h
   coreboot-v3/lib/console.c
Log:
Introduce a generic global variable storage mechanism and switch the
printk buffer management to it.

Build tested and boot tested and result tested on Qemu.

Adding a new global variable is not as easy as it looks, but the
comments in the code should be good enough to tell you how.

Signed-off-by: Carl-Daniel Hailfinger 
Acked-by: Ronald G. Minnich

Modified: coreboot-v3/arch/x86/stage1.c
===================================================================
--- coreboot-v3/arch/x86/stage1.c	2008-08-14 01:40:31 UTC (rev 759)
+++ coreboot-v3/arch/x86/stage1.c	2008-08-14 09:25:58 UTC (rev 760)
@@ -70,12 +70,21 @@

}

+/*
+ * The name is slightly misleading because this is the initial stack pointer,
+ * not the address of the first element on the stack.
+ */
 void *bottom_of_stack(void)
 {
-	/* -4-4 because CONFIG_CARBASE + CONFIG_CARSIZE - 4 is initial %esp */
-	return (void *)(CONFIG_CARBASE + CONFIG_CARSIZE - 4 - 4);
+	/* -4 because CONFIG_CARBASE + CONFIG_CARSIZE - 4 is initial %esp */
+	return (void *)(CONFIG_CARBASE + CONFIG_CARSIZE - 4);
 }

+struct global_vars *global_vars(void)
+{
+	return (struct global_vars *)(bottom_of_stack() - sizeof(struct global_vars));
+}
+
 void dump_mem_range(int msg_level, unsigned char *buf, int size)
 {
    int i;

Modified: coreboot-v3/include/arch/x86/cpu.h
===================================================================
--- coreboot-v3/include/arch/x86/cpu.h	2008-08-14 01:40:31 UTC (rev 759)
+++ coreboot-v3/include/arch/x86/cpu.h	2008-08-14 09:25:58 UTC (rev 760)
@@ -202,6 +202,7 @@
 }

SHARED(bottom_of_stack, void *, void);
+SHARED(global_vars, struct global_vars *, void);

#ifdef CONFIG_CONSOLE_BUFFER
 #define PRINTK_BUF_SIZE_CAR (CONFIG_CARSIZE / 2)

Modified: coreboot-v3/include/console.h
===================================================================
--- coreboot-v3/include/console.h	2008-08-14 01:40:31 UTC (rev 759)
+++ coreboot-v3/include/console.h	2008-08-14 09:25:58 UTC (rev 760)
@@ -59,6 +59,18 @@
 };
 #endif

+/*
+ * If you change struct global_vars in any way, you have to fix all stage0 asm
+ * code. The stage0 asm code modification is nontrivial (size of the struct,
+ * alignment, initialization, order of struct members, initialization).
+ * Depending on your compiler, real breakage may happen.
+ */
+struct global_vars {
+#ifdef CONFIG_CONSOLE_BUFFER
+	struct printk_buffer *printk_buffer;
+#endif
+};
+
 SHARED_WITH_ATTRIBUTES(printk, int, __attribute__((format (printf, 2, 3))),
    				int msg_level, const char *fmt, ...);
 SHARED(banner, void, int msg_level, const char *msg);

Modified: coreboot-v3/lib/console.c
===================================================================
--- coreboot-v3/lib/console.c	2008-08-14 01:40:31 UTC (rev 759)
+++ coreboot-v3/lib/console.c	2008-08-14 09:25:58 UTC (rev 760)
@@ -35,13 +35,16 @@
 }

#ifdef CONFIG_CONSOLE_BUFFER
+struct printk_buffer *printk_buffer_addr(void)
+{
+	return global_vars()->printk_buffer;
+}
+
 void printk_buffer_move(void *newaddr, int newsize)
 {
-	struct printk_buffer **p;
    struct printk_buffer *oldbuf, *newbuf;
    int copylen;
-	p = bottom_of_stack();
-	oldbuf = *p;
+	oldbuf = printk_buffer_addr();
    newbuf = newaddr;
    newbuf->len = newsize;
    newbuf->readoffset = 0;
@@ -68,17 +71,10 @@
    		&oldbuf->buffer[0], copylen);
    	newbuf->writeoffset += copylen;
    }
-	*p = newbuf;
+	global_vars()->printk_buffer = newbuf;
    return;
 }

-struct printk_buffer *printk_buffer_addr(void)
-{
-	struct printk_buffer **p;
-	p = bottom_of_stack();
-	return *p;
-}
-
 void printk_buffer_init(void)
 {
    struct printk_buffer *buf = printk_buffer_addr();