memdisk: move rm_args initialization to C code; export rm_size

Move the rm_args initialization (and the associated sti) to C code.
Export the total size of the real-mode code to the protected-mode
code.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

4 files changed, 21 insertions, 20 deletions

diff --git a/memdisk/memdisk.h b/memdisk/memdisk.h
index cf4a1e99..41ce13b1 100644
--- a/memdisk/memdisk.h
+++ b/memdisk/memdisk.h
@@ -72,6 +72,16 @@ static inline int memcmp(const void *__a, const void *__b, unsigned int __n)
     return 0;
 }
 
+static inline void sti(void)
+{
+    asm volatile("sti");
+}
+
+static inline void cli(void)
+{
+    asm volatile("cli");
+}
+
 /* Decompression */
 extern int check_zip(void *indata, uint32_t size, uint32_t * zbytes_p,
 		     uint32_t * dbytes_p, uint32_t * orig_crc,
diff --git a/memdisk/memdisk16.asm b/memdisk/memdisk16.asm
index e8e5d78d..2568eed4 100644
--- a/memdisk/memdisk16.asm
+++ b/memdisk/memdisk16.asm
@@ -596,10 +596,8 @@ call32_call_start:
 		;
 		mov esp, (BOUNCE_SEG << 4) + 0x10000
 
-		; Arguments for start32.S only
+		push dword stack_end		; RM size
 		push dword call32_handle_interrupt+CS_BASE
-
-		; Arguments for setup()
 		push dword CS_BASE		; Segment base
 		push dword (BOUNCE_SEG << 4)	; Bounce buffer address
 		push dword call32_syscall+CS_BASE ; Syscall entry point
diff --git a/memdisk/setup.c b/memdisk/setup.c
index c4fc7e23..f9b9ed1f 100644
--- a/memdisk/setup.c
+++ b/memdisk/setup.c
@@ -154,7 +154,6 @@ struct setup_header {
     uint32_t sssp;
     uint32_t csip;
 };
-
 struct setup_header *shdr;
 
 /* Structure passed in from the real-mode code */
@@ -164,8 +163,9 @@ struct real_mode_args {
     uint32_t rm_bounce;
     uint32_t rm_base;
     uint32_t rm_handle_interrupt;
+    uint32_t rm_size;
 };
-extern struct real_mode_args rm_args;
+struct real_mode_args rm_args;
 
 /* Access to high memory */
 
@@ -713,7 +713,7 @@ static uint32_t pnp_install_check(void)
 __cdecl syscall_t syscall;
 void *sys_bounce;
 
-void setup(void)
+void setup(const struct real_mode_args *rm_args_ptr)
 {
     unsigned int bin_size;
     char *memdisk_hook;
@@ -731,6 +731,10 @@ void setup(void)
     int do_edd = 1;		/* 0 = no, 1 = yes, default is yes */
     int no_bpt;			/* No valid BPT presented */
 
+    /* We need to copy the rm_args into their proper place */
+    memcpy(&rm_args, rm_args_ptr, sizeof rm_args);
+    sti();			/* ... then interrupts are safe */
+
     /* Set up global variables */
     syscall = (__cdecl syscall_t) rm_args.rm_syscall;
     sys_bounce = (void *)rm_args.rm_bounce;
diff --git a/memdisk/start32.S b/memdisk/start32.S
index d631875d..8fcebcc6 100644
--- a/memdisk/start32.S
+++ b/memdisk/start32.S
@@ -16,8 +16,6 @@
  * this module must be linked first
  */
 
-#define ARGS	4			/* Number of real-mode arguments */
-
 	.section ".init", "ax"
 	.globl _start
 _start:
@@ -67,19 +65,15 @@ _start:
 	lidtl	idt_ptr
 	
 	/* Save arguments, switch stacks */
-	movl	%esp, %esi
+	movl	%esp, %eax		/* Pointer to arguments */
 	movl	$__stack_end, %esp
-	movl	$rm_args, %edi
-	movl	$(ARGS+1), %ecx
-	rep; movsl
 	
-	sti			/* Ready for interrupts now */
 	call	setup
-	jmp	*(rm_args)	/* First argument is return */
+	jmp	*(rm_args)		/* First argument is return */
 
 	.section ".text","ax"
 handle_interrupt:
-	jmp	*(rm_args+4*4)	/* Interrupt pointer is argument 4 */
+	jmp	*(rm_args+4*4)		/* Interrupt pointer is argument 4 */
 
 	.section ".rodata","a"
 idt_ptr:
@@ -87,11 +81,6 @@ idt_ptr:
 	.long	idt
 	.word	0
 
-	.section ".bss","aw"
-	.globl	rm_args
-rm_args:
-	.space	(ARGS+1)*4
-
 	.section ".bss.large","aw"
 	.balign 2048
 idt: