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>

diff --git a/memdisk/memdisk.h b/memdisk/memdisk.h
index cf4a1e9..41ce13b 100644 (file)
--- 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 e8e5d78..2568eed 100644 (file)
--- 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 c4fc7e2..f9b9ed1 100644 (file)
--- 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 d631875..8fcebcc 100644 (file)
--- 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: