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Allow space for the kernel's real-mode .bss. Previously we weren't
allowing any space for this, which makes it surprising that bzImage
loading ever worked.
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Michael Brown committed Nov 4, 2007
1 parent c482fef commit 755cb83
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Showing 2 changed files with 9 additions and 1 deletion.
8 changes: 7 additions & 1 deletion src/arch/i386/image/bzimage.c
Expand Up @@ -343,6 +343,11 @@ static int bzimage_exec ( struct image *image ) {
/* Prepare for exiting */
shutdown();

DBGC ( image, "bzImage %p jumping to RM kernel at %04x:0000 "
"(stack %04x:%04x)\n", image,
( exec_ctx.rm_kernel_seg + 0x20 ),
exec_ctx.rm_kernel_seg, exec_ctx.rm_heap );

/* Jump to the kernel */
__asm__ __volatile__ ( REAL_CODE ( "movw %w0, %%ds\n\t"
"movw %w0, %%es\n\t"
Expand Down Expand Up @@ -403,8 +408,9 @@ static int bzimage_load_header ( struct image *image,
/* Calculate load address and size of real-mode portion */
load_ctx->rm_kernel_seg = 0x1000; /* place RM kernel at 1000:0000 */
load_ctx->rm_kernel = real_to_user ( load_ctx->rm_kernel_seg, 0 );
load_ctx->rm_filesz = load_ctx->rm_memsz =
load_ctx->rm_filesz =
( ( bzhdr->setup_sects ? bzhdr->setup_sects : 4 ) + 1 ) << 9;
load_ctx->rm_memsz = BZI_ASSUMED_RM_SIZE;
if ( load_ctx->rm_filesz > image->len ) {
DBGC ( image, "bzImage %p too short for %zd byte of setup\n",
image, load_ctx->rm_filesz );
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2 changes: 2 additions & 0 deletions src/arch/i386/include/bzimage.h
Expand Up @@ -117,6 +117,8 @@ struct bzimage_cmdline {
/** bzImage command line present magic marker value */
#define BZI_CMDLINE_MAGIC 0xa33f

/** Assumed size of real-mode portion (including .bss) */
#define BZI_ASSUMED_RM_SIZE 0x8000

/** Amount of stack space to provide */
#define BZI_STACK_SIZE 0x1000
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