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authorMatt Fleming <matt.fleming@intel.com>2012-05-01 08:55:45 +0100
committerMatt Fleming <matt.fleming@intel.com>2012-06-07 14:19:20 +0100
commitc0d18deeee22f3466fd863d64b432660965ec66e (patch)
tree8fce613ef56efd6d112ede4e394051a99490a66f /com32/elflink/ldlinux/loadhigh.c
parent4fc3fd1e14f4c1b9208ef262e5b6aef853e9fce4 (diff)
downloadsyslinux-c0d18deeee22f3466fd863d64b432660965ec66e.tar.gz
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elflink: Fix boot sector booting
This adds missing support for booting from a boot sector file such as .bs, .bss or .0, by re-implementing the old asm bootsec code from core/bootsect.inc in C. This has resulted in some external changes. We've had to make StackBuf a global symbol because we access it directly from execute.c. Also, we need to move dsinfo.c into MINLIBOBJS because ldlinux now needs to reference __syslinux_derivative_info. Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Diffstat (limited to 'com32/elflink/ldlinux/loadhigh.c')
-rw-r--r--com32/elflink/ldlinux/loadhigh.c112
1 files changed, 112 insertions, 0 deletions
diff --git a/com32/elflink/ldlinux/loadhigh.c b/com32/elflink/ldlinux/loadhigh.c
new file mode 100644
index 00000000..0f2f8428
--- /dev/null
+++ b/com32/elflink/ldlinux/loadhigh.c
@@ -0,0 +1,112 @@
+/*
+ * -----------------------------------------------------------------------
+ *
+ * Copyright 1994-2009 H. Peter Anvin - All Rights Reserved
+ * Copyright 2009-2010 Intel Corporation; author: H. Peter Anvin
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ * Boston MA 02111-1307, USA; either version 2 of the License, or
+ * (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * loadhigh.c
+ *
+ * An alternate interface to getfssec.
+ *
+ * Inputs: SI = file handle/cluster pointer
+ * EDI = target address in high memory
+ * EAX = maximum number of bytes to load
+ * DX = zero-padding mask (e.g. 0003h for pad to dword)
+ * BX = 16-bit subroutine to call at the top of each loop
+ * (to print status and check for abort)
+ * EBP = maximum load address
+ *
+ * Outputs: SI = file handle/cluster pointer
+ * EBX = first untouched address (not including padding)
+ * EDI = first untouched address (including padding)
+ * CF = reached EOF
+ * OF = ran out of high memory
+ */
+
+#include <com32.h>
+#include <minmax.h>
+#include "core.h"
+#include "fs.h"
+
+#define MAX_CHUNK (1UL << 20) /* 1 MB */
+
+void pm_load_high(com32sys_t *regs)
+{
+ struct fs_info *fs;
+ uint32_t bytes;
+ uint32_t zero_mask;
+ bool have_more;
+ uint32_t bytes_read;
+ char *buf, *limit;
+ struct file *file;
+ uint32_t sector_mask;
+ size_t pad;
+ uint32_t retflags = 0;
+
+ bytes = regs->eax.l;
+ zero_mask = regs->edx.w[0];
+ buf = (char *)regs->edi.l;
+ limit = (char *)(regs->ebp.l & ~zero_mask);
+ file = handle_to_file(regs->esi.w[0]);
+ fs = file->fs;
+
+ sector_mask = SECTOR_SIZE(fs) - 1;
+
+ while (bytes) {
+ uint32_t sectors;
+ uint32_t chunk;
+
+ if (buf + SECTOR_SIZE(fs) > limit) {
+ /* Can't fit even one more sector in... */
+ retflags = EFLAGS_OF;
+ break;
+ }
+
+ chunk = bytes;
+
+ if (regs->ebx.w[0]) {
+ call16((void (*)(void))(size_t)regs->ebx.w[0], &zero_regs, NULL);
+ chunk = min(chunk, MAX_CHUNK);
+ }
+
+ if (chunk > (((char *)limit - buf) & ~sector_mask))
+ chunk = ((char *)limit - buf) & ~sector_mask;
+
+ sectors = (chunk + sector_mask) >> SECTOR_SHIFT(fs);
+ bytes_read = fs->fs_ops->getfssec(file, buf, sectors, &have_more);
+
+ if (bytes_read > chunk)
+ bytes_read = chunk;
+
+ buf += bytes_read;
+ bytes -= bytes_read;
+
+ if (!have_more) {
+ /*
+ * If we reach EOF, the filesystem driver will have already closed
+ * the underlying file... this really should be cleaner.
+ */
+ _close_file(file);
+ regs->esi.w[0] = 0;
+ retflags = EFLAGS_CF;
+ break;
+ }
+ }
+
+ pad = (size_t)buf & zero_mask;
+ if (pad)
+ memset(buf, 0, pad);
+
+ regs->ebx.l = (size_t)buf;
+ regs->edi.l = (size_t)buf + pad;
+ set_flags(regs, retflags);
+}