[syslinux:pathbased] memdisk: Use real_addr_t for SEG:OFF fields
syslinux-bot for Shao Miller
shao.miller at yrdsb.edu.on.ca
Thu Jun 17 11:45:22 PDT 2010
Commit-ID: 345a7cba6786de010359607e40f96f6fccbf40a5
Gitweb: http://syslinux.zytor.com/commit/345a7cba6786de010359607e40f96f6fccbf40a5
Author: Shao Miller <shao.miller at yrdsb.edu.on.ca>
AuthorDate: Tue, 9 Mar 2010 14:45:12 -0500
Committer: Shao Miller <shao.miller at yrdsb.edu.on.ca>
CommitDate: Fri, 11 Jun 2010 01:49:10 +0000
memdisk: Use real_addr_t for SEG:OFF fields
We used uint32_t in a few places where it's also handy
to refer to those fields' segment and offset components.
Now we can do so via the real_addr_t union type.
Additionally, there are a couple of places where we now
have pointer fields instead of uint32_t fields, because
we know what kind of struct the field is pointing to.
Signed-off-by: Shao Miller <shao.miller at yrdsb.edu.on.ca>
---
memdisk/mstructs.h | 37 ++++++++++++++++++++++++++-----------
memdisk/setup.c | 32 +++++++++++++++-----------------
2 files changed, 41 insertions(+), 28 deletions(-)
diff --git a/memdisk/mstructs.h b/memdisk/mstructs.h
index 635e47e..d6b6265 100644
--- a/memdisk/mstructs.h
+++ b/memdisk/mstructs.h
@@ -15,17 +15,30 @@
/* These structures are common to MEMDISK and MDISKCHK.COM */
+#include <stdint.h>
+
+struct seg_off {
+ uint16_t offset;
+ uint16_t segment;
+};
+
+typedef union {
+ struct seg_off seg_off;
+ uint32_t uint32;
+} real_addr_t;
+
MEMDISK_PACKED_PREFIX
struct safe_hook {
uint8_t jump[3]; /* Max. three bytes for jump */
uint8_t signature[8]; /* "$INT13SF" */
uint8_t vendor[8]; /* "MEMDISK " */
- uint32_t old_hook; /* SEG:OFF for previous INT 13h hook */
+ real_addr_t old_hook; /* SEG:OFF for previous INT 13h hook */
uint32_t flags; /* "Safe hook" flags */
/* The next field is a MEMDISK extension to the "safe hook" structure */
- uint32_t mBFT; /* Offset from hook to the mBFT; refilled
- * by setup() with the physical address
- */
+ union {
+ uint32_t offset; /* Offset from hook to the mBFT; refilled */
+ struct mBFT *ptr; /* by setup() with the physical address */
+ } mBFT;
} MEMDISK_PACKED_POSTFIX;
/* Requirement for struct acpi_description_header */
@@ -34,7 +47,10 @@ struct safe_hook {
MEMDISK_PACKED_PREFIX
struct mBFT {
struct acpi_description_header acpi;
- uint32_t safe_hook; /* "Safe hook" physical address */
+ struct safe_hook *safe_hook; /* "Safe hook" physical address */
+ /* An mBFT is 70 bytes in total */
+ uint8_t _pad[70 - (sizeof(struct acpi_description_header) +
+ sizeof(uint32_t))];
} MEMDISK_PACKED_POSTFIX;
MEMDISK_PACKED_PREFIX
@@ -47,7 +63,7 @@ struct edd_dpt {
uint32_t s; /* Physical sectors/track (count!) */
uint64_t sectors; /* Total sectors */
uint16_t bytespersec; /* Bytes/sector */
- uint16_t dpte_off, dpte_seg; /* DPTE pointer */
+ real_addr_t dpte; /* DPTE pointer */
uint16_t dpikey; /* Device Path Info magic */
uint8_t dpilen; /* Device Path Info length */
uint8_t res1; /* Reserved */
@@ -67,10 +83,10 @@ MEMDISK_PACKED_PREFIX
struct patch_area {
uint32_t diskbuf;
uint32_t disksize;
- uint16_t cmdline_off, cmdline_seg;
+ real_addr_t cmdline;
- uint32_t oldint13;
- uint32_t oldint15;
+ real_addr_t oldint13;
+ real_addr_t oldint15;
uint16_t olddosmem;
uint8_t bootloaderid;
@@ -107,6 +123,5 @@ struct patch_area {
dpt_t dpt;
struct edd_dpt edd_dpt;
- struct edd4_cd_pkt cd_pkt; /* Only really in a memdisk_iso_* hook */
+ struct edd4_cd_pkt cd_pkt; /* Only really in a memdisk_iso_* hook */
} MEMDISK_PACKED_POSTFIX;
-
diff --git a/memdisk/setup.c b/memdisk/setup.c
index 067a8ac..1e0655e 100644
--- a/memdisk/setup.c
+++ b/memdisk/setup.c
@@ -1032,8 +1032,8 @@ void setup(const struct real_mode_args *rm_args_ptr)
/* Anything beyond the end is for the stack */
pptr->mystack = (uint16_t) (stddosmem - driveraddr);
- pptr->oldint13 = rdz_32(BIOS_INT13);
- pptr->oldint15 = rdz_32(BIOS_INT15);
+ pptr->oldint13.uint32 = rdz_32(BIOS_INT13);
+ pptr->oldint15.uint32 = rdz_32(BIOS_INT15);
/* Adjust the E820 table: if there are null ranges (type 0)
at the end, change them to type end of list (-1).
@@ -1048,7 +1048,7 @@ void setup(const struct real_mode_args *rm_args_ptr)
bios_drives = 0;
pptr->drivecnt = 0;
no_bpt = 1;
- pptr->oldint13 = driverptr + hptr->iret_offs;
+ pptr->oldint13.uint32 = driverptr + hptr->iret_offs;
wrz_8(BIOS_EQUIP, rdz_8(BIOS_EQUIP) & ~0xc1);
wrz_8(BIOS_HD_COUNT, 0);
} else if (getcmditem("nopass") != CMD_NOTFOUND) {
@@ -1097,7 +1097,7 @@ void setup(const struct real_mode_args *rm_args_ptr)
}
/* Note the previous INT 13h hook in the "safe hook" structure */
- safe_hook->old_hook = pptr->oldint13;
+ safe_hook->old_hook.uint32 = pptr->oldint13.uint32;
/* Add ourselves to the drive count */
pptr->drivecnt++;
@@ -1114,8 +1114,8 @@ void setup(const struct real_mode_args *rm_args_ptr)
pptr->driveshiftlimit);
/* Pointer to the command line */
- pptr->cmdline_off = bin_size + (nranges + 1) * sizeof(ranges[0]);
- pptr->cmdline_seg = driverseg;
+ pptr->cmdline.seg_off.offset = bin_size + (nranges + 1) * sizeof(ranges[0]);
+ pptr->cmdline.seg_off.segment = driverseg;
/* Copy driver followed by E820 table followed by command line */
{
@@ -1134,7 +1134,8 @@ void setup(const struct real_mode_args *rm_args_ptr)
}
/* Re-fill the "safe hook" mBFT field with the physical address */
- safe_hook->mBFT += (uint32_t)hptr;
+ safe_hook->mBFT.ptr =
+ (struct mBFT *)(((const char *)hptr) + safe_hook->mBFT.offset);
/* Update various BIOS magic data areas (gotta love this shit) */
@@ -1170,16 +1171,13 @@ void setup(const struct real_mode_args *rm_args_ptr)
}
/* Complete the mBFT */
- {
- struct mBFT *mBFT = (struct mBFT *)safe_hook->mBFT;
-
- mBFT->acpi.signature[0] = 'm'; /* "mBFT" */
- mBFT->acpi.signature[1] = 'B';
- mBFT->acpi.signature[2] = 'F';
- mBFT->acpi.signature[3] = 'T';
- mBFT->safe_hook = (uint32_t)safe_hook;
- mBFT->acpi.checksum = -checksum_buf(mBFT, mBFT->acpi.length);
- }
+ safe_hook->mBFT.ptr->acpi.signature[0] = 'm'; /* "mBFT" */
+ safe_hook->mBFT.ptr->acpi.signature[1] = 'B';
+ safe_hook->mBFT.ptr->acpi.signature[2] = 'F';
+ safe_hook->mBFT.ptr->acpi.signature[3] = 'T';
+ safe_hook->mBFT.ptr->safe_hook = safe_hook;
+ safe_hook->mBFT.ptr->acpi.checksum =
+ -checksum_buf(safe_hook->mBFT.ptr, safe_hook->mBFT.ptr->acpi.length);
/* Install the interrupt handlers */
printf("old: int13 = %08x int15 = %08x int1e = %08x\n",
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