Re: [Qemu-devel] [PATCH v4 15/23] i386: add bios linker/loader

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Sep 23, 2013 at 03:52:21PM +0200, Paolo Bonzini wrote:
> Il 23/09/2013 15:47, Michael S. Tsirkin ha scritto:
> > > It doesn't, the names were already prefixed with alloc_/pointer_/cksum_.
> > >  All it does is change underscores to periods.
> > 
> > You are right, that's cleaner. I'll do this.
> > I don't want to sprinkle QEMU_PACKED around though,
> > it's just there for documentation purposes, so one
> > place is enough.
> 
> Fair enough.  Thanks!
> 
> Paolo

At Paolo's request, I moved the header to hw/i386,
and tweaked some names a bit.
The result is below. Not reposting the full series at
this time to reduce churn.

commit 7e6224a1a0a07e59668337e7665659760e36ec64
Author: Michael S. Tsirkin <mst@redhat.com>
Date:   Wed Jul 24 18:56:06 2013 +0300

    i386: add bios linker/loader
    
    This adds a dynamic bios linker/loader.
    This will be used by acpi table generation
    code to:
        - load each table in the appropriate memory segment
        - link tables to each other
        - fix up checksums after said linking
    
    Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

---

diff --git a/hw/i386/bios-linker-loader.h b/hw/i386/bios-linker-loader.h
new file mode 100644
index 0000000..498c0af
--- /dev/null
+++ b/hw/i386/bios-linker-loader.h
@@ -0,0 +1,27 @@
+#ifndef BIOS_LINKER_LOADER_H
+#define BIOS_LINKER_LOADER_H
+
+#include <glib.h>
+#include <stdbool.h>
+#include <inttypes.h>
+
+GArray *bios_linker_loader_init(void);
+
+void bios_linker_loader_alloc(GArray *linker,
+                              const char *file,
+                              uint32_t alloc_align,
+                              bool alloc_fseg);
+
+void bios_linker_loader_add_checksum(GArray *linker, const char *file,
+                                     void *table,
+                                     void *start, unsigned size,
+                                     uint8_t *checksum);
+
+void bios_linker_loader_add_pointer(GArray *linker,
+                                    const char *dest_file,
+                                    const char *src_file,
+                                    GArray *table, void *pointer,
+                                    uint8_t pointer_size);
+
+void *bios_linker_loader_cleanup(GArray *linker);
+#endif
diff --git a/hw/i386/bios-linker-loader.c b/hw/i386/bios-linker-loader.c
new file mode 100644
index 0000000..0833853
--- /dev/null
+++ b/hw/i386/bios-linker-loader.c
@@ -0,0 +1,158 @@
+/* Dynamic linker/loader of ACPI tables
+ *
+ * Copyright (C) 2013 Red Hat Inc
+ *
+ * Author: Michael S. Tsirkin <mst@redhat.com>
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "bios-linker-loader.h"
+#include "hw/nvram/fw_cfg.h"
+
+#include <string.h>
+#include <assert.h>
+#include "qemu/bswap.h"
+
+#define BIOS_LINKER_LOADER_FILESZ FW_CFG_MAX_FILE_PATH
+
+struct BiosLinkerLoaderEntry {
+    uint32_t command;
+    union {
+        /*
+         * COMMAND_ALLOCATE - allocate a table from @alloc.file
+         * subject to @alloc.align alignment (must be power of 2)
+         * and @alloc.zone (can be HIGH or FSEG) requirements.
+         *
+         * Must appear exactly once for each file, and before
+         * this file is referenced by any other command.
+         */
+        struct {
+            char file[BIOS_LINKER_LOADER_FILESZ];
+            uint32_t align;
+            uint8_t zone;
+        } alloc;
+
+        /*
+         * COMMAND_ADD_POINTER - patch the table (originating from
+         * @dest_file) at @pointer.offset, by adding a pointer to the table
+         * originating from @src_file. 1,2,4 or 8 byte unsigned
+         * addition is used depending on @pointer.size.
+         */
+        struct {
+            char dest_file[BIOS_LINKER_LOADER_FILESZ];
+            char src_file[BIOS_LINKER_LOADER_FILESZ];
+            uint32_t offset;
+            uint8_t size;
+        } pointer;
+
+        /*
+         * COMMAND_ADD_CHECKSUM - calculate checksum of the range specified by
+         * @cksum_start and @cksum_length fields,
+         * and then add the value at @cksum.offset.
+         * Checksum simply sums -X for each byte X in the range
+         * using 8-bit math.
+         */
+        struct {
+            char file[BIOS_LINKER_LOADER_FILESZ];
+            uint32_t offset;
+            uint32_t start;
+            uint32_t length;
+        } cksum;
+
+        /* padding */
+        char pad[124];
+    };
+} QEMU_PACKED;
+typedef struct BiosLinkerLoaderEntry BiosLinkerLoaderEntry;
+
+enum {
+    BIOS_LINKER_LOADER_COMMAND_ALLOCATE     = 0x1,
+    BIOS_LINKER_LOADER_COMMAND_ADD_POINTER  = 0x2,
+    BIOS_LINKER_LOADER_COMMAND_ADD_CHECKSUM = 0x3,
+};
+
+enum {
+    BIOS_LINKER_LOADER_ALLOC_ZONE_HIGH = 0x1,
+    BIOS_LINKER_LOADER_ALLOC_ZONE_FSEG = 0x2,
+};
+
+GArray *bios_linker_loader_init(void)
+{
+    return g_array_new(false, true /* clear */, sizeof(BiosLinkerLoaderEntry));
+}
+
+/* Free linker wrapper and return the linker array. */
+void *bios_linker_loader_cleanup(GArray *linker)
+{
+    return g_array_free(linker, false);
+}
+
+void bios_linker_loader_alloc(GArray *linker,
+                              const char *file,
+                              uint32_t alloc_align,
+                              bool alloc_fseg)
+{
+    BiosLinkerLoaderEntry entry;
+
+    memset(&entry, 0, sizeof entry);
+    strncpy(entry.alloc.file, file, sizeof entry.alloc.file - 1);
+    entry.command = cpu_to_le32(BIOS_LINKER_LOADER_COMMAND_ALLOCATE);
+    entry.alloc.align = cpu_to_le32(alloc_align);
+    entry.alloc.zone = cpu_to_le32(alloc_fseg ?
+                                    BIOS_LINKER_LOADER_ALLOC_ZONE_FSEG :
+                                    BIOS_LINKER_LOADER_ALLOC_ZONE_HIGH);
+
+    /* Alloc entries must come first, so prepend them */
+    g_array_prepend_val(linker, entry);
+}
+
+void bios_linker_loader_add_checksum(GArray *linker, const char *file,
+                                     void *table,
+                                     void *start, unsigned size,
+                                     uint8_t *checksum)
+{
+    BiosLinkerLoaderEntry entry;
+
+    memset(&entry, 0, sizeof entry);
+    strncpy(entry.cksum.file, file, sizeof entry.cksum.file - 1);
+    entry.command = cpu_to_le32(BIOS_LINKER_LOADER_COMMAND_ADD_CHECKSUM);
+    entry.cksum.offset = cpu_to_le32(checksum - (uint8_t *)table);
+    entry.cksum.start = cpu_to_le32((uint8_t *)start - (uint8_t *)table);
+    entry.cksum.length = cpu_to_le32(size);
+
+    g_array_append_val(linker, entry);
+}
+
+void bios_linker_loader_add_pointer(GArray *linker,
+                                    const char *dest_file,
+                                    const char *src_file,
+                                    GArray *table, void *pointer,
+                                    uint8_t pointer_size)
+{
+    BiosLinkerLoaderEntry entry;
+
+    memset(&entry, 0, sizeof entry);
+    strncpy(entry.pointer.dest_file, dest_file,
+            sizeof entry.pointer.dest_file - 1);
+    strncpy(entry.pointer.src_file, src_file,
+            sizeof entry.pointer.src_file - 1);
+    entry.command = cpu_to_le32(BIOS_LINKER_LOADER_COMMAND_ADD_POINTER);
+    entry.pointer.offset = cpu_to_le32((gchar *)pointer - table->data);
+    entry.pointer.size = pointer_size;
+    assert(pointer_size == 1 || pointer_size == 2 ||
+           pointer_size == 4 || pointer_size == 8);
+
+    g_array_append_val(linker, entry);
+}
diff --git a/hw/i386/Makefile.objs b/hw/i386/Makefile.objs
index f950707..b9ca380 100644
--- a/hw/i386/Makefile.objs
+++ b/hw/i386/Makefile.objs
@@ -5,6 +5,7 @@ obj-y += pc_sysfw.o
 obj-$(CONFIG_XEN) += xen_domainbuild.o xen_machine_pv.o
 
 obj-y += kvmvapic.o
+obj-y += bios-linker-loader.o
 
 iasl-option=$(shell if test -z "`$(1) $(2) 2>&1 > /dev/null`" \
     ; then echo "$(2)"; else echo "$(3)"; fi ;)