[bootsvc] Decommit pages from the BOOTDATA VMO
Pages that contain unused boot items within the BOOTDATA VMO should be
decommitted.
Change-Id: I05ecc05cca71990ba274c0a9fd1f7d3032a03d3d
diff --git a/zircon/system/core/bootsvc/main.cpp b/zircon/system/core/bootsvc/main.cpp
index 8c7b2bba..327549b 100644
--- a/zircon/system/core/bootsvc/main.cpp
+++ b/zircon/system/core/bootsvc/main.cpp
@@ -205,7 +205,7 @@
status = bootfs_svc->AddBootfs(std::move(bootfs_vmo));
ZX_ASSERT_MSG(status == ZX_OK, "bootfs add failed: %s\n", zx_status_get_string(status));
- // Process the ZBI containers to get additional bootfs parts
+ // Process the ZBI boot image
printf("bootsvc: Retrieving boot image...\n");
zx::vmo image_vmo;
bootsvc::ItemMap item_map;
diff --git a/zircon/system/core/bootsvc/util.cpp b/zircon/system/core/bootsvc/util.cpp
index 3d6ed86..0c450aa 100644
--- a/zircon/system/core/bootsvc/util.cpp
+++ b/zircon/system/core/bootsvc/util.cpp
@@ -6,9 +6,11 @@
#include <ctype.h>
+#include <fbl/algorithm.h>
#include <fs/connection.h>
#include <safemath/checked_math.h>
#include <zircon/boot/image.h>
+#include <zircon/assert.h>
#include <zircon/process.h>
#include <zircon/processargs.h>
#include <zircon/status.h>
@@ -21,7 +23,6 @@
case ZBI_TYPE_CRASHLOG:
case ZBI_TYPE_KERNEL_DRIVER:
case ZBI_TYPE_PLATFORM_ID:
- case ZBI_TYPE_STORAGE_BOOTFS:
case ZBI_TYPE_STORAGE_RAMDISK:
return true;
default:
@@ -29,11 +30,21 @@
}
}
+// Discards the boot item from the boot image VMO.
+void DiscardItem(zx::vmo* vmo, uint32_t begin_in, uint32_t end_in) {
+ uint64_t begin = fbl::round_up(begin_in, static_cast<uint32_t>(PAGE_SIZE));
+ uint64_t end = fbl::round_down(end_in, static_cast<uint32_t>(PAGE_SIZE));
+ if (begin < end) {
+ zx_status_t status = vmo->op_range(ZX_VMO_OP_DECOMMIT, begin, end - begin, nullptr, 0);
+ ZX_ASSERT_MSG(status == ZX_OK, "Discarding boot item failed: %s\n",
+ zx_status_get_string(status));
+ }
+}
+
bootsvc::ItemKey CreateItemKey(uint32_t type, uint32_t extra) {
switch (type) {
- case ZBI_TYPE_STORAGE_BOOTFS:
case ZBI_TYPE_STORAGE_RAMDISK:
- // If this is for storage, set the extra value to zero.
+ // If this is for a ramdisk, set the extra value to zero.
return bootsvc::ItemKey{.type = type, .extra = 0};
default:
// Otherwise, store the extra value.
@@ -43,9 +54,8 @@
bootsvc::ItemValue CreateItemValue(uint32_t type, uint32_t off, uint32_t len) {
switch (type) {
- case ZBI_TYPE_STORAGE_BOOTFS:
case ZBI_TYPE_STORAGE_RAMDISK:
- // If this is for storage, capture the ZBI header.
+ // If this is for a ramdisk, capture the ZBI header.
len = safemath::CheckAdd(len, sizeof(zbi_header_t)).ValueOrDie<uint32_t>();
break;
default:
@@ -62,20 +72,24 @@
const char* const kLastPanicFilePath = "log/last-panic.txt";
zx_status_t RetrieveBootImage(zx::vmo* out_vmo, ItemMap* out_map) {
- // Validate boot container provided by startup handle.
+ // Validate boot image VMO provided by startup handle.
zx::vmo vmo(zx_take_startup_handle(PA_HND(PA_VMO_BOOTDATA, 0)));
zbi_header_t header;
zx_status_t status = vmo.read(&header, 0, sizeof(header));
if (status != ZX_OK) {
- printf("bootsvc: Failed to read ZBI container header: %s\n", zx_status_get_string(status));
+ printf("bootsvc: Failed to read ZBI image header: %s\n", zx_status_get_string(status));
return status;
} else if (header.type != ZBI_TYPE_CONTAINER || header.extra != ZBI_CONTAINER_MAGIC ||
header.magic != ZBI_ITEM_MAGIC || !(header.flags & ZBI_FLAG_VERSION)) {
- printf("bootsvc: Invalid ZBI container header\n");
+ printf("bootsvc: Invalid ZBI image header\n");
return ZX_ERR_IO_DATA_INTEGRITY;
}
- // Read boot items from boot container.
+ // Used to discard pages from the boot image VMO.
+ uint32_t discard_begin = 0;
+ uint32_t discard_end = 0;
+
+ // Read boot items from the boot image VMO.
ItemMap map;
uint32_t off = sizeof(header);
uint32_t len = header.length;
@@ -89,17 +103,23 @@
return ZX_ERR_IO_DATA_INTEGRITY;
}
uint32_t item_len = ZBI_ALIGN(header.length + static_cast<uint32_t>(sizeof(zbi_header_t)));
+ uint32_t next_off = safemath::CheckAdd(off, item_len).ValueOrDie();
if (item_len > len) {
printf("bootsvc: ZBI item too large (%u > %u)\n", item_len, len);
return ZX_ERR_IO_DATA_INTEGRITY;
} else if (StoreItem(header.type)) {
map.emplace(CreateItemKey(header.type, header.extra),
CreateItemValue(header.type, off, header.length));
+ DiscardItem(&vmo, discard_begin, discard_end);
+ discard_begin = next_off;
+ } else {
+ discard_end = next_off;
}
- off = safemath::CheckAdd(off, item_len).ValueOrDie();
+ off = next_off;
len = safemath::CheckSub(len, item_len).ValueOrDie();
}
+ DiscardItem(&vmo, discard_begin, discard_end);
*out_vmo = std::move(vmo);
*out_map = std::move(map);
return ZX_OK;
