Add kcmdline bootloader message
Define a new struct in the misc partition for telling the bootloader to
set kcmdline flags for enabling experimental dogfood features in the
kernel.
Test: Verified that a custom bootloader is able to read the data
Bug: 278052745
Change-Id: I5f13a9bdff940517cb7b880815dfb8f396fc3844
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
diff --git a/bootloader_message/bootloader_message.cpp b/bootloader_message/bootloader_message.cpp
index 1ea56cd..e9dd0d4 100644
--- a/bootloader_message/bootloader_message.cpp
+++ b/bootloader_message/bootloader_message.cpp
@@ -314,6 +314,16 @@
offsetof(misc_system_space_layout, memtag_message), err);
}
+bool ReadMiscKcmdlineMessage(misc_kcmdline_message* message, std::string* err) {
+ return ReadMiscPartitionSystemSpace(message, sizeof(*message),
+ offsetof(misc_system_space_layout, kcmdline_message), err);
+}
+
+bool WriteMiscKcmdlineMessage(const misc_kcmdline_message& message, std::string* err) {
+ return WriteMiscPartitionSystemSpace(&message, sizeof(message),
+ offsetof(misc_system_space_layout, kcmdline_message), err);
+}
+
extern "C" bool write_reboot_bootloader(void) {
std::string err;
return write_reboot_bootloader(&err);
diff --git a/bootloader_message/include/bootloader_message/bootloader_message.h b/bootloader_message/include/bootloader_message/bootloader_message.h
index 8d0c132..642f653 100644
--- a/bootloader_message/include/bootloader_message/bootloader_message.h
+++ b/bootloader_message/include/bootloader_message/bootloader_message.h
@@ -100,6 +100,13 @@
uint8_t reserved[55];
} __attribute__((packed));
+struct misc_kcmdline_message {
+ uint8_t version;
+ uint32_t magic;
+ uint64_t kcmdline_flags;
+ uint8_t reserved[51];
+} __attribute__((packed));
+
#define MISC_VIRTUAL_AB_MESSAGE_VERSION 2
#define MISC_VIRTUAL_AB_MAGIC_HEADER 0x56740AB0
@@ -116,11 +123,17 @@
// See system/extras/mtectrl in AOSP for more information.
#define MISC_MEMTAG_MODE_FORCED 0x20
+#define MISC_KCMDLINE_MESSAGE_VERSION 1
+#define MISC_KCMDLINE_MAGIC_HEADER 0x6ab5110c
+#define MISC_KCMDLINE_BINDER_RUST 0x1
+
#if (__STDC_VERSION__ >= 201112L) || defined(__cplusplus)
static_assert(sizeof(struct misc_virtual_ab_message) == 64,
"struct misc_virtual_ab_message has wrong size");
static_assert(sizeof(struct misc_memtag_message) == 64,
"struct misc_memtag_message has wrong size");
+static_assert(sizeof(struct misc_kcmdline_message) == 64,
+ "struct misc_kcmdline_message has wrong size");
#endif
// This struct is not meant to be used directly, rather, it is to make
@@ -128,6 +141,7 @@
struct misc_system_space_layout {
misc_virtual_ab_message virtual_ab_message;
misc_memtag_message memtag_message;
+ misc_kcmdline_message kcmdline_message;
} __attribute__((packed));
#ifdef __cplusplus
@@ -198,6 +212,10 @@
// Read or write the memtag message from system space in /misc.
bool ReadMiscMemtagMessage(misc_memtag_message* message, std::string* err);
bool WriteMiscMemtagMessage(const misc_memtag_message& message, std::string* err);
+
+// Read or write the kcmdline message from system space in /misc.
+bool ReadMiscKcmdlineMessage(misc_kcmdline_message* message, std::string* err);
+bool WriteMiscKcmdlineMessage(const misc_kcmdline_message& message, std::string* err);
#else
#include <stdbool.h>