From: "Ying-Chun Liu (PaulLiu)" <paul....@linaro.org>

Add EFI_SYSTEM_TABLE_POINTER structure for debugger to locate
the address of EFI_SYSTEM_TABLE.

This feature is described in UEFI SPEC version 2.10. Section 18.4.2.

Signed-off-by: Ying-Chun Liu (PaulLiu) <paul....@linaro.org>
Cc: Heinrich Schuchardt <xypron.g...@gmx.de>
Cc: Ilias Apalodimas <ilias.apalodi...@linaro.org>
---
V2: add Kconfig options to turn on/off this feature.
---
 include/efi_api.h             |  6 +++++
 include/efi_loader.h          |  2 ++
 lib/efi_loader/Kconfig        |  7 ++++++
 lib/efi_loader/efi_boottime.c | 44 +++++++++++++++++++++++++++++++++++
 lib/efi_loader/efi_setup.c    |  9 +++++++
 5 files changed, 68 insertions(+)

diff --git a/include/efi_api.h b/include/efi_api.h
index eb61eafa028..5017d9037cd 100644
--- a/include/efi_api.h
+++ b/include/efi_api.h
@@ -259,6 +259,12 @@ struct efi_capsule_result_variable_header {
        efi_status_t capsule_status;
 } __packed;
 
+struct efi_system_table_pointer {
+       u64 signature;
+       efi_physical_addr_t efi_system_table_base;
+       u32 crc32;
+};
+
 struct efi_memory_range {
        efi_physical_addr_t     address;
        u64                     length;
diff --git a/include/efi_loader.h b/include/efi_loader.h
index 1d75d97ebbc..370bc042f70 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -615,6 +615,8 @@ efi_status_t efi_tcg2_measure_dtb(void *dtb);
 efi_status_t efi_root_node_register(void);
 /* Called by bootefi to initialize runtime */
 efi_status_t efi_initialize_system_table(void);
+/* Called by bootefi to initialize debug */
+efi_status_t efi_initialize_system_table_pointer(void);
 /* efi_runtime_detach() - detach unimplemented runtime functions */
 void efi_runtime_detach(void);
 /* efi_convert_pointer() - convert pointer to virtual address */
diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
index d4f6b56afaa..94a75981389 100644
--- a/lib/efi_loader/Kconfig
+++ b/lib/efi_loader/Kconfig
@@ -70,6 +70,13 @@ config EFI_SECURE_BOOT
 config EFI_SIGNATURE_SUPPORT
        bool
 
+config EFI_DEBUG_SUPPORT_TABLE
+       bool "EFI Debug Support Table"
+       help
+         Select this option if you want to setup the EFI Debug Support
+         Table which is used by the debug agent or an external debugger to
+         determine loaded image information in a quiescent manner.
+
 menu "UEFI services"
 
 config EFI_GET_TIME
diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index 5164cb15986..366bc0d2b1d 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -4001,6 +4001,8 @@ struct efi_system_table __efi_runtime_data systab = {
        .tables = NULL,
 };
 
+struct efi_system_table_pointer __efi_runtime_data * systab_pointer = NULL;
+
 /**
  * efi_initialize_system_table() - Initialize system table
  *
@@ -4035,3 +4037,45 @@ efi_status_t efi_initialize_system_table(void)
 
        return ret;
 }
+
+/**
+ * efi_initialize_system_table() - Initialize system table
+ *
+ * Return:     status code
+ */
+efi_status_t efi_initialize_system_table_pointer(void)
+{
+       efi_status_t ret;
+       const int size_4MB = 0x00400000;
+       int pages = efi_size_in_pages(sizeof(struct efi_system_table_pointer));
+       int alignment_mask = size_4MB - 1;
+       int real_pages = pages + efi_size_in_pages(size_4MB);
+       u64 addr;
+       u64 aligned_addr;
+       u32 crc32_value;
+
+       /* Allocate configuration table array */
+       ret = efi_allocate_pages(EFI_ALLOCATE_ANY_PAGES,
+                                EFI_RUNTIME_SERVICES_DATA,
+                                real_pages,
+                                &addr);
+
+       /* alignment to 4MB boundary */
+       aligned_addr = (addr + alignment_mask) & ~alignment_mask;
+
+       systab_pointer = (struct efi_system_table_pointer *)aligned_addr;
+       memset(systab_pointer, 0, sizeof(struct efi_system_table_pointer));
+
+       /*
+        * These entries will be set to NULL in ExitBootServices(). To avoid
+        * relocation in SetVirtualAddressMap(), set them dynamically.
+        */
+       systab_pointer->signature = EFI_SYSTEM_TABLE_SIGNATURE;
+       systab_pointer->efi_system_table_base = (efi_physical_addr_t)&systab;
+       systab_pointer->crc32 = 0;
+       crc32_value = crc32(0,
+                           (const unsigned char *)systab_pointer,
+                           sizeof(struct efi_system_table_pointer));
+       systab_pointer->crc32 = crc32_value;
+       return ret;
+}
diff --git a/lib/efi_loader/efi_setup.c b/lib/efi_loader/efi_setup.c
index aa59bc7779d..6be23ca43bf 100644
--- a/lib/efi_loader/efi_setup.c
+++ b/lib/efi_loader/efi_setup.c
@@ -259,6 +259,15 @@ efi_status_t efi_init_obj_list(void)
        if (ret != EFI_SUCCESS)
                goto out;
 
+       /* Initialize system table */
+       if (IS_ENABLED(CONFIG_EFI_DEBUG_SUPPORT_TABLE)) {
+               ret = efi_initialize_system_table_pointer();
+               if (ret != EFI_SUCCESS) {
+                       printf("EFI init system table pointer fail\n");
+                       goto out;
+               }
+       }
+
        if (IS_ENABLED(CONFIG_EFI_ECPT)) {
                ret = efi_ecpt_register();
                if (ret != EFI_SUCCESS)
-- 
2.39.5

Reply via email to