elfloader/risc-v: improve OpenSBI support

- improve comments and variable names - allow platforms to customize OpenSBI parameters - OPENSBI_PLAT_XLEN - OPENSBI_PLAT_ISA - OPENSBI_PLAT_ABI Signed-off-by: Axel Heider <[email protected]>
seL4 · Sep 6, 2021 · 20daf3d · 20daf3d
1 parent 55cd916
commit 20daf3d
Showing 1 changed file with 34 additions and 16 deletions.
diff --git a/cmake-tool/helpers/rootserver.cmake b/cmake-tool/helpers/rootserver.cmake
@@ -93,7 +93,11 @@ function(DeclareRootserver rootservername)
         set(elf_target_file $<TARGET_FILE:elfloader>)
         if(KernelArchRiscV)
             if(UseRiscVOpenSBI)
-                # Package up our final elf image into OpenSBI.
+                # When using OpenSBI, the whole system image (usually consisting
+                # of the ELF-Loader, a device tree, the kernel, and a userland)
+                # is packaged as an OpenSBI payload.
+                file(GLOB_RECURSE deps)
+
                 if("${CROSS_COMPILER_PREFIX}" STREQUAL "")
                     message(FATAL_ERROR "CROSS_COMPILER_PREFIX not set.")
                 endif()
@@ -102,22 +106,34 @@ function(DeclareRootserver rootservername)
                     message(FATAL_ERROR "KernelOpenSBIPlatform not set.")
                 endif()
 
-                file(GLOB_RECURSE deps)
+                if(NOT OPENSBI_PLAT_XLEN)
+                    set(OPENSBI_PLAT_XLEN "${KernelWordSize}")
+                endif()
+
+                if(NOT OPENSBI_PLAT_ISA)
+                    set(OPENSBI_PLAT_ISA "rv${OPENSBI_PLAT_XLEN}imafdc")
+                endif()
+
+                if(NOT OPENSBI_PLAT_ABI)
+                    if(Kernel32)
+                        set(OPENSBI_PLAT_ABI "ilp32d")
+                    else()
+                        set(OPENSBI_PLAT_ABI "lp64d")
+                    endif()
+                endif()
+
                 set(OPENSBI_BINARY_DIR "${CMAKE_BINARY_DIR}/opensbi")
+                # OPENSBI_PLAYLOAD is a binary dump of the system image ELF
                 set(OPENSBI_PLAYLOAD "${OPENSBI_BINARY_DIR}/payload")
-                if(Kernel32)
-                    set(PLATFORM_RISCV_ISA "rv32imafdc")
-                    set(PLATFORM_RISCV_ABI "ilp32d")
-                else()
-                    set(PLATFORM_RISCV_ISA "rv64imafdc")
-                    set(PLATFORM_RISCV_ABI "lp64d")
-                endif()
+                # OPENSBI_SYSTEM_IMAGE_ELF is the OpenSBI EFL file that contains
+                # our system image as firmware payload
                 set(
-                    OPENSBI_FW_PAYLOAD_ELF
+                    OPENSBI_SYSTEM_IMAGE_ELF
                     "${OPENSBI_BINARY_DIR}/platform/${KernelOpenSBIPlatform}/firmware/fw_payload.elf"
                 )
+
                 add_custom_command(
-                    OUTPUT "${OPENSBI_FW_PAYLOAD_ELF}"
+                    OUTPUT "${OPENSBI_SYSTEM_IMAGE_ELF}"
                     COMMAND mkdir -p "${OPENSBI_BINARY_DIR}"
                     COMMAND
                         make -s -C "${OPENSBI_PATH}" O="${OPENSBI_BINARY_DIR}"
@@ -126,15 +142,17 @@ function(DeclareRootserver rootservername)
                         ${CMAKE_OBJCOPY} -O binary "${elf_target_file}" "${OPENSBI_PLAYLOAD}"
                     COMMAND
                         make -C "${OPENSBI_PATH}" O="${OPENSBI_BINARY_DIR}"
-                        CROSS_COMPILE=${CROSS_COMPILER_PREFIX} PLATFORM="${KernelOpenSBIPlatform}"
-                        PLATFORM_RISCV_XLEN=${KernelWordSize} FW_PAYLOAD_PATH="${OPENSBI_PLAYLOAD}"
-                        PLATFORM_RISCV_ISA=${PLATFORM_RISCV_ISA}
-                        PLATFORM_RISCV_ABI=${PLATFORM_RISCV_ABI}
+                        CROSS_COMPILE=${CROSS_COMPILER_PREFIX}
+                        PLATFORM="${KernelOpenSBIPlatform}"
+                        PLATFORM_RISCV_XLEN=${OPENSBI_PLAT_XLEN}
+                        PLATFORM_RISCV_ISA=${OPENSBI_PLAT_ISA}
+                        PLATFORM_RISCV_ABI=${OPENSBI_PLAT_ABI}
+                        FW_PAYLOAD_PATH="${OPENSBI_PLAYLOAD}"
                     DEPENDS "${elf_target_file}" elfloader ${USES_TERMINAL_DEBUG}
                 )
                 # overwrite elf_target_file, it's no longer the ElfLoader but
                 # the OpenSBI ELF (which contains the ElfLoader as payload)
-                set(elf_target_file "${OPENSBI_FW_PAYLOAD_ELF}")
+                set(elf_target_file "${OPENSBI_SYSTEM_IMAGE_ELF}")
             endif()
         endif()
         set(binary_efi_list "binary;efi")