Merge branch 'esp32/include_extram_bss_in_linker_fragment' into 'master'

esp32: Provision to redirect .bss to external ram through linker fragments

See merge request espressif/esp-idf!9894

components/bt/CMakeLists.txt

@@ -564,7 +564,8 @@ idf_component_register(SRCS "${srcs}"
                 INCLUDE_DIRS "${include_dirs}"
                 PRIV_INCLUDE_DIRS "${priv_include_dirs}"
                 REQUIRES nvs_flash soc esp_timer esp_pm
-                PRIV_REQUIRES esp_ipc)
+                PRIV_REQUIRES esp_ipc
+                LDFRAGMENTS "linker.lf")
 
 if(CONFIG_BT_ENABLED)
     target_compile_options(${COMPONENT_LIB} PRIVATE -Wno-implicit-fallthrough -Wno-unused-const-variable)

components/bt/linker.lf

@@ -0,0 +1,5 @@
+[mapping:bt]
+archive: libbt.a
+entries:
+    if SPIRAM_ALLOW_BSS_SEG_EXTERNAL_MEMORY = y:
+        * (extram_bss)

components/esp32/CMakeLists.txt

@@ -42,12 +42,6 @@ else()
 
     target_linker_script(${COMPONENT_LIB} INTERFACE "${CMAKE_CURRENT_BINARY_DIR}/esp32_out.ld")
 
-
-    if(CONFIG_SPIRAM_ALLOW_BSS_SEG_EXTERNAL_MEMORY)
-        # This has to be linked before esp32.project.ld
-        target_linker_script(${COMPONENT_LIB} INTERFACE "ld/esp32.extram.bss.ld")
-    endif()
-
     # Process the template file through the linker script generation mechanism, and use the output for linking the
     # final binary
     target_linker_script(${COMPONENT_LIB} INTERFACE "${CMAKE_CURRENT_LIST_DIR}/ld/esp32.project.ld.in"

components/esp32/component.mk

@@ -4,11 +4,6 @@
 
 COMPONENT_SRCDIRS := .
 
-ifdef CONFIG_SPIRAM_ALLOW_BSS_SEG_EXTERNAL_MEMORY
-   # This linker script must come before esp32.project.ld
-   LINKER_SCRIPTS += esp32.extram.bss.ld
-endif
-
 #Linker scripts used to link the final application.
 #Warning: These linker scripts are only used when the normal app is compiled; the bootloader
 #specifies its own scripts.

components/esp32/ld/esp32.extram.bss.ld

@@ -1,18 +0,0 @@
-/* This section is only included if CONFIG_SPIRAM_ALLOW_BSS_SEG_EXTERNAL_MEMORY
-   is set, to link some sections to BSS in PSRAM */
-
-SECTIONS
-{
-   /* external memory bss, from any global variable with EXT_RAM_ATTR attribute*/
-  .ext_ram.bss (NOLOAD) :
-  {
-    _ext_ram_bss_start = ABSOLUTE(.);
-    *(.ext_ram.bss*)
-    *libnet80211.a:(.dynsbss .sbss .sbss.* .gnu.linkonce.sb.* .scommon .sbss2.* .gnu.linkonce.sb2.* .dynbss .bss .bss.* .share.mem .gnu.linkonce.b.* COMMON)
-    *libpp.a:(.dynsbss .sbss .sbss.* .gnu.linkonce.sb.* .scommon .sbss2.* .gnu.linkonce.sb2.* .dynbss .bss .bss.* .share.mem .gnu.linkonce.b.* COMMON)
-    *liblwip.a:(.dynsbss .sbss .sbss.* .gnu.linkonce.sb.* .scommon .sbss2.* .gnu.linkonce.sb2.* .dynbss .bss .bss.* .share.mem .gnu.linkonce.b.* COMMON)
-    *libbt.a:(EXCLUDE_FILE (libbtdm_app.a) .dynsbss .sbss .sbss.* .gnu.linkonce.sb.* .scommon .sbss2.* .gnu.linkonce.sb2.* .dynbss .bss .bss.* .share.mem .gnu.linkonce.b.* COMMON)
-    . = ALIGN(4);
-    _ext_ram_bss_end = ABSOLUTE(.);
-  } > extern_ram_seg
-}

components/esp32/ld/esp32.project.ld.in

@@ -232,12 +232,22 @@ SECTIONS
     _noinit_end = ABSOLUTE(.);
   } > dram0_0_seg
 
+   /* external memory bss, from any global variable with EXT_RAM_ATTR attribute*/
+  .ext_ram.bss (NOLOAD) :
+  {
+    _ext_ram_bss_start = ABSOLUTE(.);
+
+    mapping[extern_ram]
+
+    . = ALIGN(4);
+    _ext_ram_bss_end = ABSOLUTE(.);
+  } > extern_ram_seg
+
   /* Shared RAM */
   .dram0.bss (NOLOAD) :
   {
     . = ALIGN (8);
     _bss_start = ABSOLUTE(.);
-    *(.ext_ram.bss*)
     _bt_bss_start = ABSOLUTE(.);
     *libbt.a:(.bss .bss.* COMMON)
     . = ALIGN (4);
@@ -253,18 +263,6 @@ SECTIONS
 
     mapping[dram0_bss]
 
-    *(.dynsbss)
-    *(.sbss)
-    *(.sbss.*)
-    *(.gnu.linkonce.sb.*)
-    *(.scommon)
-    *(.sbss2)
-    *(.sbss2.*)
-    *(.gnu.linkonce.sb2.*)
-    *(.dynbss)
-    *(.share.mem)
-    *(.gnu.linkonce.b.*)
-
     . = ALIGN (8);
     _bss_end = ABSOLUTE(.);
   } > dram0_0_seg

components/esp32/ld/esp32_fragments.lf

@@ -15,6 +15,18 @@ entries:
 entries:
     COMMON
 
+[sections:legacy_bss]
+entries:
+    .dynsbss
+    .sbss+
+    .gnu.linkonce.sb+
+    .scommon
+    .sbss2+
+    .gnu.linkonce.sb2+
+    .dynbss
+    .share.mem
+    .gnu.linkonce.b+
+
 [sections:rodata]
 entries:
     .rodata+
@@ -64,6 +76,10 @@ entries:
 entries:
     .iram.bss+
 
+[sections:extram_bss]
+entries:
+    .ext_ram.bss+
+
 [sections:dram]
 entries:
     .dram1+
@@ -87,6 +103,11 @@ entries:
     data -> dram0_data
     bss -> dram0_bss
     common -> dram0_bss
+    if SPIRAM_ALLOW_BSS_SEG_EXTERNAL_MEMORY = y:
+        extram_bss -> extern_ram
+    else:
+        extram_bss -> dram0_bss
+    legacy_bss -> dram0_bss
     iram -> iram0_text
     iram_data -> iram0_data
     iram_bss -> iram0_bss
@@ -130,3 +151,8 @@ entries:
 [scheme:wifi_rx_iram]
 entries:
     wifi_rx_iram -> iram0_text
+
+[scheme:extram_bss]
+entries:
+    bss -> extern_ram
+    common -> extern_ram

components/esp_common/Kconfig.spiram.common

@@ -94,6 +94,9 @@ config SPIRAM_ALLOW_BSS_SEG_EXTERNAL_MEMORY
     default n
     depends on SPIRAM
     help
-        If enabled the option,and add EXT_RAM_ATTR defined your variable,then your variable will be placed in
-        PSRAM instead of internal memory, and placed most of variables of lwip,net802.11,pp,bluedroid library
-        to external memory defaultly.
+        If enabled, variables with EXT_RAM_ATTR attribute will be placed in SPIRAM instead of internal DRAM.
+        BSS section of `lwip`, `net80211`, `pp`, `bt` libraries will be automatically placed
+        in SPIRAM. BSS sections from other object files and libraries can also be placed in SPIRAM through
+        linker fragment scheme `extram_bss`.
+
+        Note that the variables placed in SPIRAM using EXT_RAM_ATTR will be zero initialized.

components/esp_wifi/linker.lf

@@ -17,6 +17,9 @@ entries:
     if ESP32_WIFI_RX_IRAM_OPT = y:
         * (wifi_rx_iram)
 
+    if SPIRAM_ALLOW_BSS_SEG_EXTERNAL_MEMORY = y:
+        * (extram_bss)
+
 [mapping:net80211]
 archive: libnet80211.a
 entries:
@@ -25,3 +28,6 @@ entries:
 
     if ESP32_WIFI_RX_IRAM_OPT = y:
         * (wifi_rx_iram)
+
+    if SPIRAM_ALLOW_BSS_SEG_EXTERNAL_MEMORY = y:
+        * (extram_bss)

components/lwip/linker.lf

@@ -85,3 +85,6 @@ entries:
   else:
 
     * (default)
+
+  if SPIRAM_ALLOW_BSS_SEG_EXTERNAL_MEMORY = y:
+    * (extram_bss)

docs/en/api-guides/external-ram.rst

@@ -95,6 +95,8 @@ If enabled, a region of the address space starting from 0x3F800000 will be used
 
 Additional data can be moved from the internal BSS segment to external RAM by applying the macro ``EXT_RAM_ATTR`` to any static declaration (which is not initialized to a non-zero value).
 
+It is also possible to place the BSS section of a component or a library to external RAM using linker fragment scheme ``extram_bss``.
+
 This option reduces the internal static memory used by the BSS segment.
 
 Remaining external RAM can also be added to the capability heap allocator using the method shown above.