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Merged
tomi-font merged 4 commits into from
Dec 4, 2025
Merged

Use picolibc instead of newlib-nano #134

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450565a
[zep noup] ld: Reset linker '.' value after .ER_CODE_SRAM section
keith-packard Jul 23, 2025
35b61e6
[zep noup] platform: Include TFM_BSS in zero table for link script te…
keith-packard Oct 29, 2025
76155d0
[zep noup] platform: Add picolibc init and heap symbols to linker scr…
keith-packard Oct 28, 2025
6b820c4
[zep noup] Use picolibc instead of newlib-nano
keith-packard May 19, 2025
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1 change: 1 addition & 0 deletions bl1/bl1_1/CMakeLists.txt
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Expand Up @@ -40,6 +40,7 @@ target_link_options(bl1_1
target_sources(bl1_1
PRIVATE
main.c
$<$<BOOL:${CONFIG_PICOLIBC}>:${CMAKE_SOURCE_DIR}/platform/ext/common/picolibc.c>
$<$<BOOL:${CONFIG_GNU_SYSCALL_STUB_ENABLED}>:${CMAKE_SOURCE_DIR}/platform/ext/common/syscalls_stub.c>
)

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1 change: 1 addition & 0 deletions bl1/bl1_2/CMakeLists.txt
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Expand Up @@ -42,6 +42,7 @@ target_link_options(bl1_2
target_sources(bl1_2
PRIVATE
main.c
$<$<BOOL:${CONFIG_PICOLIBC}>:${CMAKE_SOURCE_DIR}/platform/ext/common/picolibc.c>
$<$<BOOL:${CONFIG_GNU_SYSCALL_STUB_ENABLED}>:${CMAKE_SOURCE_DIR}/platform/ext/common/syscalls_stub.c>
)

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1 change: 1 addition & 0 deletions bl2/CMakeLists.txt
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Expand Up @@ -141,6 +141,7 @@ add_executable(bl2
$<$<BOOL:${DEFAULT_MCUBOOT_FLASH_MAP}>:src/default_flash_map.c>
$<$<BOOL:${MCUBOOT_DATA_SHARING}>:src/shared_data.c>
$<$<BOOL:${PLATFORM_DEFAULT_PROVISIONING}>:src/provisioning.c>
$<$<BOOL:${CONFIG_PICOLIBC}>:${CMAKE_SOURCE_DIR}/platform/ext/common/picolibc.c>
$<$<BOOL:${CONFIG_GNU_SYSCALL_STUB_ENABLED}>:${CMAKE_SOURCE_DIR}/platform/ext/common/syscalls_stub.c>
)

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5 changes: 5 additions & 0 deletions cmake/install.cmake
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Expand Up @@ -254,6 +254,11 @@ install(DIRECTORY $<BUILD_INTERFACE:${CMSIS_PATH}/CMSIS/Core/Include>
$<BUILD_INTERFACE:${CMSIS_PATH}/CMSIS/Driver/Include>
DESTINATION ${INSTALL_PLATFORM_NS_DIR}/ext/cmsis)

if(CONFIG_PICOLIBC)
install(FILES ${PLATFORM_DIR}/ext/common/picolibc.c
DESTINATION ${INSTALL_PLATFORM_NS_DIR}/ext/common)
endif()

if(PLATFORM_DEFAULT_UART_STDOUT)
install(FILES ${PLATFORM_DIR}/ext/common/uart_stdout.c
${PLATFORM_DIR}/ext/common/uart_stdout.h
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1 change: 1 addition & 0 deletions cmake/spe-CMakeLists.cmake
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Expand Up @@ -104,6 +104,7 @@ add_subdirectory(platform)

target_sources(platform_ns
PRIVATE
$<$<BOOL:${CONFIG_PICOLIBC}>:${CMAKE_CURRENT_SOURCE_DIR}/platform/ext/common/picolibc.c>
$<$<BOOL:${PLATFORM_DEFAULT_UART_STDOUT}>:${CMAKE_CURRENT_SOURCE_DIR}/platform/ext/common/uart_stdout.c>
)

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4 changes: 4 additions & 0 deletions platform/CMakeLists.txt
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Expand Up @@ -81,6 +81,7 @@ target_sources(platform_s
$<$<BOOL:${PLATFORM_DEFAULT_PROVISIONING}>:ext/common/provisioning.c>
$<$<OR:$<BOOL:${TEST_S_FPU}>,$<BOOL:${TEST_NS_FPU}>>:${CMAKE_SOURCE_DIR}/platform/ext/common/test_interrupt.c>
$<$<BOOL:${TFM_SANITIZE}>:ext/common/tfm_sanitize_handlers.c>
$<$<BOOL:${CONFIG_PICOLIBC}>:ext/common/picolibc.c>
./ext/common/tfm_fatal_error.c
)

Expand Down Expand Up @@ -203,6 +204,7 @@ if(BL2)
$<$<OR:$<BOOL:${PLATFORM_DEFAULT_NV_COUNTERS}>,$<BOOL:${PLATFORM_DEFAULT_OTP}>>:ext/common/template/flash_otp_nv_counters_backend.c>
$<$<BOOL:${PLATFORM_DEFAULT_OTP}>:ext/common/template/otp_flash.c>
$<$<BOOL:${BL2_SANITIZE}>:ext/common/tfm_sanitize_handlers.c>
$<$<BOOL:${CONFIG_PICOLIBC}>:ext/common/picolibc.c>
./ext/common/tfm_fatal_error.c
)

Expand Down Expand Up @@ -304,6 +306,7 @@ if(BL1 AND PLATFORM_DEFAULT_BL1)
$<$<BOOL:${PLATFORM_DEFAULT_OTP}>:ext/common/template/flash_otp_nv_counters_backend.c>
$<$<BOOL:${PLATFORM_DEFAULT_OTP}>:ext/common/template/otp_flash.c>
$<$<OR:$<BOOL:${BL1_1_SANITIZE}>,$<BOOL:${TFM_BL1_2_SANITIZE}>>:ext/common/tfm_sanitize_handlers.c>
$<$<BOOL:${CONFIG_PICOLIBC}>:ext/common/picolibc.c>
./ext/common/tfm_fatal_error.c
)

Expand Down Expand Up @@ -359,6 +362,7 @@ if(BL1 AND PLATFORM_DEFAULT_BL1)
$<$<BOOL:${PLATFORM_DEFAULT_NV_COUNTERS}>:ext/common/template/nv_counters.c>
$<$<OR:$<BOOL:${PLATFORM_DEFAULT_NV_COUNTERS}>,$<BOOL:${PLATFORM_DEFAULT_OTP}>>:ext/common/template/flash_otp_nv_counters_backend.c>
$<$<BOOL:${PLATFORM_DEFAULT_OTP}>:ext/common/template/otp_flash.c>
$<$<BOOL:${CONFIG_PICOLIBC}>:ext/common/picolibc.c>
)

target_link_libraries(platform_bl1_2
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4 changes: 4 additions & 0 deletions platform/ext/common/gcc/tfm_common_bl2.ld
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Expand Up @@ -60,6 +60,7 @@ SECTIONS
. = ALIGN(4);
/* preinit data */
PROVIDE_HIDDEN (__preinit_array_start = .);
PROVIDE(__bothinit_array_start = __preinit_array_start);
KEEP(*(.preinit_array))
PROVIDE_HIDDEN (__preinit_array_end = .);

Expand All @@ -69,6 +70,7 @@ SECTIONS
KEEP(*(SORT(.init_array.*)))
KEEP(*(.init_array))
PROVIDE_HIDDEN (__init_array_end = .);
PROVIDE(__bothinit_array_end = __init_array_end);

. = ALIGN(4);
/* finit data */
Expand Down Expand Up @@ -212,8 +214,10 @@ SECTIONS
__end__ = .;
PROVIDE(end = .);
__HeapBase = .;
PROVIDE(__heap_start = __HeapBase);
. += __heap_size__;
__HeapLimit = .;
PROVIDE(__heap_end = __HeapLimit);
__heap_limit = .; /* Add for _sbrk */
} > RAM
Image$$ARM_LIB_HEAP$$ZI$$Limit = ADDR(.heap) + SIZEOF(.heap);
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4 changes: 4 additions & 0 deletions platform/ext/common/gcc/tfm_common_ns.ld
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Expand Up @@ -47,6 +47,7 @@ SECTIONS
. = ALIGN(4);
/* preinit data */
PROVIDE_HIDDEN (__preinit_array_start = .);
PROVIDE(__bothinit_array_start = __preinit_array_start);
KEEP(*(.preinit_array))
PROVIDE_HIDDEN (__preinit_array_end = .);

Expand All @@ -56,6 +57,7 @@ SECTIONS
KEEP(*(SORT(.init_array.*)))
KEEP(*(.init_array))
PROVIDE_HIDDEN (__init_array_end = .);
PROVIDE(__bothinit_array_end = __init_array_end);

. = ALIGN(4);
/* finit data */
Expand Down Expand Up @@ -158,8 +160,10 @@ SECTIONS
__end__ = .;
PROVIDE(end = .);
__HeapBase = .;
PROVIDE(__heap_start = __HeapBase);
. += __heap_size__;
__HeapLimit = .;
PROVIDE(__heap_end = __HeapLimit);
__heap_limit = .; /* Add for _sbrk */
} > RAM

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10 changes: 10 additions & 0 deletions platform/ext/common/gcc/tfm_common_s.ld.template
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Expand Up @@ -200,6 +200,9 @@ SECTIONS
. = ALIGN(4); /* This alignment is needed to make the section size 4 bytes aligned */
} > CODE_RAM AT > FLASH

/* Reset current position for subsequent sections */
. = LOADADDR(.ER_CODE_SRAM) + SIZEOF(.ER_CODE_SRAM);
Comment on lines +203 to +204
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@tomi-font tomi-font Jul 28, 2025

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How did the linker get confused exactly? Is this really needed?

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@keith-packard keith-packard Jul 28, 2025

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. got set to LOADADDR instead of ADDR when building with binutils 2.43. I'm afraid that after spending several hours chasing this down, I didn't dig into the linker code to figure out precisely why that happened.

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@keith-packard keith-packard Sep 9, 2025 •
edited
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I've re-added this patch as it is necessary even with SDK 0.17.4.


ASSERT(S_RAM_CODE_START % 4 == 0, "S_RAM_CODE_START must be divisible by 4")

Image$$ER_CODE_SRAM$$RO$$Base = ADDR(.ER_CODE_SRAM);
Expand All @@ -225,6 +228,7 @@ SECTIONS
. = ALIGN(4);
/* preinit data */
PROVIDE_HIDDEN (__preinit_array_start = .);
PROVIDE(__bothinit_array_start = __preinit_array_start);
KEEP(*(.preinit_array))
PROVIDE_HIDDEN (__preinit_array_end = .);

Expand All @@ -234,6 +238,7 @@ SECTIONS
KEEP(*(SORT(.init_array.*)))
KEEP(*(.init_array))
PROVIDE_HIDDEN (__init_array_end = .);
PROVIDE(__bothinit_array_end = __init_array_end);

. = ALIGN(4);
/* finit data */
Expand Down Expand Up @@ -273,6 +278,9 @@ SECTIONS
/* .zero.table */
. = ALIGN(4);
__zero_table_start__ = .;
LONG (ADDR(.TFM_BSS))
LONG (SIZEOF(.TFM_BSS) / 4)

LONG (ADDR(.TFM_PSA_ROT_LINKER_BSS))
LONG (SIZEOF(.TFM_PSA_ROT_LINKER_BSS) / 4) /* Aligment checked after the section */

Expand Down Expand Up @@ -406,8 +414,10 @@ SECTIONS
__end__ = .;
PROVIDE(end = .);
__HeapBase = .;
PROVIDE(__heap_start = __HeapBase);
. += __heap_size__;
__HeapLimit = .;
PROVIDE(__heap_end = __HeapLimit);
__heap_limit = .; /* Add for _sbrk */
} > RAM
#endif
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10 changes: 10 additions & 0 deletions platform/ext/common/gcc/tfm_isolation_s.ld.template
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Expand Up @@ -218,6 +218,7 @@ SECTIONS
. = ALIGN(4);
/* preinit data */
PROVIDE_HIDDEN (__preinit_array_start = .);
PROVIDE(__bothinit_array_start = __preinit_array_start);
KEEP(*(.preinit_array))
PROVIDE_HIDDEN (__preinit_array_end = .);

Expand All @@ -227,6 +228,7 @@ SECTIONS
KEEP(*(SORT(.init_array.*)))
KEEP(*(.init_array))
PROVIDE_HIDDEN (__init_array_end = .);
PROVIDE(__bothinit_array_end = __init_array_end);

. = ALIGN(4);
/* finit data */
Expand Down Expand Up @@ -264,6 +266,9 @@ SECTIONS
/* .zero.table */
. = ALIGN(4);
__zero_table_start__ = .;
LONG (ADDR(.TFM_BSS))
LONG (SIZEOF(.TFM_BSS) / 4)

{% for partition in partitions %}
LONG (ADDR(.ER_{{partition.manifest.name}}_BSS))
LONG (SIZEOF(.ER_{{partition.manifest.name}}_BSS) / 4) /* Aligment checked after the section */
Expand Down Expand Up @@ -350,6 +355,9 @@ SECTIONS
. = ALIGN(4); /* This alignment is needed to make the section size 4 bytes aligned */
} > CODE_RAM AT > FLASH

/* Reset current position for subsequent sections */
. = LOADADDR(.ER_CODE_SRAM) + SIZEOF(.ER_CODE_SRAM);

ASSERT(S_RAM_CODE_START % 4 == 0, "S_RAM_CODE_START must be divisible by 4")

Image$$ER_CODE_SRAM$$RO$$Base = ADDR(.ER_CODE_SRAM);
Expand Down Expand Up @@ -510,8 +518,10 @@ SECTIONS
__end__ = .;
PROVIDE(end = .);
__HeapBase = .;
PROVIDE(__heap_start = __HeapBase);
. += __heap_size__;
__HeapLimit = .;
PROVIDE(__heap_end = __HeapLimit);
__heap_limit = .; /* Add for _sbrk */
} > RAM
#endif
Expand Down
2 changes: 2 additions & 0 deletions platform/ext/common/llvm/tfm_common_ns.ldc
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Expand Up @@ -42,6 +42,7 @@ SECTIONS
. = ALIGN(4);
/* preinit data */
PROVIDE_HIDDEN (__preinit_array_start = .);
PROVIDE(__bothinit_array_start = __preinit_array_start);
KEEP(*(.preinit_array))
PROVIDE_HIDDEN (__preinit_array_end = .);

Expand All @@ -51,6 +52,7 @@ SECTIONS
KEEP(*(SORT(.init_array.*)))
KEEP(*(.init_array))
PROVIDE_HIDDEN (__init_array_end = .);
PROVIDE(__bothinit_array_end = __init_array_end);

. = ALIGN(4);
/* finit data */
Expand Down
5 changes: 5 additions & 0 deletions platform/ext/common/llvm/tfm_isolation_s.ld.template
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Expand Up @@ -192,6 +192,7 @@ SECTIONS
{
/* preinit data */
PROVIDE_HIDDEN (__preinit_array_start = .);
PROVIDE(__bothinit_array_start = __preinit_array_start);
KEEP(*(.preinit_array))
PROVIDE_HIDDEN (__preinit_array_end = .);

Expand All @@ -201,6 +202,7 @@ SECTIONS
KEEP(*(SORT(.init_array.*)))
KEEP(*(.init_array))
PROVIDE_HIDDEN (__init_array_end = .);
PROVIDE(__bothinit_array_end = __init_array_end);

. = ALIGN(4);
/* finit data */
Expand Down Expand Up @@ -323,6 +325,9 @@ SECTIONS
. = ALIGN(4); /* This alignment is needed to make the section size 4 bytes aligned */
} > CODE_RAM AT > FLASH

/* Reset current position for subsequent sections */
. = LOADADDR(.ER_CODE_SRAM) + SIZEOF(.ER_CODE_SRAM);

ASSERT(S_RAM_CODE_START % 4 == 0, "S_RAM_CODE_START must be divisible by 4")

Image$$ER_CODE_SRAM$$RO$$Base = ADDR(.ER_CODE_SRAM);
Expand Down
56 changes: 56 additions & 0 deletions platform/ext/common/picolibc.c
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@@ -0,0 +1,56 @@
/*
* Copyright 2025, Keith Packard <keithp@keithp.com>
*
* SPDX-License-Identifier: BSD-3-Clause
*
*/

#include <stdint.h>
#include <string.h>
#include "config_impl.h"

#ifdef __PICOLIBC__

/*
* Picolibc's startup code only initializes a single data and bss
* segment. Replace that to initialize all of the segments using
* the lists provided by the linker script.
*/

void __libc_init_array(void);
void _start(void);
int main(int, char **);

void
_start(void)
{
typedef struct __copy_table {
uint32_t const* src;
uint32_t* dest;
uint32_t wlen;
} __copy_table_t;

typedef struct __zero_table {
uint32_t* dest;
uint32_t wlen;
} __zero_table_t;

extern const __copy_table_t __copy_table_start__;
extern const __copy_table_t __copy_table_end__;
extern const __zero_table_t __zero_table_start__;
extern const __zero_table_t __zero_table_end__;

for (__copy_table_t const* pTable = &__copy_table_start__; pTable < &__copy_table_end__; ++pTable) {
memcpy(pTable->dest, pTable->src, pTable->wlen << 2);
}

for (__zero_table_t const* pTable = &__zero_table_start__; pTable < &__zero_table_end__; ++pTable) {
memset(pTable->dest, 0, pTable->wlen << 2);
}

__libc_init_array();
main(0, NULL);
return;
}

#endif /* __PICOLIBC__ */
1 change: 1 addition & 0 deletions platform/ext/common/provisioning_bundle/CMakeLists.txt
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Expand Up @@ -54,6 +54,7 @@ target_sources(provisioning_bundle
PRIVATE
./provisioning_code.c
./provisioning_data.c
$<$<BOOL:${CONFIG_PICOLIBC}>:${CMAKE_SOURCE_DIR}/platform/ext/common/picolibc.c>
$<$<BOOL:${CONFIG_GNU_SYSCALL_STUB_ENABLED}>:${CMAKE_SOURCE_DIR}/platform/ext/common/syscalls_stub.c>
)

Expand Down
10 changes: 10 additions & 0 deletions platform/ext/common/syscalls_stub.c
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Expand Up @@ -14,6 +14,14 @@
#include <stddef.h>
#include <stdint.h>

#ifdef __PICOLIBC__
__attribute__((weak))
void _exit(int status)
{
(void) status;
for(;;);
}
#else
__attribute__((weak))
void _close(void)
{
Expand Down Expand Up @@ -53,3 +61,5 @@ __attribute__((weak))
void _write(void)
{
}

#endif /* !__PICOLIBC__ */
2 changes: 1 addition & 1 deletion platform/ext/common/uart_stdout.c
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Expand Up @@ -85,7 +85,7 @@ int fputc(int ch, FILE *f)
/* Redirect sdtio for PicoLib in LLVM toolchain
as per https://github.com/picolibc/picolibc/blob/main/doc/os.md
'fputch()' named intentionally different from 'fputc()' from picolib */
#elif defined(__clang_major__)
#elif defined(__PICOLIBC__)

int fputch(char ch, struct __file *f)
{
Expand Down
4 changes: 4 additions & 0 deletions platform/ext/target/adi/max32657/device/gcc/max32657_sla.ld
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Expand Up @@ -50,6 +50,7 @@ SECTIONS
. = ALIGN(4);
/* preinit data */
PROVIDE_HIDDEN (__preinit_array_start = .);
PROVIDE(__bothinit_array_start = __preinit_array_start);
KEEP(*(.preinit_array))
PROVIDE_HIDDEN (__preinit_array_end = .);

Expand All @@ -59,6 +60,7 @@ SECTIONS
KEEP(*(SORT(.init_array.*)))
KEEP(*(.init_array))
PROVIDE_HIDDEN (__init_array_end = .);
PROVIDE(__bothinit_array_end = __init_array_end);

. = ALIGN(4);
/* finit data */
Expand Down Expand Up @@ -196,8 +198,10 @@ SECTIONS
__end__ = .;
PROVIDE(end = .);
__HeapBase = .;
PROVIDE(__heap_start = __HeapBase);
. += __heap_size__;
__HeapLimit = .;
PROVIDE(__heap_end = __HeapLimit);
__heap_limit = .; /* Add for _sbrk */
} > RAM
Image$$ARM_LIB_HEAP$$ZI$$Limit = ADDR(.heap) + SIZEOF(.heap);
Expand Down
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