[PATCH v3 2/8] ARM/ARM64/RISC-V: pbl: add constructor support

[Stefan Kerkmann]

This commit allows running functions marked with
__attribute__((constructor))[1] automatically after the C environment is
setup in setup_c, which most likely will be early setup code shared
across SoCs/Arches in the PBL.

[1]: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Common-Attributes.html#index-constructor

Signed-off-by: Stefan Kerkmann <s.kerkmann at pengutronix.de>
---
 arch/arm/cpu/setupc_32.S       |  3 +++
 arch/arm/cpu/setupc_64.S       |  3 +++
 arch/arm/lib/pbl.lds.S         |  8 ++++++++
 arch/riscv/lib/pbl.lds.S       |  9 +++++++++
 arch/riscv/lib/setupc.S        |  3 +++
 include/asm-generic/sections.h |  2 ++
 pbl/Makefile                   |  1 +
 pbl/ctors.c                    | 13 +++++++++++++
 8 files changed, 42 insertions(+)

diff --git a/arch/arm/cpu/setupc_32.S b/arch/arm/cpu/setupc_32.S
index fadfc28ae1..f34b144556 100644
--- a/arch/arm/cpu/setupc_32.S
+++ b/arch/arm/cpu/setupc_32.S
@@ -23,6 +23,9 @@ ENTRY(setup_c)
 	ldr	r0, =bss_cleared
 	mov	r1, #1
 	str	r1, [r0]		/* mark bss cleared */
+#ifdef __PBL__
+	bl	pbl_do_ctors
+#endif
 1:	pop	{r4, pc}
 ENDPROC(setup_c)
 
diff --git a/arch/arm/cpu/setupc_64.S b/arch/arm/cpu/setupc_64.S
index a0767c5136..e3c6149e27 100644
--- a/arch/arm/cpu/setupc_64.S
+++ b/arch/arm/cpu/setupc_64.S
@@ -22,6 +22,9 @@ ENTRY(setup_c)
 	adr_l	x0, bss_cleared
 	mov	w1, #1
 	str	w1, [x0]		/* mark bss cleared */
+#ifdef __PBL__
+	bl	pbl_do_ctors
+#endif
 	mov	x30, x15
 1:	ret
 ENDPROC(setup_c)
diff --git a/arch/arm/lib/pbl.lds.S b/arch/arm/lib/pbl.lds.S
index 9c51f5eb3a..72aca83495 100644
--- a/arch/arm/lib/pbl.lds.S
+++ b/arch/arm/lib/pbl.lds.S
@@ -78,6 +78,14 @@ SECTIONS
 	. = ALIGN(4);
 	.rodata : { *(.rodata*) }
 
+	. = ALIGN(ASM_SZPTR);
+	__ctors_start = .;
+	.init_array : {
+		KEEP(*(SORT_BY_INIT_PRIORITY(.init_array.*)))
+		KEEP(*(.init_array))
+	}
+	__ctors_end = .;
+
 	.barebox_imd : { BAREBOX_IMD }
 
 	. = ALIGN(PBL_SEGMENT_ALIGN);
diff --git a/arch/riscv/lib/pbl.lds.S b/arch/riscv/lib/pbl.lds.S
index 3a37d01475..17cd61ff75 100644
--- a/arch/riscv/lib/pbl.lds.S
+++ b/arch/riscv/lib/pbl.lds.S
@@ -4,6 +4,7 @@
 #include <linux/sizes.h>
 #include <asm/barebox.lds.h>
 #include <asm-generic/memory_layout.h>
+#include <asm-generic/pointer.h>
 
 OUTPUT_ARCH(BAREBOX_OUTPUT_ARCH)
 OUTPUT_FORMAT(BAREBOX_OUTPUT_FORMAT)
@@ -32,6 +33,14 @@ SECTIONS
 	__start_rodata = .;
 	.rodata : { *(.rodata*) }
 
+	. = ALIGN(ASM_SZPTR);
+	__ctors_start = .;
+	.init_array : {
+		KEEP(*(SORT_BY_INIT_PRIORITY(.init_array.*)))
+		KEEP(*(.init_array))
+	}
+	__ctors_end = .;
+
 	.barebox_imd : { BAREBOX_IMD }
 
 	__end_rodata = .;
diff --git a/arch/riscv/lib/setupc.S b/arch/riscv/lib/setupc.S
index 5370e8a48e..938c78350c 100644
--- a/arch/riscv/lib/setupc.S
+++ b/arch/riscv/lib/setupc.S
@@ -23,6 +23,9 @@ ENTRY(setup_c)
 	lla	a0, bss_cleared
 	li	a1, 1
 	sw	a1, 0(a0)
+#ifdef __PBL__
+	jal	pbl_do_ctors
+#endif
 zeroed:
 	REG_L	ra, SZREG(sp)
 	addi	sp, sp, SZREG * 2
diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index 816e30341d..c7c576970a 100644
--- a/include/asm-generic/sections.h
+++ b/include/asm-generic/sections.h
@@ -49,4 +49,6 @@ static inline bool in_barebox_efi_runtime(unsigned long addr)
 	       addr < (unsigned long)__efi_runtime_stop;
 }
 
+void pbl_do_ctors(void);
+
 #endif /* _ASM_GENERIC_SECTIONS_H_ */
diff --git a/pbl/Makefile b/pbl/Makefile
index 4506f192fe..7ce8cee077 100644
--- a/pbl/Makefile
+++ b/pbl/Makefile
@@ -3,6 +3,7 @@
 #
 # only unsed by the pbl
 #
+pbl-y += ctors.o
 pbl-y += misc.o
 pbl-y += string.o
 pbl-y += malloc.o
diff --git a/pbl/ctors.c b/pbl/ctors.c
new file mode 100644
index 0000000000..fcab599877
--- /dev/null
+++ b/pbl/ctors.c
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <asm-generic/sections.h>
+
+typedef void (*ctor_fn_t)(void);
+
+void pbl_do_ctors(void)
+{
+	ctor_fn_t *fn = (ctor_fn_t *)__ctors_start;
+
+	for (; fn < (ctor_fn_t *)__ctors_end; fn++)
+		(*fn)();
+}

-- 
2.47.3