qualcomm · quic-k · Apr 17, 2026
diff --git a/booter/Makefile b/booter/Makefile
@@ -17,27 +17,37 @@ BOOTVM_IMAGE_HEAP_SIZE := 0x1000000
 
 all: hello should_crash should_pagefault bigio $(BOOTVM_PROG)
 
-CFLAGS = $(OPTIMIZE) -mv$(TOOLARCH) -DARCHV=$(ARCHV) -Wall -Werror -Wno-builtin-requires-header -g -I. -I$(INSTALLPATH)/include -I$(KERNELPATH)/include
-LDFLAGS = -L$(INSTALLPATH)/lib -moslib=h2 -Qunused-arguments
+ifeq ($(PICOLIBC),1)
+OSLIB_FLAG = --target=hexagon-h2-picolibc
+# Derive template path from the resolved compiler location: bin/../templates/staticExecutable/
+PICOLIBC_LCS := $(abspath $(dir $(shell which $(CC)))/../templates/staticExecutable/static-executable-h2-picolibc.lcs.template)
+GUEST_LDSCRIPT = -Wl,--script=$(PICOLIBC_LCS)
+else
+OSLIB_FLAG = -moslib=h2
+GUEST_LDSCRIPT =
+endif
+
+CFLAGS = $(OSLIB_FLAG) $(OPTIMIZE) -mv$(TOOLARCH) -DARCHV=$(ARCHV) -Wall -Werror -Wno-builtin-requires-header -g -I. -I$(INSTALLPATH)/include -I$(KERNELPATH)/include
+LDFLAGS = -L$(INSTALLPATH)/lib $(OSLIB_FLAG) -Qunused-arguments
 
 include $(H2DIR)/scripts/Makefile.inc.config
 include $(H2DIR)/scripts/Makefile.inc.opensource
 include $(H2DIR)/scripts/Makefile.inc.bootvm
 
 
 hello: hello.o
-	${CC} $(LDFLAGS) $(CFLAGS)  -Wl,--section-start=.start=$(H2K_GUEST_START) -o hello hello.o
+	${CC} $(LDFLAGS) $(CFLAGS) $(GUEST_LDSCRIPT) -Wl,--section-start=.start=$(H2K_GUEST_START) -o hello hello.o
 
 should_pagefault: OPTIMIZE = -O0
 should_pagefault: should_pagefault.o
-	${CC} $(LDFLAGS) $(CFLAGS)  -O0 -Wl,--section-start=.start=$(H2K_GUEST_START) -o should_pagefault should_pagefault.o
+	${CC} $(LDFLAGS) $(CFLAGS) $(GUEST_LDSCRIPT) -O0 -Wl,--section-start=.start=$(H2K_GUEST_START) -o should_pagefault should_pagefault.o
 
 should_crash: OPTIMIZE = -O0
 should_crash: should_crash.o
-	${CC} $(LDFLAGS) $(CFLAGS)  -O0 -Wl,--section-start=.start=$(H2K_GUEST_START) -o should_crash should_crash.o
+	${CC} $(LDFLAGS) $(CFLAGS) $(GUEST_LDSCRIPT) -O0 -Wl,--section-start=.start=$(H2K_GUEST_START) -o should_crash should_crash.o
 
 bigio: bigio.o
-	${CC} $(LDFLAGS) $(CFLAGS)  -O0 -Wl,--section-start=.start=$(H2K_GUEST_START) -o bigio bigio.o
+	${CC} $(LDFLAGS) $(CFLAGS) $(GUEST_LDSCRIPT) -O0 -Wl,--section-start=.start=$(H2K_GUEST_START) -o bigio bigio.o
 
 # %.o: %.c
 # 	${CC} ${CFLAGS} -c -o $@ $<

diff --git a/booter/booter.c b/booter/booter.c
@@ -671,7 +671,7 @@ void add_linear_trans(unsigned int idx, unsigned long va, unsigned long long pa,
 		vm_params[idx].pmap_added = 1;
 	}
 
-	if (NULL == (pmap->base.raw = (h2_u32_t)realloc((void *)(pmap->base.raw), sizeof(H2K_linear_fmt_t) * (end + npages + 1)))) {
+	if (0 == (pmap->base.raw = (h2_u32_t)realloc((void *)(pmap->base.raw), sizeof(H2K_linear_fmt_t) * (end + npages + 1)))) {
 		error("realloc pmap->base", NULL);
 	}
 	base = (H2K_linear_fmt_t *)(pmap->base.raw);
@@ -764,7 +764,7 @@ void clade_setup(unsigned int idx, long offset) {
 	/* Copy high-prio exception data to TCM */
 	ex_hi_size = ex_hi_end - ex_hi_start;
 	if (ex_hi_size && tcm_size) {
-		if (NULL == (vm_params[idx].clade_ex_hi = (unsigned int)h2_galloc(&tcm_alloc, ex_hi_size, 4096, 0))) {
+		if (0 == (vm_params[idx].clade_ex_hi = (unsigned int)h2_galloc(&tcm_alloc, ex_hi_size, 4096, 0))) {
 			FAIL("\tgalloc ex_hi", "");
 		}
 		//		BOOTER_PRINTF("memcpy(0x%08x, 0x%08lx, 0x%08lx\n", vm_params[idx].clade_ex_hi, ex_hi_start + offset, ex_hi_size);
@@ -2310,6 +2310,7 @@ unsigned int process_line(int argc, char **argv, unsigned int idx) {
 	return idx;
 }
 
+#ifndef __PICOLIBC__
 size_t getline(char **lineptr, size_t *n, FILE *stream) {
 
 	char *buf = NULL;
@@ -2362,6 +2363,7 @@ size_t getline(char **lineptr, size_t *n, FILE *stream) {
 
 	return p - buf - 1;
 }
+#endif /* !__PICOLIBC__ */
 
 int main(int argc, char **argv)
 {

diff --git a/kernel/Makefile b/kernel/Makefile
@@ -5,6 +5,11 @@ H2DIR ?= ..
 
 include ../scripts/Makefile.inc.tools
 
+# Ensure toolchain path override is honored even when kernel is built directly.
+ifneq ($(TOOLCHAIN_BIN),)
+export PATH := $(TOOLCHAIN_BIN):$(PATH)
+endif
+
 ifeq ($(USE_PKW),1)
 export PKW_VERSIONS := hexagon-tools=$(TOOLS_FLAVOR_KERNEL) arch=$(ARCH_FLAVOR)
 endif
@@ -223,4 +228,3 @@ opt_install: info opt
 	cp include/asm_offsets.h $(INSTALLPATH)/include # for state trap
 
 check: build/ref/libh2check.a
-
diff --git a/kernel/build/offsets/make.inc b/kernel/build/offsets/make.inc
@@ -1,5 +1,26 @@
 # Yo.  -*- Makefile -*-
 
+# offsets is a target-side generator program (run under simulator) and uses
+# libc headers like <stdio.h>. When building with PICOLIBC, select the picolibc
+# sysroot via the target triple.
+ifeq ($(PICOLIBC),1)
+OFFSETS_TARGET_FLAG := --target=hexagon-none-picolibc
+else
+OFFSETS_TARGET_FLAG :=
+endif
+
+ifeq ($(PICOLIBC),1)
+# Provide heap symbols and default memory layout expected by picolibc's libc.
+# Use the linker script from the selected toolchain sysroot.
+ifneq ($(TOOLCHAIN_BIN),)
+OFFSETS_LDSCRIPT := -Wl,-T,$(abspath $(TOOLCHAIN_BIN)/../target/hexagon-unknown-none-picolibc/lib/v$(ARCHV)/G0/picolibc.ld)
+else
+OFFSETS_LDSCRIPT := -Wl,-T,$(shell $(CC) $(OFFSETS_TARGET_FLAG) -print-file-name=picolibc.ld)
+endif
+else
+OFFSETS_LDSCRIPT :=
+endif
+
 include/asm_offsets.h: $(BUILD_DIR)/offsets
 ifeq ($(RUN), $(RUN_TOOLSIM))
 	$(RUN) $< -- $@
@@ -8,9 +29,8 @@ else
 endif
 
 $(BUILD_DIR)/offsets: $(DIR)offsets.ref.c includes
-	$(CC) $(CFLAGS) -o $@ $<
+	$(CC) $(OFFSETS_TARGET_FLAG) $(OFFSETS_LDSCRIPT) $(CFLAGS) -o $@ $<
 
 DEST_HFILES += include/asm_offsets.h
 
 CLEAN_EXTRAS += $(BUILD_DIR)/offsets
-
diff --git a/kernel/build/offsets/offsets.ref.c b/kernel/build/offsets/offsets.ref.c
@@ -191,6 +191,7 @@ int main(int argc, char **argv)
 	fprintf(outfile, "#define STATUS_INTBLOCKED %d\n",H2K_STATUS_INTBLOCKED);
 	fprintf(outfile, "#define STATUS_VMWAIT     %d\n",H2K_STATUS_VMWAIT);
 
+	fclose(outfile);
 	return 0;
 }
 
diff --git a/libs/blast/Makefile b/libs/blast/Makefile
@@ -1,9 +1,18 @@
 
 
+
+
+# Picolibc support: if PICOLIBC=1, use --target=hexagon-h2-picolibc
+ifeq ($(PICOLIBC),1)
+TARGET_FLAG = --target=hexagon-h2-picolibc
+else
+TARGET_FLAG =
+endif
+
 CC = hexagon-clang
 AR = hexagon-ar
-CFLAGS = -mv$(TOOLARCH) -DARCHV=$(ARCHV) -Iinclude -Wall -I../h2/include -I../../kernel/include -g $(OPTIMIZE) $(OPT_ADD) -G0
-ASFLAGS = -mv$(TOOLARCH) -DARCHV=$(ARCHV) -Iinclude -Wall -I../h2/include -I../../kernel/include
+CFLAGS = $(TARGET_FLAG) -mv$(TOOLARCH) -DARCHV=$(ARCHV) -Iinclude -Wall -I../h2/include -I../../kernel/include -g $(OPTIMIZE) $(OPT_ADD) -G0
+ASFLAGS = $(TARGET_FLAG) -mv$(TOOLARCH) -DARCHV=$(ARCHV) -Iinclude -Wall -I../h2/include -I../../kernel/include
 OPTIMIZE := -O2
 
 export BLAST_LIB_INCLUDE=$(shell pwd)/include

diff --git a/libs/h2/Makefile b/libs/h2/Makefile
@@ -1,9 +1,16 @@
 
 ALL: dummy
 
+# Picolibc support: if PICOLIBC=1, use --target=hexagon-h2-picolibc
+ifeq ($(PICOLIBC),1)
+TARGET_FLAG = --target=hexagon-h2-picolibc
+else
+TARGET_FLAG =
+endif
+
 OPTIMIZE := -Os
 
-CFLAGS := -Iinclude -G0 $(OPTIMIZE) $(OPT_ADD) -mv$(TOOLARCH) -DARCHV=$(ARCHV) -Wall -Wno-builtin-requires-header -Werror -g
+CFLAGS := $(TARGET_FLAG) -Iinclude -G0 $(OPTIMIZE) $(OPT_ADD) -mv$(TOOLARCH) -DARCHV=$(ARCHV) -Wall -Wno-builtin-requires-header -Werror -g
 
 ifdef DEBUG
 CFLAGS += -DDEBUG

diff --git a/libs/h2_compat/Makefile b/libs/h2_compat/Makefile
@@ -3,7 +3,14 @@ ALL: dummy
 
 OPTIMIZE := -Os
 
-CFLAGS := -Iinclude -I$(INSTALLPATH)/include -I../h2/include -I../posix/include -I../../libs/syscall/angel/include -G0 $(OPTIMIZE) $(OPT_ADD) -mv$(TOOLARCH) -DARCHV=$(ARCHV) -Wall -Wno-builtin-requires-header -Werror -g
+# Picolibc support: if PICOLIBC=1, use --target=hexagon-h2-picolibc
+ifeq ($(PICOLIBC),1)
+TARGET_FLAG = --target=hexagon-h2-picolibc
+else
+TARGET_FLAG =
+endif
+
+CFLAGS := $(TARGET_FLAG) -Iinclude -I$(INSTALLPATH)/include -I../h2/include -I../posix/include -I../../libs/syscall/angel/include -G0 $(OPTIMIZE) $(OPT_ADD) -mv$(TOOLARCH) -DARCHV=$(ARCHV) -Wall -Wno-builtin-requires-header -Werror -g
 
 ifdef DEBUG
 CFLAGS += -DDEBUG

diff --git a/libs/h2_compat/alloc/h2_alloc.ref.c b/libs/h2_compat/alloc/h2_alloc.ref.c
@@ -6,6 +6,7 @@
 #include <h2_alloc.h>
 #include <h2_plainmutex.h>
 #include <stdlib.h>
+#include <malloc.h>
 
 /*
  * h2_alloc.c

diff --git a/libs/h2_compat/coproc/h2_coproc.ref.c b/libs/h2_compat/coproc/h2_coproc.ref.c
@@ -6,9 +6,9 @@
 #include <h2_coproc.h>
 #include <h2_alloc.h>
 
-static unsigned int *configs[CFG_TYPE_MAX][CFG_SUBTYPE_MAX] = {NULL};
-static unsigned int nunits[CFG_TYPE_MAX][CFG_SUBTYPE_MAX] = {0};
-static unsigned int *counts[CFG_TYPE_MAX][CFG_SUBTYPE_MAX][CFG_MAX] = {NULL};
+static unsigned int *configs[CFG_TYPE_MAX][CFG_SUBTYPE_MAX] = {{NULL}};
+static unsigned int nunits[CFG_TYPE_MAX][CFG_SUBTYPE_MAX] = {{0}};
+static unsigned int *counts[CFG_TYPE_MAX][CFG_SUBTYPE_MAX][CFG_MAX] = {{{NULL}}};
 static unsigned int oldstyle = 0;
 static unsigned int init_done = 0;
 

diff --git a/libs/h2_compat/prof/h2_prof.ref.c b/libs/h2_compat/prof/h2_prof.ref.c
@@ -12,7 +12,7 @@ unsigned int h2_prof_sample(unsigned long long int **res) {
 	unsigned int hthreads_mask;
 
 	if (NULL == (*res = (unsigned long long int *)h2_malloc(sizeof(unsigned long long int) * 6))) {
-		return NULL;
+		return 0;
 	}
 
 	asm volatile

diff --git a/libs/posix/Makefile b/libs/posix/Makefile
@@ -1,9 +1,16 @@
 
 ALL: dummy
 
+# Picolibc support: if PICOLIBC=1, use --target=hexagon-h2-picolibc
+ifeq ($(PICOLIBC),1)
+TARGET_FLAG = --target=hexagon-h2-picolibc
+else
+TARGET_FLAG =
+endif
+
 OPTIMIZE := -Os
 
-CFLAGS := -Iinclude -I../h2/include -G0 $(OPTIMIZE) $(OPT_ADD) -mv$(TOOLARCH) -DARCHV=$(ARCHV) -Wall -Wno-builtin-requires-header -Werror -g
+CFLAGS := $(TARGET_FLAG) -Iinclude -I../h2/include -G0 $(OPTIMIZE) $(OPT_ADD) -mv$(TOOLARCH) -DARCHV=$(ARCHV) -Wall -Wno-builtin-requires-header -Werror -g
 
 ifdef DEBUG
 CFLAGS += -DDEBUG

diff --git a/libs/posix/pthread/misc/posix_time.h b/libs/posix/pthread/misc/posix_time.h
@@ -7,6 +7,18 @@
 #define H2_POSIX_TIME_H 1
 
 #define _PROVIDE_POSIX_TIME_DECLS 1
+#ifdef __PICOLIBC__
+/* Enable POSIX clock IDs in Picolibc's time.h */
+#ifndef _POSIX_MONOTONIC_CLOCK
+#define _POSIX_MONOTONIC_CLOCK 1
+#endif
+#ifndef _POSIX_CPUTIME
+#define _POSIX_CPUTIME 1
+#endif
+#ifndef _POSIX_THREAD_CPUTIME
+#define _POSIX_THREAD_CPUTIME 1
+#endif
+#endif
 #include <time.h> // dinkumware time.h, if we change c libraries we probably need to nuke this
 
 /* In case time.h was included early without defining

diff --git a/libs/qurt/Makefile b/libs/qurt/Makefile
@@ -1,8 +1,14 @@
 
 
-CC = hexagon-clang -mv$(TOOLARCH) -Iinclude -Wall -Wno-builtin-requires-header -I../h2/include -I../posix/include -I../h2_compat/include
+# Picolibc support: if PICOLIBC=1, use --target=hexagon-h2-picolibc
+ifeq ($(PICOLIBC),1)
+TARGET_FLAG = --target=hexagon-h2-picolibc
+else
+TARGET_FLAG =
+endif
+
+CC = hexagon-clang $(TARGET_FLAG) -mv$(TOOLARCH) -Iinclude -Wall -Wno-builtin-requires-header -I../h2/include -I../posix/include -I../h2_compat/include
 AR = hexagon-ar
-
 OPTIMIZE := -O2
 
 CFLAGS = -g $(OPTIMIZE) $(OPT_ADD) -G0

diff --git a/libs/qurt/src/qurt_fd.c b/libs/qurt/src/qurt_fd.c
@@ -5,6 +5,7 @@
 
 #include <qurt_lifo.h>
 #include <qurt_fd.h>
+#include <stdint.h>
 
 /* EJP: the best thing about this file is that most of the things are commented out. */
 

diff --git a/libs/syscall/angel/Makefile b/libs/syscall/angel/Makefile
@@ -1,6 +1,15 @@
 
-CFLAGS = -mv$(TOOLARCH) -DARCHV=$(ARCHV) -Iinclude -Wall -Wno-builtin-requires-header -Werror -I../../h2/include -I../../h2_compat/include -I../../posix/include -g $(OPTIMIZE) $(OPT_ADD) -G0
-ASFLAGS = -mv$(TOOLARCH) -DARCHV=$(ARCHV) -Iinclude -Wall -I../../h2/include -I../../posix/include
+# Picolibc support: if PICOLIBC=1, use --target=hexagon-h2-picolibc
+ifeq ($(PICOLIBC),1)
+TARGET_FLAG = --target=hexagon-h2-picolibc
+# _STD_END/_STD_BEGIN are Dinkumware-specific macros; define them as no-ops
+TARGET_FLAG += -D_STD_END= -D_STD_BEGIN=
+else
+TARGET_FLAG =
+endif
+
+CFLAGS = $(TARGET_FLAG) -mv$(TOOLARCH) -DARCHV=$(ARCHV) -Iinclude -Wall -Wno-builtin-requires-header -Werror -I../../h2/include -I../../h2_compat/include -I../../posix/include -g $(OPTIMIZE) $(OPT_ADD) -G0
+ASFLAGS = $(TARGET_FLAG) -mv$(TOOLARCH) -DARCHV=$(ARCHV) -Iinclude -Wall -I../../h2/include -I../../posix/include
 
 CFLAGS += $(LIB_CFLAGS) $(H2_EXTRA_CFLAGS)
 

diff --git a/libs/syscall/angel/include/angel.h b/libs/syscall/angel/include/angel.h
@@ -97,7 +97,6 @@ struct heap_info {	/* heap information */
 	int stack_base;
 	int stack_limit;
 	};
-
 struct __sys_stat
 {
     unsigned long long int dev;
@@ -113,6 +112,7 @@ struct __sys_stat
     unsigned long __pad2;
 }__attribute__ ((aligned (8)));
 
+
 	/* SYSTEM CALL FUNCTIONS */
 errno_t sys_clock(void);
 errno_t sys_close(fd_t);

diff --git a/libs/syscall/angel/src/sys_fstat.c b/libs/syscall/angel/src/sys_fstat.c
@@ -5,7 +5,7 @@
 
 #include "allsyscalls.h"
 
-errno_t sys_fstat(fd_t fd, void *buffer)
+sys_call_ret_t sys_fstat_internal(fd_t fd, void *buffer)
 {
 	struct {
 		fd_t fd;
@@ -15,6 +15,9 @@ errno_t sys_fstat(fd_t fd, void *buffer)
 	x.buf = ANGEL_OFFSET_PTR(buffer);
 	clean(buffer, sizeof(struct __sys_stat) / 4);
 	clean(&x, 2);
-	return ANGEL(SYS_FSTAT,&x,0);
+	return angel_with_err(SYS_FSTAT, &x, 0);
 }
 
+errno_t sys_fstat(fd_t fd, void *buffer) {
+	return sys_fstat_internal(fd, buffer).ret_value;
+}