libc/picolibc: Split hooks into separate files

This splits the picolibc helper functions into separate files instead of
smashing them all together.

Signed-off-by: Keith Packard <[email protected]>

boards/qemu/x86/qemu_x86_tiny.ld

@@ -144,10 +144,10 @@ MEMORY
 #endif /* CONFIG_NEWLIB_LIBC */
 
 #ifdef CONFIG_PICOLIBC
-/* For Picolibc libc-hook.c. */
+/* For Picolibc, all files under lib/libc/picolibc */
 #define LIB_C_IN_SECT(lsect)						\
-	*liblib__libc__picolibc.a:libc-hooks.c.obj(.##lsect)		\
-	*liblib__libc__picolibc.a:libc-hooks.c.obj(.##lsect##.*)
+	*liblib__libc__picolibc.a:(.##lsect)				\
+	*liblib__libc__picolibc.a:(.##lsect##.*)
 
 #endif /* CONFIG_PICOLIBC */
 

lib/libc/picolibc/CMakeLists.txt

@@ -1,10 +1,15 @@
 # SPDX-License-Identifier: Apache-2.0
 
 zephyr_library()
-zephyr_library_sources(libc-hooks.c)
-
-# Do not allow LTO when compiling libc-hooks.c file
-set_source_files_properties(libc-hooks.c PROPERTIES COMPILE_OPTIONS $<TARGET_PROPERTY:compiler,prohibit_lto>)
+zephyr_library_sources(
+  assert.c
+  cbprintf.c
+  chk_fail.c
+  errno_wrap.c
+  exit.c
+  locks.c
+  stdio.c
+  )
 
 # define __LINUX_ERRNO_EXTENSIONS__ so we get errno defines like -ESHUTDOWN
 # used by the network stack

lib/libc/picolibc/assert.c

@@ -0,0 +1,28 @@
+/*
+ * Copyright © 2021, Keith Packard <[email protected]>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "picolibc-hooks.h"
+
+#ifdef CONFIG_PICOLIBC_ASSERT_VERBOSE
+
+FUNC_NORETURN void __assert_func(const char *file, int line,
+				 const char *function, const char *expression)
+{
+	__ASSERT(0, "assertion \"%s\" failed: file \"%s\", line %d%s%s\n",
+		 expression, file, line,
+		 function ? ", function: " : "", function ? function : "");
+	CODE_UNREACHABLE;
+}
+
+#else
+
+FUNC_NORETURN void __assert_no_args(void)
+{
+	__ASSERT_NO_MSG(0);
+	CODE_UNREACHABLE;
+}
+
+#endif

lib/libc/picolibc/cbprintf.c

@@ -0,0 +1,31 @@
+/*
+ * Copyright © 2021, Keith Packard <[email protected]>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "picolibc-hooks.h"
+
+struct cb_bits {
+	FILE f;
+	cbprintf_cb out;
+	void	*ctx;
+};
+
+static int cbputc(char c, FILE *_s)
+{
+	struct cb_bits *s = (struct cb_bits *) _s;
+
+	(*s->out) (c, s->ctx);
+	return 0;
+}
+
+int cbvprintf(cbprintf_cb out, void *ctx, const char *fp, va_list ap)
+{
+	struct cb_bits	s = {
+		.f = FDEV_SETUP_STREAM(cbputc, NULL, NULL, _FDEV_SETUP_WRITE),
+		.out = out,
+		.ctx = ctx,
+	};
+	return vfprintf(&s.f, fp, ap);
+}

lib/libc/picolibc/chk_fail.c

@@ -0,0 +1,18 @@
+/*
+ * Copyright © 2021, Keith Packard <[email protected]>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "picolibc-hooks.h"
+
+/* This function gets called if static buffer overflow detection is enabled on
+ * stdlib side (Picolibc here), in case such an overflow is detected. Picolibc
+ * provides an implementation not suitable for us, so we override it here.
+ */
+__weak FUNC_NORETURN void __chk_fail(void)
+{
+	printk("* buffer overflow detected *\n");
+	z_except_reason(K_ERR_STACK_CHK_FAIL);
+	CODE_UNREACHABLE;
+}

lib/libc/picolibc/errno_wrap.c

@@ -0,0 +1,21 @@
+/*
+ * Copyright © 2021, Keith Packard <[email protected]>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "picolibc-hooks.h"
+
+#ifndef CONFIG_LIBC_ERRNO
+
+/*
+ * Picolibc needs to be able to declare this itself so that the library
+ * doesn't end up needing zephyr header files. That means using a regular
+ * function instead of an inline.
+ */
+int *z_errno_wrap(void)
+{
+	return z_errno();
+}
+
+#endif

lib/libc/picolibc/exit.c

@@ -0,0 +1,15 @@
+/*
+ * Copyright © 2021, Keith Packard <[email protected]>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "picolibc-hooks.h"
+
+__weak void _exit(int status)
+{
+	printf("exit\n");
+	while (1) {
+		Z_SPIN_DELAY(100);
+	}
+}