How to put c-style strings (function arguments) in the specific section? - gcc

Question

I want to put some functions in a specific section named ".xip.text",
but the read only data cannot put in that section.
The following is my test code:
#include <stdio.h>
void foo(void) __attribute__((section (".xip.text")));
void foo(void)
{
printf("hello world\n");
}
In the linker script file:
MEMORY
{
RAM (rwx) : ORIGIN = 0x00010000, LENGTH = 448K
FLASH (rx) : ORIGIN = 0x10000000, LENGTH = 1024K
}
SECTIONS
{
.xip :
{
*(.xip.text .xip.text.*)
*(.xip.rodata .xip.rodata.*)
} > FLASH
.text :
{
*(.text*)
} > RAM
}
After linking, the function text is placed in ".xip" section, but the string
"hello world\n" is not put in the same section. How to solve it?
I can put the whole file in the ".xip" section to solve this problem. But I
have many files, and I only want to put some functions to ".xip" section, not
the whole file.
In the map file, text of foo() is placed in the right section,
but string "hello world\n" (.rodata.str1.1) is placed in another seciton.
*(.xip.text .xip.text.*)
.xip.text 0x1002f7b0 0xc ../foo.o
0x1002f7b0 foo
*fill* 0x1002f7bc 0x4
.rodata.str1.1
0x00025515 0xc ../foo.o
*fill* 0x00025521 0x3
After disassemble,
1002f7b0 <foo>:
void foo(void) __attribute__((section (".xip.text")));
void foo(void)
{
printf("hello world\n");
1002f7b0: 4801 ldr r0, [pc, #4] ; (1002f7b8 <foo+0x8>)
1002f7b2: f000 b95d b.w 1002fa70 <__puts_veneer>
1002f7b6: bf00 nop
1002f7b8: 00025515 .word 0x00025515
1002f7bc: 00000000 .word 0x00000000
gcc version: gcc-arm-none-eabi-7-2017-q4-major, gcc version 7.2.1 20170904 (release) [ARM/embedded-7-branch revision 255204] (GNU Tools for Arm Embedded Processors 7-2017-q4-major)

Answer 1

function text is placed in ".xip" section, but the string "hello world\n" is not put in the same section.
The read-only data is not .text, so it shouldn't be put into the same section.
If you want to control which section the read-only data goes, you need to do that yourself. Something like this should work:
__attribute__((section(".xip.rodata")))
const char my_xip_data[] = "hello, world\n";
void foo(void)
{
printf(my_xip_data);
}