When using -ffunction-sections to place each function in it's own text section so it can be randomized at load time, the linker considers these .text.* sections "orphaned sections", and will place them after the first similar section (.text). In order to accurately represent the end of the text section and the orphaned sections, _etext must be moved so that it is after both .text and .text.* The text size must also be calculated to include .text AND .text.*
Signed-off-by: Kristen Carlson Accardi <[email protected]> Reviewed-by: Tony Luck <[email protected]> Tested-by: Tony Luck <[email protected]> --- arch/x86/kernel/vmlinux.lds.S | 18 +++++++++++++++++- include/asm-generic/vmlinux.lds.h | 2 +- 2 files changed, 18 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 1bf7e312361f..044f7528a2f0 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -147,8 +147,24 @@ SECTIONS #endif } :text =0xcccc - /* End of text section, which should occupy whole number of pages */ +#ifdef CONFIG_FG_KASLR + /* + * -ffunction-sections creates .text.* sections, which are considered + * "orphan sections" and added after the first similar section (.text). + * Adding this ALIGN statement causes the address of _etext + * to be below that of all the .text.* orphaned sections + */ + . = ALIGN(PAGE_SIZE); +#endif _etext = .; + + /* + * the size of the .text section is used to calculate the address + * range for orc lookups. If we just use SIZEOF(.text), we will + * miss all the .text.* sections. Calculate the size using _etext + * and _stext and save the value for later. + */ + text_size = _etext - _stext; . = ALIGN(PAGE_SIZE); X86_ALIGN_RODATA_BEGIN diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 71e387a5fe90..f5baee74854c 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -813,7 +813,7 @@ . = ALIGN(4); \ .orc_lookup : AT(ADDR(.orc_lookup) - LOAD_OFFSET) { \ orc_lookup = .; \ - . += (((SIZEOF(.text) + LOOKUP_BLOCK_SIZE - 1) / \ + . += (((text_size + LOOKUP_BLOCK_SIZE - 1) / \ LOOKUP_BLOCK_SIZE) + 1) * 4; \ orc_lookup_end = .; \ } -- 2.20.1
