diff options
| -rw-r--r-- | arch/powerpc/Kconfig | 11 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/head-64.h | 18 | ||||
| -rw-r--r-- | arch/powerpc/kernel/vmlinux.lds.S | 5 |
3 files changed, 34 insertions, 0 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index d090275ace44..0153275e9f75 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -455,6 +455,17 @@ config PPC_TRANSACTIONAL_MEM ---help--- Support user-mode Transactional Memory on POWERPC. +config LD_HEAD_STUB_CATCH + bool "Reserve 256 bytes to cope with linker stubs in HEAD text" if EXPERT + depends on PPC64 + default n + help + Very large kernels can cause linker branch stubs to be generated by + code in head_64.S, which moves the head text sections out of their + specified location. This option can work around the problem. + + If unsure, say "N". + config DISABLE_MPROFILE_KERNEL bool "Disable use of mprofile-kernel for kernel tracing" depends on PPC64 && CPU_LITTLE_ENDIAN diff --git a/arch/powerpc/include/asm/head-64.h b/arch/powerpc/include/asm/head-64.h index 86eb87382031..68828aa6e056 100644 --- a/arch/powerpc/include/asm/head-64.h +++ b/arch/powerpc/include/asm/head-64.h @@ -63,11 +63,29 @@ . = 0x0; \ start_##sname: +/* + * .linker_stub_catch section is used to catch linker stubs from being + * inserted in our .text section, above the start_text label (which breaks + * the ABS_ADDR calculation). See kernel/vmlinux.lds.S and tools/head_check.sh + * for more details. We would prefer to just keep a cacheline (0x80), but + * 0x100 seems to be how the linker aligns branch stub groups. + */ +#ifdef CONFIG_LD_HEAD_STUB_CATCH +#define OPEN_TEXT_SECTION(start) \ + .section ".linker_stub_catch","ax",@progbits; \ +linker_stub_catch: \ + . = 0x4; \ + text_start = (start) + 0x100; \ + .section ".text","ax",@progbits; \ + .balign 0x100; \ +start_text: +#else #define OPEN_TEXT_SECTION(start) \ text_start = (start); \ .section ".text","ax",@progbits; \ . = 0x0; \ start_text: +#endif #define ZERO_FIXED_SECTION(sname, start, end) \ sname##_start = (start); \ diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S index bcfda21c3179..be8578e02ab6 100644 --- a/arch/powerpc/kernel/vmlinux.lds.S +++ b/arch/powerpc/kernel/vmlinux.lds.S @@ -103,6 +103,11 @@ SECTIONS * section placement to work. */ .text BLOCK(0) : AT(ADDR(.text) - LOAD_OFFSET) { +#ifdef CONFIG_LD_HEAD_STUB_CATCH + *(.linker_stub_catch); + . = . ; +#endif + #else .text : AT(ADDR(.text) - LOAD_OFFSET) { ALIGN_FUNCTION(); |