[PATCH v2 3/7] powerpc/build: move got, toc, plt, branch_lt sections to read-only
From: Nicholas Piggin <npiggin@gmail.com>
Date: 2022-09-16 04:10:30
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
This moves linker-related tables from .data to read-only area. Relocations are performed at early boot time before memory is protected, after which there should be no modifications required. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> --- arch/powerpc/kernel/vmlinux.lds.S | 42 ++++++++++++++++++++----------- 1 file changed, 27 insertions(+), 15 deletions(-)
diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index 607b17b1e785..16c4389d498d 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S@@ -131,6 +131,10 @@ SECTIONS /* Read-only data */ RO_DATA(PAGE_SIZE) + .branch_lt : AT(ADDR(.branch_lt) - LOAD_OFFSET) { + *(.branch_lt) + } + #ifdef CONFIG_PPC32 .got1 : AT(ADDR(.got1) - LOAD_OFFSET) { *(.got1)
@@ -140,7 +144,30 @@ SECTIONS *(.got2) __got2_end = .; } + .got : AT(ADDR(.got) - LOAD_OFFSET) SPECIAL { + *(.got) + *(.got.plt) + } + .plt : AT(ADDR(.plt) - LOAD_OFFSET) SPECIAL { + /* XXX: is .plt (and .got.plt) required? */ + *(.plt) + } + #else /* CONFIG_PPC32 */ + .toc1 : AT(ADDR(.toc1) - LOAD_OFFSET) { + *(.toc1) + } + + .got : AT(ADDR(.got) - LOAD_OFFSET) ALIGN(256) { + *(.got) +#ifndef CONFIG_RELOCATABLE + __prom_init_toc_start = .; + arch/powerpc/kernel/prom_init.o*(.toc) + __prom_init_toc_end = .; +#endif + *(.toc) + } + SOFT_MASK_TABLE(8) RESTART_TABLE(8)
@@ -327,26 +354,11 @@ SECTIONS *(.data.rel*) *(SDATA_MAIN) *(.sdata2) - *(.got.plt) *(.got) - *(.plt) - *(.branch_lt) } #else .data : AT(ADDR(.data) - LOAD_OFFSET) { DATA_DATA *(.data.rel*) - *(.toc1) - *(.branch_lt) - } - - .got : AT(ADDR(.got) - LOAD_OFFSET) ALIGN(256) { - *(.got) -#ifndef CONFIG_RELOCATABLE - __prom_init_toc_start = .; - arch/powerpc/kernel/prom_init.o*(.toc) - __prom_init_toc_end = .; -#endif - *(.toc) } #endif
--
2.37.2