Enable HAVE_OBJTOOL_FTR_FIXUP by default on PowerPC architecture.
- Remove runtime branch translation logic from patch_alt_instruction()
- Add --emit-relocs linker flags for post-link fixup processing
- Update ftr_alt section attributes to include executable flag
Co-developed-by: Nicholas Piggin <npig...@gmail.com>
Signed-off-by: Nicholas Piggin <npig...@gmail.com>
Signed-off-by: Sathvika Vasireddy <s...@linux.ibm.com>
---
arch/powerpc/Kconfig | 3 +++
arch/powerpc/Makefile | 5 +++++
arch/powerpc/include/asm/feature-fixups.h | 2 +-
arch/powerpc/kernel/vmlinux.lds.S | 8 ++++++--
arch/powerpc/lib/feature-fixups.c | 12 ------------
5 files changed, 15 insertions(+), 15 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 325c1171894d..450b5822786d 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -23,6 +23,9 @@ config 64BIT
bool
default y if PPC64
+config HAVE_OBJTOOL_FTR_FIXUP
+ def_bool y
+
config LIVEPATCH_64
def_bool PPC64
depends on LIVEPATCH
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index a58b1029592c..8e1dab5f3c9a 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -105,6 +105,11 @@ LDFLAGS_vmlinux-$(CONFIG_RELOCATABLE) := -pie
--no-dynamic-linker
LDFLAGS_vmlinux-$(CONFIG_RELOCATABLE) += -z notext
LDFLAGS_vmlinux := $(LDFLAGS_vmlinux-y)
+# --emit-relocs required for post-link fixup of alternate feature
+# text section relocations.
+LDFLAGS_vmlinux += --emit-relocs
+KBUILD_LDFLAGS_MODULE += --emit-relocs
+
ifdef CONFIG_PPC64
ifndef CONFIG_PPC_KERNEL_PCREL
# -mcmodel=medium breaks modules because it uses 32bit offsets from
diff --git a/arch/powerpc/include/asm/feature-fixups.h
b/arch/powerpc/include/asm/feature-fixups.h
index 756a6c694018..d6ae92a292ec 100644
--- a/arch/powerpc/include/asm/feature-fixups.h
+++ b/arch/powerpc/include/asm/feature-fixups.h
@@ -32,7 +32,7 @@
#define FTR_SECTION_ELSE_NESTED(label) \
label##2: \
- .pushsection __ftr_alt_##label,"a"; \
+ .pushsection __ftr_alt_##label, "ax"; \
.align 2; \
label##3:
diff --git a/arch/powerpc/kernel/vmlinux.lds.S
b/arch/powerpc/kernel/vmlinux.lds.S
index de6ee7d35cff..961ef49f8bd3 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -99,8 +99,8 @@ SECTIONS
.text : AT(ADDR(.text) - LOAD_OFFSET) {
ALIGN_FUNCTION();
#endif
- /* careful! __ftr_alt_* sections need to be close to .text */
- *(.text.hot .text.hot.* TEXT_MAIN .text.fixup .text.unlikely
.text.unlikely.* .fixup __ftr_alt_* .ref.text);
+ *(.text.hot .text.hot.* TEXT_MAIN .text.fixup .text.unlikely
+ .text.unlikely.* .fixup .ref.text);
*(.tramp.ftrace.text);
NOINSTR_TEXT
SCHED_TEXT
@@ -267,6 +267,10 @@ SECTIONS
_einittext = .;
} :text
+ .__ftr_alternates.text : AT(ADDR(.__ftr_alternates.text) - LOAD_OFFSET)
{
+ *(__ftr_alt*);
+ }
+
/* .exit.text is discarded at runtime, not link time,
* to deal with references from __bug_table
*/
diff --git a/arch/powerpc/lib/feature-fixups.c
b/arch/powerpc/lib/feature-fixups.c
index 587c8cf1230f..269e992b1631 100644
--- a/arch/powerpc/lib/feature-fixups.c
+++ b/arch/powerpc/lib/feature-fixups.c
@@ -53,22 +53,10 @@ static u32 *calc_addr(struct fixup_entry *fcur, long offset)
static int patch_alt_instruction(u32 *src, u32 *dest, u32 *alt_start, u32
*alt_end)
{
- int err;
ppc_inst_t instr;
instr = ppc_inst_read(src);
- if (instr_is_relative_branch(ppc_inst_read(src))) {
- u32 *target = (u32 *)branch_target(src);
-
- /* Branch within the section doesn't need translating */
- if (target < alt_start || target > alt_end) {
- err = translate_branch(&instr, dest, src);
- if (err)
- return 1;
- }
- }
-
raw_patch_instruction(dest, instr);
return 0;
--
2.43.0
