4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Martin Schwidefsky schwidefsky@de.ibm.com
From: Heiko Carstens heiko.carstens@de.ibm.com
[ Upstream commit 049a2c2d486e8cc82c5cd79fa479c5b105b109e9 ]
Remove the CPU_ALTERNATIVES config option and enable the code unconditionally. The config option was only added to avoid a conflict with the named saved segment support. Since that code is gone there is no reason to keep the CPU_ALTERNATIVES config option.
Just enable it unconditionally to also reduce the number of config options and make it less likely that something breaks.
Signed-off-by: Heiko Carstens heiko.carstens@de.ibm.com Signed-off-by: Martin Schwidefsky schwidefsky@de.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/s390/Kconfig | 16 ---------------- arch/s390/include/asm/alternative.h | 20 +++----------------- arch/s390/kernel/Makefile | 3 +-- arch/s390/kernel/module.c | 15 ++++++--------- 4 files changed, 10 insertions(+), 44 deletions(-)
--- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -705,22 +705,6 @@ config SECCOMP
If unsure, say Y.
-config ALTERNATIVES - def_bool y - prompt "Patch optimized instructions for running CPU type" - help - When enabled the kernel code is compiled with additional - alternative instructions blocks optimized for newer CPU types. - These alternative instructions blocks are patched at kernel boot - time when running CPU supports them. This mechanism is used to - optimize some critical code paths (i.e. spinlocks) for newer CPUs - even if kernel is build to support older machine generations. - - This mechanism could be disabled by appending "noaltinstr" - option to the kernel command line. - - If unsure, say Y. - endmenu
menu "Power Management" --- a/arch/s390/include/asm/alternative.h +++ b/arch/s390/include/asm/alternative.h @@ -15,14 +15,9 @@ struct alt_instr { u8 replacementlen; /* length of new instruction */ } __packed;
-#ifdef CONFIG_ALTERNATIVES -extern void apply_alternative_instructions(void); -extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end); -#else -static inline void apply_alternative_instructions(void) {}; -static inline void apply_alternatives(struct alt_instr *start, - struct alt_instr *end) {}; -#endif +void apply_alternative_instructions(void); +void apply_alternatives(struct alt_instr *start, struct alt_instr *end); + /* * |661: |662: |6620 |663: * +-----------+---------------------+ @@ -109,7 +104,6 @@ static inline void apply_alternatives(st b_altinstr(num)":\n\t" altinstr "\n" e_altinstr(num) ":\n" \ INSTR_LEN_SANITY_CHECK(altinstr_len(num))
-#ifdef CONFIG_ALTERNATIVES /* alternative assembly primitive: */ #define ALTERNATIVE(oldinstr, altinstr, facility) \ ".pushsection .altinstr_replacement, "ax"\n" \ @@ -130,14 +124,6 @@ static inline void apply_alternatives(st ALTINSTR_ENTRY(facility1, 1) \ ALTINSTR_ENTRY(facility2, 2) \ ".popsection\n" -#else -/* Alternative instructions are disabled, let's put just oldinstr in */ -#define ALTERNATIVE(oldinstr, altinstr, facility) \ - oldinstr "\n" - -#define ALTERNATIVE_2(oldinstr, altinstr1, facility1, altinstr2, facility2) \ - oldinstr "\n" -#endif
/* * Alternative instructions for different CPU types or capabilities. --- a/arch/s390/kernel/Makefile +++ b/arch/s390/kernel/Makefile @@ -44,7 +44,7 @@ obj-y += processor.o sys_s390.o ptrace.o obj-y += debug.o irq.o ipl.o dis.o diag.o sclp.o vdso.o obj-y += sysinfo.o jump_label.o lgr.o os_info.o machine_kexec.o pgm_check.o obj-y += runtime_instr.o cache.o dumpstack.o -obj-y += entry.o reipl.o relocate_kernel.o +obj-y += entry.o reipl.o relocate_kernel.o alternative.o
extra-y += head.o head64.o vmlinux.lds
@@ -62,7 +62,6 @@ obj-$(CONFIG_KPROBES) += kprobes.o obj-$(CONFIG_FUNCTION_TRACER) += mcount.o ftrace.o obj-$(CONFIG_CRASH_DUMP) += crash_dump.o obj-$(CONFIG_UPROBES) += uprobes.o -obj-$(CONFIG_ALTERNATIVES) += alternative.o
obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_cpum_cf.o perf_cpum_sf.o obj-$(CONFIG_PERF_EVENTS) += perf_cpum_cf_events.o --- a/arch/s390/kernel/module.c +++ b/arch/s390/kernel/module.c @@ -428,16 +428,13 @@ int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *s; char *secstrings;
- if (IS_ENABLED(CONFIG_ALTERNATIVES)) { - secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; - for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { - if (!strcmp(".altinstructions", - secstrings + s->sh_name)) { - /* patch .altinstructions */ - void *aseg = (void *)s->sh_addr; + secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; + for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { + if (!strcmp(".altinstructions", secstrings + s->sh_name)) { + /* patch .altinstructions */ + void *aseg = (void *)s->sh_addr;
- apply_alternatives(aseg, aseg + s->sh_size); - } + apply_alternatives(aseg, aseg + s->sh_size); } }