[PATCH 3.19 115/177] arm64: apply alternatives for !SMP kernels

From: Greg Kroah-Hartman
Date: Sat May 02 2015 - 16:35:39 EST


3.19-stable review patch. If anyone has any objections, please let me know.

------------------

From: Mark Rutland <mark.rutland@xxxxxxx>

commit 137650aad96c9594683445e41afa8ac5a2097520 upstream.

Currently we only perform alternative patching for kernels built with
CONFIG_SMP, as we call apply_alternatives_all() in smp.c, which is only
built for CONFIG_SMP. Thus !SMP kernels may not have necessary
alternatives patched in.

This patch ensures that we call apply_alternatives_all() once all CPUs
are booted, even for !SMP kernels, by having the smp_init_cpus() stub
call this for !SMP kernels via up_late_init. A new wrapper,
do_post_cpus_up_work, is added so we can hook other calls here later
(e.g. boot mode logging).

Cc: Andre Przywara <andre.przywara@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Fixes: e039ee4ee3fcf174 ("arm64: add alternative runtime patching")
Tested-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/arm64/Kconfig | 4 ++++
arch/arm64/include/asm/smp_plat.h | 2 ++
arch/arm64/kernel/setup.c | 12 ++++++++++++
arch/arm64/kernel/smp.c | 2 +-
4 files changed, 19 insertions(+), 1 deletion(-)

--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -416,6 +416,10 @@ config HOTPLUG_CPU

source kernel/Kconfig.preempt

+config UP_LATE_INIT
+ def_bool y
+ depends on !SMP
+
config HZ
int
default 100
--- a/arch/arm64/include/asm/smp_plat.h
+++ b/arch/arm64/include/asm/smp_plat.h
@@ -40,4 +40,6 @@ static inline u32 mpidr_hash_size(void)
extern u64 __cpu_logical_map[NR_CPUS];
#define cpu_logical_map(cpu) __cpu_logical_map[cpu]

+void __init do_post_cpus_up_work(void);
+
#endif /* __ASM_SMP_PLAT_H */
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -206,6 +206,18 @@ static void __init smp_build_mpidr_hash(
}
#endif

+void __init do_post_cpus_up_work(void)
+{
+ apply_alternatives_all();
+}
+
+#ifdef CONFIG_UP_LATE_INIT
+void __init up_late_init(void)
+{
+ do_post_cpus_up_work();
+}
+#endif /* CONFIG_UP_LATE_INIT */
+
static void __init setup_processor(void)
{
struct cpu_info *cpu_info;
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -310,7 +310,7 @@ void cpu_die(void)
void __init smp_cpus_done(unsigned int max_cpus)
{
pr_info("SMP: Total of %d processors activated.\n", num_online_cpus());
- apply_alternatives_all();
+ do_post_cpus_up_work();
}

void __init smp_prepare_boot_cpu(void)


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/