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authorPavel Tatashin <pasha.tatashin@oracle.com>2018-07-19 23:55:28 +0300
committerThomas Gleixner <tglx@linutronix.de>2018-07-20 01:02:38 +0300
commit8990cac6e5ea7fa57607736019fe8dca961b998f (patch)
tree66e9d68bab7beb5e9f6c3890010b33161e6bb897 /arch/x86/kernel/setup.c
parent6fffacb30349e0903602d664f7ab6fc87e85162e (diff)
downloadlinux-8990cac6e5ea7fa57607736019fe8dca961b998f.tar.xz
x86/jump_label: Initialize static branching early
Static branching is useful to runtime patch branches that are used in hot path, but are infrequently changed. The x86 clock framework is one example that uses static branches to setup the best clock during boot and never changes it again. It is desired to enable the TSC based sched clock early to allow fine grained boot time analysis early on. That requires the static branching functionality to be functional early as well. Static branching requires patching nop instructions, thus, arch_init_ideal_nops() must be called prior to jump_label_init(). Do all the necessary steps to call arch_init_ideal_nops() right after early_cpu_init(), which also allows to insert a call to jump_label_init() right after that. jump_label_init() will be called again from the generic init code, but the code is protected against reinitialization already. [ tglx: Massaged changelog ] Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: steven.sistare@oracle.com Cc: daniel.m.jordan@oracle.com Cc: linux@armlinux.org.uk Cc: schwidefsky@de.ibm.com Cc: heiko.carstens@de.ibm.com Cc: john.stultz@linaro.org Cc: sboyd@codeaurora.org Cc: hpa@zytor.com Cc: douly.fnst@cn.fujitsu.com Cc: prarit@redhat.com Cc: feng.tang@intel.com Cc: pmladek@suse.com Cc: gnomes@lxorguk.ukuu.org.uk Cc: linux-s390@vger.kernel.org Cc: boris.ostrovsky@oracle.com Cc: jgross@suse.com Cc: pbonzini@redhat.com Link: https://lkml.kernel.org/r/20180719205545.16512-10-pasha.tatashin@oracle.com
Diffstat (limited to 'arch/x86/kernel/setup.c')
-rw-r--r--arch/x86/kernel/setup.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index da1dbd99cb6e..7490de925a81 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -866,6 +866,8 @@ void __init setup_arch(char **cmdline_p)
idt_setup_early_traps();
early_cpu_init();
+ arch_init_ideal_nops();
+ jump_label_init();
early_ioremap_init();
setup_olpc_ofw_pgd();
@@ -1268,8 +1270,6 @@ void __init setup_arch(char **cmdline_p)
mcheck_init();
- arch_init_ideal_nops();
-
register_refined_jiffies(CLOCK_TICK_RATE);
#ifdef CONFIG_EFI