From a945c8345ec0decb2f1a7f19a8c5e60bcb1dd1eb Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 18 Aug 2020 15:57:51 +0200 Subject: static_call: Allow early init In order to use static_call() to wire up x86_pmu, we need to initialize earlier, specifically before memory allocation works; copy some of the tricks from jump_label to enable this. Primarily we overload key->next to store a sites pointer when there are no modules, this avoids having to use kmalloc() to initialize the sites and allows us to run much earlier. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Steven Rostedt (VMware) Link: https://lore.kernel.org/r/20200818135805.220737930@infradead.org --- arch/x86/kernel/static_call.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'arch/x86/kernel/static_call.c') diff --git a/arch/x86/kernel/static_call.c b/arch/x86/kernel/static_call.c index 55140d8db106..ca9a380d9c0b 100644 --- a/arch/x86/kernel/static_call.c +++ b/arch/x86/kernel/static_call.c @@ -11,7 +11,7 @@ enum insn_type { RET = 3, /* tramp / site cond-tail-call */ }; -static void __static_call_transform(void *insn, enum insn_type type, void *func) +static void __ref __static_call_transform(void *insn, enum insn_type type, void *func) { int size = CALL_INSN_SIZE; const void *code; @@ -38,6 +38,9 @@ static void __static_call_transform(void *insn, enum insn_type type, void *func) if (memcmp(insn, code, size) == 0) return; + if (unlikely(system_state == SYSTEM_BOOTING)) + return text_poke_early(insn, code, size); + text_poke_bp(insn, code, size, NULL); } -- cgit v1.2.3