From f64366efd8c60b93138b813d071d2cd201fd0f6e Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 20 Feb 2020 13:28:06 +0100 Subject: [PATCH] x86/int3: Inline bsearch() Avoid calling out to bsearch() by inlining it, for normal kernel configs this was the last external call and poke_int3_handler() is now fully self sufficient -- no calls to external code. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Reviewed-by: Alexandre Chartre Acked-by: Andy Lutomirski Link: https://lkml.kernel.org/r/20200505135313.731774429@linutronix.de --- arch/x86/kernel/alternative.c | 8 ++++---- arch/x86/kernel/traps.c | 5 +++++ 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 50a8d24a417e..8fd39ff74a49 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -1033,7 +1033,7 @@ static __always_inline void *text_poke_addr(struct text_poke_loc *tp) return _stext + tp->rel_addr; } -static int noinstr patch_cmp(const void *key, const void *elt) +static __always_inline int patch_cmp(const void *key, const void *elt) { struct text_poke_loc *tp = (struct text_poke_loc *) elt; @@ -1077,9 +1077,9 @@ int noinstr poke_int3_handler(struct pt_regs *regs) * Skip the binary search if there is a single member in the vector. */ if (unlikely(desc->nr_entries > 1)) { - tp = bsearch(ip, desc->vec, desc->nr_entries, - sizeof(struct text_poke_loc), - patch_cmp); + tp = __inline_bsearch(ip, desc->vec, desc->nr_entries, + sizeof(struct text_poke_loc), + patch_cmp); if (!tp) goto out_put; } else { diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index b28a64d7691f..280c290f414f 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -570,6 +570,11 @@ exit: dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code) { + /* + * poke_int3_handler() is completely self contained code; it does (and + * must) *NOT* call out to anything, lest it hits upon yet another + * INT3. + */ if (poke_int3_handler(regs)) return;