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) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505135313.731774429@linutronix.de

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 50a8d24a417ed64f1a5fe3ced99b3a595e48beab..8fd39ff74a499b7a89014cde08c7ebfb51b14738 100644 (file)
--- 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 b28a64d7691fbc6ebfbaf6b033d96a2c90d0d25b..280c290f414f00379f3e8c6acf26e18e6599dc11 100644 (file)
--- 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;