From 7d08b5aa28b2bdd1d1bedbd6e8722bf3799dce71 Mon Sep 17 00:00:00 2001
From: Jerome Marchand <jmarchan@redhat.com>
Date: Tue, 2 Jun 2026 15:56:31 +0200
Subject: [PATCH] scripts/sorttable: Allow matches to functions before function
 entry

JIRA: https://redhat.atlassian.net/browse/RHEL-180193

commit dc208c69c033d3caba0509da1ae065d2b5ff165f
Author: Steven Rostedt <rostedt@goodmis.org>
Date:   Tue Feb 25 13:20:08 2025 -0500

    scripts/sorttable: Allow matches to functions before function entry

    ARM 64 uses -fpatchable-function-entry=4,2 which adds padding before the
    function and the addresses in the mcount_loc point there instead of the
    function entry that is returned by nm. In order to find a function from nm
    to make sure it's not an unused weak function, the entries in the
    mcount_loc section needs to match the entries from nm. Since it can be an
    instruction before the entry, add a before_func variable that ARM 64 can
    set to 8, and if the mcount_loc entry is within 8 bytes of the nm function
    entry, then it will be considered a match.

    Cc: Masami Hiramatsu <mhiramat@kernel.org>
    Cc: Mark Rutland <mark.rutland@arm.com>
    Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Masahiro Yamada <masahiroy@kernel.org>
    Cc: Catalin Marinas <catalin.marinas@arm.com>
    Cc: Will Deacon <will@kernel.org>
    Cc: "Arnd Bergmann" <arnd@arndb.de>
    Cc: Mark Brown <broonie@kernel.org>
    Link: https://lore.kernel.org/20250225182054.815536219@goodmis.org
    Fixes: ef378c3b82338 ("scripts/sorttable: Zero out weak functions in mcount_loc table")
    Tested-by: Nathan Chancellor <nathan@kernel.org>
    Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Signed-off-by: Jerome Marchand <jmarchan@redhat.com>

diff --git a/scripts/sorttable.c b/scripts/sorttable.c
index 07ad8116bc8d..7b4b3714b1af 100644
--- a/scripts/sorttable.c
+++ b/scripts/sorttable.c
@@ -611,13 +611,16 @@ static int add_field(uint64_t addr, uint64_t size)
 	return 0;
 }
 
+/* Used for when mcount/fentry is before the function entry */
+static int before_func;
+
 /* Only return match if the address lies inside the function size */
 static int cmp_func_addr(const void *K, const void *A)
 {
 	uint64_t key = *(const uint64_t *)K;
 	const struct func_info *a = A;
 
-	if (key < a->addr)
+	if (key + before_func < a->addr)
 		return -1;
 	return key >= a->addr + a->size;
 }
@@ -1253,6 +1256,8 @@ static int do_file(char const *const fname, void *addr)
 #ifdef MCOUNT_SORT_ENABLED
 		sort_reloc = true;
 		rela_type = 0x403;
+		/* arm64 uses patchable function entry placing before function */
+		before_func = 8;
 #endif
 		/* fallthrough */
 	case EM_386:
-- 
2.50.1 (Apple Git-155)