kernel/1342-scripts-sorttable-always-use-an-array-for-the-mcount-loc-sor.patch

From d39567e1f737a3f1959b0597eeeba7bdf25d0249 Mon Sep 17 00:00:00 2001
From: Jerome Marchand <jmarchan@redhat.com>
Date: Mon, 1 Jun 2026 15:57:34 +0200
Subject: [PATCH] scripts/sorttable: Always use an array for the mcount_loc
 sorting

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

commit 5fb964f5ba53afda0e2b6dbc00b8205461ffe04a
Author: Steven Rostedt <rostedt@goodmis.org>
Date:   Tue Feb 18 14:59:21 2025 -0500

    scripts/sorttable: Always use an array for the mcount_loc sorting

    The sorting of the mcount_loc section is done directly to the section for
    x86 and arm32 but it uses a separate array for arm64 as arm64 has the
    values for the mcount_loc stored in the rela sections of the vmlinux ELF
    file.

    In order to use the same code to remove weak functions, always use a
    separate array to do the sorting. This requires splitting up the filling
    of the array into one function and the placing the contents of the array
    back into the rela sections or into the mcount_loc section into a separate
    file.

    Cc: bpf <bpf@vger.kernel.org>
    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: Peter Zijlstra <peterz@infradead.org>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Masahiro Yamada <masahiroy@kernel.org>
    Cc: Nathan Chancellor <nathan@kernel.org>
    Cc: Nicolas Schier <nicolas@fjasle.eu>
    Cc: Zheng Yejian <zhengyejian1@huawei.com>
    Cc: Martin  Kelly <martin.kelly@crowdstrike.com>
    Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
    Cc: Josh Poimboeuf <jpoimboe@redhat.com>
    Cc: Heiko Carstens <hca@linux.ibm.com>
    Cc: Catalin Marinas <catalin.marinas@arm.com>
    Cc: Will Deacon <will@kernel.org>
    Cc: Vasily Gorbik <gor@linux.ibm.com>
    Cc: Alexander Gordeev <agordeev@linux.ibm.com>
    Link: https://lore.kernel.org/20250218200022.710676551@goodmis.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 f62a91d8af0a..ec02a2852efb 100644
--- a/scripts/sorttable.c
+++ b/scripts/sorttable.c
@@ -594,31 +594,19 @@ struct elf_mcount_loc {
 	uint64_t stop_mcount_loc;
 };
 
-/* Sort the relocations not the address itself */
-static void *sort_relocs(Elf_Ehdr *ehdr, uint64_t start_loc, uint64_t size)
+/* Fill the array with the content of the relocs */
+static int fill_relocs(void *ptr, uint64_t size, Elf_Ehdr *ehdr, uint64_t start_loc)
 {
 	Elf_Shdr *shdr_start;
 	Elf_Rela *rel;
 	unsigned int shnum;
-	unsigned int count;
+	unsigned int count = 0;
 	int shentsize;
-	void *vals;
-	void *ptr;
-
-	compare_values = long_size == 4 ? compare_values_32 : compare_values_64;
+	void *array_end = ptr + size;
 
 	shdr_start = (Elf_Shdr *)((char *)ehdr + ehdr_shoff(ehdr));
 	shentsize = ehdr_shentsize(ehdr);
 
-	vals = malloc(long_size * size);
-	if (!vals) {
-		snprintf(m_err, ERRSTR_MAXSZ, "Failed to allocate sort array");
-		pthread_exit(m_err);
-		return NULL;
-	}
-
-	ptr = vals;
-
 	shnum = ehdr_shnum(ehdr);
 	if (shnum == SHN_UNDEF)
 		shnum = shdr_size(shdr_start);
@@ -637,22 +625,18 @@ static void *sort_relocs(Elf_Ehdr *ehdr, uint64_t start_loc, uint64_t size)
 			uint64_t offset = rela_offset(rel);
 
 			if (offset >= start_loc && offset < start_loc + size) {
-				if (ptr + long_size > vals + size) {
-					free(vals);
+				if (ptr + long_size > array_end) {
 					snprintf(m_err, ERRSTR_MAXSZ,
 						 "Too many relocations");
-					pthread_exit(m_err);
-					return NULL;
+					return -1;
 				}
 
 				/* Make sure this has the correct type */
 				if (rela_info(rel) != rela_type) {
-					free(vals);
 					snprintf(m_err, ERRSTR_MAXSZ,
 						"rela has type %lx but expected %lx\n",
 						(long)rela_info(rel), rela_type);
-					pthread_exit(m_err);
-					return NULL;
+					return -1;
 				}
 
 				if (long_size == 4)
@@ -660,13 +644,28 @@ static void *sort_relocs(Elf_Ehdr *ehdr, uint64_t start_loc, uint64_t size)
 				else
 					*(uint64_t *)ptr = rela_addend(rel);
 				ptr += long_size;
+				count++;
 			}
 		}
 	}
-	count = ptr - vals;
-	qsort(vals, count / long_size, long_size, compare_values);
+	return count;
+}
+
+/* Put the sorted vals back into the relocation elements */
+static void replace_relocs(void *ptr, uint64_t size, Elf_Ehdr *ehdr, uint64_t start_loc)
+{
+	Elf_Shdr *shdr_start;
+	Elf_Rela *rel;
+	unsigned int shnum;
+	int shentsize;
+
+	shdr_start = (Elf_Shdr *)((char *)ehdr + ehdr_shoff(ehdr));
+	shentsize = ehdr_shentsize(ehdr);
+
+	shnum = ehdr_shnum(ehdr);
+	if (shnum == SHN_UNDEF)
+		shnum = shdr_size(shdr_start);
 
-	ptr = vals;
 	for (int i = 0; i < shnum; i++) {
 		Elf_Shdr *shdr = get_index(shdr_start, shentsize, i);
 		void *end;
@@ -689,8 +688,32 @@ static void *sort_relocs(Elf_Ehdr *ehdr, uint64_t start_loc, uint64_t size)
 			}
 		}
 	}
-	free(vals);
-	return NULL;
+}
+
+static int fill_addrs(void *ptr, uint64_t size, void *addrs)
+{
+	void *end = ptr + size;
+	int count = 0;
+
+	for (; ptr < end; ptr += long_size, addrs += long_size, count++) {
+		if (long_size == 4)
+			*(uint32_t *)ptr = r(addrs);
+		else
+			*(uint64_t *)ptr = r8(addrs);
+	}
+	return count;
+}
+
+static void replace_addrs(void *ptr, uint64_t size, void *addrs)
+{
+	void *end = ptr + size;
+
+	for (; ptr < end; ptr += long_size, addrs += long_size) {
+		if (long_size == 4)
+			w(*(uint32_t *)ptr, addrs);
+		else
+			w8(*(uint64_t *)ptr, addrs);
+	}
 }
 
 /* Sort the addresses stored between __start_mcount_loc to __stop_mcount_loc in vmlinux */
@@ -699,14 +722,49 @@ static void *sort_mcount_loc(void *arg)
 	struct elf_mcount_loc *emloc = (struct elf_mcount_loc *)arg;
 	uint64_t offset = emloc->start_mcount_loc - shdr_addr(emloc->init_data_sec)
 					+ shdr_offset(emloc->init_data_sec);
-	uint64_t count = emloc->stop_mcount_loc - emloc->start_mcount_loc;
+	uint64_t size = emloc->stop_mcount_loc - emloc->start_mcount_loc;
 	unsigned char *start_loc = (void *)emloc->ehdr + offset;
+	Elf_Ehdr *ehdr = emloc->ehdr;
+	void *e_msg = NULL;
+	void *vals;
+	int count;
+
+	vals = malloc(long_size * size);
+	if (!vals) {
+		snprintf(m_err, ERRSTR_MAXSZ, "Failed to allocate sort array");
+		pthread_exit(m_err);
+	}
 
 	if (sort_reloc)
-		return sort_relocs(emloc->ehdr, emloc->start_mcount_loc, count);
+		count = fill_relocs(vals, size, ehdr, emloc->start_mcount_loc);
+	else
+		count = fill_addrs(vals, size, start_loc);
+
+	if (count < 0) {
+		e_msg = m_err;
+		goto out;
+	}
+
+	if (count != size / long_size) {
+		snprintf(m_err, ERRSTR_MAXSZ, "Expected %u mcount elements but found %u\n",
+			(int)(size / long_size), count);
+		e_msg = m_err;
+		goto out;
+	}
+
+	compare_values = long_size == 4 ? compare_values_32 : compare_values_64;
+
+	qsort(vals, count, long_size, compare_values);
+
+	if (sort_reloc)
+		replace_relocs(vals, size, ehdr, emloc->start_mcount_loc);
+	else
+		replace_addrs(vals, size, start_loc);
+
+out:
+	free(vals);
 
-	qsort(start_loc, count/long_size, long_size, compare_extable);
-	return NULL;
+	pthread_exit(e_msg);
 }
 
 /* Get the address of __start_mcount_loc and __stop_mcount_loc in System.map */
-- 
2.50.1 (Apple Git-155)