From: Andrey Abramov <st5pub@yandex.ru>
Date: Tue, 2 Apr 2019 20:47:22 +0000 (+0300)
Subject: powerpc: module_[32|64].c: replace swap function with built-in one
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=bac7ca7b985b72873bd4ac2553b13b5af5b1f08a;p=linux.git

powerpc: module_[32|64].c: replace swap function with built-in one

Replace relaswap with built-in one, because relaswap
does a simple byte to byte swap.

Since Spectre mitigations have made indirect function calls more
expensive, and the default simple byte copies swap is implemented
without them, an "optimized" custom swap function is now
a waste of time as well as code.

Signed-off-by: Andrey Abramov <st5pub@yandex.ru>
Reviewed-by: George Spelvin <lkml@sdf.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/994931554238042@iva8-b333b7f98ab0.qloud-c.yandex.net
---

diff --git a/arch/powerpc/kernel/module_32.c b/arch/powerpc/kernel/module_32.c
index d7134c614c16b..c27b8687b82ae 100644
--- a/arch/powerpc/kernel/module_32.c
+++ b/arch/powerpc/kernel/module_32.c
@@ -67,21 +67,6 @@ static int relacmp(const void *_x, const void *_y)
 		return 0;
 }
 
-static void relaswap(void *_x, void *_y, int size)
-{
-	uint32_t *x, *y, tmp;
-	int i;
-
-	y = (uint32_t *)_x;
-	x = (uint32_t *)_y;
-
-	for (i = 0; i < sizeof(Elf32_Rela) / sizeof(uint32_t); i++) {
-		tmp = x[i];
-		x[i] = y[i];
-		y[i] = tmp;
-	}
-}
-
 /* Get the potential trampolines size required of the init and
    non-init sections */
 static unsigned long get_plt_size(const Elf32_Ehdr *hdr,
@@ -118,7 +103,7 @@ static unsigned long get_plt_size(const Elf32_Ehdr *hdr,
 			 */
 			sort((void *)hdr + sechdrs[i].sh_offset,
 			     sechdrs[i].sh_size / sizeof(Elf32_Rela),
-			     sizeof(Elf32_Rela), relacmp, relaswap);
+			     sizeof(Elf32_Rela), relacmp, NULL);
 
 			ret += count_relocs((void *)hdr
 					     + sechdrs[i].sh_offset,
diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
index 007606a48fd98..f808159f3dfd2 100644
--- a/arch/powerpc/kernel/module_64.c
+++ b/arch/powerpc/kernel/module_64.c
@@ -226,21 +226,6 @@ static int relacmp(const void *_x, const void *_y)
 		return 0;
 }
 
-static void relaswap(void *_x, void *_y, int size)
-{
-	uint64_t *x, *y, tmp;
-	int i;
-
-	y = (uint64_t *)_x;
-	x = (uint64_t *)_y;
-
-	for (i = 0; i < sizeof(Elf64_Rela) / sizeof(uint64_t); i++) {
-		tmp = x[i];
-		x[i] = y[i];
-		y[i] = tmp;
-	}
-}
-
 /* Get size of potential trampolines required. */
 static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
 				    const Elf64_Shdr *sechdrs)
@@ -264,7 +249,7 @@ static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
 			 */
 			sort((void *)sechdrs[i].sh_addr,
 			     sechdrs[i].sh_size / sizeof(Elf64_Rela),
-			     sizeof(Elf64_Rela), relacmp, relaswap);
+			     sizeof(Elf64_Rela), relacmp, NULL);
 
 			relocs += count_relocs((void *)sechdrs[i].sh_addr,
 					       sechdrs[i].sh_size