linux-kernel - [PATCH v3 7/7] x86/alternatives: remove text

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Date:   Fri, 2 Nov 2018 16:29:46 -0700
From:   Nadav Amit <namit@...are.com>
To:     Ingo Molnar <mingo@...hat.com>
CC:     <linux-kernel@...r.kernel.org>, <x86@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Nadav Amit <namit@...are.com>,
        Andy Lutomirski <luto@...nel.org>,
        Kees Cook <keescook@...omium.org>,
        Peter Zijlstra <peterz@...radead.org>
Subject: [PATCH v3 7/7] x86/alternatives: remove text_poke() return value

The return value of text_poke() is meaningless - it is one of the
function inputs. One day someone may allow the callers to deal with
text_poke() failures, if those actually happen.

In the meanwhile, remove the return value.

Cc: Andy Lutomirski <luto@...nel.org>
Cc: Kees Cook <keescook@...omium.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Reviewed-by: Masami Hiramatsu <mhiramat@...nel.org>
Tested-by: Masami Hiramatsu <mhiramat@...nel.org>
Signed-off-by: Nadav Amit <namit@...are.com>
---
 arch/x86/include/asm/text-patching.h | 2 +-
 arch/x86/kernel/alternative.c        | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h
index ffe7902cc326..1f73f71b4de2 100644
--- a/arch/x86/include/asm/text-patching.h
+++ b/arch/x86/include/asm/text-patching.h
@@ -34,7 +34,7 @@ extern void *text_poke_early(void *addr, const void *opcode, size_t len);
  * On the local CPU you need to be protected again NMI or MCE handlers seeing an
  * inconsistent instruction while you patch.
  */
-extern void *text_poke(void *addr, const void *opcode, size_t len);
+extern void text_poke(void *addr, const void *opcode, size_t len);
 extern int poke_int3_handler(struct pt_regs *regs);
 extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler);
 extern int after_bootmem;
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 1a40df4db450..6d64d7f8c2ed 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -698,7 +698,7 @@ __ro_after_init unsigned long poking_addr;
  *	    holding the mutex and ensures that none of them will acquire the
  *	    mutex while the code runs.
  */
-void *text_poke(void *addr, const void *opcode, size_t len)
+void text_poke(void *addr, const void *opcode, size_t len)
 {
 	bool cross_page_boundary = offset_in_page(addr) + len > PAGE_SIZE;
 	temporary_mm_state_t prev;
@@ -805,7 +805,6 @@ void *text_poke(void *addr, const void *opcode, size_t len)
 	 */
 	BUG_ON(memcmp(addr, opcode, len));
 	local_irq_restore(flags);
-	return addr;
 }
 
 static void do_sync_core(void *info)
-- 
2.17.1