linux-kernel - [PATCH] x86/entry: Remove put_ret_addr_in

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Date:   Thu, 14 Jan 2021 14:28:09 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Nick Desaulniers <ndesaulniers@...gle.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Mark Brown <broonie@...nel.org>,
        Andy Lutomirski <luto@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Fangrui Song <maskray@...gle.com>,
        Arnd Bergmann <arnd@...db.de>,
        Jonathan Corbet <corbet@....net>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Nathan Chancellor <natechancellor@...il.com>,
        Miguel Ojeda <ojeda@...nel.org>,
        Jiri Slaby <jirislaby@...nel.org>,
        Joe Perches <joe@...ches.com>,
        Linux Doc Mailing List <linux-doc@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        clang-built-linux <clang-built-linux@...glegroups.com>
Subject: [PATCH] x86/entry: Remove put_ret_addr_in_rdi THUNK macro argument

On Thu, Jan 14, 2021 at 12:36:45PM +0100, Peter Zijlstra wrote:
> And while looking, I suppose we can delete the put_ret_addr_in_rdi crud,
> but that's another patch.

---
From: Borislav Petkov <bp@...e.de>
Date: Thu, 14 Jan 2021 14:25:35 +0100
Subject: [PATCH] x86/entry: Remove put_ret_addr_in_rdi THUNK macro argument

That logic is unused since

  320100a5ffe5 ("x86/entry: Remove the TRACE_IRQS cruft")

Remove it.

Suggested-by: Peter Zijlstra <peterz@...radead.org>
Signed-off-by: Borislav Petkov <bp@...e.de>
---
 arch/x86/entry/thunk_64.S | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/arch/x86/entry/thunk_64.S b/arch/x86/entry/thunk_64.S
index c9a9fbf1655f..496b11ec469d 100644
--- a/arch/x86/entry/thunk_64.S
+++ b/arch/x86/entry/thunk_64.S
@@ -10,7 +10,7 @@
 #include <asm/export.h>
 
 	/* rdi:	arg1 ... normal C conventions. rax is saved/restored. */
-	.macro THUNK name, func, put_ret_addr_in_rdi=0
+	.macro THUNK name, func
 SYM_FUNC_START_NOALIGN(\name)
 	pushq %rbp
 	movq %rsp, %rbp
@@ -25,11 +25,6 @@ SYM_FUNC_START_NOALIGN(\name)
 	pushq %r10
 	pushq %r11
 
-	.if \put_ret_addr_in_rdi
-	/* 8(%rbp) is return addr on stack */
-	movq 8(%rbp), %rdi
-	.endif
-
 	call \func
 	jmp  __thunk_restore
 SYM_FUNC_END(\name)
-- 
2.29.2

-- 
Regards/Gruss,
    Boris.

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