linux-kernel - [PATCH v3 16/51] x86/32: put real return address on stack in entry code

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Date:	Fri, 12 Aug 2016 09:28:35 -0500
From:	Josh Poimboeuf <jpoimboe@...hat.com>
To:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...nel.org>,
	"H . Peter Anvin" <hpa@...or.com>
Cc:	x86@...nel.org, linux-kernel@...r.kernel.org,
	Andy Lutomirski <luto@...capital.net>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	Brian Gerst <brgerst@...il.com>,
	Kees Cook <keescook@...omium.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Byungchul Park <byungchul.park@....com>,
	Nilay Vaish <nilayvaish@...il.com>
Subject: [PATCH v3 16/51] x86/32: put real return address on stack in entry code

This standardizes the stacks of idle tasks to be consistent with other
tasks on 32-bit.

Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
---
 arch/x86/kernel/head_32.S | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index f2298e9..6fc4f1d 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -290,7 +290,7 @@ num_subarch_entries = (. - subarch_entries) / 4
 ENTRY(start_cpu0)
 	movl initial_stack, %ecx
 	movl %ecx, %esp
-	jmp  *(initial_code)
+	call *(initial_code)
 ENDPROC(start_cpu0)
 #endif
 
@@ -471,8 +471,7 @@ is486:
 	xorl %eax,%eax			# Clear LDT
 	lldt %ax
 
-	pushl $0		# fake return address for unwinder
-	jmp *(initial_code)
+	call *(initial_code)
 
 #include "verify_cpu.S"
 
-- 
2.7.4