linux-kernel - [PATCH v9 04/28] x86/asm/entry: Annotate THUNKs

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Date:   Fri, 11 Oct 2019 13:50:44 +0200
From:   Jiri Slaby <jslaby@...e.cz>
To:     bp@...en8.de
Cc:     tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
        x86@...nel.org, linux-arch@...r.kernel.org,
        linux-kernel@...r.kernel.org, Jiri Slaby <jslaby@...e.cz>,
        Andy Lutomirski <luto@...nel.org>
Subject: [PATCH v9 04/28] x86/asm/entry: Annotate THUNKs

Place SYM_*_START_NOALIGN and SYM_*_END around the THUNK macro body.
Preserve @function by FUNC (64bit) and CODE (32bit). Given it was not
marked as aligned, use NOALIGN.

The result:
 Value  Size Type    Bind   Vis      Ndx Name
  0000    28 FUNC    GLOBAL DEFAULT    1 trace_hardirqs_on_thunk
  001c    28 FUNC    GLOBAL DEFAULT    1 trace_hardirqs_off_thunk
  0038    24 FUNC    GLOBAL DEFAULT    1 lockdep_sys_exit_thunk
  0050    24 FUNC    GLOBAL DEFAULT    1 ___preempt_schedule
  0068    24 FUNC    GLOBAL DEFAULT    1 ___preempt_schedule_notra

The annotation of .L_restore does not generate anything to the code (at
the moment). Here, it just serves documentation purposes (as opening and
closing brackets of functions).

Signed-off-by: Jiri Slaby <jslaby@...e.cz>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: <x86@...nel.org>
---
 arch/x86/entry/thunk_32.S | 4 ++--
 arch/x86/entry/thunk_64.S | 7 ++++---
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/arch/x86/entry/thunk_32.S b/arch/x86/entry/thunk_32.S
index 2713490611a3..e010d4ae11f1 100644
--- a/arch/x86/entry/thunk_32.S
+++ b/arch/x86/entry/thunk_32.S
@@ -10,8 +10,7 @@
 
 	/* put return address in eax (arg1) */
 	.macro THUNK name, func, put_ret_addr_in_eax=0
-	.globl \name
-\name:
+SYM_CODE_START_NOALIGN(\name)
 	pushl %eax
 	pushl %ecx
 	pushl %edx
@@ -27,6 +26,7 @@
 	popl %eax
 	ret
 	_ASM_NOKPROBE(\name)
+SYM_CODE_END(\name)
 	.endm
 
 #ifdef CONFIG_TRACE_IRQFLAGS
diff --git a/arch/x86/entry/thunk_64.S b/arch/x86/entry/thunk_64.S
index ea5c4167086c..c5c3b6e86e62 100644
--- a/arch/x86/entry/thunk_64.S
+++ b/arch/x86/entry/thunk_64.S
@@ -12,7 +12,7 @@
 
 	/* rdi:	arg1 ... normal C conventions. rax is saved/restored. */
 	.macro THUNK name, func, put_ret_addr_in_rdi=0
-	ENTRY(\name)
+SYM_FUNC_START_NOALIGN(\name)
 	pushq %rbp
 	movq %rsp, %rbp
 
@@ -33,7 +33,7 @@
 
 	call \func
 	jmp  .L_restore
-	ENDPROC(\name)
+SYM_FUNC_END(\name)
 	_ASM_NOKPROBE(\name)
 	.endm
 
@@ -56,7 +56,7 @@
 #if defined(CONFIG_TRACE_IRQFLAGS) \
  || defined(CONFIG_DEBUG_LOCK_ALLOC) \
  || defined(CONFIG_PREEMPTION)
-.L_restore:
+SYM_CODE_START_LOCAL_NOALIGN(.L_restore)
 	popq %r11
 	popq %r10
 	popq %r9
@@ -69,4 +69,5 @@
 	popq %rbp
 	ret
 	_ASM_NOKPROBE(.L_restore)
+SYM_CODE_END(.L_restore)
 #endif
-- 
2.23.0