Commit a37f34a3 authored by Denys Vlasenko's avatar Denys Vlasenko Committed by Ingo Molnar
Browse files

x86/asm/entry/64: Reduce padding in execve stubs 



execve stubs are 7 bytes only. Padding them to 16 bytes is a
waste.

   text	   data	    bss	    dec	    hex	filename
  12594	      0	      0	  12594	   3132	entry_64.o.before
  12530	      0	      0	  12530	   30f2	entry_64.o

Run-tested.

Signed-off-by: default avatarDenys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1428439424-7258-8-git-send-email-dvlasenk@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 54a81e91

arch/x86/kernel/entry_64.S

+14 −6
Original line number Original line Diff line number Diff line
@@ -511,8 +511,12 @@ return_from_execve: 
	jmp	int_ret_from_sys_call

	jmp	int_ret_from_sys_call

	CFI_ENDPROC

	CFI_ENDPROC

END(stub_execve)

END(stub_execve)



/*

ENTRY(stub_execveat)

 * Remaining execve stubs are only 7 bytes long.

 * ENTRY() often aligns to 16 bytes, which in this case has no benefits.

 */

	.align	8

GLOBAL(stub_execveat)

	CFI_STARTPROC

	CFI_STARTPROC

	DEFAULT_FRAME 0, 8

	DEFAULT_FRAME 0, 8

	call	sys_execveat

	call	sys_execveat
@@ -521,14 +525,16 @@ ENTRY(stub_execveat) 
END(stub_execveat)

END(stub_execveat)





#ifdef CONFIG_X86_X32_ABI

#ifdef CONFIG_X86_X32_ABI

ENTRY(stub_x32_execve)

	.align	8

GLOBAL(stub_x32_execve)

	CFI_STARTPROC

	CFI_STARTPROC

	DEFAULT_FRAME 0, 8

	DEFAULT_FRAME 0, 8

	call	compat_sys_execve

	call	compat_sys_execve

	jmp	return_from_execve

	jmp	return_from_execve

	CFI_ENDPROC

	CFI_ENDPROC

END(stub_x32_execve)

END(stub_x32_execve)

ENTRY(stub_x32_execveat)

	.align	8

GLOBAL(stub_x32_execveat)

	CFI_STARTPROC

	CFI_STARTPROC

	DEFAULT_FRAME 0, 8

	DEFAULT_FRAME 0, 8

	call	compat_sys_execveat

	call	compat_sys_execveat
@@ -538,13 +544,15 @@ END(stub_x32_execveat) 
#endif

#endif





#ifdef CONFIG_IA32_EMULATION

#ifdef CONFIG_IA32_EMULATION

ENTRY(stub32_execve)

	.align	8

GLOBAL(stub32_execve)

	CFI_STARTPROC

	CFI_STARTPROC

	call	compat_sys_execve

	call	compat_sys_execve

	jmp	return_from_execve

	jmp	return_from_execve

	CFI_ENDPROC

	CFI_ENDPROC

END(stub32_execve)

END(stub32_execve)

ENTRY(stub32_execveat)

	.align	8

GLOBAL(stub32_execveat)

	CFI_STARTPROC

	CFI_STARTPROC

	call	compat_sys_execveat

	call	compat_sys_execveat

	jmp	return_from_execve

	jmp	return_from_execve

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