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x86/retpoline: Avoid retpolines for built-in __init functions

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There's no point in building init code with retpolines, since it runs before
any potentially hostile userspace does. And before the retpoline is actually
ALTERNATIVEd into place, for much of it.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: karahmed@amazon.de
Cc: peterz@infradead.org
Cc: bp@alien8.de
Link: https://lkml.kernel.org/r/1517484441-1420-2-git-send-email-dwmw@amazon.co.uk
This commit is contained in:
David Woodhouse 2018-02-01 11:27:20 +00:00 committed by Thomas Gleixner
parent 085331dfc6
commit 66f793099a
1 changed files with 8 additions and 1 deletions
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9
include/linux/init.h
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@ -5,6 +5,13 @@
#include <linux/compiler.h>
#include <linux/types.h>
/* Built-in __init functions needn't be compiled with retpoline */
#if defined(RETPOLINE) && !defined(MODULE)
#define __noretpoline __attribute__((indirect_branch("keep")))
#else
#define __noretpoline
#endif
/* These macros are used to mark some functions or
* initialized data (doesn't apply to uninitialized data)
* as `initialization' functions. The kernel can take this
@ -40,7 +47,7 @@
/* These are for everybody (although not all archs will actually
discard it in modules) */
#define __init __section(.init.text) __cold __latent_entropy
#define __init __section(.init.text) __cold __latent_entropy __noretpoline
#define __initdata __section(.init.data)
#define __initconst __section(.init.rodata)
#define __exitdata __section(.exit.data)