From 2066f5c4135f7d919a10bd6ff1f79d900e44aab8 Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Thu, 1 Feb 2018 11:27:20 +0000 Subject: [PATCH] x86/retpoline: Avoid retpolines for built-in __init functions commit 66f793099a636862a71c59d4a6ba91387b155e0c upstream. 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 Signed-off-by: Thomas Gleixner 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 [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- include/linux/init.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/include/linux/init.h b/include/linux/init.h index 9146f39cdddf..13dfc98844fa 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -3,6 +3,13 @@ #include +/* 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 notrace +#define __init __section(.init.text) __cold notrace __noretpoline #define __initdata __section(.init.data) #define __initconst __section(.init.rodata) #define __exitdata __section(.exit.data) -- 2.39.2