From: Mike Frysinger <vapier@gentoo.org>
To: linux-numa@vger.kernel.org
Subject: [PATCH] fix building as PIEs on x86
Date: Mon, 18 Apr 2016 18:56:22 -0400 [thread overview]
Message-ID: <1461020182-20317-1-git-send-email-vapier@gentoo.org> (raw)
You can't declare ebx as clobbered with most versions of gcc when you
build as PIC/PIE. Save/restore the code ourselves using xchg & esi.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
---
clearcache.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clearcache.c b/clearcache.c
index 82469c1..4acf024 100644
--- a/clearcache.c
+++ b/clearcache.c
@@ -57,7 +57,7 @@ void clearcache(unsigned char *mem, unsigned size)
#if defined(__i386__) || defined(__x86_64__)
unsigned i, cl, eax, feat;
/* get clflush unit and feature */
- asm("cpuid" : "=a" (eax), "=b" (cl), "=d" (feat) : "0" (1) : "cx");
+ asm("xchg %%ebx, %%esi; cpuid; xchg %%esi, %%ebx;" : "=a" (eax), "=S" (cl), "=d" (feat) : "0" (1) : "cx");
if (!(feat & (1 << 19)))
fallback_clearcache();
cl = ((cl >> 8) & 0xff) * 8;
--
2.7.4
reply other threads:[~2016-04-18 22:56 UTC|newest]
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