LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
* [PATCH 14/23] x86/speculation: Move firmware_restrict_branch_speculation_*() from C to CPP
       [not found] <1523903583-14881-1-git-send-email-youquan.song@intel.com>
@ 2018-04-16 18:32 ` Youquan Song
  0 siblings, 0 replies; only message in thread
From: Youquan Song @ 2018-04-16 18:32 UTC (permalink / raw)
  To: youquan.song
  Cc: youquan.song, Ingo Molnar, David Woodhouse, Thomas Gleixner,
	Linus Torvalds, Peter Zijlstra, arjan.van.de.ven, bp,
	dave.hansen, jmattson, karahmed, kvm, pbonzini, rkrcmar,
	linux-kernel, Greg Kroah-Hartman

From: Ingo Molnar <mingo@kernel.org>

(cherry picked from commit d72f4e29e6d84b7ec02ae93088aa459ac70e733b)

firmware_restrict_branch_speculation_*() recently started using
preempt_enable()/disable(), but those are relatively high level
primitives and cause build failures on some 32-bit builds.

Since we want to keep <asm/nospec-branch.h> low level, convert
them to macros to avoid header hell...

Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: arjan.van.de.ven@intel.com
Cc: bp@alien8.de
Cc: dave.hansen@intel.com
Cc: jmattson@google.com
Cc: karahmed@amazon.de
Cc: kvm@vger.kernel.org
Cc: pbonzini@redhat.com
Cc: rkrcmar@redhat.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[Youquan Song: port to 4.4]
Signed-off-by: Youquan Song <youquan.song@linux.intel.com>
---
 arch/x86/include/asm/nospec-branch.h | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 27582aa..4675f65 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -214,20 +214,22 @@ static inline void indirect_branch_prediction_barrier(void)
 /*
  * With retpoline, we must use IBRS to restrict branch prediction
  * before calling into firmware.
+ *
+ * (Implemented as CPP macros due to header hell.)
  */
-static inline void firmware_restrict_branch_speculation_start(void)
-{
-	preempt_disable();
-	alternative_msr_write(MSR_IA32_SPEC_CTRL, SPEC_CTRL_IBRS,
-			      X86_FEATURE_USE_IBRS_FW);
-}
+#define firmware_restrict_branch_speculation_start()			\
+do {									\
+	preempt_disable();						\
+	alternative_msr_write(MSR_IA32_SPEC_CTRL, SPEC_CTRL_IBRS,	\
+			      X86_FEATURE_USE_IBRS_FW);			\
+} while (0)
 
-static inline void firmware_restrict_branch_speculation_end(void)
-{
-	alternative_msr_write(MSR_IA32_SPEC_CTRL, 0,
-			      X86_FEATURE_USE_IBRS_FW);
-	preempt_enable();
-}
+#define firmware_restrict_branch_speculation_end()			\
+do {									\
+	alternative_msr_write(MSR_IA32_SPEC_CTRL, 0,			\
+			      X86_FEATURE_USE_IBRS_FW);			\
+	preempt_enable();						\
+} while (0)
 
 #endif /* __ASSEMBLY__ */
 
-- 
1.9.1

^ permalink raw reply	[flat|nested] only message in thread

only message in thread, other threads:[~2018-04-16 18:32 UTC | newest]

Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
     [not found] <1523903583-14881-1-git-send-email-youquan.song@intel.com>
2018-04-16 18:32 ` [PATCH 14/23] x86/speculation: Move firmware_restrict_branch_speculation_*() from C to CPP Youquan Song

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).