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From: tip-bot for Dave Hansen <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: bp@alien8.de, luto@amacapital.net, mingo@kernel.org,
	brgerst@gmail.com, tglx@linutronix.de, fenghua.yu@intel.com,
	tim.c.chen@linux.intel.com, peterz@infradead.org,
	linux-kernel@vger.kernel.org, dvlasenk@redhat.com,
	torvalds@linux-foundation.org, hpa@zytor.com,
	dave.hansen@linux.intel.com
Subject: [tip:x86/fpu] x86/fpu: Add xfeature_enabled() helper instead of test_bit()
Date: Mon, 14 Sep 2015 05:22:32 -0700	[thread overview]
Message-ID: <tip-633d54c47a5bedfb42f10e6a63eeeebd35abdb4c@git.kernel.org> (raw)
In-Reply-To: <20150902233129.B1534F86@viggo.jf.intel.com>

Commit-ID:  633d54c47a5bedfb42f10e6a63eeeebd35abdb4c
Gitweb:     http://git.kernel.org/tip/633d54c47a5bedfb42f10e6a63eeeebd35abdb4c
Author:     Dave Hansen <dave.hansen@linux.intel.com>
AuthorDate: Wed, 2 Sep 2015 16:31:29 -0700
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 14 Sep 2015 12:21:59 +0200

x86/fpu: Add xfeature_enabled() helper instead of test_bit()

We currently use test_bit() in a few places to see if an
xfeature is enabled.  It ends up being a bit ugly because
'xfeatures_mask' is a u64 and test_bit wants an 'unsigned long'
so it requires a cast.  The *_bit() functions are also
techincally atomic, which we have no need for here.

So, remove the test_bit()s and replace with the new
xfeature_enabled() helper.

This also provides a central place to add a comment about the
future need to support 'system xstates'.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: dave@sr71.net
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20150902233129.B1534F86@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/fpu/xstate.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 61ec60b..ba6b6e0 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -226,6 +226,16 @@ static void __init print_xstate_features(void)
 }
 
 /*
+ * Note that in the future we will likely need a pair of
+ * functions here: one for user xstates and the other for
+ * system xstates.  For now, they are the same.
+ */
+static int xfeature_enabled(enum xfeature xfeature)
+{
+	return !!(xfeatures_mask & (1UL << xfeature));
+}
+
+/*
  * This function sets up offsets and sizes of all extended states in
  * xsave area. This supports both standard format and compacted format
  * of the xsave aread.
@@ -245,7 +255,7 @@ static void __init setup_xstate_comp(void)
 
 	if (!cpu_has_xsaves) {
 		for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {
-			if (test_bit(i, (unsigned long *)&xfeatures_mask)) {
+			if (xfeature_enabled(i)) {
 				xstate_comp_offsets[i] = xstate_offsets[i];
 				xstate_comp_sizes[i] = xstate_sizes[i];
 			}
@@ -257,7 +267,7 @@ static void __init setup_xstate_comp(void)
 		FXSAVE_SIZE + XSAVE_HDR_SIZE;
 
 	for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {
-		if (test_bit(i, (unsigned long *)&xfeatures_mask))
+		if (xfeature_enabled(i))
 			xstate_comp_sizes[i] = xstate_sizes[i];
 		else
 			xstate_comp_sizes[i] = 0;
@@ -319,7 +329,7 @@ static unsigned int __init calculate_xstate_size(void)
 
 	calculated_xstate_size = FXSAVE_SIZE + XSAVE_HDR_SIZE;
 	for (i = FIRST_EXTENDED_XFEATURE; i < 64; i++) {
-		if (test_bit(i, (unsigned long *)&xfeatures_mask)) {
+		if (xfeature_enabled(i)) {
 			cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx);
 			calculated_xstate_size += eax;
 		}

  reply	other threads:[~2015-09-14 12:23 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-02 23:31 [PATCH 00/15] [v4] x86, fpu: XSAVE cleanups and sanity checks Dave Hansen
2015-09-02 23:31 ` [PATCH 01/15] x86, fpu: print xfeature buffer size in decimal Dave Hansen
2015-09-14 12:19   ` [tip:x86/fpu] x86/fpu: Print " tip-bot for Dave Hansen
2015-09-02 23:31 ` [PATCH 02/15] x86, fpu: move XSAVE-disabling code to a helper Dave Hansen
2015-09-14 12:19   ` [tip:x86/fpu] x86/fpu: Move " tip-bot for Dave Hansen
2015-09-02 23:31 ` [PATCH 03/15] x86, fpu: remove XSTATE_RESERVE Dave Hansen
2015-09-14 12:20   ` [tip:x86/fpu] x86/fpu: Remove XSTATE_RESERVE tip-bot for Dave Hansen
2015-09-02 23:31 ` [PATCH 04/15] x86, fpu: kill LWP support Dave Hansen
2015-09-14 12:20   ` [tip:x86/fpu] x86/fpu: Remove partial LWP support definitions tip-bot for Dave Hansen
2015-09-02 23:31 ` [PATCH 05/15] x86, fpu: XSAVE macro renames Dave Hansen
2015-09-14 12:21   ` [tip:x86/fpu] x86/fpu: Rename XSAVE macros tip-bot for Dave Hansen
2015-09-23 10:49     ` Borislav Petkov
2015-09-24  7:24       ` [tip:x86/fpu] x86/fpu: Fixup uninitialized feature_name warning tip-bot for Borislav Petkov
2015-09-02 23:31 ` [PATCH 06/15] x86, fpu: rename XFEATURES_NR_MAX Dave Hansen
2015-09-14 12:21   ` [tip:x86/fpu] x86/fpu: Rename XFEATURES_NR_MAX tip-bot for Dave Hansen
2015-09-02 23:31 ` [PATCH 08/15] x86, fpu: remove xfeature_nr Dave Hansen
2015-09-14 12:22   ` [tip:x86/fpu] x86/fpu: Remove 'xfeature_nr' tip-bot for Dave Hansen
2015-09-02 23:31 ` [PATCH 07/15] x86, fpu: rework XSTATE_* macros to remove magic '2' Dave Hansen
2015-09-14 12:21   ` [tip:x86/fpu] x86/fpu: Rework " tip-bot for Dave Hansen
2015-09-02 23:31 ` [PATCH 10/15] x86, fpu: rework MPX 'xstate' types Dave Hansen
2015-09-14 12:22   ` [tip:x86/fpu] x86/fpu/mpx: Rework " tip-bot for Dave Hansen
2015-09-02 23:31 ` [PATCH 09/15] x86, fpu: add helper xfeature_enabled() instead of test_bit() Dave Hansen
2015-09-14 12:22   ` tip-bot for Dave Hansen [this message]
2015-09-02 23:31 ` [PATCH 12/15] x86, fpu: add C structures for AVX-512 state components Dave Hansen
2015-09-14 12:23   ` [tip:x86/fpu] x86/fpu: Add " tip-bot for Dave Hansen
2015-09-02 23:31 ` [PATCH 11/15] x86, fpu: rework YMM definition Dave Hansen
2015-09-14 12:23   ` [tip:x86/fpu] x86/fpu: Rework " tip-bot for Dave Hansen
2015-09-02 23:31 ` [PATCH 13/15] x86, fpu: correct and check XSAVE xstate size calculations Dave Hansen
2015-09-14 12:23   ` [tip:x86/fpu] x86/fpu: Correct " tip-bot for Dave Hansen
2015-09-02 23:31 ` [PATCH 14/15] x86, fpu: check to ensure increasing-offset xstate offsets Dave Hansen
2015-09-14 12:24   ` [tip:x86/fpu] x86/fpu: Check " tip-bot for Dave Hansen
2015-09-02 23:31 ` [PATCH 15/15] x86, fpu: check CPU-provided sizes against struct declarations Dave Hansen
2015-09-14 12:24   ` [tip:x86/fpu] x86/fpu: Check " tip-bot for Dave Hansen
2015-09-14 10:07 ` [PATCH 00/15] [v4] x86, fpu: XSAVE cleanups and sanity checks Ingo Molnar

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