x86/fpu: Rework XSTATE_* macros to remove magic '2'

The 'xstate.c' code has a bunch of references to '2'.  This
is because we have a lot more work to do for the "extended"
xstates than the "legacy" ones and state component 2 is the
first "extended" state.

This patch replaces all of the instances of '2' with
FIRST_EXTENDED_XFEATURE, which clearly explains what is
going on.

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/20150902233128.A8C0BF51@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h
index 8764df32f115436b0cb5cdbb343b3b5280ffd64d..9f579305dd11a1e4b5121a7d592f0a587ee8f803 100644 (file)
--- a/arch/x86/include/asm/fpu/types.h
+++ b/arch/x86/include/asm/fpu/types.h
@@ -126,6 +126,8 @@ enum xfeature {
                                         | XFEATURE_MASK_ZMM_Hi256 \
                                         | XFEATURE_MASK_Hi16_ZMM)
 
+#define FIRST_EXTENDED_XFEATURE        XFEATURE_YMM
+
 /*
  * There are 16x 256-bit AVX registers named YMM0-YMM15.
  * The low 128 bits are aliased to the 16 SSE registers (XMM0-XMM15)

diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index f94e236e7e086390d31a6b790e0fff7e3502d45e..c1a0bf4668def4ac7403b6d8ce805060afa9b211 100644 (file)
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -200,7 +200,7 @@ static void __init setup_xstate_features(void)
 
        xfeatures_nr = fls64(xfeatures_mask);
 
-       for (leaf = 2; leaf < xfeatures_nr; leaf++) {
+       for (leaf = FIRST_EXTENDED_XFEATURE; leaf < xfeatures_nr; leaf++) {
                cpuid_count(XSTATE_CPUID, leaf, &eax, &ebx, &ecx, &edx);
 
                xstate_offsets[leaf] = ebx;
@@ -252,7 +252,7 @@ static void __init setup_xstate_comp(void)
        xstate_comp_offsets[1] = offsetof(struct fxregs_state, xmm_space);
 
        if (!cpu_has_xsaves) {
-               for (i = 2; i < xfeatures_nr; i++) {
+               for (i = FIRST_EXTENDED_XFEATURE; i < xfeatures_nr; i++) {
                        if (test_bit(i, (unsigned long *)&xfeatures_mask)) {
                                xstate_comp_offsets[i] = xstate_offsets[i];
                                xstate_comp_sizes[i] = xstate_sizes[i];
@@ -261,15 +261,16 @@ static void __init setup_xstate_comp(void)
                return;
        }
 
-       xstate_comp_offsets[2] = FXSAVE_SIZE + XSAVE_HDR_SIZE;
+       xstate_comp_offsets[FIRST_EXTENDED_XFEATURE] =
+               FXSAVE_SIZE + XSAVE_HDR_SIZE;
 
-       for (i = 2; i < xfeatures_nr; i++) {
+       for (i = FIRST_EXTENDED_XFEATURE; i < xfeatures_nr; i++) {
                if (test_bit(i, (unsigned long *)&xfeatures_mask))
                        xstate_comp_sizes[i] = xstate_sizes[i];
                else
                        xstate_comp_sizes[i] = 0;
 
-               if (i > 2)
+               if (i > FIRST_EXTENDED_XFEATURE)
                        xstate_comp_offsets[i] = xstate_comp_offsets[i-1]
                                        + xstate_comp_sizes[i-1];
 
@@ -325,7 +326,7 @@ static unsigned int __init calculate_xstate_size(void)
        }
 
        calculated_xstate_size = FXSAVE_SIZE + XSAVE_HDR_SIZE;
-       for (i = 2; i < 64; i++) {
+       for (i = FIRST_EXTENDED_XFEATURE; i < 64; i++) {
                if (test_bit(i, (unsigned long *)&xfeatures_mask)) {
                        cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx);
                        calculated_xstate_size += eax;