Merge branch 'x86-xsave-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-xsave-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, xsave: Make xstate_enable_boot_cpu() __init, protect on CPU 0 x86, xsave: Add __init attribute to setup_xstate_features() x86, xsave: Make init_xstate_buf static x86, xsave: Check cpuid level for XSTATE_CPUID (0x0d) x86, xsave: Introduce xstate enable functions x86, xsave: Separate fpu and xsave initialization x86, xsave: Move boot cpu initialization to xsave_init() x86, xsave: 32/64 bit boot cpu check unification in initialization x86, xsave: Do not include asm/i387.h in asm/xsave.h x86, xsave: Use xsaveopt in context-switch path when supported x86, xsave: Sync xsave memory layout with its header for user handling x86, xsave: Track the offset, size of state in the xsave layout
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@@ -16,11 +16,88 @@
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*/
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u64 pcntxt_mask;
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/*
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* Represents init state for the supported extended state.
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*/
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static struct xsave_struct *init_xstate_buf;
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struct _fpx_sw_bytes fx_sw_reserved;
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#ifdef CONFIG_IA32_EMULATION
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struct _fpx_sw_bytes fx_sw_reserved_ia32;
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#endif
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static unsigned int *xstate_offsets, *xstate_sizes, xstate_features;
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/*
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* If a processor implementation discern that a processor state component is
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* in its initialized state it may modify the corresponding bit in the
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* xsave_hdr.xstate_bv as '0', with out modifying the corresponding memory
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* layout in the case of xsaveopt. While presenting the xstate information to
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* the user, we always ensure that the memory layout of a feature will be in
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* the init state if the corresponding header bit is zero. This is to ensure
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* that the user doesn't see some stale state in the memory layout during
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* signal handling, debugging etc.
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*/
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void __sanitize_i387_state(struct task_struct *tsk)
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{
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u64 xstate_bv;
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int feature_bit = 0x2;
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struct i387_fxsave_struct *fx = &tsk->thread.fpu.state->fxsave;
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if (!fx)
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return;
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BUG_ON(task_thread_info(tsk)->status & TS_USEDFPU);
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xstate_bv = tsk->thread.fpu.state->xsave.xsave_hdr.xstate_bv;
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/*
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* None of the feature bits are in init state. So nothing else
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* to do for us, as the memory layout is upto date.
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*/
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if ((xstate_bv & pcntxt_mask) == pcntxt_mask)
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return;
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/*
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* FP is in init state
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*/
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if (!(xstate_bv & XSTATE_FP)) {
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fx->cwd = 0x37f;
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fx->swd = 0;
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fx->twd = 0;
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fx->fop = 0;
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fx->rip = 0;
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fx->rdp = 0;
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memset(&fx->st_space[0], 0, 128);
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}
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/*
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* SSE is in init state
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*/
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if (!(xstate_bv & XSTATE_SSE))
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memset(&fx->xmm_space[0], 0, 256);
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xstate_bv = (pcntxt_mask & ~xstate_bv) >> 2;
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/*
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* Update all the other memory layouts for which the corresponding
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* header bit is in the init state.
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*/
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while (xstate_bv) {
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if (xstate_bv & 0x1) {
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int offset = xstate_offsets[feature_bit];
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int size = xstate_sizes[feature_bit];
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memcpy(((void *) fx) + offset,
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((void *) init_xstate_buf) + offset,
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size);
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}
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xstate_bv >>= 1;
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feature_bit++;
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}
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}
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/*
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* Check for the presence of extended state information in the
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* user fpstate pointer in the sigcontext.
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@@ -102,6 +179,7 @@ int save_i387_xstate(void __user *buf)
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task_thread_info(tsk)->status &= ~TS_USEDFPU;
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stts();
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} else {
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sanitize_i387_state(tsk);
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if (__copy_to_user(buf, &tsk->thread.fpu.state->fxsave,
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xstate_size))
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return -1;
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@@ -267,11 +345,6 @@ static void prepare_fx_sw_frame(void)
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#endif
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}
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/*
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* Represents init state for the supported extended state.
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*/
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struct xsave_struct *init_xstate_buf;
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#ifdef CONFIG_X86_64
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unsigned int sig_xstate_size = sizeof(struct _fpstate);
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#endif
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@@ -279,37 +352,77 @@ unsigned int sig_xstate_size = sizeof(struct _fpstate);
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/*
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* Enable the extended processor state save/restore feature
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*/
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void __cpuinit xsave_init(void)
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static inline void xstate_enable(void)
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{
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if (!cpu_has_xsave)
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return;
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set_in_cr4(X86_CR4_OSXSAVE);
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/*
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* Enable all the features that the HW is capable of
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* and the Linux kernel is aware of.
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*/
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xsetbv(XCR_XFEATURE_ENABLED_MASK, pcntxt_mask);
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}
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/*
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* Record the offsets and sizes of different state managed by the xsave
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* memory layout.
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*/
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static void __init setup_xstate_features(void)
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{
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int eax, ebx, ecx, edx, leaf = 0x2;
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xstate_features = fls64(pcntxt_mask);
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xstate_offsets = alloc_bootmem(xstate_features * sizeof(int));
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xstate_sizes = alloc_bootmem(xstate_features * sizeof(int));
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do {
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cpuid_count(XSTATE_CPUID, leaf, &eax, &ebx, &ecx, &edx);
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if (eax == 0)
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break;
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xstate_offsets[leaf] = ebx;
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xstate_sizes[leaf] = eax;
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leaf++;
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} while (1);
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}
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/*
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* setup the xstate image representing the init state
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*/
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static void __init setup_xstate_init(void)
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{
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setup_xstate_features();
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/*
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* Setup init_xstate_buf to represent the init state of
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* all the features managed by the xsave
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*/
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init_xstate_buf = alloc_bootmem(xstate_size);
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init_xstate_buf->i387.mxcsr = MXCSR_DEFAULT;
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clts();
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/*
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* Init all the features state with header_bv being 0x0
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*/
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xrstor_state(init_xstate_buf, -1);
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/*
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* Dump the init state again. This is to identify the init state
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* of any feature which is not represented by all zero's.
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*/
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xsave_state(init_xstate_buf, -1);
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stts();
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}
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/*
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* Enable and initialize the xsave feature.
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*/
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void __ref xsave_cntxt_init(void)
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static void __init xstate_enable_boot_cpu(void)
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{
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unsigned int eax, ebx, ecx, edx;
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cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx);
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if (boot_cpu_data.cpuid_level < XSTATE_CPUID) {
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WARN(1, KERN_ERR "XSTATE_CPUID missing\n");
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return;
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}
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cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
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pcntxt_mask = eax + ((u64)edx << 32);
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if ((pcntxt_mask & XSTATE_FPSSE) != XSTATE_FPSSE) {
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@@ -322,12 +435,13 @@ void __ref xsave_cntxt_init(void)
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* Support only the state known to OS.
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*/
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pcntxt_mask = pcntxt_mask & XCNTXT_MASK;
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xsave_init();
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xstate_enable();
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/*
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* Recompute the context size for enabled features
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*/
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cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx);
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cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
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xstate_size = ebx;
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update_regset_xstate_info(xstate_size, pcntxt_mask);
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@@ -339,3 +453,23 @@ void __ref xsave_cntxt_init(void)
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"cntxt size 0x%x\n",
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pcntxt_mask, xstate_size);
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}
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/*
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* For the very first instance, this calls xstate_enable_boot_cpu();
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* for all subsequent instances, this calls xstate_enable().
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*
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* This is somewhat obfuscated due to the lack of powerful enough
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* overrides for the section checks.
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*/
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void __cpuinit xsave_init(void)
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{
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static __refdata void (*next_func)(void) = xstate_enable_boot_cpu;
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void (*this_func)(void);
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if (!cpu_has_xsave)
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return;
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this_func = next_func;
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next_func = xstate_enable;
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this_func();
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}
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