summaryrefslogtreecommitdiff
path: root/arch/x86/kernel/xsave.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/kernel/xsave.c')
-rw-r--r--arch/x86/kernel/xsave.c724
1 files changed, 0 insertions, 724 deletions
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
deleted file mode 100644
index 87a815b85..000000000
--- a/arch/x86/kernel/xsave.c
+++ /dev/null
@@ -1,724 +0,0 @@
-/*
- * xsave/xrstor support.
- *
- * Author: Suresh Siddha <suresh.b.siddha@intel.com>
- */
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <linux/bootmem.h>
-#include <linux/compat.h>
-#include <linux/cpu.h>
-#include <asm/i387.h>
-#include <asm/fpu-internal.h>
-#include <asm/sigframe.h>
-#include <asm/tlbflush.h>
-#include <asm/xcr.h>
-
-/*
- * Supported feature mask by the CPU and the kernel.
- */
-u64 pcntxt_mask;
-
-/*
- * Represents init state for the supported extended state.
- */
-struct xsave_struct *init_xstate_buf;
-
-static struct _fpx_sw_bytes fx_sw_reserved, fx_sw_reserved_ia32;
-static unsigned int *xstate_offsets, *xstate_sizes;
-static unsigned int xstate_comp_offsets[sizeof(pcntxt_mask)*8];
-static unsigned int xstate_features;
-
-/*
- * If a processor implementation discern that a processor state component is
- * in its initialized state it may modify the corresponding bit in the
- * xsave_hdr.xstate_bv as '0', with out modifying the corresponding memory
- * layout in the case of xsaveopt. While presenting the xstate information to
- * the user, we always ensure that the memory layout of a feature will be in
- * the init state if the corresponding header bit is zero. This is to ensure
- * that the user doesn't see some stale state in the memory layout during
- * signal handling, debugging etc.
- */
-void __sanitize_i387_state(struct task_struct *tsk)
-{
- struct i387_fxsave_struct *fx = &tsk->thread.fpu.state->fxsave;
- int feature_bit = 0x2;
- u64 xstate_bv;
-
- if (!fx)
- return;
-
- xstate_bv = tsk->thread.fpu.state->xsave.xsave_hdr.xstate_bv;
-
- /*
- * None of the feature bits are in init state. So nothing else
- * to do for us, as the memory layout is up to date.
- */
- if ((xstate_bv & pcntxt_mask) == pcntxt_mask)
- return;
-
- /*
- * FP is in init state
- */
- if (!(xstate_bv & XSTATE_FP)) {
- fx->cwd = 0x37f;
- fx->swd = 0;
- fx->twd = 0;
- fx->fop = 0;
- fx->rip = 0;
- fx->rdp = 0;
- memset(&fx->st_space[0], 0, 128);
- }
-
- /*
- * SSE is in init state
- */
- if (!(xstate_bv & XSTATE_SSE))
- memset(&fx->xmm_space[0], 0, 256);
-
- xstate_bv = (pcntxt_mask & ~xstate_bv) >> 2;
-
- /*
- * Update all the other memory layouts for which the corresponding
- * header bit is in the init state.
- */
- while (xstate_bv) {
- if (xstate_bv & 0x1) {
- int offset = xstate_offsets[feature_bit];
- int size = xstate_sizes[feature_bit];
-
- memcpy(((void *) fx) + offset,
- ((void *) init_xstate_buf) + offset,
- size);
- }
-
- xstate_bv >>= 1;
- feature_bit++;
- }
-}
-
-/*
- * Check for the presence of extended state information in the
- * user fpstate pointer in the sigcontext.
- */
-static inline int check_for_xstate(struct i387_fxsave_struct __user *buf,
- void __user *fpstate,
- struct _fpx_sw_bytes *fx_sw)
-{
- int min_xstate_size = sizeof(struct i387_fxsave_struct) +
- sizeof(struct xsave_hdr_struct);
- unsigned int magic2;
-
- if (__copy_from_user(fx_sw, &buf->sw_reserved[0], sizeof(*fx_sw)))
- return -1;
-
- /* Check for the first magic field and other error scenarios. */
- if (fx_sw->magic1 != FP_XSTATE_MAGIC1 ||
- fx_sw->xstate_size < min_xstate_size ||
- fx_sw->xstate_size > xstate_size ||
- fx_sw->xstate_size > fx_sw->extended_size)
- return -1;
-
- /*
- * Check for the presence of second magic word at the end of memory
- * layout. This detects the case where the user just copied the legacy
- * fpstate layout with out copying the extended state information
- * in the memory layout.
- */
- if (__get_user(magic2, (__u32 __user *)(fpstate + fx_sw->xstate_size))
- || magic2 != FP_XSTATE_MAGIC2)
- return -1;
-
- return 0;
-}
-
-/*
- * Signal frame handlers.
- */
-static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
-{
- if (use_fxsr()) {
- struct xsave_struct *xsave = &tsk->thread.fpu.state->xsave;
- struct user_i387_ia32_struct env;
- struct _fpstate_ia32 __user *fp = buf;
-
- convert_from_fxsr(&env, tsk);
-
- if (__copy_to_user(buf, &env, sizeof(env)) ||
- __put_user(xsave->i387.swd, &fp->status) ||
- __put_user(X86_FXSR_MAGIC, &fp->magic))
- return -1;
- } else {
- struct i387_fsave_struct __user *fp = buf;
- u32 swd;
- if (__get_user(swd, &fp->swd) || __put_user(swd, &fp->status))
- return -1;
- }
-
- return 0;
-}
-
-static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
-{
- struct xsave_struct __user *x = buf;
- struct _fpx_sw_bytes *sw_bytes;
- u32 xstate_bv;
- int err;
-
- /* Setup the bytes not touched by the [f]xsave and reserved for SW. */
- sw_bytes = ia32_frame ? &fx_sw_reserved_ia32 : &fx_sw_reserved;
- err = __copy_to_user(&x->i387.sw_reserved, sw_bytes, sizeof(*sw_bytes));
-
- if (!use_xsave())
- return err;
-
- err |= __put_user(FP_XSTATE_MAGIC2, (__u32 *)(buf + xstate_size));
-
- /*
- * Read the xstate_bv which we copied (directly from the cpu or
- * from the state in task struct) to the user buffers.
- */
- err |= __get_user(xstate_bv, (__u32 *)&x->xsave_hdr.xstate_bv);
-
- /*
- * For legacy compatible, we always set FP/SSE bits in the bit
- * vector while saving the state to the user context. This will
- * enable us capturing any changes(during sigreturn) to
- * the FP/SSE bits by the legacy applications which don't touch
- * xstate_bv in the xsave header.
- *
- * xsave aware apps can change the xstate_bv in the xsave
- * header as well as change any contents in the memory layout.
- * xrestore as part of sigreturn will capture all the changes.
- */
- xstate_bv |= XSTATE_FPSSE;
-
- err |= __put_user(xstate_bv, (__u32 *)&x->xsave_hdr.xstate_bv);
-
- return err;
-}
-
-static inline int save_user_xstate(struct xsave_struct __user *buf)
-{
- int err;
-
- if (use_xsave())
- err = xsave_user(buf);
- else if (use_fxsr())
- err = fxsave_user((struct i387_fxsave_struct __user *) buf);
- else
- err = fsave_user((struct i387_fsave_struct __user *) buf);
-
- if (unlikely(err) && __clear_user(buf, xstate_size))
- err = -EFAULT;
- return err;
-}
-
-/*
- * Save the fpu, extended register state to the user signal frame.
- *
- * 'buf_fx' is the 64-byte aligned pointer at which the [f|fx|x]save
- * state is copied.
- * 'buf' points to the 'buf_fx' or to the fsave header followed by 'buf_fx'.
- *
- * buf == buf_fx for 64-bit frames and 32-bit fsave frame.
- * buf != buf_fx for 32-bit frames with fxstate.
- *
- * If the fpu, extended register state is live, save the state directly
- * to the user frame pointed by the aligned pointer 'buf_fx'. Otherwise,
- * copy the thread's fpu state to the user frame starting at 'buf_fx'.
- *
- * If this is a 32-bit frame with fxstate, put a fsave header before
- * the aligned state at 'buf_fx'.
- *
- * For [f]xsave state, update the SW reserved fields in the [f]xsave frame
- * indicating the absence/presence of the extended state to the user.
- */
-int save_xstate_sig(void __user *buf, void __user *buf_fx, int size)
-{
- struct xsave_struct *xsave = &current->thread.fpu.state->xsave;
- struct task_struct *tsk = current;
- int ia32_fxstate = (buf != buf_fx);
-
- ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
- config_enabled(CONFIG_IA32_EMULATION));
-
- if (!access_ok(VERIFY_WRITE, buf, size))
- return -EACCES;
-
- if (!static_cpu_has(X86_FEATURE_FPU))
- return fpregs_soft_get(current, NULL, 0,
- sizeof(struct user_i387_ia32_struct), NULL,
- (struct _fpstate_ia32 __user *) buf) ? -1 : 1;
-
- if (user_has_fpu()) {
- /* Save the live register state to the user directly. */
- if (save_user_xstate(buf_fx))
- return -1;
- /* Update the thread's fxstate to save the fsave header. */
- if (ia32_fxstate)
- fpu_fxsave(&tsk->thread.fpu);
- } else {
- sanitize_i387_state(tsk);
- if (__copy_to_user(buf_fx, xsave, xstate_size))
- return -1;
- }
-
- /* Save the fsave header for the 32-bit frames. */
- if ((ia32_fxstate || !use_fxsr()) && save_fsave_header(tsk, buf))
- return -1;
-
- if (use_fxsr() && save_xstate_epilog(buf_fx, ia32_fxstate))
- return -1;
-
- return 0;
-}
-
-static inline void
-sanitize_restored_xstate(struct task_struct *tsk,
- struct user_i387_ia32_struct *ia32_env,
- u64 xstate_bv, int fx_only)
-{
- struct xsave_struct *xsave = &tsk->thread.fpu.state->xsave;
- struct xsave_hdr_struct *xsave_hdr = &xsave->xsave_hdr;
-
- if (use_xsave()) {
- /* These bits must be zero. */
- memset(xsave_hdr->reserved, 0, 48);
-
- /*
- * Init the state that is not present in the memory
- * layout and not enabled by the OS.
- */
- if (fx_only)
- xsave_hdr->xstate_bv = XSTATE_FPSSE;
- else
- xsave_hdr->xstate_bv &= (pcntxt_mask & xstate_bv);
- }
-
- if (use_fxsr()) {
- /*
- * mscsr reserved bits must be masked to zero for security
- * reasons.
- */
- xsave->i387.mxcsr &= mxcsr_feature_mask;
-
- convert_to_fxsr(tsk, ia32_env);
- }
-}
-
-/*
- * Restore the extended state if present. Otherwise, restore the FP/SSE state.
- */
-static inline int restore_user_xstate(void __user *buf, u64 xbv, int fx_only)
-{
- if (use_xsave()) {
- if ((unsigned long)buf % 64 || fx_only) {
- u64 init_bv = pcntxt_mask & ~XSTATE_FPSSE;
- xrstor_state(init_xstate_buf, init_bv);
- return fxrstor_user(buf);
- } else {
- u64 init_bv = pcntxt_mask & ~xbv;
- if (unlikely(init_bv))
- xrstor_state(init_xstate_buf, init_bv);
- return xrestore_user(buf, xbv);
- }
- } else if (use_fxsr()) {
- return fxrstor_user(buf);
- } else
- return frstor_user(buf);
-}
-
-int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size)
-{
- int ia32_fxstate = (buf != buf_fx);
- struct task_struct *tsk = current;
- int state_size = xstate_size;
- u64 xstate_bv = 0;
- int fx_only = 0;
-
- ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
- config_enabled(CONFIG_IA32_EMULATION));
-
- if (!buf) {
- fpu_reset_state(tsk);
- return 0;
- }
-
- if (!access_ok(VERIFY_READ, buf, size))
- return -EACCES;
-
- if (!used_math() && init_fpu(tsk))
- return -1;
-
- if (!static_cpu_has(X86_FEATURE_FPU))
- return fpregs_soft_set(current, NULL,
- 0, sizeof(struct user_i387_ia32_struct),
- NULL, buf) != 0;
-
- if (use_xsave()) {
- struct _fpx_sw_bytes fx_sw_user;
- if (unlikely(check_for_xstate(buf_fx, buf_fx, &fx_sw_user))) {
- /*
- * Couldn't find the extended state information in the
- * memory layout. Restore just the FP/SSE and init all
- * the other extended state.
- */
- state_size = sizeof(struct i387_fxsave_struct);
- fx_only = 1;
- } else {
- state_size = fx_sw_user.xstate_size;
- xstate_bv = fx_sw_user.xstate_bv;
- }
- }
-
- if (ia32_fxstate) {
- /*
- * For 32-bit frames with fxstate, copy the user state to the
- * thread's fpu state, reconstruct fxstate from the fsave
- * header. Sanitize the copied state etc.
- */
- struct fpu *fpu = &tsk->thread.fpu;
- struct user_i387_ia32_struct env;
- int err = 0;
-
- /*
- * Drop the current fpu which clears used_math(). This ensures
- * that any context-switch during the copy of the new state,
- * avoids the intermediate state from getting restored/saved.
- * Thus avoiding the new restored state from getting corrupted.
- * We will be ready to restore/save the state only after
- * set_used_math() is again set.
- */
- drop_fpu(tsk);
-
- if (__copy_from_user(&fpu->state->xsave, buf_fx, state_size) ||
- __copy_from_user(&env, buf, sizeof(env))) {
- fpu_finit(fpu);
- err = -1;
- } else {
- sanitize_restored_xstate(tsk, &env, xstate_bv, fx_only);
- }
-
- set_used_math();
- if (use_eager_fpu()) {
- preempt_disable();
- math_state_restore();
- preempt_enable();
- }
-
- return err;
- } else {
- /*
- * For 64-bit frames and 32-bit fsave frames, restore the user
- * state to the registers directly (with exceptions handled).
- */
- user_fpu_begin();
- if (restore_user_xstate(buf_fx, xstate_bv, fx_only)) {
- fpu_reset_state(tsk);
- return -1;
- }
- }
-
- return 0;
-}
-
-/*
- * Prepare the SW reserved portion of the fxsave memory layout, indicating
- * the presence of the extended state information in the memory layout
- * pointed by the fpstate pointer in the sigcontext.
- * This will be saved when ever the FP and extended state context is
- * saved on the user stack during the signal handler delivery to the user.
- */
-static void prepare_fx_sw_frame(void)
-{
- int fsave_header_size = sizeof(struct i387_fsave_struct);
- int size = xstate_size + FP_XSTATE_MAGIC2_SIZE;
-
- if (config_enabled(CONFIG_X86_32))
- size += fsave_header_size;
-
- fx_sw_reserved.magic1 = FP_XSTATE_MAGIC1;
- fx_sw_reserved.extended_size = size;
- fx_sw_reserved.xstate_bv = pcntxt_mask;
- fx_sw_reserved.xstate_size = xstate_size;
-
- if (config_enabled(CONFIG_IA32_EMULATION)) {
- fx_sw_reserved_ia32 = fx_sw_reserved;
- fx_sw_reserved_ia32.extended_size += fsave_header_size;
- }
-}
-
-/*
- * Enable the extended processor state save/restore feature
- */
-static inline void xstate_enable(void)
-{
- cr4_set_bits(X86_CR4_OSXSAVE);
- xsetbv(XCR_XFEATURE_ENABLED_MASK, pcntxt_mask);
-}
-
-/*
- * Record the offsets and sizes of different state managed by the xsave
- * memory layout.
- */
-static void __init setup_xstate_features(void)
-{
- int eax, ebx, ecx, edx, leaf = 0x2;
-
- xstate_features = fls64(pcntxt_mask);
- xstate_offsets = alloc_bootmem(xstate_features * sizeof(int));
- xstate_sizes = alloc_bootmem(xstate_features * sizeof(int));
-
- do {
- cpuid_count(XSTATE_CPUID, leaf, &eax, &ebx, &ecx, &edx);
-
- if (eax == 0)
- break;
-
- xstate_offsets[leaf] = ebx;
- xstate_sizes[leaf] = eax;
-
- leaf++;
- } while (1);
-}
-
-/*
- * 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.
- *
- * Input: void
- * Output: void
- */
-void setup_xstate_comp(void)
-{
- unsigned int xstate_comp_sizes[sizeof(pcntxt_mask)*8];
- int i;
-
- /*
- * The FP xstates and SSE xstates are legacy states. They are always
- * in the fixed offsets in the xsave area in either compacted form
- * or standard form.
- */
- xstate_comp_offsets[0] = 0;
- xstate_comp_offsets[1] = offsetof(struct i387_fxsave_struct, xmm_space);
-
- if (!cpu_has_xsaves) {
- for (i = 2; i < xstate_features; i++) {
- if (test_bit(i, (unsigned long *)&pcntxt_mask)) {
- xstate_comp_offsets[i] = xstate_offsets[i];
- xstate_comp_sizes[i] = xstate_sizes[i];
- }
- }
- return;
- }
-
- xstate_comp_offsets[2] = FXSAVE_SIZE + XSAVE_HDR_SIZE;
-
- for (i = 2; i < xstate_features; i++) {
- if (test_bit(i, (unsigned long *)&pcntxt_mask))
- xstate_comp_sizes[i] = xstate_sizes[i];
- else
- xstate_comp_sizes[i] = 0;
-
- if (i > 2)
- xstate_comp_offsets[i] = xstate_comp_offsets[i-1]
- + xstate_comp_sizes[i-1];
-
- }
-}
-
-/*
- * setup the xstate image representing the init state
- */
-static void __init setup_init_fpu_buf(void)
-{
- /*
- * Setup init_xstate_buf to represent the init state of
- * all the features managed by the xsave
- */
- init_xstate_buf = alloc_bootmem_align(xstate_size,
- __alignof__(struct xsave_struct));
- fx_finit(&init_xstate_buf->i387);
-
- if (!cpu_has_xsave)
- return;
-
- setup_xstate_features();
-
- if (cpu_has_xsaves) {
- init_xstate_buf->xsave_hdr.xcomp_bv =
- (u64)1 << 63 | pcntxt_mask;
- init_xstate_buf->xsave_hdr.xstate_bv = pcntxt_mask;
- }
-
- /*
- * Init all the features state with header_bv being 0x0
- */
- xrstor_state_booting(init_xstate_buf, -1);
- /*
- * Dump the init state again. This is to identify the init state
- * of any feature which is not represented by all zero's.
- */
- xsave_state_booting(init_xstate_buf, -1);
-}
-
-static enum { AUTO, ENABLE, DISABLE } eagerfpu = AUTO;
-static int __init eager_fpu_setup(char *s)
-{
- if (!strcmp(s, "on"))
- eagerfpu = ENABLE;
- else if (!strcmp(s, "off"))
- eagerfpu = DISABLE;
- else if (!strcmp(s, "auto"))
- eagerfpu = AUTO;
- return 1;
-}
-__setup("eagerfpu=", eager_fpu_setup);
-
-
-/*
- * Calculate total size of enabled xstates in XCR0/pcntxt_mask.
- */
-static void __init init_xstate_size(void)
-{
- unsigned int eax, ebx, ecx, edx;
- int i;
-
- if (!cpu_has_xsaves) {
- cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
- xstate_size = ebx;
- return;
- }
-
- xstate_size = FXSAVE_SIZE + XSAVE_HDR_SIZE;
- for (i = 2; i < 64; i++) {
- if (test_bit(i, (unsigned long *)&pcntxt_mask)) {
- cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx);
- xstate_size += eax;
- }
- }
-}
-
-/*
- * Enable and initialize the xsave feature.
- */
-static void __init xstate_enable_boot_cpu(void)
-{
- unsigned int eax, ebx, ecx, edx;
-
- if (boot_cpu_data.cpuid_level < XSTATE_CPUID) {
- WARN(1, KERN_ERR "XSTATE_CPUID missing\n");
- return;
- }
-
- cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
- pcntxt_mask = eax + ((u64)edx << 32);
-
- if ((pcntxt_mask & XSTATE_FPSSE) != XSTATE_FPSSE) {
- pr_err("FP/SSE not shown under xsave features 0x%llx\n",
- pcntxt_mask);
- BUG();
- }
-
- /*
- * Support only the state known to OS.
- */
- pcntxt_mask = pcntxt_mask & XCNTXT_MASK;
-
- xstate_enable();
-
- /*
- * Recompute the context size for enabled features
- */
- init_xstate_size();
-
- update_regset_xstate_info(xstate_size, pcntxt_mask);
- prepare_fx_sw_frame();
- setup_init_fpu_buf();
-
- /* Auto enable eagerfpu for xsaveopt */
- if (cpu_has_xsaveopt && eagerfpu != DISABLE)
- eagerfpu = ENABLE;
-
- if (pcntxt_mask & XSTATE_EAGER) {
- if (eagerfpu == DISABLE) {
- pr_err("eagerfpu not present, disabling some xstate features: 0x%llx\n",
- pcntxt_mask & XSTATE_EAGER);
- pcntxt_mask &= ~XSTATE_EAGER;
- } else {
- eagerfpu = ENABLE;
- }
- }
-
- pr_info("enabled xstate_bv 0x%llx, cntxt size 0x%x using %s\n",
- pcntxt_mask, xstate_size,
- cpu_has_xsaves ? "compacted form" : "standard form");
-}
-
-/*
- * For the very first instance, this calls xstate_enable_boot_cpu();
- * for all subsequent instances, this calls xstate_enable().
- *
- * This is somewhat obfuscated due to the lack of powerful enough
- * overrides for the section checks.
- */
-void xsave_init(void)
-{
- static __refdata void (*next_func)(void) = xstate_enable_boot_cpu;
- void (*this_func)(void);
-
- if (!cpu_has_xsave)
- return;
-
- this_func = next_func;
- next_func = xstate_enable;
- this_func();
-}
-
-/*
- * setup_init_fpu_buf() is __init and it is OK to call it here because
- * init_xstate_buf will be unset only once during boot.
- */
-void __init_refok eager_fpu_init(void)
-{
- WARN_ON(used_math());
- current_thread_info()->status = 0;
-
- if (eagerfpu == ENABLE)
- setup_force_cpu_cap(X86_FEATURE_EAGER_FPU);
-
- if (!cpu_has_eager_fpu) {
- stts();
- return;
- }
-
- if (!init_xstate_buf)
- setup_init_fpu_buf();
-}
-
-/*
- * Given the xsave area and a state inside, this function returns the
- * address of the state.
- *
- * This is the API that is called to get xstate address in either
- * standard format or compacted format of xsave area.
- *
- * Inputs:
- * xsave: base address of the xsave area;
- * xstate: state which is defined in xsave.h (e.g. XSTATE_FP, XSTATE_SSE,
- * etc.)
- * Output:
- * address of the state in the xsave area.
- */
-void *get_xsave_addr(struct xsave_struct *xsave, int xstate)
-{
- int feature = fls64(xstate) - 1;
- if (!test_bit(feature, (unsigned long *)&pcntxt_mask))
- return NULL;
-
- return (void *)xsave + xstate_comp_offsets[feature];
-}
-EXPORT_SYMBOL_GPL(get_xsave_addr);