*/
u64 pcntxt_mask;
+/*
+ * Represents init state for the supported extended state.
+ */
+static struct xsave_struct *init_xstate_buf;
+
struct _fpx_sw_bytes fx_sw_reserved;
#ifdef CONFIG_IA32_EMULATION
struct _fpx_sw_bytes fx_sw_reserved_ia32;
#endif
+static unsigned int *xstate_offsets, *xstate_sizes, 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)
+{
+ u64 xstate_bv;
+ int feature_bit = 0x2;
+ struct i387_fxsave_struct *fx = &tsk->thread.fpu.state->fxsave;
+
+ if (!fx)
+ return;
+
+ BUG_ON(task_thread_info(tsk)->status & TS_USEDFPU);
+
+ 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 upto 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.
err = __copy_from_user(fx_sw_user, &buf->sw_reserved[0],
sizeof(struct _fpx_sw_bytes));
-
if (err)
- return err;
+ return -EFAULT;
/*
* First Magic check failed.
*/
if (fx_sw_user->magic1 != FP_XSTATE_MAGIC1)
- return -1;
+ return -EINVAL;
/*
* Check for error scenarios.
if (fx_sw_user->xstate_size < min_xstate_size ||
fx_sw_user->xstate_size > xstate_size ||
fx_sw_user->xstate_size > fx_sw_user->extended_size)
- return -1;
+ return -EINVAL;
err = __get_user(magic2, (__u32 *) (((void *)fpstate) +
fx_sw_user->extended_size -
FP_XSTATE_MAGIC2_SIZE));
+ if (err)
+ return err;
/*
* 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 (err || magic2 != FP_XSTATE_MAGIC2)
- return -1;
+ if (magic2 != FP_XSTATE_MAGIC2)
+ return -EFAULT;
return 0;
}
return 0;
if (task_thread_info(tsk)->status & TS_USEDFPU) {
- /*
- * Start with clearing the user buffer. This will present a
- * clean context for the bytes not touched by the fxsave/xsave.
- */
- err = __clear_user(buf, sig_xstate_size);
- if (err)
- return err;
-
if (use_xsave())
err = xsave_user(buf);
else
task_thread_info(tsk)->status &= ~TS_USEDFPU;
stts();
} else {
+ sanitize_i387_state(tsk);
if (__copy_to_user(buf, &tsk->thread.fpu.state->fxsave,
xstate_size))
return -1;
* init the state skipped by the user.
*/
mask = pcntxt_mask & ~mask;
-
- xrstor_state(init_xstate_buf, mask);
+ if (unlikely(mask))
+ xrstor_state(init_xstate_buf, mask);
return 0;
#endif
}
-/*
- * Represents init state for the supported extended state.
- */
-struct xsave_struct *init_xstate_buf;
-
#ifdef CONFIG_X86_64
unsigned int sig_xstate_size = sizeof(struct _fpstate);
#endif
/*
* Enable the extended processor state save/restore feature
*/
-void __cpuinit xsave_init(void)
+static inline void xstate_enable(void)
{
- if (!cpu_has_xsave)
- return;
-
set_in_cr4(X86_CR4_OSXSAVE);
-
- /*
- * Enable all the features that the HW is capable of
- * and the Linux kernel is aware of.
- */
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);
+}
+
/*
* setup the xstate image representing the init state
*/
static void __init setup_xstate_init(void)
{
+ setup_xstate_features();
+
+ /*
+ * Setup init_xstate_buf to represent the init state of
+ * all the features managed by the xsave
+ */
init_xstate_buf = alloc_bootmem(xstate_size);
init_xstate_buf->i387.mxcsr = MXCSR_DEFAULT;
+
+ clts();
+ /*
+ * Init all the features state with header_bv being 0x0
+ */
+ xrstor_state(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(init_xstate_buf, -1);
+ stts();
}
/*
* Enable and initialize the xsave feature.
*/
-void __ref xsave_cntxt_init(void)
+static void __init xstate_enable_boot_cpu(void)
{
unsigned int eax, ebx, ecx, edx;
- cpuid_count(0xd, 0, &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) {
* Support only the state known to OS.
*/
pcntxt_mask = pcntxt_mask & XCNTXT_MASK;
- xsave_init();
+
+ xstate_enable();
/*
* Recompute the context size for enabled features
*/
- cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx);
+ cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
xstate_size = ebx;
update_regset_xstate_info(xstate_size, pcntxt_mask);
"cntxt size 0x%x\n",
pcntxt_mask, xstate_size);
}
+
+/*
+ * 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 __cpuinit 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();
+}
git.openpandora.org / pandora-kernel.git / blobdiff