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@@ -6,12 +6,68 @@
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#include <linux/bootmem.h>
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#include <linux/compat.h>
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#include <asm/i387.h>
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+#ifdef CONFIG_IA32_EMULATION
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+#include <asm/sigcontext32.h>
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+#endif
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/*
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* Supported feature mask by the CPU and the kernel.
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*/
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unsigned int pcntxt_hmask, pcntxt_lmask;
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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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+
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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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+ */
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+int check_for_xstate(struct i387_fxsave_struct __user *buf,
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+ void __user *fpstate,
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+ struct _fpx_sw_bytes *fx_sw_user)
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+{
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+ int min_xstate_size = sizeof(struct i387_fxsave_struct) +
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+ sizeof(struct xsave_hdr_struct);
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+ unsigned int magic2;
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+ int err;
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+
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+ err = __copy_from_user(fx_sw_user, &buf->sw_reserved[0],
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+ sizeof(struct _fpx_sw_bytes));
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+
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+ if (err)
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+ return err;
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+
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+ /*
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+ * First Magic check failed.
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+ */
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+ if (fx_sw_user->magic1 != FP_XSTATE_MAGIC1)
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+ return -1;
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+
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+ /*
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+ * Check for error scenarios.
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+ */
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+ if (fx_sw_user->xstate_size < min_xstate_size ||
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+ fx_sw_user->xstate_size > xstate_size ||
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+ fx_sw_user->xstate_size > fx_sw_user->extended_size)
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+ return -1;
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+
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+ err = __get_user(magic2, (__u32 *) (((void *)fpstate) +
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+ fx_sw_user->extended_size -
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+ FP_XSTATE_MAGIC2_SIZE));
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+ /*
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+ * Check for the presence of second magic word at the end of memory
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+ * layout. This detects the case where the user just copied the legacy
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+ * fpstate layout with out copying the extended state information
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+ * in the memory layout.
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+ */
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+ if (err || magic2 != FP_XSTATE_MAGIC2)
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+ return -1;
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+
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+ return 0;
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+}
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+
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#ifdef CONFIG_X86_64
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/*
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* Signal frame handlers.
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@@ -28,15 +84,18 @@ int save_i387_xstate(void __user *buf)
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BUILD_BUG_ON(sizeof(struct user_i387_struct) !=
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sizeof(tsk->thread.xstate->fxsave));
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- if ((unsigned long)buf % 16)
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+ if ((unsigned long)buf % 64)
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printk("save_i387_xstate: bad fpstate %p\n", buf);
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if (!used_math())
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return 0;
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clear_used_math(); /* trigger finit */
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if (task_thread_info(tsk)->status & TS_USEDFPU) {
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- err = save_i387_checking((struct i387_fxsave_struct __user *)
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- buf);
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+ if (task_thread_info(tsk)->status & TS_XSAVE)
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+ err = xsave_user(buf);
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+ else
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+ err = fxsave_user(buf);
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+
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if (err)
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return err;
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task_thread_info(tsk)->status &= ~TS_USEDFPU;
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@@ -46,23 +105,77 @@ int save_i387_xstate(void __user *buf)
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xstate_size))
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return -1;
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}
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+
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+ if (task_thread_info(tsk)->status & TS_XSAVE) {
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+ struct _fpstate __user *fx = buf;
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+
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+ err = __copy_to_user(&fx->sw_reserved, &fx_sw_reserved,
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+ sizeof(struct _fpx_sw_bytes));
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+
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+ err |= __put_user(FP_XSTATE_MAGIC2,
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+ (__u32 __user *) (buf + sig_xstate_size
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+ - FP_XSTATE_MAGIC2_SIZE));
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+ }
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+
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return 1;
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}
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+/*
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+ * Restore the extended state if present. Otherwise, restore the FP/SSE
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+ * state.
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+ */
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+int restore_user_xstate(void __user *buf)
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+{
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+ struct _fpx_sw_bytes fx_sw_user;
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+ unsigned int lmask, hmask;
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+ int err;
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+
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+ if (((unsigned long)buf % 64) ||
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+ check_for_xstate(buf, buf, &fx_sw_user))
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+ goto fx_only;
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+
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+ lmask = fx_sw_user.xstate_bv;
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+ hmask = fx_sw_user.xstate_bv >> 32;
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+
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+ /*
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+ * restore the state passed by the user.
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+ */
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+ err = xrestore_user(buf, lmask, hmask);
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+ if (err)
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+ return err;
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+
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+ /*
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+ * init the state skipped by the user.
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+ */
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+ lmask = pcntxt_lmask & ~lmask;
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+ hmask = pcntxt_hmask & ~hmask;
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+
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+ xrstor_state(init_xstate_buf, lmask, hmask);
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+
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+ return 0;
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+
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+fx_only:
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+ /*
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+ * couldn't find the extended state information in the
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+ * memory layout. Restore just the FP/SSE and init all
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+ * the other extended state.
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+ */
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+ xrstor_state(init_xstate_buf, pcntxt_lmask & ~XSTATE_FPSSE,
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+ pcntxt_hmask);
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+ return fxrstor_checking((__force struct i387_fxsave_struct *)buf);
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+}
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+
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/*
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* This restores directly out of user space. Exceptions are handled.
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*/
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int restore_i387_xstate(void __user *buf)
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{
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struct task_struct *tsk = current;
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- int err;
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+ int err = 0;
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if (!buf) {
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- if (used_math()) {
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- clear_fpu(tsk);
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- clear_used_math();
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- }
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-
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+ if (used_math())
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+ goto clear;
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return 0;
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} else
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if (!access_ok(VERIFY_READ, buf, sig_xstate_size))
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@@ -78,12 +191,17 @@ int restore_i387_xstate(void __user *buf)
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clts();
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task_thread_info(current)->status |= TS_USEDFPU;
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}
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- err = fxrstor_checking((__force struct i387_fxsave_struct *)buf);
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+ if (task_thread_info(tsk)->status & TS_XSAVE)
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+ err = restore_user_xstate(buf);
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+ else
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+ err = fxrstor_checking((__force struct i387_fxsave_struct *)
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+ buf);
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if (unlikely(err)) {
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/*
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* Encountered an error while doing the restore from the
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* user buffer, clear the fpu state.
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*/
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+clear:
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clear_fpu(tsk);
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clear_used_math();
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}
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@@ -91,6 +209,38 @@ int restore_i387_xstate(void __user *buf)
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}
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#endif
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+/*
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+ * Prepare the SW reserved portion of the fxsave memory layout, indicating
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+ * the presence of the extended state information in the memory layout
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+ * pointed by the fpstate pointer in the sigcontext.
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+ * This will be saved when ever the FP and extended state context is
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+ * saved on the user stack during the signal handler delivery to the user.
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+ */
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+void prepare_fx_sw_frame(void)
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+{
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+ int size_extended = (xstate_size - sizeof(struct i387_fxsave_struct)) +
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+ FP_XSTATE_MAGIC2_SIZE;
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+
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+ sig_xstate_size = sizeof(struct _fpstate) + size_extended;
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+
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+#ifdef CONFIG_IA32_EMULATION
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+ sig_xstate_ia32_size = sizeof(struct _fpstate_ia32) + size_extended;
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+#endif
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+
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+ memset(&fx_sw_reserved, 0, sizeof(fx_sw_reserved));
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+
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+ fx_sw_reserved.magic1 = FP_XSTATE_MAGIC1;
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+ fx_sw_reserved.extended_size = sig_xstate_size;
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+ fx_sw_reserved.xstate_bv = pcntxt_lmask |
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+ (((u64) (pcntxt_hmask)) << 32);
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+ fx_sw_reserved.xstate_size = xstate_size;
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+#ifdef CONFIG_IA32_EMULATION
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+ memcpy(&fx_sw_reserved_ia32, &fx_sw_reserved,
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+ sizeof(struct _fpx_sw_bytes));
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+ fx_sw_reserved_ia32.extended_size = sig_xstate_ia32_size;
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+#endif
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+}
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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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@@ -162,6 +312,8 @@ void __init xsave_cntxt_init(void)
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xstate_size = ebx;
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+ prepare_fx_sw_frame();
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+
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setup_xstate_init();
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printk(KERN_INFO "xsave/xrstor: enabled xstate_bv 0x%Lx, "
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Suresh Siddha