diff options
Diffstat (limited to 'trunk/2.6.20/20965_linux-2.6-xen-sleazy-fpu-i386.patch')
| -rw-r--r-- | trunk/2.6.20/20965_linux-2.6-xen-sleazy-fpu-i386.patch | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/trunk/2.6.20/20965_linux-2.6-xen-sleazy-fpu-i386.patch b/trunk/2.6.20/20965_linux-2.6-xen-sleazy-fpu-i386.patch new file mode 100644 index 0000000..0145385 --- /dev/null +++ b/trunk/2.6.20/20965_linux-2.6-xen-sleazy-fpu-i386.patch @@ -0,0 +1,96 @@ +# HG changeset patch +# User "Eduardo Habkost <ehabkost@redhat.com>" +# Date 1190313016 10800 +# Node ID 8792a16b6dd531cad0ed28d9bef86e3e597ea8db +# Parent 35983eae211a531bd50bcd177a9da77d48631e2c +Fix sleazy-fpu under Xen + +- Make it reset fpu_counter when needed (like __unlazy_fpu() does) +- Make it call clts() before restoring the fpu state during task switch + (clts() will still not be called during the device_not_available trap, + because it is not needed under Xen) + +diff -r 35983eae211a -r 8792a16b6dd5 arch/i386/kernel/entry-xen.S +--- a/arch/i386/kernel/entry-xen.S Wed Aug 08 16:15:30 2007 -0300 ++++ b/arch/i386/kernel/entry-xen.S Thu Sep 20 15:30:16 2007 -0300 +@@ -950,7 +950,9 @@ device_available_emulate: + device_available_emulate: + #endif + preempt_stop(CLBR_ANY) +- call math_state_restore ++ # 'clts' is done by Xen during virtual trap, so we can call ++ # __math_state_restore instead of math_state_restore ++ call __math_state_restore + jmp ret_from_exception + CFI_ENDPROC + +diff -r 35983eae211a -r 8792a16b6dd5 arch/i386/kernel/process-xen.c +--- a/arch/i386/kernel/process-xen.c Wed Aug 08 16:15:30 2007 -0300 ++++ b/arch/i386/kernel/process-xen.c Thu Sep 20 15:30:16 2007 -0300 +@@ -597,7 +597,9 @@ struct task_struct fastcall * __switch_t + mcl->op = __HYPERVISOR_fpu_taskswitch; + mcl->args[0] = 1; + mcl++; +- } ++ } else ++ prev_p->fpu_counter = 0; ++ + #if 0 /* lazy fpu sanity check */ + else BUG_ON(!(read_cr0() & 8)); + #endif +diff -r 35983eae211a -r 8792a16b6dd5 arch/i386/kernel/traps-xen.c +--- a/arch/i386/kernel/traps-xen.c Wed Aug 08 16:15:30 2007 -0300 ++++ b/arch/i386/kernel/traps-xen.c Thu Sep 20 15:30:16 2007 -0300 +@@ -1012,17 +1012,22 @@ fastcall unsigned long patch_espfix_desc + * Must be called with kernel preemption disabled (in this case, + * local interrupts are disabled at the call-site in entry.S). + */ +-asmlinkage void math_state_restore(void) ++asmlinkage void __math_state_restore(void) + { + struct thread_info *thread = current_thread_info(); + struct task_struct *tsk = thread->task; + +- /* NB. 'clts' is done for us by Xen during virtual trap. */ + if (!tsk_used_math(tsk)) + init_fpu(tsk); + restore_fpu(tsk); + thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */ + tsk->fpu_counter++; ++} ++ ++asmlinkage void math_state_restore(void) ++{ ++ clts(); /* Allow maths ops (or we recurse) */ ++ __math_state_restore(); + } + + #ifndef CONFIG_MATH_EMULATION +diff -r 35983eae211a -r 8792a16b6dd5 arch/i386/kernel/traps.c +--- a/arch/i386/kernel/traps.c Wed Aug 08 16:15:30 2007 -0300 ++++ b/arch/i386/kernel/traps.c Thu Sep 20 15:30:16 2007 -0300 +@@ -1041,17 +1041,22 @@ fastcall unsigned long patch_espfix_desc + * Must be called with kernel preemption disabled (in this case, + * local interrupts are disabled at the call-site in entry.S). + */ +-asmlinkage void math_state_restore(void) ++asmlinkage void __math_state_restore(void) + { + struct thread_info *thread = current_thread_info(); + struct task_struct *tsk = thread->task; + +- clts(); /* Allow maths ops (or we recurse) */ + if (!tsk_used_math(tsk)) + init_fpu(tsk); + restore_fpu(tsk); + thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */ + tsk->fpu_counter++; ++} ++ ++asmlinkage void math_state_restore(void) ++{ ++ clts(); /* Allow maths ops (or we recurse) */ ++ __math_state_restore(); + } + + #ifndef CONFIG_MATH_EMULATION |