BMC/Intel-BMC/linux.git/arch/x86/math-emu, branch dev

x86/ldt: Further fix FPU emulation

2015-08-16T22:11:05+00:00

The previous fix confused a selector with a segment prefix. Fix it. Compile-tested only. Cc: stable@vger.kernel.org Cc: Juergen Gross Reported-by: Linus Torvalds Fixes: 4809146b86c3 ("x86/ldt: Correct FPU emulation access to LDT") Signed-off-by: Andy Lutomirski Signed-off-by: Linus Torvalds

x86/ldt: Correct FPU emulation access to LDT

2015-08-08T08:20:45+00:00

Commit 37868fe113ff ("x86/ldt: Make modify_ldt synchronous") introduced a new struct ldt_struct anchored at mm->context.ldt. Adapt the x86 fpu emulation code to use that new structure. Signed-off-by: Juergen Gross Reviewed-by: Andy Lutomirski Cc: # On top of: 37868fe113ff: x86/ldt: Make modify_ldt synchronous Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: billm@melbpc.org.au Link: http://lkml.kernel.org/r/1438883674-1240-1-git-send-email-jgross@suse.com Signed-off-by: Ingo Molnar

x86/fpu: Harmonize FPU register state types

2015-05-19T13:48:09+00:00

Use these consistent names: struct fregs_state # was: i387_fsave_struct struct fxregs_state # was: i387_fxsave_struct struct swregs_state # was: i387_soft_struct struct xregs_state # was: xsave_struct union fpregs_state # was: thread_xstate Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar

x86/fpu: Harmonize the names of the fpstate_init() helper functions

2015-05-19T13:48:07+00:00

Harmonize the inconsistent naming of these related functions: fpstate_init() finit_soft_fpu() => fpstate_init_fsoft() fx_finit() => fpstate_init_fxstate() fx_finit() => fpstate_init_fstate() # split out Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar

x86/fpu: Simplify fpstate_init_curr() usage

2015-05-19T13:47:51+00:00

Now that fpstate_init_curr() is not doing implicit allocations anymore, almost all uses of it involve a very simple pattern: if (!fpu->fpstate_active) fpstate_init_curr(fpu); which is basically activating the FPU fpstate if it was not active before. So propagate the check into the function itself, and rename the function according to its new purpose: fpu__activate_curr(fpu); Reviewed-by: Borislav Petkov Cc: Andy Lutomirski Cc: Dave Hansen Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar

x86/fpu: Rename fpstate_alloc_init() to fpstate_init_curr()

2015-05-19T13:47:50+00:00

Now that there are no FPU context allocations, rename fpstate_alloc_init() to fpstate_init_curr(), to signal that it initializes the fpstate and marks it active, for the current task. Reviewed-by: Borislav Petkov Cc: Andy Lutomirski Cc: Dave Hansen Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar

x86/fpu: Remove failure return from fpstate_alloc_init()

2015-05-19T13:47:50+00:00

Remove the failure code and propagate this down to callers. Note that this function still has an 'init' aspect, which must be called. Reviewed-by: Borislav Petkov Cc: Andy Lutomirski Cc: Dave Hansen Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar

x86/fpu: Simplify FPU handling by embedding the fpstate in task_struct (again)

2015-05-19T13:47:49+00:00

So 6 years ago we made the FPU fpstate dynamically allocated: aa283f49276e ("x86, fpu: lazy allocation of FPU area - v5") 61c4628b5386 ("x86, fpu: split FPU state from task struct - v5") In hindsight this was a mistake: - it complicated context allocation failure handling, such as: /* kthread execs. TODO: cleanup this horror. */ if (WARN_ON(fpstate_alloc_init(fpu))) force_sig(SIGKILL, tsk); - it caused us to enable irqs in fpu__restore(): local_irq_enable(); /* * does a slab alloc which can sleep */ if (fpstate_alloc_init(fpu)) { /* * ran out of memory! */ do_group_exit(SIGKILL); return; } local_irq_disable(); - it (slightly) slowed down task creation/destruction by adding slab allocation/free pattens. - it made access to context contents (slightly) slower by adding one more pointer dereference. The motivation for the dynamic allocation was two-fold: - reduce memory consumption by non-FPU tasks - allocate and handle only the necessary amount of context for various XSAVE processors that have varying hardware frame sizes. These days, with glibc using SSE memcpy by default and GCC optimizing for SSE/AVX by default, the scope of FPU using apps on an x86 system is much larger than it was 6 years ago. For example on a freshly installed Fedora 21 desktop system, with a recent kernel, all non-kthread tasks have used the FPU shortly after bootup. Also, even modern embedded x86 CPUs try to support the latest vector instruction set - so they'll too often use the larger xstate frame sizes. So remove the dynamic allocation complication by embedding the FPU fpstate in task_struct again. This should make the FPU a lot more accessible to all sorts of atomic contexts. We could still optimize for the xstate frame size in the future, by moving the state structure to the last element of task_struct, and allocating only a part of that. This change is kept minimal by still keeping the ctx_alloc()/free() routines (that now do nothing substantial) - we'll remove them in the following patches. Reviewed-by: Borislav Petkov Cc: Andy Lutomirski Cc: Dave Hansen Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar

x86/fpu: Move various internal function prototypes to fpu/internal.h

2015-05-19T13:47:48+00:00

There are a number of FPU internal function prototypes and an inline function in fpu/api.h, mostly placed so historically as the code grew over the years. Move them over into fpu/internal.h where they belong. (Add sched.h include to stackprotector.h which incorrectly relied on getting it from fpu/api.h.) fpu/api.h is now a pure file that only contains FPU APIs intended for driver use. Reviewed-by: Borislav Petkov Cc: Andy Lutomirski Cc: Dave Hansen Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar

x86/fpu: Rename i387.h to fpu/api.h

2015-05-19T13:47:30+00:00

We already have fpu/types.h, move i387.h to fpu/api.h. The file name has become a misnomer anyway: it offers generic FPU APIs, but is not limited to i387 functionality. Reviewed-by: Borislav Petkov Cc: Andy Lutomirski Cc: Dave Hansen Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar