BMC/Intel-BMC/linux.git/arch/x86/kernel/fpu/regset.c, branch dev

x86/fpu: Rename fpu__activate_fpstate() to fpu__activate_fpstate_write()

2015-05-27T12:11:26+00:00

Remaining users of fpu__activate_fpstate() are all places that want to modify FPU registers, rename the function to fpu__activate_fpstate_write() according to this usage. Cc: Andy Lutomirski Cc: Bobby Powers Cc: Borislav Petkov Cc: Dave Hansen Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Thomas Gleixner Signed-off-by: Ingo Molnar

x86/fpu: Split out the fpu__activate_fpstate_read() method

2015-05-27T12:11:24+00:00

Currently fpu__activate_fpstate() is used for two distinct purposes: - read access by ptrace and core dumping, where in the core dumping case the current task's FPU state may be examined as well. - write access by ptrace, which modifies FPU registers and expects the modified registers to be reloaded on the next context switch. Split out the reading side into fpu__activate_fpstate_read(). ( Note that this is just a pure duplication of fpu__activate_fpstate() for the time being, we'll optimize the new function in the next patch. ) Cc: Andy Lutomirski Cc: Bobby Powers Cc: Borislav Petkov Cc: Dave Hansen Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Thomas Gleixner Signed-off-by: Ingo Molnar

x86/fpu: Fix FPU register read access to the current task

2015-05-27T10:40:18+00:00

Bobby Powers reported the following FPU warning during ELF coredumping: WARNING: CPU: 0 PID: 27452 at arch/x86/kernel/fpu/core.c:324 fpu__activate_stopped+0x8a/0xa0() This warning unearthed an invalid assumption about fpu__activate_stopped() that I added in: 67e97fc2ec57 ("x86/fpu: Rename init_fpu() to fpu__unlazy_stopped() and add debugging check") the old init_fpu() function had an (intentional but obscure) side effect: when FPU registers are accessed for the current task, for reading, then it synchronized live in-register FPU state with the fpstate by saving it. So fix this bug by saving the FPU if we are the current task. We'll still warn in fpu__save() if this is called for not yet stopped child tasks, so the debugging check is still preserved. Also rename the function to fpu__activate_fpstate(), because it's not exclusively used for stopped tasks, but for the current task as well. ( Note that this bug calls for a cleaner separation of access-for-read and access-for-modification FPU methods, but we'll do that in separate patches. ) Reported-by: Bobby Powers 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 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: Factor out the FPU regset code into fpu/regset.c

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

So much of fpu/core.c is the regset code, but it just obscures the generic FPU state machine logic. Factor out the regset code into fpu/regset.c, where it can be read in isolation. This affects one API: fpu__activate_stopped() has to be made available from the core to fpu/regset.c. No change in functionality. 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