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

Revert x86 sigcontext cleanups

2015-08-13T19:42:22+00:00

This reverts commits 9a036b93a344 ("x86/signal/64: Remove 'fs' and 'gs' from sigcontext") and c6f2062935c8 ("x86/signal/64: Fix SS handling for signals delivered to 64-bit programs"). They were cleanups, but they break dosemu by changing the signal return behavior (and removing 'fs' and 'gs' from the sigcontext struct - while not actually changing any behavior - causes build problems). Reported-and-tested-by: Stas Sergeev Acked-by: Andy Lutomirski Cc: Ingo Molnar Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds

x86/fpu: Split out fpu/signal.h from fpu/internal.h for signal frame handling functions

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

Most of the FPU does not use them, so split it out and include them in signal.c and ia32_signal.c Also fix header file dependency assumption in fpu/core.c. 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: Move is_ia32*frame() helpers out of fpu/internal.h

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

Move them to their only user. This makes the code easier to read, the header is less cluttered, and it also speeds up the build a bit. 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: Merge fpureset() and fpuclear()

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

With recent cleanups and fixes the fpu__reset() and fpu__clear() functions have become almost identical in functionality: the only difference is that fpu__reset() assumed that the fpstate was already active in the eagerfpu case, while fpu__clear() activated it if it was inactive. This distinction almost never matters, the only case where such fpstate activation happens if if the init thread (PID 1) gets exec()-ed for the first time. So keep fpu__clear() and change all fpu__reset() uses to fpu__clear() to simpify the logic. ( In a later patch we'll further simplify fpu__clear() by making sure that all contexts it is called on are already active. ) 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: Move the signal frame handling code closer to each other

2015-05-19T13:48:04+00:00

Consolidate more signal frame related functions: text data bss dec filename 14108070 2575280 1634304 18317654 vmlinux.before 14107944 2575344 1634304 18317592 vmlinux.after Also, while moving it, rename alloc_mathframe() to fpu__alloc_mathframe(). 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: Rename restore_xstate_sig() to fpu__restore_sig()

2015-05-19T13:48:04+00:00

restore_xstate_sig() is a misnomer: it's not limited to 'xstate' at all, it is the high level 'restore FPU state from a signal frame' function that works with all legacy FPU formats as well. Rename it (and its helper) accordingly, and also move it to the fpu__*() namespace. 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: Synchronize the naming of drop_fpu() and fpu_reset_state()

2015-05-19T13:48:03+00:00

drop_fpu() and fpu_reset_state() are similar in functionality and in scope, yet this is not apparent from their names. drop_fpu() deactivates FPU contents (both the fpregs and the fpstate), but leaves register contents intact in the eager-FPU case, mostly as an optimization. It disables fpregs in the lazy FPU case. The drop_fpu() method can be used to destroy FPU state in an optimized way, when we know that a new state will be loaded before user-space might see any remains of the old FPU state: - such as in sys_exit()'s exit_thread() where we know this task won't execute any user-space instructions anymore and the next context switch cleans up the FPU. The old FPU state might still be around in the eagerfpu case but won't be saved. - in __restore_xstate_sig(), where we use drop_fpu() before copying a new state into the fpstate and activating that one. No user-pace instructions can execute between those steps. - in sys_execve()'s fpu__clear(): there we use drop_fpu() in the !eagerfpu case, where it's equivalent to a full reinit. fpu_reset_state() is a stronger version of drop_fpu(): both in the eagerfpu and the lazy-FPU case it guarantees that fpregs are reinitialized to init state. This method is used in cases where we need a full reset: - handle_signal() uses fpu_reset_state() to reset the FPU state to init before executing a user-space signal handler. While we have already saved the original FPU state at this point, and always restore the original state, the signal handling code still has to do this reinit, because signals may interrupt any user-space instruction, and the FPU might be in various intermediate states (such as an unbalanced x87 stack) that is not immediately usable for general C signal handler code. - __restore_xstate_sig() uses fpu_reset_state() when the signal frame has no FP context. Since the signal handler may have modified the FPU state, it gets reset back to init state. - in another branch __restore_xstate_sig() uses fpu_reset_state() to handle a restoration error: when restore_user_xstate() fails to restore FPU state and we might have inconsistent FPU data, fpu_reset_state() is used to reset it back to a known good state. - __kernel_fpu_end() uses fpu_reset_state() in an error branch. This is in a 'must not trigger' error branch, so on bug-free kernels this never triggers. - fpu__restore() uses fpu_reset_state() in an error path as well: if the fpstate was set up with invalid FPU state (via ptrace or via a signal handler), then it's reset back to init state. - likewise, the scheduler's switch_fpu_finish() uses it in a restoration error path too. Move both drop_fpu() and fpu_reset_state() to the fpu__*() namespace and harmonize their naming with their function: fpu__drop() fpu__reset() This clearly shows that both methods operate on the full state of the FPU, just like fpu__restore(). Also add comments to explain what each function does. 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: Rename save_xstate_sig() to copy_fpstate_to_sigframe()

2015-05-19T13:48:01+00:00

Standardize the naming of save_xstate_sig() by renaming it to copy_fpstate_to_sigframe(): this tells us at a glance that the function copies an FPU fpstate to a signal frame. This naming also follows the naming of copy_fpregs_to_fpstate(). Don't put 'xstate' into the name: since this is a generic name, it's expected that the function is able to handle xstate frames as well, beyond legacy frames. xstate used to be the odd case in the x86 FPU code - now it's the common case. 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: Rename fpu-internal.h to fpu/internal.h

2015-05-19T13:47:31+00:00

This unifies all the FPU related header files under a unified, hiearchical naming scheme: - asm/fpu/types.h: FPU related data types, needed for 'struct task_struct', widely included in almost all kernel code, and hence kept as small as possible. - asm/fpu/api.h: FPU related 'public' methods exported to other subsystems. - asm/fpu/internal.h: FPU subsystem internal methods - asm/fpu/xsave.h: XSAVE support internal methods (Also standardize the header guard in asm/fpu/internal.h.) 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: Use 'struct fpu' in fpu_reset_state()

2015-05-19T13:47:26+00:00

Migrate this function to pure 'struct fpu' usage. 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

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

Revert x86 sigcontext cleanups

x86/fpu: Split out fpu/signal.h from fpu/internal.h for signal frame handling functions

x86/fpu: Move is_ia32*frame() helpers out of fpu/internal.h

x86/fpu: Merge fpu__reset() and fpu__clear()

x86/fpu: Move the signal frame handling code closer to each other

x86/fpu: Rename restore_xstate_sig() to fpu__restore_sig()

x86/fpu: Synchronize the naming of drop_fpu() and fpu_reset_state()

x86/fpu: Rename save_xstate_sig() to copy_fpstate_to_sigframe()

x86/fpu: Rename fpu-internal.h to fpu/internal.h

x86/fpu: Use 'struct fpu' in fpu_reset_state()

x86/fpu: Merge fpureset() and fpuclear()