kernel.git/arch/powerpc/include/asm/switch_to.h, branch linux-4.10.y

powerpc/ptrace: Fix coredump since ptrace TM changes

2016-08-10T06:34:20Z

Commit 8d460f6156cd ("powerpc/process: Add the function flush_tmregs_to_thread") added flush_tmregs_to_thread() and included the assumption that it would only be called for a task which is not current. Although this is correct for ptrace, when generating a core dump, some of the routines which call flush_tmregs_to_thread() are called. This leads to a WARNing such as: Not expecting ptrace on self: TM regs may be incorrect ------------[ cut here ]------------ WARNING: CPU: 123 PID: 7727 at arch/powerpc/kernel/process.c:1088 flush_tmregs_to_thread+0x78/0x80 CPU: 123 PID: 7727 Comm: libvirtd Not tainted 4.8.0-rc1-gcc6x-g61e8a0d #1 task: c000000fe631b600 task.stack: c000000fe63b0000 NIP: c00000000001a1a8 LR: c00000000001a1a4 CTR: c000000000717780 REGS: c000000fe63b3420 TRAP: 0700 Not tainted (4.8.0-rc1-gcc6x-g61e8a0d) MSR: 900000010282b033 CR: 28004222 XER: 20000000 ... NIP [c00000000001a1a8] flush_tmregs_to_thread+0x78/0x80 LR [c00000000001a1a4] flush_tmregs_to_thread+0x74/0x80 Call Trace: flush_tmregs_to_thread+0x74/0x80 (unreliable) vsr_get+0x64/0x1a0 elf_core_dump+0x604/0x1430 do_coredump+0x5fc/0x1200 get_signal+0x398/0x740 do_signal+0x54/0x2b0 do_notify_resume+0x98/0xb0 ret_from_except_lite+0x70/0x74 So fix flush_tmregs_to_thread() to detect the case where it is called on current, and a transaction is active, and in that case flush the TM regs to the thread_struct. This patch also moves flush_tmregs_to_thread() into ptrace.c as it is only called from that file. Fixes: 8d460f6156cd ("powerpc/process: Add the function flush_tmregs_to_thread") Signed-off-by: Cyril Bur [mpe: Flesh out change log] Signed-off-by: Michael Ellerman

powerpc/process: Add the function flush_tmregs_to_thread

2016-08-01T01:15:15Z

This patch creates a function flush_tmregs_to_thread which will then be used by subsequent patches in this series. The function checks for self tracing ptrace interface attempts while in the TM context and logs appropriate warning message. Signed-off-by: Anshuman Khandual Signed-off-by: Simon Guo Signed-off-by: Michael Ellerman

powerpc: Add the ability to save VSX without giving it up

2016-03-02T12:34:50Z

This patch adds the ability to be able to save the VSX registers to the thread struct without giving up (disabling the facility) next time the process returns to userspace. This patch builds on a previous optimisation for the FPU and VEC registers in the thread copy path to avoid a possibly pointless reload of VSX state. Signed-off-by: Cyril Bur Signed-off-by: Michael Ellerman

powerpc: Add the ability to save Altivec without giving it up

2016-03-02T12:34:49Z

This patch adds the ability to be able to save the VEC registers to the thread struct without giving up (disabling the facility) next time the process returns to userspace. This patch builds on a previous optimisation for the FPU registers in the thread copy path to avoid a possibly pointless reload of VEC state. Signed-off-by: Cyril Bur Signed-off-by: Michael Ellerman

powerpc: Add the ability to save FPU without giving it up

2016-03-02T12:34:49Z

This patch adds the ability to be able to save the FPU registers to the thread struct without giving up (disabling the facility) next time the process returns to userspace. This patch optimises the thread copy path (as a result of a fork() or clone()) so that the parent thread can return to userspace with hot registers avoiding a possibly pointless reload of FPU register state. Signed-off-by: Cyril Bur Signed-off-by: Michael Ellerman

powerpc: Prepare for splitting giveup_{fpu, altivec, vsx} in two

2016-03-02T12:34:48Z

This prepares for the decoupling of saving {fpu,altivec,vsx} registers and marking {fpu,altivec,vsx} as being unused by a thread. Currently giveup_{fpu,altivec,vsx}() does both however optimisations to task switching can be made if these two operations are decoupled. save_all() will permit the saving of registers to thread structs and leave threads MSR with bits enabled. This patch introduces no functional change. Signed-off-by: Cyril Bur Signed-off-by: Michael Ellerman

powerpc: clean up asm/switch_to.h

2015-12-02T08:34:41Z

Remove a bunch of unnecessary fallback functions and group things in a more logical way. Signed-off-by: Anton Blanchard Signed-off-by: Michael Ellerman

powerpc: create flush_all_to_thread()

2015-12-02T08:34:40Z

Create a single function that flushes everything (FP, VMX, VSX, SPE). Doing this all at once means we only do one MSR write. Signed-off-by: Anton Blanchard Signed-off-by: Michael Ellerman

powerpc: create giveup_all()

2015-12-02T08:34:26Z

Create a single function that gives everything up (FP, VMX, VSX, SPE). Doing this all at once means we only do one MSR write. A context switch microbenchmark using yield(): http://ozlabs.org/~anton/junkcode/context_switch2.c ./context_switch2 --test=yield --fp --altivec --vector 0 0 shows an improvement of 3% on POWER8. Signed-off-by: Anton Blanchard [mpe: giveup_all() needs to be EXPORT_SYMBOL'ed] Signed-off-by: Michael Ellerman

powerpc: Add ppc_strict_facility_enable boot option

2015-12-01T02:52:26Z

Add a boot option that strictly manages the MSR unavailable bits. This catches kernel uses of FP/Altivec/SPE that would otherwise corrupt user state. Signed-off-by: Anton Blanchard Signed-off-by: Michael Ellerman