Re: [PATCH v2 00/25] powerpc: Switch signal 32 to using unsafe_put_user() and friends
On Tue, 18 Aug 2020 17:19:11 + (UTC), Christophe Leroy wrote: > This series leads to a reduction from 2.55s to 1.73s of > the system CPU time with the following microbench app > on an mpc832x with KUAP (approx 32%) > > This series replaces copies to users by unsafe_put_user() and friends > with user_write_access_begin() dance in signal32. > > [...] Applied to powerpc/next. [01/25] powerpc/signal: Move inline functions in signal.h https://git.kernel.org/powerpc/c/95593e930d7d067ca9bbee996c845248930a01f9 [02/25] powerpc/ptrace: Move declaration of ptrace_get_reg() and ptrace_set_reg() https://git.kernel.org/powerpc/c/67e364b3295f9dbf3b820d0edde86fb7c95efc98 [03/25] powerpc/ptrace: Consolidate reg index calculation https://git.kernel.org/powerpc/c/e009fa433542cd09d6279e361b767a1f44ffd29a [04/25] powerpc/ptrace: Create ptrace_get_fpr() and ptrace_put_fpr() https://git.kernel.org/powerpc/c/4d90eb97e292c7b14de8ba59fded35b340c73101 [05/25] powerpc/signal: Don't manage floating point regs when no FPU https://git.kernel.org/powerpc/c/b6254ced4da6cf28d49fbffe24ee4b3286dcb3f4 [06/25] powerpc/32s: Allow deselecting CONFIG_PPC_FPU on mpc832x https://git.kernel.org/powerpc/c/7d68c89169508064c460a1208f38ed0589d226fa [07/25] powerpc/signal: Remove BUG_ON() in handler_signal functions https://git.kernel.org/powerpc/c/3fcfb5d1bf731bdbd847c29df57a5372d8ea58d3 [08/25] powerpc/signal: Move access_ok() out of get_sigframe() https://git.kernel.org/powerpc/c/454b1abb588b3942655638a8bcf1ea4501260579 [09/25] powerpc/signal: Remove get_clean_sp() https://git.kernel.org/powerpc/c/0ecbc6ad18e324012234183e21805423f5e0cc79 [10/25] powerpc/signal: Call get_tm_stackpointer() from get_sigframe() https://git.kernel.org/powerpc/c/c180cb305c9bba094657259487d563c8fbfb648b [11/25] powerpc/signal: Refactor bad frame logging https://git.kernel.org/powerpc/c/7fe8f773ee248c726cec2addcdb94056049d6e34 [12/25] powerpc/signal32: Simplify logging in handle_rt_signal32() https://git.kernel.org/powerpc/c/debf122c777f361137a3114db7be8aecc65f6af2 [13/25] powerpc/signal32: Move handle_signal32() close to handle_rt_signal32() https://git.kernel.org/powerpc/c/3eea688be0ccba2221e047b7df6f9ae87361cdd6 [14/25] powerpc/signal32: Rename local pointers in handle_rt_signal32() https://git.kernel.org/powerpc/c/8e91cf8501f14d8b6727c71c98fd743e95e9b402 [15/25] powerpc/signal32: Misc changes to make handle_[rt_]_signal32() more similar https://git.kernel.org/powerpc/c/91b8ecd419cb46058e99b3a574184883c02b7729 [16/25] powerpc/signal32: Move signal trampoline setup to handle_[rt_]signal32 https://git.kernel.org/powerpc/c/8d33001dd650b88e915a1a13e2ca807350e374df [17/25] powerpc/signal32: Switch handle_signal32() to user_access_begin() logic https://git.kernel.org/powerpc/c/ad65f4909fd3736d84533784cd9ab76905536b34 [18/25] powerpc/signal32: Switch handle_rt_signal32() to user_access_begin() logic https://git.kernel.org/powerpc/c/9504db3e90b22dca19d8152ed5a82c68512dac0e [19/25] powerpc/signal32: Remove ifdefery in middle of if/else https://git.kernel.org/powerpc/c/f1cf4f93de2ff66313a091320d7683735816a0bc [20/25] signal: Add unsafe_put_compat_sigset() https://git.kernel.org/powerpc/c/14026b94ccfe626e512bc9fa01e0e72ee75c7a98 [21/25] powerpc/signal32: Add and use unsafe_put_sigset_t() https://git.kernel.org/powerpc/c/de781ebdf6b8a256742da4fd6b0e39bb22ed9fe3 [22/25] powerpc/signal32: Switch swap_context() to user_access_begin() logic https://git.kernel.org/powerpc/c/31147d7d6133ea17504b118114a191a8af85f3de [23/25] powerpc/signal: Create 'unsafe' versions of copy_[ck][fpr/vsx]_to_user() https://git.kernel.org/powerpc/c/b3484a1d4d1fb54ad7b615a13003d8bc11919c96 [24/25] powerpc/signal32: Isolate non-copy actions in save_user_regs() and save_tm_user_regs() https://git.kernel.org/powerpc/c/968c4fccd1bb8b440326dac5078ad87d17af4a47 [25/25] powerpc/signal32: Transform save_user_regs() and save_tm_user_regs() in 'unsafe' version https://git.kernel.org/powerpc/c/ef75e73182949a94bde169a774de1b62ae21fbbc cheers
[PATCH v2 00/25] powerpc: Switch signal 32 to using unsafe_put_user() and friends
This series leads to a reduction from 2.55s to 1.73s of
the system CPU time with the following microbench app
on an mpc832x with KUAP (approx 32%)
This series replaces copies to users by unsafe_put_user() and friends
with user_write_access_begin() dance in signal32.
The advantages are:
- No KUAP unlock/lock at every copy
- More readable code.
- Better generated code.
Without KUAP, the difference is in the noise.
void sigusr1(int sig) { }
int main(int argc, char **argv)
{
int i = 10;
signal(SIGUSR1, sigusr1);
for (;i--;)
raise(SIGUSR1);
exit(0);
}
An additional 0.10s reduction is achieved by removing
CONFIG_PPC_FPU, as the mpc832x has no FPU.
A bit less spectacular on an 8xx as KUAP is less heavy, prior to
the series (with KUAP) it ran in 8.10 ms. Once applies the removal
of FPU regs handling, we get 7.05s. With the full series, we get 6.9s.
If artificially re-activating FPU regs handling with the full series,
we get 7.6s.
So for the 8xx, the removal of the FPU regs copy is what makes the
difference, but the rework of handle_signal also have a benefit.
Same as above, without KUAP the difference is in the noise.
Difference since v1(RFC):
- Almost copies to user are now replaced by unsafe_ alternative.
- Reworked a bit the FPU registers handling following feedback from Michael.
- Fixed a few build failures reported by Mr Robot on the RFC.
Christophe Leroy (25):
powerpc/signal: Move inline functions in signal.h
powerpc/ptrace: Move declaration of ptrace_get_reg() and
ptrace_set_reg()
powerpc/ptrace: Consolidate reg index calculation
powerpc/ptrace: Create ptrace_get_fpr() and ptrace_put_fpr()
powerpc/signal: Don't manage floating point regs when no FPU
powerpc/32s: Allow deselecting CONFIG_PPC_FPU on mpc832x
powerpc/signal: Remove BUG_ON() in handler_signal functions
powerpc/signal: Move access_ok() out of get_sigframe()
powerpc/signal: Remove get_clean_sp()
powerpc/signal: Call get_tm_stackpointer() from get_sigframe()
powerpc/signal: Refactor bad frame logging
powerpc/signal32: Simplify logging in handle_rt_signal32()
powerpc/signal32: Move handle_signal32() close to handle_rt_signal32()
powerpc/signal32: Rename local pointers in handle_rt_signal32()
powerpc/signal32: Misc changes to make handle_[rt_]_signal32() more
similar
powerpc/signal32: Move signal trampoline setup to handle_[rt_]signal32
powerpc/signal32: Switch handle_signal32() to user_access_begin()
logic
powerpc/signal32: Switch handle_rt_signal32() to user_access_begin()
logic
powerpc/signal32: Remove ifdefery in middle of if/else
signal: Add unsafe_put_compat_sigset()
powerpc/signal32: Add and use unsafe_put_sigset_t()
powerpc/signal32: Switch swap_context() to user_access_begin() logic
powerpc/signal: Create 'unsafe' versions of
copy_[ck][fpr/vsx]_to_user()
powerpc/signal32: Isolate non-copy actions in save_user_regs() and
save_tm_user_regs()
powerpc/signal32: Transform save_user_regs() and save_tm_user_regs()
in 'unsafe' version
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/processor.h | 16 +-
arch/powerpc/include/asm/ptrace.h| 6 -
arch/powerpc/kernel/asm-offsets.c| 2 +
arch/powerpc/kernel/head_32.S| 4 +
arch/powerpc/kernel/process.c| 4 +
arch/powerpc/kernel/ptrace/Makefile | 3 +-
arch/powerpc/kernel/ptrace/ptrace-decl.h | 21 +
arch/powerpc/kernel/ptrace/ptrace-fpu.c | 40 ++
arch/powerpc/kernel/ptrace/ptrace-view.c | 2 +
arch/powerpc/kernel/ptrace/ptrace.c | 54 +-
arch/powerpc/kernel/ptrace/ptrace32.c| 2 +
arch/powerpc/kernel/signal.c | 59 +--
arch/powerpc/kernel/signal.h | 115 -
arch/powerpc/kernel/signal_32.c | 598 +++
arch/powerpc/kernel/signal_64.c | 21 +-
arch/powerpc/kernel/traps.c | 2 +
arch/powerpc/platforms/Kconfig.cputype | 15 +-
include/linux/compat.h | 32 ++
19 files changed, 566 insertions(+), 431 deletions(-)
create mode 100644 arch/powerpc/kernel/ptrace/ptrace-fpu.c
--
2.25.0
