RFC sycalls: Remove args i and n from syscall_get_arguments()
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- v1 RFC Latest3 patches 8 repliesIn review
Patches in v1 No applies recorded yet
| # | Subject and files | Size | Replies | Applied |
|---|---|---|---|---|
| 1/3 | ptrace: Remove maxargs from task_current_syscall()fs/ include/ lib/ | +11 | 6 replies | |
| 2/3 | tracing/syscalls: Pass in hardcoded 6 into syscall_get_arguments()kernel/ | +7 | 0 replies | |
| 3/3 | syscalls: Remove start and number from syscall_get_arguments() argsarch/ arch/ arch/ +26 more | +124 | 2 replies |
Reviews trailers per patch
2 of 3 patches have a Reviewed-by or Acked-by.
| Patch | Andy Lutomirski |
|---|---|
| 1/3 | R-b |
| 2/3 | |
| 3/3 | R-b |
Trailers given in replies are filled; those carried in the patches from earlier versions are outlined with dashes.
Cover letter [RFC][ATCH 0/3] sycalls: Remove args i and n from syscall_get_arguments()
At Linux Plumbers, Andy Lutomirski approached me to tell me that the syscall_get_arguments() implementation in x86 was horrible and gcc certainly gets it wrong. He said that since the tracepoints only pass in 0 and 6 for i and n repectively, it should be optimized for that case. Inspecting the kernel, I discovered that all users pass in 0 for i and only one file passing in something other than 6 for the number of arguments. That code happens to be my own code used for the special syscall tracing. That can easily be converted to just using 0 and 6 as well, and only copying what is needed. Which is probably the faster path anyway for that case.
I haven't run the numbers (I can do that when I get some time), but since pretty much all use cases use 0 and 6 and that would allow these functions not to need strange logic to handle odd cases, I think this is still a win.
I haven't looked at removing those same parameters from syscall_set_arguments() yet.
Thoughts?
-- Steve
Steven Rostedt (3):
ptrace: Remove maxargs from task_current_syscall() tracing/syscalls: Pass in hardcoded '6' into syscall_get_arguments()
syscalls: Remove start and number from syscall_get_arguments() args
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arch/arc/include/asm/syscall.h | 7 ++-- arch/arm/include/asm/syscall.h | 23 ++--------- arch/arm64/include/asm/syscall.h | 22 ++--------- arch/blackfin/include/asm/syscall.h | 22 +++++++---- arch/c6x/include/asm/syscall.h | 41 ++++---------------- arch/frv/include/asm/syscall.h | 26 +++---------- arch/h8300/include/asm/syscall.h | 34 ++++------------- arch/hexagon/include/asm/syscall.h | 4 +- arch/ia64/include/asm/syscall.h | 5 +-- arch/metag/include/asm/syscall.h | 4 +- arch/microblaze/include/asm/syscall.h | 4 +- arch/mips/include/asm/syscall.h | 3 +- arch/mn10300/include/asm/syscall.h | 32 +++------------- arch/nios2/include/asm/syscall.h | 42 ++++---------------- arch/openrisc/include/asm/syscall.h | 6 +-- arch/parisc/include/asm/syscall.h | 30 ++++----------- arch/powerpc/include/asm/syscall.h | 8 ++-- arch/s390/include/asm/syscall.h | 11 +++--- arch/sh/include/asm/syscall_32.h | 26 +++---------- arch/sh/include/asm/syscall_64.h | 4 +- arch/sparc/include/asm/syscall.h | 4 +- arch/tile/include/asm/syscall.h | 4 +- arch/um/include/asm/syscall-generic.h | 39 +++---------------- arch/x86/include/asm/syscall.h | 72 ++++++++--------------------------- fs/proc/base.c | 2 +- include/asm-generic/syscall.h | 11 ++---- include/linux/ptrace.h | 4 +- include/trace/events/syscalls.h | 2 +- kernel/seccomp.c | 2 +- kernel/trace/trace_syscalls.c | 10 +++-- lib/syscall.c | 22 ++++------- 31 files changed, 139 insertions(+), 387 deletions(-)