Messages in this thread | | | From | YiFei Zhu <> | Date | Thu, 24 Sep 2020 09:16:48 -0500 | Subject | Re: [PATCH v2 seccomp 2/6] asm/syscall.h: Add syscall_arches[] array |
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On Thu, Sep 24, 2020 at 8:47 AM David Laight <David.Laight@aculab.com> wrote: > I doubt the compiler will do what you want. > Looking at it, in most cases there are one or two entries. > I think only MIPS has three.
It does ;) GCC 10.2.0:
$ objdump -d kernel/seccomp.o | less [...] 0000000000001520 <__seccomp_filter>: [...] 1587: 41 8b 54 24 04 mov 0x4(%r12),%edx 158c: b9 08 01 00 00 mov $0x108,%ecx 1591: 81 fa 3e 00 00 c0 cmp $0xc000003e,%edx 1597: 75 2e jne 15c7 <__seccomp_filter+0xa7> [...] 15c7: 81 fa 03 00 00 40 cmp $0x40000003,%edx 15cd: b9 40 01 00 00 mov $0x140,%ecx 15d2: 74 c5 je 1599 <__seccomp_filter+0x79> 15d4: 0f 0b ud2 [...] 0000000000001cb0 <seccomp_cache_prepare>: [...] 1cc4: 41 b9 3e 00 00 c0 mov $0xc000003e,%r9d [...] 1dba: 41 b9 03 00 00 40 mov $0x40000003,%r9d [...] 0000000000002e30 <proc_pid_seccomp_cache>: [...] 2e72: ba 3e 00 00 c0 mov $0xc000003e,%edx [...] 2eb5: ba 03 00 00 40 mov $0x40000003,%edx
Granted, I have CC_OPTIMIZE_FOR_PERFORMANCE rather than CC_OPTIMIZE_FOR_SIZE, but this patch itself is trying to sacrifice some of the memory for speed.
YiFei Zhu
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