From: Bob <bo-liu@xxxxxxxxxxx> Date: Thu, 11 Dec 2008 15:16:17 +0800 > I have read the code about syscall in file entry.S and didn't > known what's a fast syscall. > > And why line 1322 can distinguish it through "andcc" (there %l7 is > the sys_* funtions' address?) ? We used to have fast syscall handlers that ran directly in assembler without doing a trap entry and exit which is normally necessary to call the normal C code implementations. The way this was distinguished was by setting the low bit in the syscall table entry. Since all Sparc instructios must be 4 byte aligned, this works. We just need to clear that bit before jumping to the address. Fast syscalls were removed a long time ago, but the support code still lives :) -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
