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Jamie Lokier wrote: > > No, your "real" code sequence is wrong. > > %ebx/%edi/%esi are preserved across sysenter/sysexit, whereas > %ecx/%edx are call-clobbered registers in the i386 function call ABI. > > This is not a coincidence. > > So, getpid looks like this with the _smaller_ vsyscall code: > > getpid(): > movl $__NR_getpid,%eax > call *%gs:0x18 > ret ... or just... getpid: movl $__NR_getpid, %eax jmp *%gs:0x18 This doesn't mess up the call/return stack, even, because the ret in the stub matches the call to getpid. -hpa - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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