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Date: Thu, 8 Jan 2009 13:03:38 +0100 From: Adam Osuchowski <adwol@...k.pl> To: linux-kernel@...r.kernel.org Subject: Is 386 processor still supported? Recently, I found such piece of code in kernel 2.6.28 compiled for 386 processor: # grep M386 .config CONFIG_M386=y # objdump -d vmlinux | grep -A11 '<_spin_lock>:' c0321827 <_spin_lock>: c0321827: 89 e2 mov %esp,%edx c0321829: 81 e2 00 f0 ff ff and $0xfffff000,%edx c032182f: ff 42 14 incl 0x14(%edx) c0321832: ba 00 01 00 00 mov $0x100,%edx c0321837: f0 66 0f c1 10 lock xadd %dx,(%eax) c032183c: 38 f2 cmp %dh,%dl c032183e: 74 06 je c0321846 <_spin_lock+0x1f> c0321840: f3 90 pause c0321842: 8a 10 mov (%eax),%dl c0321844: eb f6 jmp c032183c <_spin_lock+0x15> c0321846: c3 ret But there is no xadd instruction on 386 processors. It is available on 486+ only. I have no chance to run this kernel on real 386 box, so I can't check it in practice, but I think it will not run. It is not compiler problem because it is explicitly written in assembly in __raw_spin_lock() function (include/asm-x86/spinlock.h) and there is no alternative code depending on CONFIG_M386. Regards. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.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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