Messages in this thread | | | Date | Sat, 23 Feb 2008 12:21:36 +0300 | From | Cyrill Gorcunov <> | Subject | Re: [Q] x86 - boot/header.S |
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[Sam Ravnborg - Sat, Feb 23, 2008 at 10:18:17AM +0100] | On Sat, Feb 23, 2008 at 12:07:39PM +0300, Cyrill Gorcunov wrote: | > [Yinghai Lu - Sat, Feb 23, 2008 at 12:44:49AM -0800] | > | On Sat, Feb 23, 2008 at 12:20 AM, Cyrill Gorcunov <gorcunov@gmail.com> wrote: | > | > Hi Peter, Sam, | > | > | > | > could you take a look on x86/boot/header.S:280 please? | > | > | > | > # Zero the bss | > | > movw $__bss_start, %di | > | > movw $_end+3, %cx | > | > xorl %eax, %eax | > | > subw %di, %cx | > | > shrw $2, %cx | > | > rep; stosl | > | > | > | > I wonder why is $_end there instead of $__bss_stop? | > | > Well, accroding to vmlinux_32.lsd both _end and __bss_stop | > | > are the same BUT __bss_stop is more convenient methink. | > | > Would it be usefull to change? | > | | > | we should have head32.c like head64.c | > | and x86_32_start_kernel. | > | | > | Eric's patch long time ago... | > | | > | YH | > | | > | > Hi Yinghai, | > | > thanks for reply BUT that is not the point (or maybe I miss something). | > | > Look, we only have head64.c - there is no head32.c at all. Both | > vmlinux_32/64.lds defines _end exactly the same as __bss_stop. So in | > code which DO fillup bss section with zeros the prefered name is | > __bss_stop. The only thing I'm trying to say that it would be clean | > naming scheme and I think it would help for further review - instead | > of searching all over x86 files to find _end definition __bss_stop | > tell us WHAT we are zeroing from the code. | | We should introduce head32.c and then we can use the exact same function | as 64 bit does: | | /* Don't add a printk in there. printk relies on the PDA which is not initialized | yet. */ | static void __init clear_bss(void) | { | memset(__bss_start, 0, | (unsigned long) __bss_stop - (unsigned long) __bss_start); | } | | This answers your Q. | | I already resubmitted Eric's original patch to introduce head32.c as I also | liked the cleanup in two Makefiles. | | Sam |
thanks Sam, i just saw your patch.
- Cyrill -
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