Is *.text 1 *the same as *.section*??? .text 1 occurs in entry.S Please tell me what it means? Furquan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On 24/12/2008 11:29, "Furquan Shaikh" <furquan.m.shaikh@gmail.com> wrote:> Is .text 1 the same as .section??? > > .text 1 occurs in entry.S > > Please tell me what it means?It specifies a numeric subsection. It¹s still part of the text section, but it will presumably be placed after the normal part of the text section. It¹s being used here to place rarely used code out of line. It also means that straight-line flow of control skips to the next instance of .previous, without needing an extra JMP instruction. Tricky code. :-) -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Hello Keir, Thanks a lot for the information. I am having a tough time understanding the interrupt handling part in Xen as AT&T syntax is new for me. Could you please give me a brief overview of the flow of control when control is transferred to Xen after interrupt? Your guidance would be a lot of help for me. Thanking you Furquan On Wed, Dec 24, 2008 at 5:16 PM, Keir Fraser <keir.fraser@eu.citrix.com>wrote:> On 24/12/2008 11:29, "Furquan Shaikh" <furquan.m.shaikh@gmail.com> wrote: > > Is *.text 1 *the same as *.section*??? > > .text 1 occurs in entry.S > > Please tell me what it means? > > > It specifies a numeric subsection. It''s still part of the text section, but > it will presumably be placed after the normal part of the text section. It''s > being used here to place rarely used code out of line. It also means that > straight-line flow of control skips to the next instance of .previous, > without needing an extra JMP instruction. Tricky code. :-) > > -- Keir >_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
I doubt the AT&T syntax is the most significant hurdle. The entry stubs are hidden away in macros in include/asm-x86/x86_32/asm_defns.h, and instantiated at the top of arch/x86/i8259.c. They get poked into the IDT in the first for() loop in init_IRQ(). -- Keir On 24/12/2008 12:54, "Furquan Shaikh" <furquan.m.shaikh@gmail.com> wrote:> Hello Keir, > Thanks a lot for the information. > I am having a tough time understanding the interrupt handling part in Xen as > AT&T syntax is new for me. > Could you please give me a brief overview of the flow of control when control > is transferred to Xen after interrupt? > Your guidance would be a lot of help for me. > > Thanking you > > Furquan > > On Wed, Dec 24, 2008 at 5:16 PM, Keir Fraser <keir.fraser@eu.citrix.com> > wrote: >> On 24/12/2008 11:29, "Furquan Shaikh" <furquan.m.shaikh@gmail.com >> <http://furquan.m.shaikh@gmail.com> > wrote: >> >>> Is .text 1 the same as .section??? >>> >>> .text 1 occurs in entry.S >>> >>> Please tell me what it means? >> >> It specifies a numeric subsection. It''s still part of the text section, but >> it will presumably be placed after the normal part of the text section. It''s >> being used here to place rarely used code out of line. It also means that >> straight-line flow of control skips to the next instance of .previous, >> without needing an extra JMP instruction. Tricky code. :-) >> >> -- Keir > >_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel