Re: [Xen-devel] [PATCH v3 11/25] x86emul: place test blobs in executable section
>>> On 05.02.18 at 14:11, wrote: > On 02/02/18 15:27, Jan Beulich wrote: > On 02.02.18 at 14:03, wrote: >>> On 07/12/17 14:06, Jan Beulich wrote: This allows the section contents to be disassembled without going through any extra hoops, simplifying the analysis of problems in test and/or emulation code. The blobs being emitted as (r/o) data means we need to accept an assembler warning here (about the differing section attributes). Signed-off-by: Jan Beulich >>> What about just giving up their constness? This is a test program after >>> all. >> Then the conflict would be in two attributes (writable and >> executable) rather than just one. The issue is that we emit them >> as data, but want them to be in an executable section. If anything >> we'd have to re-do how they're emitted (e.g. by using asm()), but >> that seems overkill to me. > > Ok. Instead, how about having a second .test.const? wouldn't that > resolve the warnings, but still leave the instructions in an executable > section? Well, with just the above I can't see how you'd expect that to work: Whatever we name the section that the const arrays are emitted to, it'll have a section directive with just "a" as attributes. Somehow we'd need to add the missing "x", and that would require a second section directive. Which would trigger the very warning again. Now we could of course have a second source file, but besides this imo going too far, it would also have the downside that in the .o we'd then again have a non-executable section containing code (and which most tools won't easily disassemble). > Either way, this is just a developer utility, so Acked-by: Andrew Cooper > Thanks, Jan ___ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
Re: [Xen-devel] [PATCH v3 11/25] x86emul: place test blobs in executable section
On 02/02/18 15:27, Jan Beulich wrote: On 02.02.18 at 14:03, wrote: >> On 07/12/17 14:06, Jan Beulich wrote: >>> This allows the section contents to be disassembled without going >>> through any extra hoops, simplifying the analysis of problems in test >>> and/or emulation code. >>> >>> The blobs being emitted as (r/o) data means we need to accept an >>> assembler warning here (about the differing section attributes). >>> >>> Signed-off-by: Jan Beulich >> What about just giving up their constness? This is a test program after >> all. > Then the conflict would be in two attributes (writable and > executable) rather than just one. The issue is that we emit them > as data, but want them to be in an executable section. If anything > we'd have to re-do how they're emitted (e.g. by using asm()), but > that seems overkill to me. Ok. Instead, how about having a second .test.const? wouldn't that resolve the warnings, but still leave the instructions in an executable section? Either way, this is just a developer utility, so Acked-by: Andrew Cooper ___ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
Re: [Xen-devel] [PATCH v3 11/25] x86emul: place test blobs in executable section
>>> On 02.02.18 at 14:03, wrote: > On 07/12/17 14:06, Jan Beulich wrote: >> This allows the section contents to be disassembled without going >> through any extra hoops, simplifying the analysis of problems in test >> and/or emulation code. >> >> The blobs being emitted as (r/o) data means we need to accept an >> assembler warning here (about the differing section attributes). >> >> Signed-off-by: Jan Beulich > > What about just giving up their constness? This is a test program after > all. Then the conflict would be in two attributes (writable and executable) rather than just one. The issue is that we emit them as data, but want them to be in an executable section. If anything we'd have to re-do how they're emitted (e.g. by using asm()), but that seems overkill to me. Jan ___ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
Re: [Xen-devel] [PATCH v3 11/25] x86emul: place test blobs in executable section
On 07/12/17 14:06, Jan Beulich wrote: > This allows the section contents to be disassembled without going > through any extra hoops, simplifying the analysis of problems in test > and/or emulation code. > > The blobs being emitted as (r/o) data means we need to accept an > assembler warning here (about the differing section attributes). > > Signed-off-by: Jan Beulich What about just giving up their constness? This is a test program after all. ~Andrew ___ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
