Bug#696041: ia64 (Itanium) Mozilla JS engine needs pointers have their high 17 bits cleared

[Stephan Schreiber]

Package: iceweasel
Version: 10.0.11esr-1
Severity: serious
Tags: patch


Machine: Dell PowerEdge 3250
Processor: 2x Itanium Madison 1.5GHz 6M
Memory: 16G



The Mozilla JS engine needs pointers have their high 17 bits cleared  
because it would break a variant data type which the engine uses.
This bug is actually the same as we had for the Mozilla Spider Mokey  
JS engine library - libmozsjs185-1.0, bug#659186.
Mapping of pages should be patched. Furthermore, the memory for  
'static strings' must not be global static variables (text segment).

The code of Iceweasel is somewhat newer than the one of libmozjs185.  
It has slightly changed.

At first I had a patch which was very similar to the one of  
bug#659186. But disabling the static strings optimization of the js  
engine was a serious performance penalty that a lot of tests of the  
test suite timed out and failed. (Bug#692053 wasn't the reason for  
that.)

So I decided to keep the static strings optimization; the patch  
allocates mapped memory and puts the static strings into it upon  
startup on ia64. So any address of an item in the static strings array  
always have their high 17 bits cleared.

The patches don't change anything on archs other than ia64.

- Please apply 01-fix-map-pages-on-ia64.patch first.
- At next 02-static-str-in-mmem-on-ia64.patch.

You also need the patch of bug#692053.

Stephan

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