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path: root/arch/powerpc/lib/feature-fixups.c
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* powerpc: Use WARN_ON(1) instead of __WARN()Michael Ellerman2008-07-221-1/+1
| | | | | | | __WARN() is not defined for all configs, use WARN_ON(1) instead. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc: Fixup lwsync at runtimeKumar Gala2008-07-031-0/+36
| | | | | | | | | | | | | | | | | To allow for a single kernel image on e500 v1/v2/mc we need to fixup lwsync at runtime. On e500v1/v2 lwsync causes an illop so we need to patch up the code. We default to 'sync' since that is always safe and if the cpu is capable we will replace 'sync' with 'lwsync'. We introduce CPU_FTR_LWSYNC as a way to determine at runtime if this is needed. This flag could be moved elsewhere since we dont really use it for the normal CPU_FTR purpose. Finally we only store the relative offset in the fixup section to keep it as small as possible rather than using a full fixup_entry. Signed-off-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
* powerpc: Add self-tests of the feature fixup codeMichael Ellerman2008-07-011-0/+206
| | | | | | | | | | | | | This commit adds tests of the feature fixup code, they are run during boot if CONFIG_FTR_FIXUP_SELFTEST=y. Some of the tests manually invoke the patching routines to check their behaviour, and others use the macros and so are patched during the normal patching done during boot. Because we have two sets of macros with different names, we use a macro to generate the test of the macros, very niiiice. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
* powerpc: Add logic to patch alternative feature sectionsMichael Ellerman2008-07-011-14/+65
| | | | | | | | | | This commit adds the logic to patch alternative sections. This is fairly straightforward, except for branches. Relative branches that jump from inside the else section to outside of it need to be translated as they're moved, otherwise they will jump to the wrong location. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
* powerpc: Introduce infrastructure for feature sections with alternativesMichael Ellerman2008-07-011-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current feature section logic only supports nop'ing out code, this means if you want to choose at runtime between instruction sequences, one or both cases will have to execute the nop'ed out contents of the other section, eg: BEGIN_FTR_SECTION or 1,1,1 END_FTR_SECTION_IFSET(FOO) BEGIN_FTR_SECTION or 2,2,2 END_FTR_SECTION_IFCLR(FOO) and the resulting code will be either, or 1,1,1 nop or, nop or 2,2,2 For small code segments this is fine, but for larger code blocks and in performance criticial code segments, it would be nice to avoid the nops. This commit starts to implement logic to allow the following: BEGIN_FTR_SECTION or 1,1,1 FTR_SECTION_ELSE or 2,2,2 ALT_FTR_SECTION_END_IFSET(FOO) and the resulting code will be: or 1,1,1 or, or 2,2,2 We achieve this by extending the existing FTR macros. The current feature section semantic just becomes a special case, ie. if the else case is empty we nop out the default case. The key limitation is that the size of the else case must be less than or equal to the size of the default case. If the else case is smaller the remainder of the section is nop'ed. We let the linker put the else case code in with the rest of the text, so that relative branches from the else case are more likley to link, this has the disadvantage that we can't free the unused else cases. This commit introduces the required macro and linker script changes, but does not enable the patching of the alternative sections. We also need to update two hand-made section entries in reg.h and timex.h Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
* powerpc: Split out do_feature_fixups() from cputable.cMichael Ellerman2008-07-011-0/+56
The logic to patch CPU feature sections lives in cputable.c, but these days it's used for CPU features as well as firmware features. Move it into it's own file for neatness and as preparation for some additions. While we're moving the code, we pull the loop body logic into a separate routine, and remove a comment which doesn't apply anymore. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Acked-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>