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* powerpc/64s: Add EX_SIZE definition for paca exception save areasNicholas Piggin2017-06-201-0/+3
| | | | | | | | Rather than open-coding it 4 times. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Move __ASSEMBLY__ guards into head-64.h where they're really needed] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc/64: Tool to check head sections location sanityNicholas Piggin2017-05-301-2/+2
| | | | | | | | | | | | | | | | Use a tool to check that the location of "fixed sections" are where we expected them to be, which catches cases the linker script can't (stubs being added to start of .text section), and which ends up being neater. Sample output: ERROR: start_text address is c000000000008100, should be c000000000008000 ERROR: see comments in arch/powerpc/tools/head_check.sh Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Fold in fix from Nick for 4.6 era toolchains] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc/64: Handle linker stubs in low .text codeNicholas Piggin2017-05-301-0/+18
| | | | | | | | | | | | | | | | | | | | | | Very large kernels may require linker stubs for branches from HEAD text code. The linker may place these stubs before the HEAD text sections, which breaks the assumption that HEAD text is located at 0 (or the .text section being located at 0x7000/0x8000 on Book3S kernels). Provide an option to create a small section just before the .text section with an empty 256 - 4 bytes, and adjust the start of the .text section to match. The linker will tend to put stubs in that section and not break our relative-to-absolute offset assumptions. This causes a small waste of space on common kernels, but allows large kernels to build and boot. For now, it is an EXPERT config option, defaulting to =n, but a reference is provided for it in the build-time check for such breakage. This is good enough for allyesconfig and custom users / hackers. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc/kprobes: Blacklist common exception handlersNaveen N. Rao2017-04-231-0/+1
| | | | | | | | Blacklist all the exception common/OOL handlers as the kernel stack is not yet setup, which means we can't take a trap at this point. Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* Merge branch 'topic/ppc-kvm' into nextMichael Ellerman2017-02-141-1/+1
|\ | | | | | | Merge the topic branch we're sharing with the kvm-ppc tree.
| * KVM: PPC: Book3S: Move 64-bit KVM interrupt handler out from alt sectionNicholas Piggin2017-01-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A subsequent patch to make KVM handlers relocation-safe makes them unusable from within alt section "else" cases (due to the way fixed addresses are taken from within fixed section head code). Stop open-coding the KVM handlers, and add them both as normal. A more optimal fix may be to allow some level of alternate feature patching in the exception macros themselves, but for now this will do. The TRAMP_KVM handlers must be moved to the "virt" fixed section area (name is arbitrary) in order to be closer to .text and avoid the dreaded "relocation truncated to fit" error. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Acked-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* | powerpc/64s: Use (start, size) rather than (start, end) for exception handlersNicholas Piggin2017-02-071-76/+82
| | | | | | | | | | | | | | | | | | | | start,size has the benefit of being easier to search for (start,end usually gives you the preceeding vector from the one you want, as first result). Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* | powerpc/64s: Tidy up after exception handler reworkNicholas Piggin2017-02-071-80/+80
|/ | | | | | | | | Somewhere along the line, search/replace left some naming garbled, and untidy alignment (aka. mpe stuffed it up). Might as well fix them all up now while git blame history doesn't extend too far. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc/64s: Reduce exception alignmentNicholas Piggin2016-11-141-4/+4
| | | | | | | | | | | | | | | | | Exception handlers are aligned to 128 bytes (L1 cache) on 64s, which is overkill. It can reduce the icache footprint of any individual exception path. However taken as a whole, the expansion in icache footprint seems likely to be counter-productive and cause more total misses. Create IFETCH_ALIGN_SHIFT/BYTES, which should give optimal ifetch alignment with much more reasonable alignment. This saves 1792 bytes from head_64.o text with an allmodconfig build. Other subarchitectures should define appropriate IFETCH_ALIGN_SHIFT values if this becomes more widely used. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc: Use gas sections for arranging exception vectorsNicholas Piggin2016-10-041-16/+245
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use assembler sections of fixed size and location to arrange the 64-bit Book3S exception vector code (64-bit Book3E also uses it in head_64.S for 0x0..0x100). This allows better flexibility in arranging exception code and hiding unimportant details behind macros. Gas sections can be a bit painful to use this way, mainly because the assembler does not know where they will be finally linked. Taking absolute addresses requires a bit of trickery for example, but it can be hidden behind macros for the most part. Generated code is mostly the same except locations, offsets, alignments. The "+ 0x2" is only required for the trap number / kvm exit number, which gets loaded as a constant into a register. Previously, code also used + 0x2 for label names, but we changed to using "H" to distinguish HV case for that. Remove the last vestiges of that. __after_prom_start is taking absolute address of a label in another fixed section. Newer toolchains seemed to compile this okay, but older ones do not. FIXED_SYMBOL_ABS_ADDR is more foolproof, it just takes an additional line to define. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc/64s: Consolidate exception handler alignmentNicholas Piggin2016-10-041-0/+1
| | | | | | | | | | | Move exception handler alignment directives into the head-64.h macros, beause they will no longer work in-place after the next patch. This slightly changes functions that have alignments applied and therefore code generation, which is why it was not done initially (see earlier patch). Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc/64s: Add new exception vector macrosMichael Ellerman2016-10-041-0/+163
Create arch/powerpc/include/asm/head-64.h with macros that specify an exception vector (name, type, location), which will be used to label and lay out exceptions into the object file. Naming is moved out of exception-64s.h, which is used to specify the implementation of exception handlers. objdump of generated code in exception vectors is unchanged except for names. Alignment directives scattered around are annoying, but done this way so that disassembly can verify identical instruction generation before and after patch. These get cleaned up in future patch. We change the way KVMTEST works, explicitly passing EXC_HV or EXC_STD rather than overloading the trap number. This removes the need to have SOFTEN values for the overloaded trap numbers, eg. 0x502. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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