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8a649045e7
The copy paste facility introduced in POWER9 provides an optimised mechanism for a userspace application to copy a cacheline. This is provided by a pair of instructions, copy and paste, while a third, cp_abort (copy paste abort), provides a clean up of the state in case of a failure. The copy instruction will read a 128 byte cacheline and store it in an internal buffer. The subsequent paste instruction will store this internal buffer to memory and set a CR field if the paste succeeds. Since the state of the copy paste buffer is internal (and not architecturally visible), in the unlikely event of a context switch, the state cannot be stored and the paste should therefore fail. The cp_abort instruction exists to fail and clean up any such interrupted copy paste sequence and is to be called by the kernel as part of the context switch. Doing so prevents data from a preceding copy in one process leaking into the paste of another. This code enables use of the cp_abort instruction if a supported processor is detected. NOTE: this is for userspace only, not in kernel, and does not deal with KVM guests. Patch created with much assistance from Michael Neuling <mikey@neuling.org> Signed-off-by: Chris Smart <chris@distroguy.com> Reviewed-by: Cyril Bur <cyrilbur@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> |
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| kvm | ||
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| math-emu | ||
| mm | ||
| net | ||
| oprofile | ||
| perf | ||
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| sysdev | ||
| xmon | ||
| Kconfig | ||
| Kconfig.debug | ||
| Makefile | ||
| relocs_check.sh | ||