wireguard-linux/arch/arc/include/asm/entry-arcv2.h, branch jd/unified-crypt-queue

ARC: add support for DSP-enabled userspace applications

2020-03-16T17:30:49Z

To be able to run DSP-enabled userspace applications we need to save and restore following DSP-related registers: At IRQ/exception entry/exit: * DSP_CTRL (save it and reset to value suitable for kernel) * ACC0_LO, ACC0_HI (we already save them as r58, r59 pair) At context switch: * ACC0_GLO, ACC0_GHI * DSP_BFLY0, DSP_FFT_CTRL Reviewed-by: Vineet Gupta Signed-off-by: Eugeniy Paltsev Signed-off-by: Vineet Gupta

ARC: handle DSP presence in HW

2020-03-16T17:23:44Z

When DSP extensions are present, some of the regular integer instructions such as DIV, MACD etc are executed in the DSP unit with semantics alterable by flags in DSP_CTRL aux register. This register is writable by userspace and thus can potentially affect corresponding instructions in kernel code, intentionally or otherwise. So safegaurd kernel by effectively disabling DSP_CTRL upon bootup and every entry to kernel. Do note that for this config we simply zero out the DSP_CTRL reg assuming userspace doesn't really care about DSP. The next patch caters to the DSP aware userspace where this reg is saved/restored upon kernel entry/exit. Reviewed-by: Vineet Gupta Signed-off-by: Eugeniy Paltsev Signed-off-by: Vineet Gupta

ARC: pt_regs: remove hardcoded registers offset

2019-12-28T21:05:08Z

Replace hardcoded registers offset numbers by calculated via offsetof. Signed-off-by: Eugeniy Paltsev Signed-off-by: Vineet Gupta

ARCv2: entry: early return from exception need not clear U & DE bits

2019-08-05T07:01:29Z

Exception handlers call FAKE_RET_FROM_EXCPN to - clear AE bit: drop down from exception active to pure kernel mode allowing further excptions - set IE bit: re-enable interrupts It additionally also clears U bit (user mode) and DE bit (delay slot execution) which is redundant as hardware does that already on any taken exception. Morevoer the current software clearing is bogus anyways as the KFLAG instruction being used for purpose can't possibly write those bits anyways. So don't pretend to clear them. Signed-off-by: Alexey Brodkin Signed-off-by: Vineet Gupta [vgupta: rewrote changelog]

ARC: entry: EV_Trap expects r10 (vs. r9) to have exception cause

2019-07-08T08:24:44Z

avoids 1 MOV instruction in light of double load/store code Signed-off-by: Vineet Gupta

ARCv2: entry: rewrite to enable use of double load/stores LDD/STD

2019-07-01T18:02:22Z

- the motivation was to be remove blatent copy-paste due to hasty support of CONFIG_ARC_IRQ_NO_AUTOSAVE support - but with refactoring we could use LDD/STD to greatly optimize the code Signed-off-by: Vineet Gupta

ARCv2: entry: avoid a branch

2019-07-01T18:02:22Z

Signed-off-by: Vineet Gupta

ARCv2: entry: push out the Z flag unclobber from common EXCEPTION_PROLOGUE

2019-07-01T18:02:22Z

Upon a taken interrupt/exception from User mode, HS hardware auto sets Z flag. This helps shave a few instructions from EXCEPTION_PROLOGUE by eliding re-reading ERSTATUS and some bit fiddling. However TLB Miss Exception handler can clobber the CPU flags and still end up in EXCEPTION_PROLOGUE in the slow path handling TLB handling case: EV_TLBMissD do_slow_path_pf EV_TLBProtV (aliased to call_do_page_fault) EXCEPTION_PROLOGUE As a result, EXCEPTION_PROLOGUE need to "unclobber" the Z flag which this patch changes. It is now pushed out to TLB Miss Exception handler. The reasons beings: - The flag restoration is only needed for slowpath TLB Miss Exception handling, but currently being in EXCEPTION_PROLOGUE penalizes all exceptions such as ProtV and syscall Trap, where Z flag is already as expected. - Pushing unclobber out to where it was clobbered is much cleaner and also serves to document the fact. - Makes EXCEPTION_PROLGUE similar to INTERRUPT_PROLOGUE so easier to refactor the common parts which is what this series aims to do Signed-off-by: Vineet Gupta

ARCv2: entry: comments about hardware auto-save on taken interrupts

2019-07-01T18:02:22Z

Signed-off-by: Vineet Gupta

ARCv2: support manual regfile save on interrupts

2019-02-21T19:03:18Z

There's a hardware bug which affects the HSDK platform, triggered by micro-ops for auto-saving regfile on taken interrupt. The workaround is to inhibit autosave. Signed-off-by: Vineet Gupta