summaryrefslogtreecommitdiff
path: root/target-arm/op_helper.c
AgeCommit message (Collapse)AuthorFilesLines
2015-07-06target-arm: Split DISAS_YIELD from DISAS_WFEPeter Maydell1-3/+15
Currently we use DISAS_WFE for both WFE and YIELD instructions. This is functionally correct because at the moment both of them are implemented as "yield this CPU back to the top level loop so another CPU has a chance to run". However it's rather confusing that YIELD ends up calling HELPER(wfe), and if we ever want to implement real behaviour for WFE and SEV it's likely to trip us up. Split out the yield codepath to use DISAS_YIELD and a new HELPER(yield) function, and have HELPER(wfe) call HELPER(yield). Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1435672316-3311-2-git-send-email-peter.maydell@linaro.org Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
2015-06-15arm: Refactor get_phys_addr FSR return mechanismPeter Crosthwaite1-5/+6
Currently, the return code for get_phys_addr is overloaded for both success/fail and FSR value return. This doesn't handle the case where there is an error with a 0 FSR. This case exists in PMSAv7. So rework get_phys_addr and friends to return a success/failure boolean return code and populate the FSR via a caller provided uint32_t pointer. Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com> Message-id: a209e3d8ae00cda55260c970891f520210e26bad.1434066412.git.peter.crosthwaite@xilinx.com Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2015-06-02target-arm: Correct check for non-EL3Edgar E. Iglesias1-1/+1
This fixes a compile warning from clang 3.5 (the assertion could never fire). Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Message-id: 1432881807-18164-2-git-send-email-edgar.iglesias@gmail.com Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: John Snow <jsnow@redhat.com> [PMM: added note in commit message that this is fixing a build warning] Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2015-05-29target-arm: Add WFx instruction trap supportGreg Bellows1-1/+59
Add support for trapping WFI and WFE instructions to the proper EL when SCTLR/SCR/HCR settings apply. Signed-off-by: Greg Bellows <greg.bellows@linaro.org> [PMM: removed unnecessary tweaking of syn_wfx() prototype; use raise_exception(); don't trap on WFE (and add comment explaining why not); remove unnecessary ARM_FEATURE checks; trap to EL3, not EL1, if in S-EL0 and SCTLR check fires] Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
2015-05-29target-arm: Don't halt on WFI unless we don't have any workPeter Maydell1-0/+7
Just NOP the WFI instruction if we have work to do. This doesn't make much difference currently (though it does avoid jumping out to the top level loop and immediately restarting), but the distinction between "halt" and "don't halt" will become more important when the decision to halt requires us to trap to a higher exception level instead. Suggested-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
2015-05-29target-arm: Allow cp access functions to indicate traps to EL2 or EL3Peter Maydell1-1/+14
Some coprocessor access functions will need to indicate that the instruction should trap to EL2 or EL3 rather than the default target exception level; add corresponding CPAccessResult enum entries and handling code. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
2015-05-29target-arm: Make raise_exception() take syndrome and target ELPeter Maydell1-40/+28
Rather than making every caller of raise_exception set the syndrome and target EL by hand, make these arguments to raise_exception() and have that do the job. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
2015-05-29target-arm: Set exception target EL in tlb_fillPeter Maydell1-0/+1
Set the exception target EL for MMU faults in tlb_fill. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
2015-05-29target-arm: Move setting of exception info into tlb_fillPeter Maydell1-2/+25
Move the code which sets exception information out of arm_cpu_handle_mmu_fault and into tlb_fill. tlb_fill is the only caller which wants to raise_exception() so it makes more sense for it to handle the whole of the exception setup. As part of this cleanup, move the user-mode-only implementation function for the handle_mmu_fault CPU method into cpu.c so we don't need to make it globally visible, and rename the softmmu-only utility function arm_cpu_handle_mmu_fault to arm_tlb_fill so it's clear that it's not the same thing. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
2015-05-29target-arm: Set correct syndrome for faults on MSR DAIF*, immPeter Maydell1-0/+3
If the SCTLR.UMA trap bit is set then attempts by EL0 to update the PSTATE DAIF bits via "MSR DAIFSet, imm" and "MSR DAIFClr, imm" instructions will raise an exception. We were failing to set the syndrome information for this exception, which meant that it would be reported as a repeat of whatever the previous exception was. Set the correct syndrome information. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
2015-05-29target-arm: Extend helpers to route exceptionsGreg Bellows1-0/+21
Updated the various helper routines to set the target EL as needed using a dedicated function. Signed-off-by: Greg Bellows <greg.bellows@linaro.org> Acked-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Message-id: 1429722561-12651-3-git-send-email-greg.bellows@linaro.org [PMM: Also set target_el in fault cases in access_check_cp_reg()] Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2015-05-29target-arm: Add exception target el infrastructureGreg Bellows1-1/+2
Add a CPU state exception target EL field that will be used for communicating the EL to which an exception should be routed. Add a disassembly context field for tracking the EL3 architecture needed for determining the target exception EL. Add a target EL argument to the generic exception helper for callers to specify the EL to which the exception should be routed. Extended the helper to set the newly added CPU state exception target el. Added a function for setting the target exception EL and updated calls to helpers to call it. Signed-off-by: Greg Bellows <greg.bellows@linaro.org> Acked-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Message-id: 1429722561-12651-2-git-send-email-greg.bellows@linaro.org Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2015-04-26target-arm: Check watchpoints against CPU security statePeter Maydell1-2/+4
Fix a TODO in bp_wp_matches() now that we have a function for testing whether the CPU is currently in Secure mode or not. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
2015-04-26target-arm: Use attribute info to handle user-only watchpointsPeter Maydell1-11/+12
Now that we have memory access attribute information in the watchpoint checking code, we can correctly implement handling of watchpoints which should match only on userspace accesses, where LDRT/STRT/LDT/STT from EL1 are treated as userspace accesses. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
2015-02-13target-arm: Add 32/64-bit register syncGreg Bellows1-4/+2
Add AArch32 to AArch64 register sychronization functions. Replace manual register synchronization with new functions in aarch64_cpu_do_interrupt() and HELPER(exception_return)(). Signed-off-by: Greg Bellows <greg.bellows@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1423736974-14254-4-git-send-email-greg.bellows@linaro.org Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-12-11target-arm: make c13 cp regs banked (FCSEIDR, ...)Fabian Aggeler1-1/+1
When EL3 is running in AArch32 (or ARMv7 with Security Extensions) FCSEIDR, CONTEXTIDR, TPIDRURW, TPIDRURO and TPIDRPRW have a secure and a non-secure instance. Signed-off-by: Fabian Aggeler <aggelerf@ethz.ch> Signed-off-by: Greg Bellows <greg.bellows@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1416242878-876-25-git-send-email-greg.bellows@linaro.org Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-12-11target-arm: add SCTLR_EL3 and make SCTLR bankedFabian Aggeler1-1/+1
Implements SCTLR_EL3 and uses secure/non-secure instance when needed. Signed-off-by: Fabian Aggeler <aggelerf@ethz.ch> Signed-off-by: Greg Bellows <greg.bellows@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1416242878-876-14-git-send-email-greg.bellows@linaro.org Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-10-24target-arm: A32: Emulate the SMC instructionFabian Aggeler1-2/+1
Implements SMC instruction in AArch32 using the A32 syndrome. When executing SMC instruction from monitor CPU mode SCR.NS bit is reset. Signed-off-by: Sergey Fedorov <s.fedorov@samsung.com> Signed-off-by: Fabian Aggeler <aggelerf@ethz.ch> Signed-off-by: Greg Bellows <greg.bellows@linaro.org> Message-id: 1413910544-20150-7-git-send-email-greg.bellows@linaro.org Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-10-24target-arm: rename arm_current_pl to arm_current_elGreg Bellows1-8/+8
Renamed the arm_current_pl CPU function to more accurately represent that it returns the ARMv8 EL rather than ARMv7 PL. Signed-off-by: Greg Bellows <greg.bellows@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1413910544-20150-5-git-send-email-greg.bellows@linaro.org [PMM: fixed a minor merge resolution error in a couple of hunks] Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-10-24target-arm: add emulation of PSCI calls for system emulationRob Herring1-0/+16
Add support for handling PSCI calls in system emulation. Both version 0.1 and 0.2 of the PSCI spec are supported. Platforms can enable support by setting the "psci-conduit" QOM property on the cpus to SMC or HVC emulation and having a PSCI binding in their dtb. Signed-off-by: Rob Herring <rob.herring@linaro.org> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1412865028-17725-7-git-send-email-peter.maydell@linaro.org [PMM: made system reset/off PSCI functions power down the CPU so we obey the PSCI API requirement never to return from them; rearranged how the code is plumbed into the exception system, so that we split "is this a valid call?" from "do the call"] Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-10-24target-arm: Handle SMC/HVC undef-if-no-ELx in pre_* helpersPeter Maydell1-7/+10
SMC must UNDEF if EL3 is not implemented; similarly HVC UNDEFs if EL2 is not implemented. Move the handling of this from translate-a64.c into the pre_smc and pre_hvc helper functions. This is necessary because use of these instructions for PSCI takes precedence over this UNDEF case, and we can't tell if this is a PSCI call until runtime. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1412865028-17725-5-git-send-email-peter.maydell@linaro.org
2014-09-29target-arm: A64: Emulate the SMC insnEdgar E. Iglesias1-0/+26
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Message-id: 1411718914-6608-10-git-send-email-edgar.iglesias@gmail.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-09-29target-arm: A64: Emulate the HVC insnEdgar E. Iglesias1-0/+31
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Message-id: 1411718914-6608-8-git-send-email-edgar.iglesias@gmail.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-09-29target-arm: Don't handle c15_cpar changes via tb_flush()Peter Maydell1-0/+11
At the moment we try to handle c15_cpar with the strategy of: * emit generated code which makes assumptions about its value * when the register value changes call tb_flush() to throw away the now-invalid generated code This works because XScale CPUs are always uniprocessor, but it's confusing because it suggests that the same approach can be taken for other registers. It also means we do a tb_flush() on CPU reset, which makes multithreaded linux-user binaries even more likely to fail than would otherwise be the case. Replace it with a combination of TB flags for the access checks done on cp0/cp1 for the XScale and iwMMXt instructions, plus a runtime check for cp2..cp13 coprocessor accesses. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1411056959-23070-1-git-send-email-peter.maydell@linaro.org
2014-09-29target-arm: Implement handling of breakpoint firingPeter Maydell1-15/+60
Implement handling of breakpoint event firing to correctly inject the debug exception into the guest. Since the breakpoint and watchpoint control register format is very similar we adjust wp_matches() to also handle breakpoints as well rather than using a separate function. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1410523465-13400-3-git-send-email-peter.maydell@linaro.org
2014-09-12target-arm: Implement handling of fired watchpointsPeter Maydell1-0/+188
Implement the ARM debug exception handler for dealing with fired watchpoints. Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-08-19target-arm: Implement ARMv8 single-step handling for A64 codePeter Maydell1-0/+5
Implement ARMv8 software single-step handling for A64 code: correctly update the single-step state machine and generate debug exceptions when stepping A64 code. This patch has no behavioural change since MDSCR_EL1.SS can't be set by the guest yet. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
2014-08-19target-arm: Set PSTATE.SS correctly on exception return from AArch64Peter Maydell1-0/+20
Set the PSTATE.SS bit correctly on exception returns from AArch64, as required by the debug single-step functionality. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
2014-08-19target-arm: Don't allow AArch32 to access RES0 CPSR bitsPeter Maydell1-1/+1
The CPSR has a new-in-v8 execution state bit (IL), and also some state which has effects in AArch32 but appears only in the SPSR format (SS) but is RES0 in the CPSR. Add the IL bit to CPSR_EXEC, and enforce that guest direct reads and writes to CPSR can't read or write the RES0 bits, so the guest can't get at the SS bit which we store in uncached_cpsr. This includes not permitting exception returns to copy reserved bits from an SPSR into CPSR. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
2014-08-04target-arm: A64: Respect SPSEL in ERET SP restoreEdgar E. Iglesias1-1/+1
Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Reviewed-by: Greg Bellows <greg.bellows@linaro.org> Message-id: 1402994746-8328-3-git-send-email-edgar.iglesias@gmail.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-08-04target-arm: A64: Break out aarch64_save/restore_spEdgar E. Iglesias1-5/+1
Break out code to save/restore AArch64 SP into functions. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Reviewed-by: Greg Bellows <greg.bellows@linaro.org> Message-id: 1402994746-8328-2-git-send-email-edgar.iglesias@gmail.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-06-05softmmu: introduce cpu_ldst.hPaolo Bonzini1-2/+1
This will collect all load and store helpers soon. For now it is just a replacement for softmmu_exec.h, which this patch stops including directly, but we also include it where this will be necessary in order to simplify the next patch. Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-06-05softmmu: commonize helper definitionsPaolo Bonzini1-14/+0
They do not need to be in op_helper.c. Because cputlb.c now includes softmmu_template.h twice for each size, io_readX must be elided the second time through. Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-28tcg: Invert the inclusion of helper.hRichard Henderson1-1/+1
Rather than include helper.h with N values of GEN_HELPER, include a secondary file that sets up the macros to include helper.h. This minimizes the files that must be rebuilt when changing the macros for file N. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <rth@twiddle.net>
2014-05-27target-arm: A64: Generalize ERET to various ELsEdgar E. Iglesias1-5/+6
Adds support for ERET to and from AArch64 EL2 and 3. Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Message-id: 1400980132-25949-20-git-send-email-edgar.iglesias@gmail.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-05-27target-arm: A64: Forbid ERET to higher or unimplemented ELsEdgar E. Iglesias1-2/+6
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Message-id: 1400980132-25949-18-git-send-email-edgar.iglesias@gmail.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-05-27target-arm: A64: Introduce aarch64_banked_spsr_index()Edgar E. Iglesias1-1/+2
Add aarch64_banked_spsr_index(), used to map an Exception Level to an index in the banked_spsr array. Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Message-id: 1400980132-25949-13-git-send-email-edgar.iglesias@gmail.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-05-27target-arm: Make elr_el1 an arrayEdgar E. Iglesias1-3/+3
No functional change. Prepares for future additions of the EL2 and 3 versions of this reg. Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Message-id: 1400980132-25949-7-git-send-email-edgar.iglesias@gmail.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-05-01target-arm: Correct a comment refering to EL0Edgar E. Iglesias1-1/+1
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Message-id: 1398926097-28097-5-git-send-email-edgar.iglesias@gmail.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-04-17target-arm: Implement AArch64 EL1 exception handlingRob Herring1-0/+60
Implement exception handling for AArch64 EL1. Exceptions from AArch64 or AArch32 EL0 are supported. Signed-off-by: Rob Herring <rob.herring@linaro.org> [PMM: fixed minor style nits; updated to match changes in previous patches; added some of the simpler cases of illegal-exception-return support] Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
2014-04-17target-arm: Implement SP_EL0, SP_EL1Peter Maydell1-1/+1
Implement handling for the AArch64 SP_EL0 system register. This holds the EL0 stack pointer, and is only accessible when it's not being used as the stack pointer, ie when we're in EL1 and EL1 is using its own stack pointer. We also provide a definition of the SP_EL1 register; this isn't guest visible as a system register for an implementation like QEMU which doesn't provide EL2 or EL3; however it is useful for ensuring the underlying state is migrated. We need to update the state fields in the CPU state whenever we switch stack pointers; this happens when we take an exception and also when SPSEL is used to change the bit in PSTATE which indicates which stack pointer EL1 should use. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
2014-04-17target-arm: Add support for generating exceptions with syndrome informationPeter Maydell1-1/+20
Add new helpers exception_with_syndrome (for generating an exception with syndrome information) and exception_uncategorized (for generating an exception with "Unknown or Uncategorized Reason", which have a syndrome register value of zero), and use them to generate the correct syndrome information for exceptions which are raised directly from generated code. This patch includes moving the A32/T32 gen_exception_insn functions further up in the source file; they will be needed for "VFP/Neon disabled" exception generation later. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
2014-04-17target-arm: Provide correct syndrome information for cpreg access trapsPeter Maydell1-4/+4
For exceptions taken to AArch64, if a coprocessor/system register access fails due to a trap or enable bit then the syndrome information must include details of the failing instruction (crn/crm/opc1/opc2 fields, etc). Make the decoder construct the syndrome information at translate time so it can be passed at runtime to the access-check helper function and used as required. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
2014-04-17target-arm: Split out private-to-target functions into internals.hPeter Maydell1-0/+1
Currently cpu.h defines a mixture of functions and types needed by the rest of QEMU and those needed only by files within target-arm/. Split the latter out into a new header so they aren't needlessly exposed further than required. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
2014-03-13translate-all: Change cpu_restore_state() argument to CPUStateAndreas Färber1-1/+1
This lets us drop some local variables in tlb_fill() functions. Signed-off-by: Andreas Färber <afaerber@suse.de>
2014-03-13cpu-exec: Change cpu_loop_exit() argument to CPUStateAndreas Färber1-4/+4
Signed-off-by: Andreas Färber <afaerber@suse.de>
2014-03-13exec: Change tlb_fill() argument to CPUStateAndreas Färber1-5/+7
Signed-off-by: Andreas Färber <afaerber@suse.de>
2014-03-13cpu: Move exception_index field from CPU_COMMON to CPUStateAndreas Färber1-6/+14
Signed-off-by: Andreas Färber <afaerber@suse.de>
2014-03-13cpu: Turn cpu_handle_mmu_fault() into a CPUClass hookAndreas Färber1-1/+2
Note that while such functions may exist both for *-user and softmmu, only *-user uses the CPUState hook, while softmmu reuses the prototype for calling it directly. Signed-off-by: Andreas Färber <afaerber@suse.de>
2014-03-10target-arm: Implement WFE as a yield operationPeter Maydell1-0/+9
Implement WFE to yield our timeslice to the next CPU. This avoids slowdowns in multicore configurations caused by one core busy-waiting on a spinlock which can't possibly be unlocked until the other core has an opportunity to run. This speeds up my test case A15 dual-core boot by a factor of three (though it is still four or five times slower than a single-core boot). Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1393339545-22111-1-git-send-email-peter.maydell@linaro.org Reviewed-by: Richard Henderson <rth@twiddle.net> Tested-by: Rob Herring <rob.herring@linaro.org>
generated by cgit v1.2.1 (git 2.18.0) at 2024-07-02 04:00:44 +0000