- 01 Apr, 2020 40 commits
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Christophe Leroy authored
Move ADV_DEBUG_REGS functions out of ptrace.c, into ptrace-adv.c and ptrace-noadv.c Signed-off-by:
Christophe Leroy <christophe.leroy@c-s.fr> [mpe: Squash in fixup patch from Christophe] Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/e2bd7d275bd5933d848aad4fee3ca652a14d039b.1582848567.git.christophe.leroy@c-s.fr
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Christophe Leroy authored
Create a dedicated ptrace-view.c file. Signed-off-by:
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Christophe Leroy authored
Move TRANSACTIONAL_MEM functions out of ptrace.c, into ptrace-tm.c Signed-off-by:
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Christophe Leroy authored
Move CONFIG_SPE functions out of ptrace.c, into ptrace-spe.c Signed-off-by:
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Christophe Leroy authored
Move CONFIG_ALTIVEC functions out of ptrace.c, into ptrace-altivec.c Signed-off-by:
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Christophe Leroy authored
Move CONFIG_VSX functions out of ptrace.c, into ptrace-vsx.c and ptrace-novsx.c Signed-off-by:
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Christophe Leroy authored
PARAMETER_SAVE_AREA_OFFSET is not used, drop it. Signed-off-by:
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Christophe Leroy authored
Drop a bunch of #ifdefs CONFIG_PPC64 that are not vital. Signed-off-by:
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Christophe Leroy authored
Remove unused header includes in ptrace.c and ptrace32.c Signed-off-by:
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Christophe Leroy authored
In order to allow splitting of ptrace depending on the different CONFIG_ options, create a subdirectory dedicated to ptrace and move ptrace.c and ptrace32.c into it. Signed-off-by:
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Nicholas Piggin authored
This reconciles interrupts in the system call case like all other interrupts. This allows system_call_common to be shared with the scv system call implementation in a subsequent patch. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
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Nicholas Piggin authored
Regular interrupt return restores NVGPRS whereas lite returns do not. This is clumsy: most interrupts can return without restoring NVGPRS in most of the time, but there are special cases that require it (when registers have been modified by the kernel). So change interrupt return to not restore NVGPRS, and have interrupt handlers restore them explicitly in the cases that requires it. Signed-off-by:
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Nicholas Piggin authored
Implement the bulk of interrupt return logic in C. The asm return code must handle a few cases: restoring full GPRs, and emulating stack store. The stack store emulation is significantly simplfied, rather than creating a new return frame and switching to that before performing the store, it uses the PACA to keep a scratch register around to perform the store. The asm return code is moved into 64e for now. The new logic has made allowance for 64e, but I don't have a full environment that works well to test it, and even booting in emulated qemu is not great for stress testing. 64e shouldn't be too far off working with this, given a bit more testing and auditing of the logic. This is slightly faster on a POWER9 (page fault speed increases about 1.1%), probably due to reduced mtmsrd. mpe: Includes fixes from Nick for _TIF_EMULATE_STACK_STORE handling (including the fast_interrupt_return path), to remove trace_hardirqs_on(), and fixes the interrupt-return part of the MSR_VSX restore bug caught by tm-unavailable selftest. mpe: Incorporate fix from Nick: The return-to-kernel path has to replay any soft-pending interrupts if it is returning to a context that had interrupts soft-enabled. It has to do this carefully and avoid plain enabling interrupts if this is an irq context, which can cause multiple nesting of interrupts on the stack, and other unexpected issues. The code which avoided this case got the soft-mask state wrong, and marked interrupts as enabled before going around again to retry. This seems to be mostly harmless except when PREEMPT=y, this calls preempt_schedule_irq with irqs apparently enabled and runs into a BUG in kernel/sched/core.c Signed-off-by:
Michal Suchanek <msuchanek@suse.de> Signed-off-by:
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Nicholas Piggin authored
When local_irq_enable() finds a pending soft-masked interrupt, it "replays" it by setting up registers like the initial interrupt entry, then calls into the low level handler to set up an interrupt stack frame and process the interrupt. This is not necessary, and uses more stack than needed. The high level interrupt handler can be called directly from C, with just pt_regs set up on stack. This should be faster and use less stack. Signed-off-by:
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Nicholas Piggin authored
Kernel addresses and potentially other sensitive data could be leaked in volatile registers after a syscall. Signed-off-by:
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Nicholas Piggin authored
System call entry and particularly exit code is beyond the limit of what is reasonable to implement in asm. This conversion moves all conditional branches out of the asm code, except for the case that all GPRs should be restored at exit. Null syscall test is about 5% faster after this patch, because the exit work is handled under local_irq_disable, and the hard mask and pending interrupt replay is handled after that, which avoids games with MSR. mpe: Includes subsequent fixes from Nick: This fixes 4 issues caught by TM selftests. First was a tm-syscall bug that hit due to tabort_syscall being called after interrupts were reconciled (in a subsequent patch), which led to interrupts being enabled before tabort_syscall was called. Rather than going through an un-reconciling interrupts for the return, I just go back to putting the test early in asm, the C-ification of that wasn't a big win anyway. Second is the syscall return _TIF_USER_WORK_MASK check would go into an infinite loop if _TIF_RESTORE_TM became set. The asm code uses _TIF_USER_WORK_MASK to brach to slowpath which includes restore_tm_state. Third is system call return was not calling restore_tm_state, I missed this completely (alhtough it's in the return from interrupt C conversion because when the asm syscall code encountered problems it would branch to the interrupt return code. Fourth is MSR_VEC missing from restore_math, which was caught by tm-unavailable selftest taking an unexpected facility unavailable interrupt when testing VSX unavailble exception with MSR.FP=1 MSR.VEC=1. Fourth case also has a fixup in a subsequent patch. Signed-off-by:
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Nicholas Piggin authored
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Nicholas Piggin authored
powerpc has an optimisation where interrupts avoid saving the non-volatile (or callee saved) registers to the interrupt stack frame if they are not required. Two problems with this are that an interrupt does not always know whether it will need non-volatiles; and if it does need them, they can only be saved from the entry-scoped asm code (because we don't control what the C compiler does with these registers). system calls are the most difficult: some system calls always require all registers (e.g., fork, to copy regs into the child). Sometimes registers are only required under certain conditions (e.g., tracing, signal delivery). These cases require ugly logic in the call chains (e.g., ppc_fork), and require a lot of logic to be implemented in asm. So remove the optimisation for system calls, and always save NVGPRs on entry. Modern high performance CPUs are not so sensitive, because the stores are dense in cache and can be hidden by other expensive work in the syscall path -- the null syscall selftests benchmark on POWER9 is not slowed (124.40ns before and 123.64ns after, i.e., within the noise). Other interrupts retain the NVGPR optimisation for now. Signed-off-by:
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Nicholas Piggin authored
The soft NMI handler does not reconcile interrupt state, so it should not return via the normal ret_from_except path. Return like other NMIs, using the EXCEPTION_RESTORE_REGS macro. This becomes important when the scv interrupt is implemented, which must handle soft-masked interrupts that have r13 set to something other than the PACA -- returning to kernel in this case must restore r13. Signed-off-by:
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Nicholas Piggin authored
This adds IRQ_HARD_DIS to irq_happened. Although it doesn't seem to matter much because we're not allowed to enable irqs in an NMI handler, the soft-irq debugging code is becoming more strict about ensuring IRQ_HARD_DIS is in sync with MSR[EE], this may help avoid asserts or other issues. Add a comment explaining why MCE does not have this. Early machine check is generally much smaller and more contained code which will explode if you look at it wrong anyway as it runs in real mode, though there's an argument that we should do similar reconciling for the MCE as well. Signed-off-by:
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Nicholas Piggin authored
Apart from SRESET, MCE, and syscall (hcall variant), the SRR type interrupts are not escalated to hypervisor mode, so are delivered to the OS. When running PR KVM, the OS is the hypervisor, and the guest runs with MSR[PR]=1 (ie. usermode), so these interrupts must test if a guest was running when interrupted. These tests are required at the real-mode entry points because the PR KVM host runs with LPCR[AIL]=0. In HV KVM and nested HV KVM, the guest always receives these interrupts, so there is no need for the host to make this test. So remove the tests if PR KVM is not configured. Signed-off-by:
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Nicholas Piggin authored
A few of the non-standard handlers are left uncommented. Some more description could be added to some. Signed-off-by:
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Nicholas Piggin authored
Remove more magic numbers and replace with nicely named bools. Signed-off-by:
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Nicholas Piggin authored
The reduction in interrupt entry size allows some handlers to be re-inlined. Signed-off-by:
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Nicholas Piggin authored
The hdec interrupt handler is reported to sometimes fire in Linux if KVM leaves it pending after a guest exists. This is harmless, so there is a no-op handler for it. The interrupt handler currently uses the regular kernel stack. Change this to avoid touching the stack entirely. This should be the last place where the regular Linux stack can be accessed with asynchronous interrupts (including PMI) soft-masked. It might be possible to take advantage of this invariant, e.g., to context switch the kernel stack SLB entry without clearing MSR[EE]. Signed-off-by:
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Nicholas Piggin authored
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Nicholas Piggin authored
These are used infrequently enough they don't provide much help, so inline them. Signed-off-by:
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Nicholas Piggin authored
Replace IEARLY=1 and IEARLY=2 with IBRANCH_COMMON, which controls if the entry code branches to a common handler; and IREALMODE_COMMON, which controls whether the common handler should remain in real mode. These special cases no longer avoid loading the SRR registers, there is no point as most of them load the registers immediately anyway. Signed-off-by:
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Nicholas Piggin authored
This allows more code to be moved out of unrelocated regions. The system call KVMTEST is changed to be open-coded and remain in the tramp area to avoid having to move it to entry_64.S. The custom nature of the system call entry code means the hcall case can be made more streamlined than regular interrupt handlers. mpe: Incorporate fix from Nick: Moving KVM test to the common entry code missed the case of HMI and MCE, which do not do __GEN_COMMON_ENTRY (because they don't want to switch to virt mode). This means a MCE or HMI exception that is taken while KVM is running a guest context will not be switched out of that context, and KVM won't be notified. Found by running sigfuz in guest with patched host on POWER9 DD2.3, which causes some TM related HMI interrupts (which are expected and supposed to be handled by KVM). This fix adds a __GEN_REALMODE_COMMON_ENTRY for those handlers to add the KVM test. This makes them look a little more like other handlers that all use __GEN_COMMON_ENTRY. Signed-off-by:
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Nicholas Piggin authored
As well as moving code out of the unrelocated vectors, this allows the masked handlers to be moved to common code, and allows the soft_nmi handler to be generated more like a regular handler. Signed-off-by:
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Nicholas Piggin authored
The real mode interrupt entry points currently use rfid to branch to the common handler in virtual mode. This is a significant amount of code, and forces other code (notably the KVM test) to live in the real mode handler. In the interest of minimising the amount of code that runs unrelocated move the switch to virt mode into the common code, and do it with mtmsrd, which avoids clobbering SRRs (although the post-KVMTEST performance of real-mode interrupt handlers is not a big concern these days). This requires CTR to always be saved (real-mode needs to reach 0xc...) but that's not a huge impact these days. It could be optimized away in future. mpe: Incorporate fix from Nick: It's possible for interrupts to be replayed when TM is enabled and suspended, for example rt_sigreturn, where the mtmsrd MSR_KERNEL in the real-mode entry point to the common handler causes a TM Bad Thing exception (due to attempting to clear suspended). The fix for this is to have replay interrupts go to the _virt entry point and skip the mtmsrd, which matches what happens before this patch. Signed-off-by:
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Nicholas Piggin authored
Rather than using DAR=2 to select the i-side registers, add an explicit option. Signed-off-by:
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Nicholas Piggin authored
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Nicholas Piggin authored
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Nicholas Piggin authored
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Nicholas Piggin authored
Aside from label names and BUG line numbers, the generated code change is an additional HMI KVM handler added for the "late" KVM handler, because early and late HMI generation is achieved by defining two different interrupt types. Signed-off-by:
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Nicholas Piggin authored
These don't provide a large amount of code sharing. Removing them makes code easier to shuffle around. For example, some of the common instructions will be moved into the common code gen macro. No generated code change. Signed-off-by:
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Nicholas Piggin authored
No generated code change. Signed-off-by:
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Nicholas Piggin authored
No generated code change. Signed-off-by:
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Nicholas Piggin authored
The code generation macro arguments are difficult to read, and defaults can't easily be used. This introduces a block where parameters can be set for interrupt handler code generation by the subsequent macros, and adds the first generation macro for interrupt entry. One interrupt handler is converted to the new macros to demonstrate the change, the rest will be coverted all at once. No generated code change. Signed-off-by:
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