linux_dsm_epyc7002/arch/powerpc/include/asm/paca.h

295 lines
8.6 KiB
C
Raw Normal View History

/*
* This control block defines the PACA which defines the processor
* specific data for each logical processor on the system.
* There are some pointers defined that are utilized by PLIC.
*
* C 2001 PPC 64 Team, IBM Corp
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _ASM_POWERPC_PACA_H
#define _ASM_POWERPC_PACA_H
#ifdef __KERNEL__
#ifdef CONFIG_PPC64
#include <linux/string.h>
#include <asm/types.h>
#include <asm/lppaca.h>
#include <asm/mmu.h>
#include <asm/page.h>
#ifdef CONFIG_PPC_BOOK3E
#include <asm/exception-64e.h>
#else
#include <asm/exception-64s.h>
#endif
#ifdef CONFIG_KVM_BOOK3S_64_HANDLER
#include <asm/kvm_book3s_asm.h>
#endif
#include <asm/accounting.h>
KVM: PPC: Book3S HV: Fix TB corruption in guest exit path on HMI interrupt When a guest is assigned to a core it converts the host Timebase (TB) into guest TB by adding guest timebase offset before entering into guest. During guest exit it restores the guest TB to host TB. This means under certain conditions (Guest migration) host TB and guest TB can differ. When we get an HMI for TB related issues the opal HMI handler would try fixing errors and restore the correct host TB value. With no guest running, we don't have any issues. But with guest running on the core we run into TB corruption issues. If we get an HMI while in the guest, the current HMI handler invokes opal hmi handler before forcing guest to exit. The guest exit path subtracts the guest TB offset from the current TB value which may have already been restored with host value by opal hmi handler. This leads to incorrect host and guest TB values. With split-core, things become more complex. With split-core, TB also gets split and each subcore gets its own TB register. When a hmi handler fixes a TB error and restores the TB value, it affects all the TB values of sibling subcores on the same core. On TB errors all the thread in the core gets HMI. With existing code, the individual threads call opal hmi handle independently which can easily throw TB out of sync if we have guest running on subcores. Hence we will need to co-ordinate with all the threads before making opal hmi handler call followed by TB resync. This patch introduces a sibling subcore state structure (shared by all threads in the core) in paca which holds information about whether sibling subcores are in Guest mode or host mode. An array in_guest[] of size MAX_SUBCORE_PER_CORE=4 is used to maintain the state of each subcore. The subcore id is used as index into in_guest[] array. Only primary thread entering/exiting the guest is responsible to set/unset its designated array element. On TB error, we get HMI interrupt on every thread on the core. Upon HMI, this patch will now force guest to vacate the core/subcore. Primary thread from each subcore will then turn off its respective bit from the above bitmap during the guest exit path just after the guest->host partition switch is complete. All other threads that have just exited the guest OR were already in host will wait until all other subcores clears their respective bit. Once all the subcores turn off their respective bit, all threads will will make call to opal hmi handler. It is not necessary that opal hmi handler would resync the TB value for every HMI interrupts. It would do so only for the HMI caused due to TB errors. For rest, it would not touch TB value. Hence to make things simpler, primary thread would call TB resync explicitly once for each core immediately after opal hmi handler instead of subtracting guest offset from TB. TB resync call will restore the TB with host value. Thus we can be sure about the TB state. One of the primary threads exiting the guest will take up the responsibility of calling TB resync. It will use one of the top bits (bit 63) from subcore state flags bitmap to make the decision. The first primary thread (among the subcores) that is able to set the bit will have to call the TB resync. Rest all other threads will wait until TB resync is complete. Once TB resync is complete all threads will then proceed. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2016-05-15 11:14:26 +07:00
#include <asm/hmi.h>
#include <asm/cpuidle.h>
powerpc/powernv: Provide a way to force a core into SMT4 mode POWER9 processors up to and including "Nimbus" v2.2 have hardware bugs relating to transactional memory and thread reconfiguration. One of these bugs has a workaround which is to get the core into SMT4 state temporarily. This workaround is only needed when running bare-metal. This patch provides a function which gets the core into SMT4 mode by preventing threads from going to a stop state, and waking up those which are already in a stop state. Once at least 3 threads are not in a stop state, the core will be in SMT4 and we can continue. To do this, we add a "dont_stop" flag to the paca to tell the thread not to go into a stop state. If this flag is set, power9_idle_stop() just returns immediately with a return value of 0. The pnv_power9_force_smt4_catch() function does the following: 1. Set the dont_stop flag for each thread in the core, except ourselves (in fact we use an atomic_inc() in case more than one thread is calling this function concurrently). 2. See how many threads are awake, indicated by their requested_psscr field in the paca being 0. If this is at least 3, skip to step 5. 3. Send a doorbell interrupt to each thread that was seen as being in a stop state in step 2. 4. Until at least 3 threads are awake, scan the threads to which we sent a doorbell interrupt and check if they are awake now. This relies on the following properties: - Once dont_stop is non-zero, requested_psccr can't go from zero to non-zero, except transiently (and without the thread doing stop). - requested_psscr being zero guarantees that the thread isn't in a state-losing stop state where thread reconfiguration could occur. - Doing stop with a PSSCR value of 0 won't be a state-losing stop and thus won't allow thread reconfiguration. - Once threads_per_core/2 + 1 (i.e. 3) threads are awake, the core must be in SMT4 mode, since SMT modes are powers of 2. This does add a sync to power9_idle_stop(), which is necessary to provide the correct ordering between setting requested_psscr and checking dont_stop. The overhead of the sync should be unnoticeable compared to the latency of going into and out of a stop state. Because some objected to incurring this extra latency on systems where the XER[SO] bug is not relevant, I have put the test in power9_idle_stop inside a feature section. This means that pnv_power9_force_smt4_catch() WILL NOT WORK correctly on systems without the CPU_FTR_P9_TM_XER_SO_BUG feature bit set, and will probably hang the system. In order to cater for uses where the caller has an operation that has to be done while the core is in SMT4, the core continues to be kept in SMT4 after pnv_power9_force_smt4_catch() function returns, until the pnv_power9_force_smt4_release() function is called. It undoes the effect of step 1 above and allows the other threads to go into a stop state. Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-03-21 17:32:00 +07:00
#include <asm/atomic.h>
#include <asm-generic/mmiowb_types.h>
register struct paca_struct *local_paca asm("r13");
#if defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_SMP)
extern unsigned int debug_smp_processor_id(void); /* from linux/smp.h */
/*
* Add standard checks that preemption cannot occur when using get_paca():
* otherwise the paca_struct it points to may be the wrong one just after.
*/
#define get_paca() ((void) debug_smp_processor_id(), local_paca)
#else
#define get_paca() local_paca
#endif
#ifdef CONFIG_PPC_PSERIES
#define get_lppaca() (get_paca()->lppaca_ptr)
#endif
#define get_slb_shadow() (get_paca()->slb_shadow_ptr)
struct task_struct;
/*
* Defines the layout of the paca.
*
* This structure is not directly accessed by firmware or the service
* processor.
*/
struct paca_struct {
#ifdef CONFIG_PPC_PSERIES
/*
* Because hw_cpu_id, unlike other paca fields, is accessed
* routinely from other CPUs (from the IRQ code), we stick to
* read-only (after boot) fields in the first cacheline to
* avoid cacheline bouncing.
*/
struct lppaca *lppaca_ptr; /* Pointer to LpPaca for PLIC */
#endif /* CONFIG_PPC_PSERIES */
/*
* MAGIC: the spinlock functions in arch/powerpc/lib/locks.c
* load lock_token and paca_index with a single lwz
* instruction. They must travel together and be properly
* aligned.
*/
#ifdef __BIG_ENDIAN__
u16 lock_token; /* Constant 0x8000, used in locks */
u16 paca_index; /* Logical processor number */
#else
u16 paca_index; /* Logical processor number */
u16 lock_token; /* Constant 0x8000, used in locks */
#endif
u64 kernel_toc; /* Kernel TOC address */
powerpc: Make it possible to move the interrupt handlers away from the kernel This changes the way that the exception prologs transfer control to the handlers in 64-bit kernels with the aim of making it possible to have the prologs separate from the main body of the kernel. Now, instead of computing the address of the handler by taking the top 32 bits of the paca address (to get the 0xc0000000........ part) and ORing in something in the bottom 16 bits, we get the base address of the kernel by doing a load from the paca and add an offset. This also replaces an mfmsr and an ori to compute the MSR value for the handler with a load from the paca. That makes it unnecessary to have a separate version of EXCEPTION_PROLOG_PSERIES that forces 64-bit mode. We can no longer use a direct branches in the exception prolog code, which means that the SLB miss handlers can't branch directly to .slb_miss_realmode any more. Instead we have to compute the address and do an indirect branch. This is conditional on CONFIG_RELOCATABLE; for non-relocatable kernels we use a direct branch as before. (A later change will allow CONFIG_RELOCATABLE to be set on 64-bit powerpc.) Since the secondary CPUs on pSeries start execution in the first 0x100 bytes of real memory and then have to get to wherever the kernel is, we can't use a direct branch to get there. Instead this changes __secondary_hold_spinloop from a flag to a function pointer. When it is set to a non-NULL value, the secondary CPUs jump to the function pointed to by that value. Finally this eliminates one code difference between 32-bit and 64-bit by making __secondary_hold be the text address of the secondary CPU spinloop rather than a function descriptor for it. Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-08-30 08:40:24 +07:00
u64 kernelbase; /* Base address of kernel */
u64 kernel_msr; /* MSR while running in kernel */
void *emergency_sp; /* pointer to emergency stack */
[PATCH] powerpc/64: per cpu data optimisations The current ppc64 per cpu data implementation is quite slow. eg: lhz 11,18(13) /* smp_processor_id() */ ld 9,.LC63-.LCTOC1(30) /* per_cpu__variable_name */ ld 8,.LC61-.LCTOC1(30) /* __per_cpu_offset */ sldi 11,11,3 /* form index into __per_cpu_offset */ mr 10,9 ldx 9,11,8 /* __per_cpu_offset[smp_processor_id()] */ ldx 0,10,9 /* load per cpu data */ 5 loads for something that is supposed to be fast, pretty awful. One reason for the large number of loads is that we have to synthesize 2 64bit constants (per_cpu__variable_name and __per_cpu_offset). By putting __per_cpu_offset into the paca we can avoid the 2 loads associated with it: ld 11,56(13) /* paca->data_offset */ ld 9,.LC59-.LCTOC1(30) /* per_cpu__variable_name */ ldx 0,9,11 /* load per cpu data Longer term we can should be able to do even better than 3 loads. If per_cpu__variable_name wasnt a 64bit constant and paca->data_offset was in a register we could cut it down to one load. A suggestion from Rusty is to use gcc's __thread extension here. In order to do this we would need to free up r13 (the __thread register and where the paca currently is). So far Ive had a few unsuccessful attempts at doing that :) The patch also allocates per cpu memory node local on NUMA machines. This patch from Rusty has been sitting in my queue _forever_ but stalled when I hit the compiler bug. Sorry about that. Finally I also only allocate per cpu data for possible cpus, which comes straight out of the x86-64 port. On a pseries kernel (with NR_CPUS == 128) and 4 possible cpus we see some nice gains: total used free shared buffers cached Mem: 4012228 212860 3799368 0 0 162424 total used free shared buffers cached Mem: 4016200 212984 3803216 0 0 162424 A saving of 3.75MB. Quite nice for smaller machines. Note: we now have to be careful of per cpu users that touch data for !possible cpus. At this stage it might be worth making the NUMA and possible cpu optimisations generic, but per cpu init is done so early we have to be careful that all architectures have their possible map setup correctly. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-01-11 09:16:44 +07:00
u64 data_offset; /* per cpu data offset */
s16 hw_cpu_id; /* Physical processor number */
u8 cpu_start; /* At startup, processor spins until */
/* this becomes non-zero. */
u8 kexec_state; /* set when kexec down has irqs off */
#ifdef CONFIG_PPC_BOOK3S_64
struct slb_shadow *slb_shadow_ptr;
powerpc: Account time using timebase rather than PURR Currently, when CONFIG_VIRT_CPU_ACCOUNTING is enabled, we use the PURR register for measuring the user and system time used by processes, as well as other related times such as hardirq and softirq times. This turns out to be quite confusing for users because it means that a program will often be measured as taking less time when run on a multi-threaded processor (SMT2 or SMT4 mode) than it does when run on a single-threaded processor (ST mode), even though the program takes longer to finish. The discrepancy is accounted for as stolen time, which is also confusing, particularly when there are no other partitions running. This changes the accounting to use the timebase instead, meaning that the reported user and system times are the actual number of real-time seconds that the program was executing on the processor thread, regardless of which SMT mode the processor is in. Thus a program will generally show greater user and system times when run on a multi-threaded processor than on a single-threaded processor. On pSeries systems on POWER5 or later processors, we measure the stolen time (time when this partition wasn't running) using the hypervisor dispatch trace log. We check for new entries in the log on every entry from user mode and on every transition from kernel process context to soft or hard IRQ context (i.e. when account_system_vtime() gets called). So that we can correctly distinguish time stolen from user time and time stolen from system time, without having to check the log on every exit to user mode, we store separate timestamps for exit to user mode and entry from user mode. On systems that have a SPURR (POWER6 and POWER7), we read the SPURR in account_system_vtime() (as before), and then apportion the SPURR ticks since the last time we read it between scaled user time and scaled system time according to the relative proportions of user time and system time over the same interval. This avoids having to read the SPURR on every kernel entry and exit. On systems that have PURR but not SPURR (i.e., POWER5), we do the same using the PURR rather than the SPURR. This disables the DTL user interface in /sys/debug/kernel/powerpc/dtl for now since it conflicts with the use of the dispatch trace log by the time accounting code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-08-27 02:56:43 +07:00
struct dtl_entry *dispatch_log;
struct dtl_entry *dispatch_log_end;
#endif
u64 dscr_default; /* per-CPU default DSCR */
#ifdef CONFIG_PPC_BOOK3S_64
/*
* Now, starting in cacheline 2, the exception save areas
*/
/* used for most interrupts/exceptions */
u64 exgen[EX_SIZE] __attribute__((aligned(0x80)));
u64 exslb[EX_SIZE]; /* used for SLB/segment table misses
* on the linear mapping */
/* SLB related definitions */
powerpc: Use 64k pages without needing cache-inhibited large pages Some POWER5+ machines can do 64k hardware pages for normal memory but not for cache-inhibited pages. This patch lets us use 64k hardware pages for most user processes on such machines (assuming the kernel has been configured with CONFIG_PPC_64K_PAGES=y). User processes start out using 64k pages and get switched to 4k pages if they use any non-cacheable mappings. With this, we use 64k pages for the vmalloc region and 4k pages for the imalloc region. If anything creates a non-cacheable mapping in the vmalloc region, the vmalloc region will get switched to 4k pages. I don't know of any driver other than the DRM that would do this, though, and these machines don't have AGP. When a region gets switched from 64k pages to 4k pages, we do not have to clear out all the 64k HPTEs from the hash table immediately. We use the _PAGE_COMBO bit in the Linux PTE to indicate whether the page was hashed in as a 64k page or a set of 4k pages. If hash_page is trying to insert a 4k page for a Linux PTE and it sees that it has already been inserted as a 64k page, it first invalidates the 64k HPTE before inserting the 4k HPTE. The hash invalidation routines also use the _PAGE_COMBO bit, to determine whether to look for a 64k HPTE or a set of 4k HPTEs to remove. With those two changes, we can tolerate a mix of 4k and 64k HPTEs in the hash table, and they will all get removed when the address space is torn down. Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-06-15 07:45:18 +07:00
u16 vmalloc_sllp;
u8 slb_cache_ptr;
u8 stab_rr; /* stab/slb round-robin counter */
#ifdef CONFIG_DEBUG_VM
u8 in_kernel_slb_handler;
#endif
u32 slb_used_bitmap; /* Bitmaps for first 32 SLB entries. */
u32 slb_kern_bitmap;
u32 slb_cache[SLB_CACHE_ENTRIES];
#endif /* CONFIG_PPC_BOOK3S_64 */
#ifdef CONFIG_PPC_BOOK3E
u64 exgen[8] __aligned(0x40);
/* Keep pgd in the same cacheline as the start of extlb */
pgd_t *pgd __aligned(0x40); /* Current PGD */
pgd_t *kernel_pgd; /* Kernel PGD */
/* Shared by all threads of a core -- points to tcd of first thread */
struct tlb_core_data *tcd_ptr;
/*
* We can have up to 3 levels of reentrancy in the TLB miss handler,
* in each of four exception levels (normal, crit, mcheck, debug).
*/
u64 extlb[12][EX_TLB_SIZE / sizeof(u64)];
u64 exmc[8]; /* used for machine checks */
u64 excrit[8]; /* used for crit interrupts */
u64 exdbg[8]; /* used for debug interrupts */
/* Kernel stack pointers for use by special exceptions */
void *mc_kstack;
void *crit_kstack;
void *dbg_kstack;
struct tlb_core_data tcd;
#endif /* CONFIG_PPC_BOOK3E */
#ifdef CONFIG_PPC_BOOK3S
mm_context_id_t mm_ctx_id;
#ifdef CONFIG_PPC_MM_SLICES
unsigned char mm_ctx_low_slices_psize[BITS_PER_LONG / BITS_PER_BYTE];
unsigned char mm_ctx_high_slices_psize[SLICE_ARRAY_SIZE];
unsigned long mm_ctx_slb_addr_limit;
#else
u16 mm_ctx_user_psize;
u16 mm_ctx_sllp;
#endif
#endif
/*
* then miscellaneous read-write fields
*/
struct task_struct *__current; /* Pointer to current */
u64 kstack; /* Saved Kernel stack addr */
u64 saved_r1; /* r1 save for RTAS calls or PM or EE=0 */
u64 saved_msr; /* MSR saved here by enter_rtas */
u16 trap_save; /* Used when bad stack is encountered */
u8 irq_soft_mask; /* mask for irq soft masking */
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 14:27:59 +07:00
u8 irq_happened; /* irq happened while soft-disabled */
u8 irq_work_pending; /* IRQ_WORK interrupt while soft-disable */
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
u8 pmcregs_in_use; /* pseries puts this in lppaca */
#endif
powerpc/booke64: Use SPRG7 for VDSO Previously SPRG3 was marked for use by both VDSO and critical interrupts (though critical interrupts were not fully implemented). In commit 8b64a9dfb091f1eca8b7e58da82f1e7d1d5fe0ad ("powerpc/booke64: Use SPRG0/3 scratch for bolted TLB miss & crit int"), Mihai Caraman made an attempt to resolve this conflict by restoring the VDSO value early in the critical interrupt, but this has some issues: - It's incompatible with EXCEPTION_COMMON which restores r13 from the by-then-overwritten scratch (this cost me some debugging time). - It forces critical exceptions to be a special case handled differently from even machine check and debug level exceptions. - It didn't occur to me that it was possible to make this work at all (by doing a final "ld r13, PACA_EXCRIT+EX_R13(r13)") until after I made (most of) this patch. :-) It might be worth investigating using a load rather than SPRG on return from all exceptions (except TLB misses where the scratch never leaves the SPRG) -- it could save a few cycles. Until then, let's stick with SPRG for all exceptions. Since we cannot use SPRG4-7 for scratch without corrupting the state of a KVM guest, move VDSO to SPRG7 on book3e. Since neither SPRG4-7 nor critical interrupts exist on book3s, SPRG3 is still used for VDSO there. Signed-off-by: Scott Wood <scottwood@freescale.com> Cc: Mihai Caraman <mihai.caraman@freescale.com> Cc: Anton Blanchard <anton@samba.org> Cc: Paul Mackerras <paulus@samba.org> Cc: kvm-ppc@vger.kernel.org
2014-03-11 05:29:38 +07:00
u64 sprg_vdso; /* Saved user-visible sprg */
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
u64 tm_scratch; /* TM scratch area for reclaim */
#endif
powerpc: Implement accurate task and CPU time accounting This implements accurate task and cpu time accounting for 64-bit powerpc kernels. Instead of accounting a whole jiffy of time to a task on a timer interrupt because that task happened to be running at the time, we now account time in units of timebase ticks according to the actual time spent by the task in user mode and kernel mode. We also count the time spent processing hardware and software interrupts accurately. This is conditional on CONFIG_VIRT_CPU_ACCOUNTING. If that is not set, we do tick-based approximate accounting as before. To get this accurate information, we read either the PURR (processor utilization of resources register) on POWER5 machines, or the timebase on other machines on * each entry to the kernel from usermode * each exit to usermode * transitions between process context, hard irq context and soft irq context in kernel mode * context switches. On POWER5 systems with shared-processor logical partitioning we also read both the PURR and the timebase at each timer interrupt and context switch in order to determine how much time has been taken by the hypervisor to run other partitions ("steal" time). Unfortunately, since we need values of the PURR on both threads at the same time to accurately calculate the steal time, and since we can only calculate steal time on a per-core basis, the apportioning of the steal time between idle time (time which we ceded to the hypervisor in the idle loop) and actual stolen time is somewhat approximate at the moment. This is all based quite heavily on what s390 does, and it uses the generic interfaces that were added by the s390 developers, i.e. account_system_time(), account_user_time(), etc. This patch doesn't add any new interfaces between the kernel and userspace, and doesn't change the units in which time is reported to userspace by things such as /proc/stat, /proc/<pid>/stat, getrusage(), times(), etc. Internally the various task and cpu times are stored in timebase units, but they are converted to USER_HZ units (1/100th of a second) when reported to userspace. Some precision is therefore lost but there should not be any accumulating error, since the internal accumulation is at full precision. Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-02-24 06:06:59 +07:00
#ifdef CONFIG_PPC_POWERNV
powerpc/64s: Reimplement book3s idle code in C Reimplement Book3S idle code in C, moving POWER7/8/9 implementation speific HV idle code to the powernv platform code. Book3S assembly stubs are kept in common code and used only to save the stack frame and non-volatile GPRs before executing architected idle instructions, and restoring the stack and reloading GPRs then returning to C after waking from idle. The complex logic dealing with threads and subcores, locking, SPRs, HMIs, timebase resync, etc., is all done in C which makes it more maintainable. This is not a strict translation to C code, there are some significant differences: - Idle wakeup no longer uses the ->cpu_restore call to reinit SPRs, but saves and restores them itself. - The optimisation where EC=ESL=0 idle modes did not have to save GPRs or change MSR is restored, because it's now simple to do. ESL=1 sleeps that do not lose GPRs can use this optimization too. - KVM secondary entry and cede is now more of a call/return style rather than branchy. nap_state_lost is not required because KVM always returns via NVGPR restoring path. - KVM secondary wakeup from offline sequence is moved entirely into the offline wakeup, which avoids a hwsync in the normal idle wakeup path. Performance measured with context switch ping-pong on different threads or cores, is possibly improved a small amount, 1-3% depending on stop state and core vs thread test for shallow states. Deep states it's in the noise compared with other latencies. KVM improvements: - Idle sleepers now always return to caller rather than branch out to KVM first. - This allows optimisations like very fast return to caller when no state has been lost. - KVM no longer requires nap_state_lost because it controls NVGPR save/restore itself on the way in and out. - The heavy idle wakeup KVM request check can be moved out of the normal host idle code and into the not-performance-critical offline code. - KVM nap code now returns from where it is called, which makes the flow a bit easier to follow. Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Squash the KVM changes in] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-04-12 21:30:52 +07:00
/* PowerNV idle fields */
/* PNV_CORE_IDLE_* bits, all siblings work on thread 0 paca */
unsigned long idle_state;
union {
/* P7/P8 specific fields */
struct {
/* PNV_THREAD_RUNNING/NAP/SLEEP */
u8 thread_idle_state;
/* Mask to denote subcore sibling threads */
u8 subcore_sibling_mask;
};
/* P9 specific fields */
struct {
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
/* The PSSCR value that the kernel requested before going to stop */
u64 requested_psscr;
/* Flag to request this thread not to stop */
atomic_t dont_stop;
#endif
};
};
#endif
#ifdef CONFIG_PPC_BOOK3S_64
/* Non-maskable exceptions that are not performance critical */
u64 exnmi[EX_SIZE]; /* used for system reset (nmi) */
u64 exmc[EX_SIZE]; /* used for machine checks */
#endif
#ifdef CONFIG_PPC_BOOK3S_64
/* Exclusive stacks for system reset and machine check exception. */
void *nmi_emergency_sp;
void *mc_emergency_sp;
u16 in_nmi; /* In nmi handler */
/*
* Flag to check whether we are in machine check early handler
* and already using emergency stack.
*/
u16 in_mce;
u8 hmi_event_available; /* HMI event is available */
u8 hmi_p9_special_emu; /* HMI P9 special emulation */
#endif
u8 ftrace_enabled; /* Hard disable ftrace */
powerpc: Implement accurate task and CPU time accounting This implements accurate task and cpu time accounting for 64-bit powerpc kernels. Instead of accounting a whole jiffy of time to a task on a timer interrupt because that task happened to be running at the time, we now account time in units of timebase ticks according to the actual time spent by the task in user mode and kernel mode. We also count the time spent processing hardware and software interrupts accurately. This is conditional on CONFIG_VIRT_CPU_ACCOUNTING. If that is not set, we do tick-based approximate accounting as before. To get this accurate information, we read either the PURR (processor utilization of resources register) on POWER5 machines, or the timebase on other machines on * each entry to the kernel from usermode * each exit to usermode * transitions between process context, hard irq context and soft irq context in kernel mode * context switches. On POWER5 systems with shared-processor logical partitioning we also read both the PURR and the timebase at each timer interrupt and context switch in order to determine how much time has been taken by the hypervisor to run other partitions ("steal" time). Unfortunately, since we need values of the PURR on both threads at the same time to accurately calculate the steal time, and since we can only calculate steal time on a per-core basis, the apportioning of the steal time between idle time (time which we ceded to the hypervisor in the idle loop) and actual stolen time is somewhat approximate at the moment. This is all based quite heavily on what s390 does, and it uses the generic interfaces that were added by the s390 developers, i.e. account_system_time(), account_user_time(), etc. This patch doesn't add any new interfaces between the kernel and userspace, and doesn't change the units in which time is reported to userspace by things such as /proc/stat, /proc/<pid>/stat, getrusage(), times(), etc. Internally the various task and cpu times are stored in timebase units, but they are converted to USER_HZ units (1/100th of a second) when reported to userspace. Some precision is therefore lost but there should not be any accumulating error, since the internal accumulation is at full precision. Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-02-24 06:06:59 +07:00
/* Stuff for accurate time accounting */
struct cpu_accounting_data accounting;
powerpc: Account time using timebase rather than PURR Currently, when CONFIG_VIRT_CPU_ACCOUNTING is enabled, we use the PURR register for measuring the user and system time used by processes, as well as other related times such as hardirq and softirq times. This turns out to be quite confusing for users because it means that a program will often be measured as taking less time when run on a multi-threaded processor (SMT2 or SMT4 mode) than it does when run on a single-threaded processor (ST mode), even though the program takes longer to finish. The discrepancy is accounted for as stolen time, which is also confusing, particularly when there are no other partitions running. This changes the accounting to use the timebase instead, meaning that the reported user and system times are the actual number of real-time seconds that the program was executing on the processor thread, regardless of which SMT mode the processor is in. Thus a program will generally show greater user and system times when run on a multi-threaded processor than on a single-threaded processor. On pSeries systems on POWER5 or later processors, we measure the stolen time (time when this partition wasn't running) using the hypervisor dispatch trace log. We check for new entries in the log on every entry from user mode and on every transition from kernel process context to soft or hard IRQ context (i.e. when account_system_vtime() gets called). So that we can correctly distinguish time stolen from user time and time stolen from system time, without having to check the log on every exit to user mode, we store separate timestamps for exit to user mode and entry from user mode. On systems that have a SPURR (POWER6 and POWER7), we read the SPURR in account_system_vtime() (as before), and then apportion the SPURR ticks since the last time we read it between scaled user time and scaled system time according to the relative proportions of user time and system time over the same interval. This avoids having to read the SPURR on every kernel entry and exit. On systems that have PURR but not SPURR (i.e., POWER5), we do the same using the PURR rather than the SPURR. This disables the DTL user interface in /sys/debug/kernel/powerpc/dtl for now since it conflicts with the use of the dispatch trace log by the time accounting code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-08-27 02:56:43 +07:00
u64 dtl_ridx; /* read index in dispatch log */
struct dtl_entry *dtl_curr; /* pointer corresponding to dtl_ridx */
#ifdef CONFIG_KVM_BOOK3S_HANDLER
#ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
/* We use this to store guest state in */
struct kvmppc_book3s_shadow_vcpu shadow_vcpu;
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 07:21:34 +07:00
#endif
struct kvmppc_host_state kvm_hstate;
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
/*
* Bitmap for sibling subcore status. See kvm/book3s_hv_ras.c for
* more details
*/
struct sibling_subcore_state *sibling_subcore_state;
#endif
#endif
powerpc/64s: Add support for RFI flush of L1-D cache On some CPUs we can prevent the Meltdown vulnerability by flushing the L1-D cache on exit from kernel to user mode, and from hypervisor to guest. This is known to be the case on at least Power7, Power8 and Power9. At this time we do not know the status of the vulnerability on other CPUs such as the 970 (Apple G5), pasemi CPUs (AmigaOne X1000) or Freescale CPUs. As more information comes to light we can enable this, or other mechanisms on those CPUs. The vulnerability occurs when the load of an architecturally inaccessible memory region (eg. userspace load of kernel memory) is speculatively executed to the point where its result can influence the address of a subsequent speculatively executed load. In order for that to happen, the first load must hit in the L1, because before the load is sent to the L2 the permission check is performed. Therefore if no kernel addresses hit in the L1 the vulnerability can not occur. We can ensure that is the case by flushing the L1 whenever we return to userspace. Similarly for hypervisor vs guest. In order to flush the L1-D cache on exit, we add a section of nops at each (h)rfi location that returns to a lower privileged context, and patch that with some sequence. Newer firmwares are able to advertise to us that there is a special nop instruction that flushes the L1-D. If we do not see that advertised, we fall back to doing a displacement flush in software. For guest kernels we support migration between some CPU versions, and different CPUs may use different flush instructions. So that we are prepared to migrate to a machine with a different flush instruction activated, we may have to patch more than one flush instruction at boot if the hypervisor tells us to. In the end this patch is mostly the work of Nicholas Piggin and Michael Ellerman. However a cast of thousands contributed to analysis of the issue, earlier versions of the patch, back ports testing etc. Many thanks to all of them. Tested-by: Jon Masters <jcm@redhat.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-09 23:07:15 +07:00
#ifdef CONFIG_PPC_BOOK3S_64
/*
* rfi fallback flush must be in its own cacheline to prevent
* other paca data leaking into the L1d
*/
u64 exrfi[EX_SIZE] __aligned(0x80);
void *rfi_flush_fallback_area;
u64 l1d_flush_size;
powerpc/64s: Add support for RFI flush of L1-D cache On some CPUs we can prevent the Meltdown vulnerability by flushing the L1-D cache on exit from kernel to user mode, and from hypervisor to guest. This is known to be the case on at least Power7, Power8 and Power9. At this time we do not know the status of the vulnerability on other CPUs such as the 970 (Apple G5), pasemi CPUs (AmigaOne X1000) or Freescale CPUs. As more information comes to light we can enable this, or other mechanisms on those CPUs. The vulnerability occurs when the load of an architecturally inaccessible memory region (eg. userspace load of kernel memory) is speculatively executed to the point where its result can influence the address of a subsequent speculatively executed load. In order for that to happen, the first load must hit in the L1, because before the load is sent to the L2 the permission check is performed. Therefore if no kernel addresses hit in the L1 the vulnerability can not occur. We can ensure that is the case by flushing the L1 whenever we return to userspace. Similarly for hypervisor vs guest. In order to flush the L1-D cache on exit, we add a section of nops at each (h)rfi location that returns to a lower privileged context, and patch that with some sequence. Newer firmwares are able to advertise to us that there is a special nop instruction that flushes the L1-D. If we do not see that advertised, we fall back to doing a displacement flush in software. For guest kernels we support migration between some CPU versions, and different CPUs may use different flush instructions. So that we are prepared to migrate to a machine with a different flush instruction activated, we may have to patch more than one flush instruction at boot if the hypervisor tells us to. In the end this patch is mostly the work of Nicholas Piggin and Michael Ellerman. However a cast of thousands contributed to analysis of the issue, earlier versions of the patch, back ports testing etc. Many thanks to all of them. Tested-by: Jon Masters <jcm@redhat.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-09 23:07:15 +07:00
#endif
powerpc/pseries: Defer the logging of rtas error to irq work queue. rtas_log_buf is a buffer to hold RTAS event data that are communicated to kernel by hypervisor. This buffer is then used to pass RTAS event data to user through proc fs. This buffer is allocated from vmalloc (non-linear mapping) area. On Machine check interrupt, register r3 points to RTAS extended event log passed by hypervisor that contains the MCE event. The pseries machine check handler then logs this error into rtas_log_buf. The rtas_log_buf is a vmalloc-ed (non-linear) buffer we end up taking up a page fault (vector 0x300) while accessing it. Since machine check interrupt handler runs in NMI context we can not afford to take any page fault. Page faults are not honored in NMI context and causes kernel panic. Apart from that, as Nick pointed out, pSeries_log_error() also takes a spin_lock while logging error which is not safe in NMI context. It may endup in deadlock if we get another MCE before releasing the lock. Fix this by deferring the logging of rtas error to irq work queue. Current implementation uses two different buffers to hold rtas error log depending on whether extended log is provided or not. This makes bit difficult to identify which buffer has valid data that needs to logged later in irq work. Simplify this using single buffer, one per paca, and copy rtas log to it irrespective of whether extended log is provided or not. Allocate this buffer below RMA region so that it can be accessed in real mode mce handler. Fixes: b96672dd840f ("powerpc: Machine check interrupt is a non-maskable interrupt") Cc: stable@vger.kernel.org # v4.14+ Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-07-05 00:57:21 +07:00
#ifdef CONFIG_PPC_PSERIES
u8 *mce_data_buf; /* buffer to hold per cpu rtas errlog */
#endif /* CONFIG_PPC_PSERIES */
powerpc/pseries: Dump the SLB contents on SLB MCE errors. If we get a machine check exceptions due to SLB errors then dump the current SLB contents which will be very much helpful in debugging the root cause of SLB errors. Introduce an exclusive buffer per cpu to hold faulty SLB entries. In real mode mce handler saves the old SLB contents into this buffer accessible through paca and print it out later in virtual mode. With this patch the console will log SLB contents like below on SLB MCE errors: [ 507.297236] SLB contents of cpu 0x1 [ 507.297237] Last SLB entry inserted at slot 16 [ 507.297238] 00 c000000008000000 400ea1b217000500 [ 507.297239] 1T ESID= c00000 VSID= ea1b217 LLP:100 [ 507.297240] 01 d000000008000000 400d43642f000510 [ 507.297242] 1T ESID= d00000 VSID= d43642f LLP:110 [ 507.297243] 11 f000000008000000 400a86c85f000500 [ 507.297244] 1T ESID= f00000 VSID= a86c85f LLP:100 [ 507.297245] 12 00007f0008000000 4008119624000d90 [ 507.297246] 1T ESID= 7f VSID= 8119624 LLP:110 [ 507.297247] 13 0000000018000000 00092885f5150d90 [ 507.297247] 256M ESID= 1 VSID= 92885f5150 LLP:110 [ 507.297248] 14 0000010008000000 4009e7cb50000d90 [ 507.297249] 1T ESID= 1 VSID= 9e7cb50 LLP:110 [ 507.297250] 15 d000000008000000 400d43642f000510 [ 507.297251] 1T ESID= d00000 VSID= d43642f LLP:110 [ 507.297252] 16 d000000008000000 400d43642f000510 [ 507.297253] 1T ESID= d00000 VSID= d43642f LLP:110 [ 507.297253] ---------------------------------- [ 507.297254] SLB cache ptr value = 3 [ 507.297254] Valid SLB cache entries: [ 507.297255] 00 EA[0-35]= 7f000 [ 507.297256] 01 EA[0-35]= 1 [ 507.297257] 02 EA[0-35]= 1000 [ 507.297257] Rest of SLB cache entries: [ 507.297258] 03 EA[0-35]= 7f000 [ 507.297258] 04 EA[0-35]= 1 [ 507.297259] 05 EA[0-35]= 1000 [ 507.297260] 06 EA[0-35]= 12 [ 507.297260] 07 EA[0-35]= 7f000 Suggested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Suggested-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-09-11 21:27:15 +07:00
#ifdef CONFIG_PPC_BOOK3S_64
/* Capture SLB related old contents in MCE handler. */
struct slb_entry *mce_faulty_slbs;
u16 slb_save_cache_ptr;
#endif /* CONFIG_PPC_BOOK3S_64 */
#ifdef CONFIG_STACKPROTECTOR
unsigned long canary;
#endif
#ifdef CONFIG_MMIOWB
struct mmiowb_state mmiowb_state;
#endif
} ____cacheline_aligned;
extern void copy_mm_to_paca(struct mm_struct *mm);
extern struct paca_struct **paca_ptrs;
extern void initialise_paca(struct paca_struct *new_paca, int cpu);
extern void setup_paca(struct paca_struct *new_paca);
extern void allocate_paca_ptrs(void);
extern void allocate_paca(int cpu);
extern void free_unused_pacas(void);
#else /* CONFIG_PPC64 */
static inline void allocate_paca_ptrs(void) { };
static inline void allocate_paca(int cpu) { };
static inline void free_unused_pacas(void) { };
#endif /* CONFIG_PPC64 */
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_PACA_H */