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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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0a882e2846
The bad stack test in interrupt handlers has a few problems. For performance it is taken in the common case, which is a fetch bubble and a waste of i-cache. For code development and maintainence, it requires yet another stack frame setup routine, and that constrains all exception handlers to follow the same register save pattern which inhibits future optimisation. Remove the test/branch and replace it with a trap. Teach the program check handler to use the emergency stack for this case. This does not result in quite so nice a message, however the SRR0 and SRR1 of the crashed interrupt can be seen in r11 and r12, as is the original r1 (adjusted by INT_FRAME_SIZE). These are the most important parts to debugging the issue. The original r9-12 and cr0 is lost, which is the main downside. kernel BUG at linux/arch/powerpc/kernel/exceptions-64s.S:847! Oops: Exception in kernel mode, sig: 5 [#1] BE SMP NR_CPUS=2048 NUMA PowerNV Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted NIP: c000000000009108 LR: c000000000cadbcc CTR: c0000000000090f0 REGS: c0000000fffcbd70 TRAP: 0700 Not tainted MSR: 9000000000021032 <SF,HV,ME,IR,DR,RI> CR: 28222448 XER: 20040000 CFAR: c000000000009100 IRQMASK: 0 GPR00: 000000000000003d fffffffffffffd00 c0000000018cfb00 c0000000f02b3166 GPR04: fffffffffffffffd 0000000000000007 fffffffffffffffb 0000000000000030 GPR08: 0000000000000037 0000000028222448 0000000000000000 c000000000ca8de0 GPR12: 9000000002009032 c000000001ae0000 c000000000010a00 0000000000000000 GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR20: c0000000f00322c0 c000000000f85200 0000000000000004 ffffffffffffffff GPR24: fffffffffffffffe 0000000000000000 0000000000000000 000000000000000a GPR28: 0000000000000000 0000000000000000 c0000000f02b391c c0000000f02b3167 NIP [c000000000009108] decrementer_common+0x18/0x160 LR [c000000000cadbcc] .vsnprintf+0x3ec/0x4f0 Call Trace: Instruction dump: 996d098a 994d098b 38610070 480246ed 48005518 60000000 38200000 718a4000 7c2a0b78 3821fd00 41c20008 e82d0970 <0981fd00> f92101a0 f9610170 f9810178 Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
297 lines
8.7 KiB
C
297 lines
8.7 KiB
C
/*
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* This control block defines the PACA which defines the processor
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* specific data for each logical processor on the system.
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* There are some pointers defined that are utilized by PLIC.
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*
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* C 2001 PPC 64 Team, IBM Corp
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef _ASM_POWERPC_PACA_H
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#define _ASM_POWERPC_PACA_H
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#ifdef __KERNEL__
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#ifdef CONFIG_PPC64
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#include <linux/string.h>
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#include <asm/types.h>
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#include <asm/lppaca.h>
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#include <asm/mmu.h>
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#include <asm/page.h>
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#ifdef CONFIG_PPC_BOOK3E
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#include <asm/exception-64e.h>
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#else
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#include <asm/exception-64s.h>
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#endif
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#ifdef CONFIG_KVM_BOOK3S_64_HANDLER
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#include <asm/kvm_book3s_asm.h>
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#endif
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#include <asm/accounting.h>
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#include <asm/hmi.h>
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#include <asm/cpuidle.h>
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#include <asm/atomic.h>
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#include <asm-generic/mmiowb_types.h>
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register struct paca_struct *local_paca asm("r13");
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#if defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_SMP)
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extern unsigned int debug_smp_processor_id(void); /* from linux/smp.h */
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/*
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* Add standard checks that preemption cannot occur when using get_paca():
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* otherwise the paca_struct it points to may be the wrong one just after.
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*/
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#define get_paca() ((void) debug_smp_processor_id(), local_paca)
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#else
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#define get_paca() local_paca
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#endif
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#ifdef CONFIG_PPC_PSERIES
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#define get_lppaca() (get_paca()->lppaca_ptr)
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#endif
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#define get_slb_shadow() (get_paca()->slb_shadow_ptr)
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struct task_struct;
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/*
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* Defines the layout of the paca.
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*
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* This structure is not directly accessed by firmware or the service
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* processor.
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*/
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struct paca_struct {
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#ifdef CONFIG_PPC_PSERIES
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/*
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* Because hw_cpu_id, unlike other paca fields, is accessed
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* routinely from other CPUs (from the IRQ code), we stick to
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* read-only (after boot) fields in the first cacheline to
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* avoid cacheline bouncing.
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*/
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struct lppaca *lppaca_ptr; /* Pointer to LpPaca for PLIC */
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#endif /* CONFIG_PPC_PSERIES */
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/*
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* MAGIC: the spinlock functions in arch/powerpc/lib/locks.c
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* load lock_token and paca_index with a single lwz
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* instruction. They must travel together and be properly
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* aligned.
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*/
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#ifdef __BIG_ENDIAN__
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u16 lock_token; /* Constant 0x8000, used in locks */
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u16 paca_index; /* Logical processor number */
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#else
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u16 paca_index; /* Logical processor number */
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u16 lock_token; /* Constant 0x8000, used in locks */
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#endif
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u64 kernel_toc; /* Kernel TOC address */
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u64 kernelbase; /* Base address of kernel */
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u64 kernel_msr; /* MSR while running in kernel */
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void *emergency_sp; /* pointer to emergency stack */
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u64 data_offset; /* per cpu data offset */
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s16 hw_cpu_id; /* Physical processor number */
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u8 cpu_start; /* At startup, processor spins until */
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/* this becomes non-zero. */
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u8 kexec_state; /* set when kexec down has irqs off */
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#ifdef CONFIG_PPC_BOOK3S_64
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struct slb_shadow *slb_shadow_ptr;
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struct dtl_entry *dispatch_log;
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struct dtl_entry *dispatch_log_end;
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#endif
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u64 dscr_default; /* per-CPU default DSCR */
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#ifdef CONFIG_PPC_BOOK3S_64
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/*
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* Now, starting in cacheline 2, the exception save areas
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*/
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/* used for most interrupts/exceptions */
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u64 exgen[EX_SIZE] __attribute__((aligned(0x80)));
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u64 exslb[EX_SIZE]; /* used for SLB/segment table misses
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* on the linear mapping */
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/* SLB related definitions */
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u16 vmalloc_sllp;
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u8 slb_cache_ptr;
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u8 stab_rr; /* stab/slb round-robin counter */
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#ifdef CONFIG_DEBUG_VM
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u8 in_kernel_slb_handler;
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#endif
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u32 slb_used_bitmap; /* Bitmaps for first 32 SLB entries. */
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u32 slb_kern_bitmap;
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u32 slb_cache[SLB_CACHE_ENTRIES];
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#endif /* CONFIG_PPC_BOOK3S_64 */
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#ifdef CONFIG_PPC_BOOK3E
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u64 exgen[8] __aligned(0x40);
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/* Keep pgd in the same cacheline as the start of extlb */
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pgd_t *pgd __aligned(0x40); /* Current PGD */
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pgd_t *kernel_pgd; /* Kernel PGD */
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/* Shared by all threads of a core -- points to tcd of first thread */
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struct tlb_core_data *tcd_ptr;
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/*
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* We can have up to 3 levels of reentrancy in the TLB miss handler,
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* in each of four exception levels (normal, crit, mcheck, debug).
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*/
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u64 extlb[12][EX_TLB_SIZE / sizeof(u64)];
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u64 exmc[8]; /* used for machine checks */
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u64 excrit[8]; /* used for crit interrupts */
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u64 exdbg[8]; /* used for debug interrupts */
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/* Kernel stack pointers for use by special exceptions */
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void *mc_kstack;
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void *crit_kstack;
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void *dbg_kstack;
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struct tlb_core_data tcd;
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#endif /* CONFIG_PPC_BOOK3E */
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#ifdef CONFIG_PPC_BOOK3S
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mm_context_id_t mm_ctx_id;
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#ifdef CONFIG_PPC_MM_SLICES
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unsigned char mm_ctx_low_slices_psize[BITS_PER_LONG / BITS_PER_BYTE];
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unsigned char mm_ctx_high_slices_psize[SLICE_ARRAY_SIZE];
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unsigned long mm_ctx_slb_addr_limit;
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#else
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u16 mm_ctx_user_psize;
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u16 mm_ctx_sllp;
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#endif
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#endif
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/*
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* then miscellaneous read-write fields
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*/
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struct task_struct *__current; /* Pointer to current */
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u64 kstack; /* Saved Kernel stack addr */
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u64 saved_r1; /* r1 save for RTAS calls or PM or EE=0 */
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u64 saved_msr; /* MSR saved here by enter_rtas */
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#ifdef CONFIG_PPC_BOOK3E
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u16 trap_save; /* Used when bad stack is encountered */
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#endif
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u8 irq_soft_mask; /* mask for irq soft masking */
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u8 irq_happened; /* irq happened while soft-disabled */
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u8 irq_work_pending; /* IRQ_WORK interrupt while soft-disable */
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#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
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u8 pmcregs_in_use; /* pseries puts this in lppaca */
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#endif
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u64 sprg_vdso; /* Saved user-visible sprg */
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#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
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u64 tm_scratch; /* TM scratch area for reclaim */
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#endif
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#ifdef CONFIG_PPC_POWERNV
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/* PowerNV idle fields */
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/* PNV_CORE_IDLE_* bits, all siblings work on thread 0 paca */
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unsigned long idle_state;
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union {
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/* P7/P8 specific fields */
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struct {
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/* PNV_THREAD_RUNNING/NAP/SLEEP */
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u8 thread_idle_state;
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/* Mask to denote subcore sibling threads */
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u8 subcore_sibling_mask;
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};
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/* P9 specific fields */
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struct {
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#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
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/* The PSSCR value that the kernel requested before going to stop */
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u64 requested_psscr;
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/* Flag to request this thread not to stop */
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atomic_t dont_stop;
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#endif
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};
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};
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#endif
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#ifdef CONFIG_PPC_BOOK3S_64
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/* Non-maskable exceptions that are not performance critical */
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u64 exnmi[EX_SIZE]; /* used for system reset (nmi) */
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u64 exmc[EX_SIZE]; /* used for machine checks */
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#endif
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#ifdef CONFIG_PPC_BOOK3S_64
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/* Exclusive stacks for system reset and machine check exception. */
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void *nmi_emergency_sp;
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void *mc_emergency_sp;
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u16 in_nmi; /* In nmi handler */
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/*
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* Flag to check whether we are in machine check early handler
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* and already using emergency stack.
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*/
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u16 in_mce;
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u8 hmi_event_available; /* HMI event is available */
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u8 hmi_p9_special_emu; /* HMI P9 special emulation */
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#endif
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u8 ftrace_enabled; /* Hard disable ftrace */
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/* Stuff for accurate time accounting */
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struct cpu_accounting_data accounting;
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u64 dtl_ridx; /* read index in dispatch log */
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struct dtl_entry *dtl_curr; /* pointer corresponding to dtl_ridx */
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#ifdef CONFIG_KVM_BOOK3S_HANDLER
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#ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
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/* We use this to store guest state in */
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struct kvmppc_book3s_shadow_vcpu shadow_vcpu;
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#endif
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struct kvmppc_host_state kvm_hstate;
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#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
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/*
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* Bitmap for sibling subcore status. See kvm/book3s_hv_ras.c for
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* more details
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*/
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struct sibling_subcore_state *sibling_subcore_state;
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#endif
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#endif
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#ifdef CONFIG_PPC_BOOK3S_64
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/*
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* rfi fallback flush must be in its own cacheline to prevent
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* other paca data leaking into the L1d
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*/
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u64 exrfi[EX_SIZE] __aligned(0x80);
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void *rfi_flush_fallback_area;
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u64 l1d_flush_size;
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#endif
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#ifdef CONFIG_PPC_PSERIES
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u8 *mce_data_buf; /* buffer to hold per cpu rtas errlog */
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#endif /* CONFIG_PPC_PSERIES */
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#ifdef CONFIG_PPC_BOOK3S_64
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/* Capture SLB related old contents in MCE handler. */
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struct slb_entry *mce_faulty_slbs;
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u16 slb_save_cache_ptr;
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#endif /* CONFIG_PPC_BOOK3S_64 */
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#ifdef CONFIG_STACKPROTECTOR
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unsigned long canary;
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#endif
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#ifdef CONFIG_MMIOWB
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struct mmiowb_state mmiowb_state;
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#endif
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} ____cacheline_aligned;
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extern void copy_mm_to_paca(struct mm_struct *mm);
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extern struct paca_struct **paca_ptrs;
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extern void initialise_paca(struct paca_struct *new_paca, int cpu);
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extern void setup_paca(struct paca_struct *new_paca);
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extern void allocate_paca_ptrs(void);
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extern void allocate_paca(int cpu);
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extern void free_unused_pacas(void);
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#else /* CONFIG_PPC64 */
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static inline void allocate_paca_ptrs(void) { };
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static inline void allocate_paca(int cpu) { };
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static inline void free_unused_pacas(void) { };
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#endif /* CONFIG_PPC64 */
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_PACA_H */
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