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640e922501
linux_dsm_epyc7002/arch/powerpc/include/asm/processor.h
Joseph Myers 640e922501 powerpc: fix exception clearing in e500 SPE float emulation 
The e500 SPE floating-point emulation code clears existing exceptions
(__FPU_FPSCR &= ~FP_EX_MASK;) before ORing in the exceptions from the
emulated operation.  However, these exception bits are the "sticky",
cumulative exception bits, and should only be cleared by the user
program setting SPEFSCR, not implicitly by any floating-point
instruction (whether executed purely by the hardware or emulated).
The spurious clearing of these bits shows up as missing exceptions in
glibc testing.

Fixing this, however, is not as simple as just not clearing the bits,
because while the bits may be from previous floating-point operations
(in which case they should not be cleared), the processor can also set
the sticky bits itself before the interrupt for an exception occurs,
and this can happen in cases when IEEE 754 semantics are that the
sticky bit should not be set.  Specifically, the "invalid" sticky bit
is set in various cases with non-finite operands, where IEEE 754
semantics do not involve raising such an exception, and the
"underflow" sticky bit is set in cases of exact underflow, whereas
IEEE 754 semantics are that this flag is set only for inexact
underflow.  Thus, for correct emulation the kernel needs to know the
setting of these two sticky bits before the instruction being
emulated.

When a floating-point operation raises an exception, the kernel can
note the state of the sticky bits immediately afterwards.  Some
<fenv.h> functions that affect the state of these bits, such as
fesetenv and feholdexcept, need to use prctl with PR_GET_FPEXC and
PR_SET_FPEXC anyway, and so it is natural to record the state of those
bits during that call into the kernel and so avoid any need for a
separate call into the kernel to inform it of a change to those bits.
Thus, the interface I chose to use (in this patch and the glibc port)
is that one of those prctl calls must be made after any userspace
change to those sticky bits, other than through a floating-point
operation that traps into the kernel anyway.  feclearexcept and
fesetexceptflag duly make those calls, which would not be required
were it not for this issue.

The previous EGLIBC port, and the uClibc code copied from it, is
fundamentally broken as regards any use of prctl for floating-point
exceptions because it didn't use the PR_FP_EXC_SW_ENABLE bit in its
prctl calls (and did various worse things, such as passing a pointer
when prctl expected an integer).  If you avoid anything where prctl is
used, the clearing of sticky bits still means it will never give
anything approximating correct exception semantics with existing
kernels.  I don't believe the patch makes things any worse for
existing code that doesn't try to inform the kernel of changes to
sticky bits - such code may get incorrect exceptions in some cases,
but it would have done so anyway in other cases.

Signed-off-by: Joseph Myers <joseph@codesourcery.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
2014-01-07 18:32:21 -06:00

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#ifndef _ASM_POWERPC_PROCESSOR_H
#define _ASM_POWERPC_PROCESSOR_H
/*
* Copyright (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.
*/
#include <asm/reg.h>
#ifdef CONFIG_VSX
#define TS_FPRWIDTH 2
#ifdef __BIG_ENDIAN__
#define TS_FPROFFSET 0
#define TS_VSRLOWOFFSET 1
#else
#define TS_FPROFFSET 1
#define TS_VSRLOWOFFSET 0
#endif
#else
#define TS_FPRWIDTH 1
#define TS_FPROFFSET 0
#endif
#ifdef CONFIG_PPC64
/* Default SMT priority is set to 3. Use 11- 13bits to save priority. */
#define PPR_PRIORITY 3
#ifdef __ASSEMBLY__
#define INIT_PPR (PPR_PRIORITY << 50)
#else
#define INIT_PPR ((u64)PPR_PRIORITY << 50)
#endif /* __ASSEMBLY__ */
#endif /* CONFIG_PPC64 */
#ifndef __ASSEMBLY__
#include <linux/compiler.h>
#include <linux/cache.h>
#include <asm/ptrace.h>
#include <asm/types.h>
#include <asm/hw_breakpoint.h>
/* We do _not_ want to define new machine types at all, those must die
* in favor of using the device-tree
* -- BenH.
*/
/* PREP sub-platform types. Unused */
#define _PREP_Motorola 0x01 /* motorola prep */
#define _PREP_Firm 0x02 /* firmworks prep */
#define _PREP_IBM 0x00 /* ibm prep */
#define _PREP_Bull 0x03 /* bull prep */
/* CHRP sub-platform types. These are arbitrary */
#define _CHRP_Motorola 0x04 /* motorola chrp, the cobra */
#define _CHRP_IBM 0x05 /* IBM chrp, the longtrail and longtrail 2 */
#define _CHRP_Pegasos 0x06 /* Genesi/bplan's Pegasos and Pegasos2 */
#define _CHRP_briq 0x07 /* TotalImpact's briQ */
#if defined(__KERNEL__) && defined(CONFIG_PPC32)
extern int _chrp_type;
#endif /* defined(__KERNEL__) && defined(CONFIG_PPC32) */
/*
* Default implementation of macro that returns current
* instruction pointer ("program counter").
*/
#define current_text_addr() ({ __label__ _l; _l: &&_l;})
/* Macros for adjusting thread priority (hardware multi-threading) */
#define HMT_very_low() asm volatile("or 31,31,31 # very low priority")
#define HMT_low() asm volatile("or 1,1,1 # low priority")
#define HMT_medium_low() asm volatile("or 6,6,6 # medium low priority")
#define HMT_medium() asm volatile("or 2,2,2 # medium priority")
#define HMT_medium_high() asm volatile("or 5,5,5 # medium high priority")
#define HMT_high() asm volatile("or 3,3,3 # high priority")
#ifdef __KERNEL__
struct task_struct;
void start_thread(struct pt_regs *regs, unsigned long fdptr, unsigned long sp);
void release_thread(struct task_struct *);
/* Lazy FPU handling on uni-processor */
extern struct task_struct *last_task_used_math;
extern struct task_struct *last_task_used_altivec;
extern struct task_struct *last_task_used_vsx;
extern struct task_struct *last_task_used_spe;
#ifdef CONFIG_PPC32
#if CONFIG_TASK_SIZE > CONFIG_KERNEL_START
#error User TASK_SIZE overlaps with KERNEL_START address
#endif
#define TASK_SIZE (CONFIG_TASK_SIZE)
/* This decides where the kernel will search for a free chunk of vm
* space during mmap's.
*/
#define TASK_UNMAPPED_BASE (TASK_SIZE / 8 * 3)
#endif
#ifdef CONFIG_PPC64
/* 64-bit user address space is 46-bits (64TB user VM) */
#define TASK_SIZE_USER64 (0x0000400000000000UL)
/*
* 32-bit user address space is 4GB - 1 page
* (this 1 page is needed so referencing of 0xFFFFFFFF generates EFAULT
*/
#define TASK_SIZE_USER32 (0x0000000100000000UL - (1*PAGE_SIZE))
#define TASK_SIZE_OF(tsk) (test_tsk_thread_flag(tsk, TIF_32BIT) ? \
TASK_SIZE_USER32 : TASK_SIZE_USER64)
#define TASK_SIZE TASK_SIZE_OF(current)
/* This decides where the kernel will search for a free chunk of vm
* space during mmap's.
*/
#define TASK_UNMAPPED_BASE_USER32 (PAGE_ALIGN(TASK_SIZE_USER32 / 4))
#define TASK_UNMAPPED_BASE_USER64 (PAGE_ALIGN(TASK_SIZE_USER64 / 4))
#define TASK_UNMAPPED_BASE ((is_32bit_task()) ? \
TASK_UNMAPPED_BASE_USER32 : TASK_UNMAPPED_BASE_USER64 )
#endif
#ifdef __powerpc64__
#define STACK_TOP_USER64 TASK_SIZE_USER64
#define STACK_TOP_USER32 TASK_SIZE_USER32
#define STACK_TOP (is_32bit_task() ? \
STACK_TOP_USER32 : STACK_TOP_USER64)
#define STACK_TOP_MAX STACK_TOP_USER64
#else /* __powerpc64__ */
#define STACK_TOP TASK_SIZE
#define STACK_TOP_MAX STACK_TOP
#endif /* __powerpc64__ */
typedef struct {
unsigned long seg;
} mm_segment_t;
#define TS_FPR(i) fp_state.fpr[i][TS_FPROFFSET]
#define TS_TRANS_FPR(i) transact_fp.fpr[i][TS_FPROFFSET]
/* FP and VSX 0-31 register set */
struct thread_fp_state {
u64 fpr[32][TS_FPRWIDTH] __attribute__((aligned(16)));
u64 fpscr; /* Floating point status */
};
/* Complete AltiVec register set including VSCR */
struct thread_vr_state {
vector128 vr[32] __attribute__((aligned(16)));
vector128 vscr __attribute__((aligned(16)));
};
struct debug_reg {
#ifdef CONFIG_PPC_ADV_DEBUG_REGS
/*
* The following help to manage the use of Debug Control Registers
* om the BookE platforms.
*/
uint32_t dbcr0;
uint32_t dbcr1;
#ifdef CONFIG_BOOKE
uint32_t dbcr2;
#endif
/*
* The stored value of the DBSR register will be the value at the
* last debug interrupt. This register can only be read from the
* user (will never be written to) and has value while helping to
* describe the reason for the last debug trap. Torez
*/
uint32_t dbsr;
/*
* The following will contain addresses used by debug applications
* to help trace and trap on particular address locations.
* The bits in the Debug Control Registers above help define which
* of the following registers will contain valid data and/or addresses.
*/
unsigned long iac1;
unsigned long iac2;
#if CONFIG_PPC_ADV_DEBUG_IACS > 2
unsigned long iac3;
unsigned long iac4;
#endif
unsigned long dac1;
unsigned long dac2;
#if CONFIG_PPC_ADV_DEBUG_DVCS > 0
unsigned long dvc1;
unsigned long dvc2;
#endif
#endif
};
struct thread_struct {
unsigned long ksp; /* Kernel stack pointer */
#ifdef CONFIG_PPC64
unsigned long ksp_vsid;
#endif
struct pt_regs *regs; /* Pointer to saved register state */
mm_segment_t fs; /* for get_fs() validation */
#ifdef CONFIG_BOOKE
/* BookE base exception scratch space; align on cacheline */
unsigned long normsave[8] ____cacheline_aligned;
#endif
#ifdef CONFIG_PPC32
void *pgdir; /* root of page-table tree */
unsigned long ksp_limit; /* if ksp <= ksp_limit stack overflow */
#endif
/* Debug Registers */
struct debug_reg debug;
struct thread_fp_state fp_state;
struct thread_fp_state *fp_save_area;
int fpexc_mode; /* floating-point exception mode */
unsigned int align_ctl; /* alignment handling control */
#ifdef CONFIG_PPC64
unsigned long start_tb; /* Start purr when proc switched in */
unsigned long accum_tb; /* Total accumilated purr for process */
#ifdef CONFIG_HAVE_HW_BREAKPOINT
struct perf_event *ptrace_bps[HBP_NUM];
/*
* Helps identify source of single-step exception and subsequent
* hw-breakpoint enablement
*/
struct perf_event *last_hit_ubp;
#endif /* CONFIG_HAVE_HW_BREAKPOINT */
#endif
struct arch_hw_breakpoint hw_brk; /* info on the hardware breakpoint */
unsigned long trap_nr; /* last trap # on this thread */
#ifdef CONFIG_ALTIVEC
struct thread_vr_state vr_state;
struct thread_vr_state *vr_save_area;
unsigned long vrsave;
int used_vr; /* set if process has used altivec */
#endif /* CONFIG_ALTIVEC */
#ifdef CONFIG_VSX
/* VSR status */
int used_vsr; /* set if process has used altivec */
#endif /* CONFIG_VSX */
#ifdef CONFIG_SPE
unsigned long evr[32]; /* upper 32-bits of SPE regs */
u64 acc; /* Accumulator */
unsigned long spefscr; /* SPE & eFP status */
unsigned long spefscr_last; /* SPEFSCR value on last prctl
call or trap return */
int used_spe; /* set if process has used spe */
#endif /* CONFIG_SPE */
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
u64 tm_tfhar; /* Transaction fail handler addr */
u64 tm_texasr; /* Transaction exception & summary */
u64 tm_tfiar; /* Transaction fail instr address reg */
unsigned long tm_orig_msr; /* Thread's MSR on ctx switch */
struct pt_regs ckpt_regs; /* Checkpointed registers */
unsigned long tm_tar;
unsigned long tm_ppr;
unsigned long tm_dscr;
/*
* Transactional FP and VSX 0-31 register set.
* NOTE: the sense of these is the opposite of the integer ckpt_regs!
*
* When a transaction is active/signalled/scheduled etc., *regs is the
* most recent set of/speculated GPRs with ckpt_regs being the older
* checkpointed regs to which we roll back if transaction aborts.
*
* However, fpr[] is the checkpointed 'base state' of FP regs, and
* transact_fpr[] is the new set of transactional values.
* VRs work the same way.
*/
struct thread_fp_state transact_fp;
struct thread_vr_state transact_vr;
unsigned long transact_vrsave;
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
#ifdef CONFIG_KVM_BOOK3S_32_HANDLER
void* kvm_shadow_vcpu; /* KVM internal data */
#endif /* CONFIG_KVM_BOOK3S_32_HANDLER */
#if defined(CONFIG_KVM) && defined(CONFIG_BOOKE)
struct kvm_vcpu *kvm_vcpu;
#endif
#ifdef CONFIG_PPC64
unsigned long dscr;
int dscr_inherit;
unsigned long ppr; /* used to save/restore SMT priority */
#endif
#ifdef CONFIG_PPC_BOOK3S_64
unsigned long tar;
unsigned long ebbrr;
unsigned long ebbhr;
unsigned long bescr;
unsigned long siar;
unsigned long sdar;
unsigned long sier;
unsigned long mmcr2;
unsigned mmcr0;
unsigned used_ebb;
#endif
};
#define ARCH_MIN_TASKALIGN 16
#define INIT_SP (sizeof(init_stack) + (unsigned long) &init_stack)
#define INIT_SP_LIMIT \
(_ALIGN_UP(sizeof(init_thread_info), 16) + (unsigned long) &init_stack)
#ifdef CONFIG_SPE
#define SPEFSCR_INIT \
.spefscr = SPEFSCR_FINVE | SPEFSCR_FDBZE | SPEFSCR_FUNFE | SPEFSCR_FOVFE, \
.spefscr_last = SPEFSCR_FINVE | SPEFSCR_FDBZE | SPEFSCR_FUNFE | SPEFSCR_FOVFE,
#else
#define SPEFSCR_INIT
#endif
#ifdef CONFIG_PPC32
#define INIT_THREAD { \
.ksp = INIT_SP, \
.ksp_limit = INIT_SP_LIMIT, \
.fs = KERNEL_DS, \
.pgdir = swapper_pg_dir, \
.fpexc_mode = MSR_FE0 | MSR_FE1, \
SPEFSCR_INIT \
}
#else
#define INIT_THREAD { \
.ksp = INIT_SP, \
.regs = (struct pt_regs *)INIT_SP - 1, /* XXX bogus, I think */ \
.fs = KERNEL_DS, \
.fpexc_mode = 0, \
.ppr = INIT_PPR, \
}
#endif
/*
* Return saved PC of a blocked thread. For now, this is the "user" PC
*/
#define thread_saved_pc(tsk) \
((tsk)->thread.regs? (tsk)->thread.regs->nip: 0)
#define task_pt_regs(tsk) ((struct pt_regs *)(tsk)->thread.regs)
unsigned long get_wchan(struct task_struct *p);
#define KSTK_EIP(tsk) ((tsk)->thread.regs? (tsk)->thread.regs->nip: 0)
#define KSTK_ESP(tsk) ((tsk)->thread.regs? (tsk)->thread.regs->gpr[1]: 0)
/* Get/set floating-point exception mode */
#define GET_FPEXC_CTL(tsk, adr) get_fpexc_mode((tsk), (adr))
#define SET_FPEXC_CTL(tsk, val) set_fpexc_mode((tsk), (val))
extern int get_fpexc_mode(struct task_struct *tsk, unsigned long adr);
extern int set_fpexc_mode(struct task_struct *tsk, unsigned int val);
#define GET_ENDIAN(tsk, adr) get_endian((tsk), (adr))
#define SET_ENDIAN(tsk, val) set_endian((tsk), (val))
extern int get_endian(struct task_struct *tsk, unsigned long adr);
extern int set_endian(struct task_struct *tsk, unsigned int val);
#define GET_UNALIGN_CTL(tsk, adr) get_unalign_ctl((tsk), (adr))
#define SET_UNALIGN_CTL(tsk, val) set_unalign_ctl((tsk), (val))
extern int get_unalign_ctl(struct task_struct *tsk, unsigned long adr);
extern int set_unalign_ctl(struct task_struct *tsk, unsigned int val);
extern void load_fp_state(struct thread_fp_state *fp);
extern void store_fp_state(struct thread_fp_state *fp);
extern void load_vr_state(struct thread_vr_state *vr);
extern void store_vr_state(struct thread_vr_state *vr);
static inline unsigned int __unpack_fe01(unsigned long msr_bits)
{
return ((msr_bits & MSR_FE0) >> 10) | ((msr_bits & MSR_FE1) >> 8);
}
static inline unsigned long __pack_fe01(unsigned int fpmode)
{
return ((fpmode << 10) & MSR_FE0) | ((fpmode << 8) & MSR_FE1);
}
#ifdef CONFIG_PPC64
#define cpu_relax() do { HMT_low(); HMT_medium(); barrier(); } while (0)
#else
#define cpu_relax() barrier()
#endif
/* Check that a certain kernel stack pointer is valid in task_struct p */
int validate_sp(unsigned long sp, struct task_struct *p,
unsigned long nbytes);
/*
* Prefetch macros.
*/
#define ARCH_HAS_PREFETCH
#define ARCH_HAS_PREFETCHW
#define ARCH_HAS_SPINLOCK_PREFETCH
static inline void prefetch(const void *x)
{
if (unlikely(!x))
return;
__asm__ __volatile__ ("dcbt 0,%0" : : "r" (x));
}
static inline void prefetchw(const void *x)
{
if (unlikely(!x))
return;
__asm__ __volatile__ ("dcbtst 0,%0" : : "r" (x));
}
#define spin_lock_prefetch(x) prefetchw(x)
#define HAVE_ARCH_PICK_MMAP_LAYOUT
#ifdef CONFIG_PPC64
static inline unsigned long get_clean_sp(unsigned long sp, int is_32)
{
if (is_32)
return sp & 0x0ffffffffUL;
return sp;
}
#else
static inline unsigned long get_clean_sp(unsigned long sp, int is_32)
{
return sp;
}
#endif
extern unsigned long cpuidle_disable;
enum idle_boot_override {IDLE_NO_OVERRIDE = 0, IDLE_POWERSAVE_OFF};
extern int powersave_nap; /* set if nap mode can be used in idle loop */
extern void power7_nap(void);
#ifdef CONFIG_PSERIES_IDLE
extern void update_smt_snooze_delay(int cpu, int residency);
#else
static inline void update_smt_snooze_delay(int cpu, int residency) {}
#endif
extern void flush_instruction_cache(void);
extern void hard_reset_now(void);
extern void poweroff_now(void);
extern int fix_alignment(struct pt_regs *);
extern void cvt_fd(float *from, double *to);
extern void cvt_df(double *from, float *to);
extern void _nmask_and_or_msr(unsigned long nmask, unsigned long or_val);
#ifdef CONFIG_PPC64
/*
* We handle most unaligned accesses in hardware. On the other hand
* unaligned DMA can be very expensive on some ppc64 IO chips (it does
* powers of 2 writes until it reaches sufficient alignment).
*
* Based on this we disable the IP header alignment in network drivers.
*/
#define NET_IP_ALIGN 0
#endif
#endif /* __KERNEL__ */
#endif /* __ASSEMBLY__ */
#endif /* _ASM_POWERPC_PROCESSOR_H */
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