OpenCloudOS-Kernel/arch/powerpc/include/asm/interrupt.h

690 lines
20 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later */
#ifndef _ASM_POWERPC_INTERRUPT_H
#define _ASM_POWERPC_INTERRUPT_H
/* BookE/4xx */
#define INTERRUPT_CRITICAL_INPUT 0x100
/* BookE */
#define INTERRUPT_DEBUG 0xd00
#ifdef CONFIG_BOOKE
#define INTERRUPT_PERFMON 0x260
#define INTERRUPT_DOORBELL 0x280
#endif
/* BookS/4xx/8xx */
#define INTERRUPT_MACHINE_CHECK 0x200
/* BookS/8xx */
#define INTERRUPT_SYSTEM_RESET 0x100
/* BookS */
#define INTERRUPT_DATA_SEGMENT 0x380
#define INTERRUPT_INST_SEGMENT 0x480
#define INTERRUPT_TRACE 0xd00
#define INTERRUPT_H_DATA_STORAGE 0xe00
#define INTERRUPT_HMI 0xe60
#define INTERRUPT_H_FAC_UNAVAIL 0xf80
#ifdef CONFIG_PPC_BOOK3S
#define INTERRUPT_DOORBELL 0xa00
#define INTERRUPT_PERFMON 0xf00
#define INTERRUPT_ALTIVEC_UNAVAIL 0xf20
#endif
/* BookE/BookS/4xx/8xx */
#define INTERRUPT_DATA_STORAGE 0x300
#define INTERRUPT_INST_STORAGE 0x400
#define INTERRUPT_EXTERNAL 0x500
#define INTERRUPT_ALIGNMENT 0x600
#define INTERRUPT_PROGRAM 0x700
#define INTERRUPT_SYSCALL 0xc00
#define INTERRUPT_TRACE 0xd00
/* BookE/BookS/44x */
#define INTERRUPT_FP_UNAVAIL 0x800
/* BookE/BookS/44x/8xx */
#define INTERRUPT_DECREMENTER 0x900
#ifndef INTERRUPT_PERFMON
#define INTERRUPT_PERFMON 0x0
#endif
/* 8xx */
#define INTERRUPT_SOFT_EMU_8xx 0x1000
#define INTERRUPT_INST_TLB_MISS_8xx 0x1100
#define INTERRUPT_DATA_TLB_MISS_8xx 0x1200
#define INTERRUPT_INST_TLB_ERROR_8xx 0x1300
#define INTERRUPT_DATA_TLB_ERROR_8xx 0x1400
#define INTERRUPT_DATA_BREAKPOINT_8xx 0x1c00
#define INTERRUPT_INST_BREAKPOINT_8xx 0x1d00
/* 603 */
#define INTERRUPT_INST_TLB_MISS_603 0x1000
#define INTERRUPT_DATA_LOAD_TLB_MISS_603 0x1100
#define INTERRUPT_DATA_STORE_TLB_MISS_603 0x1200
#ifndef __ASSEMBLY__
#include <linux/context_tracking.h>
#include <linux/hardirq.h>
#include <asm/cputime.h>
#include <asm/firmware.h>
#include <asm/ftrace.h>
#include <asm/kprobes.h>
#include <asm/runlatch.h>
#ifdef CONFIG_PPC64
/*
* WARN/BUG is handled with a program interrupt so minimise checks here to
* avoid recursion and maximise the chance of getting the first oops handled.
*/
#define INT_SOFT_MASK_BUG_ON(regs, cond) \
do { \
if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG) && \
(user_mode(regs) || (TRAP(regs) != INTERRUPT_PROGRAM))) \
BUG_ON(cond); \
} while (0)
#endif
#ifdef CONFIG_PPC_BOOK3S_64
extern char __end_soft_masked[];
bool search_kernel_soft_mask_table(unsigned long addr);
unsigned long search_kernel_restart_table(unsigned long addr);
DECLARE_STATIC_KEY_FALSE(interrupt_exit_not_reentrant);
static inline bool is_implicit_soft_masked(struct pt_regs *regs)
{
if (regs->msr & MSR_PR)
return false;
if (regs->nip >= (unsigned long)__end_soft_masked)
return false;
return search_kernel_soft_mask_table(regs->nip);
}
static inline void srr_regs_clobbered(void)
{
local_paca->srr_valid = 0;
local_paca->hsrr_valid = 0;
}
#else
static inline unsigned long search_kernel_restart_table(unsigned long addr)
{
return 0;
}
static inline bool is_implicit_soft_masked(struct pt_regs *regs)
{
return false;
}
static inline void srr_regs_clobbered(void)
{
}
#endif
static inline void nap_adjust_return(struct pt_regs *regs)
{
#ifdef CONFIG_PPC_970_NAP
if (unlikely(test_thread_local_flags(_TLF_NAPPING))) {
/* Can avoid a test-and-clear because NMIs do not call this */
clear_thread_local_flags(_TLF_NAPPING);
regs_set_return_ip(regs, (unsigned long)power4_idle_nap_return);
}
#endif
}
static inline void booke_restore_dbcr0(void)
{
#ifdef CONFIG_PPC_ADV_DEBUG_REGS
unsigned long dbcr0 = current->thread.debug.dbcr0;
if (IS_ENABLED(CONFIG_PPC32) && unlikely(dbcr0 & DBCR0_IDM)) {
mtspr(SPRN_DBSR, -1);
mtspr(SPRN_DBCR0, global_dbcr0[smp_processor_id()]);
}
#endif
}
static inline void interrupt_enter_prepare(struct pt_regs *regs)
{
#ifdef CONFIG_PPC32
if (!arch_irq_disabled_regs(regs))
trace_hardirqs_off();
if (user_mode(regs))
kuap_lock();
else
kuap_save_and_lock(regs);
if (user_mode(regs))
account_cpu_user_entry();
#endif
#ifdef CONFIG_PPC64
bool trace_enable = false;
if (IS_ENABLED(CONFIG_TRACE_IRQFLAGS)) {
if (irq_soft_mask_set_return(IRQS_ALL_DISABLED) == IRQS_ENABLED)
trace_enable = true;
} else {
irq_soft_mask_set(IRQS_ALL_DISABLED);
}
/*
* If the interrupt was taken with HARD_DIS clear, then enable MSR[EE].
* Asynchronous interrupts get here with HARD_DIS set (see below), so
* this enables MSR[EE] for synchronous interrupts. IRQs remain
* soft-masked. The interrupt handler may later call
* interrupt_cond_local_irq_enable() to achieve a regular process
* context.
*/
if (!(local_paca->irq_happened & PACA_IRQ_HARD_DIS)) {
INT_SOFT_MASK_BUG_ON(regs, !(regs->msr & MSR_EE));
__hard_irq_enable();
} else {
__hard_RI_enable();
}
/* Do this when RI=1 because it can cause SLB faults */
if (trace_enable)
trace_hardirqs_off();
if (user_mode(regs)) {
kuap_lock();
CT_WARN_ON(ct_state() != CONTEXT_USER);
user_exit_irqoff();
account_cpu_user_entry();
account_stolen_time();
} else {
kuap_save_and_lock(regs);
/*
* CT_WARN_ON comes here via program_check_exception,
* so avoid recursion.
*/
if (TRAP(regs) != INTERRUPT_PROGRAM)
CT_WARN_ON(ct_state() != CONTEXT_KERNEL &&
ct_state() != CONTEXT_IDLE);
INT_SOFT_MASK_BUG_ON(regs, is_implicit_soft_masked(regs));
INT_SOFT_MASK_BUG_ON(regs, arch_irq_disabled_regs(regs) &&
search_kernel_restart_table(regs->nip));
}
INT_SOFT_MASK_BUG_ON(regs, !arch_irq_disabled_regs(regs) &&
!(regs->msr & MSR_EE));
#endif
booke_restore_dbcr0();
}
/*
* Care should be taken to note that interrupt_exit_prepare and
* interrupt_async_exit_prepare do not necessarily return immediately to
* regs context (e.g., if regs is usermode, we don't necessarily return to
* user mode). Other interrupts might be taken between here and return,
* context switch / preemption may occur in the exit path after this, or a
* signal may be delivered, etc.
*
* The real interrupt exit code is platform specific, e.g.,
* interrupt_exit_user_prepare / interrupt_exit_kernel_prepare for 64s.
*
* However interrupt_nmi_exit_prepare does return directly to regs, because
* NMIs do not do "exit work" or replay soft-masked interrupts.
*/
static inline void interrupt_exit_prepare(struct pt_regs *regs)
{
}
static inline void interrupt_async_enter_prepare(struct pt_regs *regs)
{
#ifdef CONFIG_PPC64
/* Ensure interrupt_enter_prepare does not enable MSR[EE] */
local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
#endif
interrupt_enter_prepare(regs);
#ifdef CONFIG_PPC_BOOK3S_64
/*
* RI=1 is set by interrupt_enter_prepare, so this thread flags access
* has to come afterward (it can cause SLB faults).
*/
if (cpu_has_feature(CPU_FTR_CTRL) &&
!test_thread_local_flags(_TLF_RUNLATCH))
__ppc64_runlatch_on();
#endif
irq_enter();
}
static inline void interrupt_async_exit_prepare(struct pt_regs *regs)
{
/*
* Adjust at exit so the main handler sees the true NIA. This must
* come before irq_exit() because irq_exit can enable interrupts, and
* if another interrupt is taken before nap_adjust_return has run
* here, then that interrupt would return directly to idle nap return.
*/
nap_adjust_return(regs);
irq_exit();
interrupt_exit_prepare(regs);
}
struct interrupt_nmi_state {
#ifdef CONFIG_PPC64
u8 irq_soft_mask;
u8 irq_happened;
u8 ftrace_enabled;
u64 softe;
#endif
};
static inline bool nmi_disables_ftrace(struct pt_regs *regs)
{
/* Allow DEC and PMI to be traced when they are soft-NMI */
if (IS_ENABLED(CONFIG_PPC_BOOK3S_64)) {
if (TRAP(regs) == INTERRUPT_DECREMENTER)
return false;
if (TRAP(regs) == INTERRUPT_PERFMON)
return false;
}
if (IS_ENABLED(CONFIG_PPC_BOOK3E_64)) {
if (TRAP(regs) == INTERRUPT_PERFMON)
return false;
}
return true;
}
static inline void interrupt_nmi_enter_prepare(struct pt_regs *regs, struct interrupt_nmi_state *state)
{
#ifdef CONFIG_PPC64
state->irq_soft_mask = local_paca->irq_soft_mask;
state->irq_happened = local_paca->irq_happened;
state->softe = regs->softe;
/*
* Set IRQS_ALL_DISABLED unconditionally so irqs_disabled() does
* the right thing, and set IRQ_HARD_DIS. We do not want to reconcile
* because that goes through irq tracing which we don't want in NMI.
*/
local_paca->irq_soft_mask = IRQS_ALL_DISABLED;
local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
if (!(regs->msr & MSR_EE) || is_implicit_soft_masked(regs)) {
/*
* Adjust regs->softe to be soft-masked if it had not been
* reconcied (e.g., interrupt entry with MSR[EE]=0 but softe
* not yet set disabled), or if it was in an implicit soft
* masked state. This makes arch_irq_disabled_regs(regs)
* behave as expected.
*/
regs->softe = IRQS_ALL_DISABLED;
}
__hard_RI_enable();
/* Don't do any per-CPU operations until interrupt state is fixed */
if (nmi_disables_ftrace(regs)) {
state->ftrace_enabled = this_cpu_get_ftrace_enabled();
this_cpu_set_ftrace_enabled(0);
}
#endif
/* If data relocations are enabled, it's safe to use nmi_enter() */
if (mfmsr() & MSR_DR) {
nmi_enter();
return;
}
/*
* But do not use nmi_enter() for pseries hash guest taking a real-mode
* NMI because not everything it touches is within the RMA limit.
*/
if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) &&
firmware_has_feature(FW_FEATURE_LPAR) &&
!radix_enabled())
return;
/*
* Likewise, don't use it if we have some form of instrumentation (like
* KASAN shadow) that is not safe to access in real mode (even on radix)
*/
if (IS_ENABLED(CONFIG_KASAN))
return;
/* Otherwise, it should be safe to call it */
nmi_enter();
}
static inline void interrupt_nmi_exit_prepare(struct pt_regs *regs, struct interrupt_nmi_state *state)
{
if (mfmsr() & MSR_DR) {
// nmi_exit if relocations are on
nmi_exit();
} else if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) &&
firmware_has_feature(FW_FEATURE_LPAR) &&
!radix_enabled()) {
// no nmi_exit for a pseries hash guest taking a real mode exception
} else if (IS_ENABLED(CONFIG_KASAN)) {
// no nmi_exit for KASAN in real mode
} else {
nmi_exit();
}
/*
* nmi does not call nap_adjust_return because nmi should not create
* new work to do (must use irq_work for that).
*/
#ifdef CONFIG_PPC64
#ifdef CONFIG_PPC_BOOK3S
if (arch_irq_disabled_regs(regs)) {
unsigned long rst = search_kernel_restart_table(regs->nip);
if (rst)
regs_set_return_ip(regs, rst);
}
#endif
if (nmi_disables_ftrace(regs))
this_cpu_set_ftrace_enabled(state->ftrace_enabled);
/* Check we didn't change the pending interrupt mask. */
WARN_ON_ONCE((state->irq_happened | PACA_IRQ_HARD_DIS) != local_paca->irq_happened);
regs->softe = state->softe;
local_paca->irq_happened = state->irq_happened;
local_paca->irq_soft_mask = state->irq_soft_mask;
#endif
}
/*
* Don't use noinstr here like x86, but rather add NOKPROBE_SYMBOL to each
* function definition. The reason for this is the noinstr section is placed
* after the main text section, i.e., very far away from the interrupt entry
* asm. That creates problems with fitting linker stubs when building large
* kernels.
*/
#define interrupt_handler __visible noinline notrace __no_kcsan __no_sanitize_address
/**
* DECLARE_INTERRUPT_HANDLER_RAW - Declare raw interrupt handler function
* @func: Function name of the entry point
* @returns: Returns a value back to asm caller
*/
#define DECLARE_INTERRUPT_HANDLER_RAW(func) \
__visible long func(struct pt_regs *regs)
/**
* DEFINE_INTERRUPT_HANDLER_RAW - Define raw interrupt handler function
* @func: Function name of the entry point
* @returns: Returns a value back to asm caller
*
* @func is called from ASM entry code.
*
* This is a plain function which does no tracing, reconciling, etc.
* The macro is written so it acts as function definition. Append the
* body with a pair of curly brackets.
*
* raw interrupt handlers must not enable or disable interrupts, or
* schedule, tracing and instrumentation (ftrace, lockdep, etc) would
* not be advisable either, although may be possible in a pinch, the
* trace will look odd at least.
*
* A raw handler may call one of the other interrupt handler functions
* to be converted into that interrupt context without these restrictions.
*
* On PPC64, _RAW handlers may return with fast_interrupt_return.
*
* Specific handlers may have additional restrictions.
*/
#define DEFINE_INTERRUPT_HANDLER_RAW(func) \
static __always_inline __no_sanitize_address __no_kcsan long \
____##func(struct pt_regs *regs); \
\
interrupt_handler long func(struct pt_regs *regs) \
{ \
long ret; \
\
__hard_RI_enable(); \
\
ret = ____##func (regs); \
\
return ret; \
} \
NOKPROBE_SYMBOL(func); \
\
static __always_inline __no_sanitize_address __no_kcsan long \
____##func(struct pt_regs *regs)
/**
* DECLARE_INTERRUPT_HANDLER - Declare synchronous interrupt handler function
* @func: Function name of the entry point
*/
#define DECLARE_INTERRUPT_HANDLER(func) \
__visible void func(struct pt_regs *regs)
/**
* DEFINE_INTERRUPT_HANDLER - Define synchronous interrupt handler function
* @func: Function name of the entry point
*
* @func is called from ASM entry code.
*
* The macro is written so it acts as function definition. Append the
* body with a pair of curly brackets.
*/
#define DEFINE_INTERRUPT_HANDLER(func) \
static __always_inline void ____##func(struct pt_regs *regs); \
\
interrupt_handler void func(struct pt_regs *regs) \
{ \
interrupt_enter_prepare(regs); \
\
____##func (regs); \
\
interrupt_exit_prepare(regs); \
} \
NOKPROBE_SYMBOL(func); \
\
static __always_inline void ____##func(struct pt_regs *regs)
/**
* DECLARE_INTERRUPT_HANDLER_RET - Declare synchronous interrupt handler function
* @func: Function name of the entry point
* @returns: Returns a value back to asm caller
*/
#define DECLARE_INTERRUPT_HANDLER_RET(func) \
__visible long func(struct pt_regs *regs)
/**
* DEFINE_INTERRUPT_HANDLER_RET - Define synchronous interrupt handler function
* @func: Function name of the entry point
* @returns: Returns a value back to asm caller
*
* @func is called from ASM entry code.
*
* The macro is written so it acts as function definition. Append the
* body with a pair of curly brackets.
*/
#define DEFINE_INTERRUPT_HANDLER_RET(func) \
static __always_inline long ____##func(struct pt_regs *regs); \
\
interrupt_handler long func(struct pt_regs *regs) \
{ \
long ret; \
\
interrupt_enter_prepare(regs); \
\
ret = ____##func (regs); \
\
interrupt_exit_prepare(regs); \
\
return ret; \
} \
NOKPROBE_SYMBOL(func); \
\
static __always_inline long ____##func(struct pt_regs *regs)
/**
* DECLARE_INTERRUPT_HANDLER_ASYNC - Declare asynchronous interrupt handler function
* @func: Function name of the entry point
*/
#define DECLARE_INTERRUPT_HANDLER_ASYNC(func) \
__visible void func(struct pt_regs *regs)
/**
* DEFINE_INTERRUPT_HANDLER_ASYNC - Define asynchronous interrupt handler function
* @func: Function name of the entry point
*
* @func is called from ASM entry code.
*
* The macro is written so it acts as function definition. Append the
* body with a pair of curly brackets.
*/
#define DEFINE_INTERRUPT_HANDLER_ASYNC(func) \
static __always_inline void ____##func(struct pt_regs *regs); \
\
interrupt_handler void func(struct pt_regs *regs) \
{ \
interrupt_async_enter_prepare(regs); \
\
____##func (regs); \
\
interrupt_async_exit_prepare(regs); \
} \
NOKPROBE_SYMBOL(func); \
\
static __always_inline void ____##func(struct pt_regs *regs)
/**
* DECLARE_INTERRUPT_HANDLER_NMI - Declare NMI interrupt handler function
* @func: Function name of the entry point
* @returns: Returns a value back to asm caller
*/
#define DECLARE_INTERRUPT_HANDLER_NMI(func) \
__visible long func(struct pt_regs *regs)
/**
* DEFINE_INTERRUPT_HANDLER_NMI - Define NMI interrupt handler function
* @func: Function name of the entry point
* @returns: Returns a value back to asm caller
*
* @func is called from ASM entry code.
*
* The macro is written so it acts as function definition. Append the
* body with a pair of curly brackets.
*/
#define DEFINE_INTERRUPT_HANDLER_NMI(func) \
static __always_inline __no_sanitize_address __no_kcsan long \
____##func(struct pt_regs *regs); \
\
interrupt_handler long func(struct pt_regs *regs) \
{ \
struct interrupt_nmi_state state; \
long ret; \
\
interrupt_nmi_enter_prepare(regs, &state); \
\
ret = ____##func (regs); \
\
interrupt_nmi_exit_prepare(regs, &state); \
\
return ret; \
} \
NOKPROBE_SYMBOL(func); \
\
static __always_inline __no_sanitize_address __no_kcsan long \
____##func(struct pt_regs *regs)
/* Interrupt handlers */
/* kernel/traps.c */
DECLARE_INTERRUPT_HANDLER_NMI(system_reset_exception);
#ifdef CONFIG_PPC_BOOK3S_64
DECLARE_INTERRUPT_HANDLER_RAW(machine_check_early_boot);
DECLARE_INTERRUPT_HANDLER_ASYNC(machine_check_exception_async);
#endif
DECLARE_INTERRUPT_HANDLER_NMI(machine_check_exception);
DECLARE_INTERRUPT_HANDLER(SMIException);
DECLARE_INTERRUPT_HANDLER(handle_hmi_exception);
DECLARE_INTERRUPT_HANDLER(unknown_exception);
DECLARE_INTERRUPT_HANDLER_ASYNC(unknown_async_exception);
DECLARE_INTERRUPT_HANDLER_NMI(unknown_nmi_exception);
DECLARE_INTERRUPT_HANDLER(instruction_breakpoint_exception);
DECLARE_INTERRUPT_HANDLER(RunModeException);
DECLARE_INTERRUPT_HANDLER(single_step_exception);
DECLARE_INTERRUPT_HANDLER(program_check_exception);
DECLARE_INTERRUPT_HANDLER(emulation_assist_interrupt);
DECLARE_INTERRUPT_HANDLER(alignment_exception);
DECLARE_INTERRUPT_HANDLER(StackOverflow);
DECLARE_INTERRUPT_HANDLER(stack_overflow_exception);
DECLARE_INTERRUPT_HANDLER(kernel_fp_unavailable_exception);
DECLARE_INTERRUPT_HANDLER(altivec_unavailable_exception);
DECLARE_INTERRUPT_HANDLER(vsx_unavailable_exception);
DECLARE_INTERRUPT_HANDLER(facility_unavailable_exception);
DECLARE_INTERRUPT_HANDLER(fp_unavailable_tm);
DECLARE_INTERRUPT_HANDLER(altivec_unavailable_tm);
DECLARE_INTERRUPT_HANDLER(vsx_unavailable_tm);
DECLARE_INTERRUPT_HANDLER_NMI(performance_monitor_exception_nmi);
DECLARE_INTERRUPT_HANDLER_ASYNC(performance_monitor_exception_async);
DECLARE_INTERRUPT_HANDLER_RAW(performance_monitor_exception);
DECLARE_INTERRUPT_HANDLER(DebugException);
DECLARE_INTERRUPT_HANDLER(altivec_assist_exception);
DECLARE_INTERRUPT_HANDLER(CacheLockingException);
DECLARE_INTERRUPT_HANDLER(SPEFloatingPointException);
DECLARE_INTERRUPT_HANDLER(SPEFloatingPointRoundException);
DECLARE_INTERRUPT_HANDLER_NMI(WatchdogException);
DECLARE_INTERRUPT_HANDLER(kernel_bad_stack);
/* slb.c */
DECLARE_INTERRUPT_HANDLER_RAW(do_slb_fault);
DECLARE_INTERRUPT_HANDLER(do_bad_segment_interrupt);
/* hash_utils.c */
DECLARE_INTERRUPT_HANDLER(do_hash_fault);
/* fault.c */
DECLARE_INTERRUPT_HANDLER(do_page_fault);
DECLARE_INTERRUPT_HANDLER(do_bad_page_fault_segv);
/* process.c */
DECLARE_INTERRUPT_HANDLER(do_break);
/* time.c */
DECLARE_INTERRUPT_HANDLER_ASYNC(timer_interrupt);
/* mce.c */
DECLARE_INTERRUPT_HANDLER_NMI(machine_check_early);
DECLARE_INTERRUPT_HANDLER_NMI(hmi_exception_realmode);
DECLARE_INTERRUPT_HANDLER_ASYNC(TAUException);
/* irq.c */
DECLARE_INTERRUPT_HANDLER_ASYNC(do_IRQ);
void __noreturn unrecoverable_exception(struct pt_regs *regs);
void replay_system_reset(void);
void replay_soft_interrupts(void);
static inline void interrupt_cond_local_irq_enable(struct pt_regs *regs)
{
if (!arch_irq_disabled_regs(regs))
local_irq_enable();
}
long system_call_exception(struct pt_regs *regs, unsigned long r0);
notrace unsigned long syscall_exit_prepare(unsigned long r3, struct pt_regs *regs, long scv);
notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs);
notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs);
#ifdef CONFIG_PPC64
unsigned long syscall_exit_restart(unsigned long r3, struct pt_regs *regs);
unsigned long interrupt_exit_user_restart(struct pt_regs *regs);
unsigned long interrupt_exit_kernel_restart(struct pt_regs *regs);
#endif
#endif /* __ASSEMBLY__ */
#endif /* _ASM_POWERPC_INTERRUPT_H */