From a1cddb88920b915eaba10712ecfd0fc698b00a22 Mon Sep 17 00:00:00 2001 From: Jack Steiner Date: Wed, 31 Aug 2005 08:05:00 -0700 Subject: [IA64-SGI] Add new vendor-specific SAL calls for: - notifying the PROM of specific features that are supported by the OS. This is used to enable PROM feature if and only if the corresponding feature is implemented in the OS - fetch feature sets that are supported by the current PROM. This allows the OS to selectively enable features when the PROM support is available. Signed-off-by: Jack Steiner Signed-off-by: Tony Luck --- include/asm-ia64/sn/sn_feature_sets.h | 57 +++++++++++++++++++++++++++++++++++ include/asm-ia64/sn/sn_sal.h | 36 ++++++++++++++++------ 2 files changed, 84 insertions(+), 9 deletions(-) create mode 100644 include/asm-ia64/sn/sn_feature_sets.h (limited to 'include') diff --git a/include/asm-ia64/sn/sn_feature_sets.h b/include/asm-ia64/sn/sn_feature_sets.h new file mode 100644 index 00000000000..e68a80853d5 --- /dev/null +++ b/include/asm-ia64/sn/sn_feature_sets.h @@ -0,0 +1,57 @@ +#ifndef _ASM_IA64_SN_FEATURE_SETS_H +#define _ASM_IA64_SN_FEATURE_SETS_H + +/* + * SN PROM Features + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (c) 2005 Silicon Graphics, Inc. All rights reserved. + */ + + +#include +#include + +/* --------------------- PROM Features -----------------------------*/ +extern int sn_prom_feature_available(int id); + +#define MAX_PROM_FEATURE_SETS 2 + +/* + * The following defines features that may or may not be supported by the + * current PROM. The OS uses sn_prom_feature_available(feature) to test for + * the presence of a PROM feature. Down rev (old) PROMs will always test + * "false" for new features. + * + * Use: + * if (sn_prom_feature_available(PRF_FEATURE_XXX)) + * ... + */ + +/* + * Example: feature XXX + */ +#define PRF_FEATURE_XXX 0 + + + +/* --------------------- OS Features -------------------------------*/ + +/* + * The following defines OS features that are optionally present in + * the operating system. + * During boot, PROM is notified of these features via a series of calls: + * + * ia64_sn_set_os_feature(feature1); + * + * Once enabled, a feature cannot be disabled. + * + * By default, features are disabled unless explicitly enabled. + */ +#define OSF_MCA_SLV_TO_OS_INIT_SLV 0 +#define OSF_FEAT_LOG_SBES 1 + +#endif /* _ASM_IA64_SN_FEATURE_SETS_H */ diff --git a/include/asm-ia64/sn/sn_sal.h b/include/asm-ia64/sn/sn_sal.h index 27976d22318..231d0d04c3e 100644 --- a/include/asm-ia64/sn/sn_sal.h +++ b/include/asm-ia64/sn/sn_sal.h @@ -80,6 +80,9 @@ #define SN_SAL_BTE_RECOVER 0x02000061 #define SN_SAL_IOIF_GET_PCI_TOPOLOGY 0x02000062 +#define SN_SAL_GET_PROM_FEATURE_SET 0x02000065 +#define SN_SAL_SET_OS_FEATURE_SET 0x02000066 + /* * Service-specific constants */ @@ -118,8 +121,8 @@ /* * Error Handling Features */ -#define SAL_ERR_FEAT_MCA_SLV_TO_OS_INIT_SLV 0x1 -#define SAL_ERR_FEAT_LOG_SBES 0x2 +#define SAL_ERR_FEAT_MCA_SLV_TO_OS_INIT_SLV 0x1 // obsolete +#define SAL_ERR_FEAT_LOG_SBES 0x2 // obsolete #define SAL_ERR_FEAT_MFR_OVERRIDE 0x4 #define SAL_ERR_FEAT_SBE_THRESHOLD 0xffff0000 @@ -151,12 +154,6 @@ sn_sal_rev(void) return (u32)(systab->sal_b_rev_major << 8 | systab->sal_b_rev_minor); } -/* - * Specify the minimum PROM revsion required for this kernel. - * Note that they're stored in hex format... - */ -#define SN_SAL_MIN_VERSION 0x0404 - /* * Returns the master console nasid, if the call fails, return an illegal * value. @@ -336,7 +333,7 @@ ia64_sn_plat_cpei_handler(void) } /* - * Set Error Handling Features + * Set Error Handling Features (Obsolete) */ static inline u64 ia64_sn_plat_set_error_handling_features(void) @@ -1100,4 +1097,25 @@ ia64_sn_is_fake_prom(void) return (rv.status == 0); } +static inline int +ia64_sn_get_prom_feature_set(int set, unsigned long *feature_set) +{ + struct ia64_sal_retval rv; + + SAL_CALL_NOLOCK(rv, SN_SAL_GET_PROM_FEATURE_SET, set, 0, 0, 0, 0, 0, 0); + if (rv.status != 0) + return rv.status; + *feature_set = rv.v0; + return 0; +} + +static inline int +ia64_sn_set_os_feature(int feature) +{ + struct ia64_sal_retval rv; + + SAL_CALL_NOLOCK(rv, SN_SAL_SET_OS_FEATURE_SET, feature, 0, 0, 0, 0, 0, 0); + return rv.status; +} + #endif /* _ASM_IA64_SN_SN_SAL_H */ -- cgit v1.2.3 From a2a979821b6ab75a4f143cfaa1c4672cc259ec10 Mon Sep 17 00:00:00 2001 From: Keith Owens Date: Sun, 11 Sep 2005 17:19:06 +1000 Subject: [PATCH] MCA/INIT: scheduler hooks Scheduler hooks to see/change which process is deemed to be on a cpu. Signed-off-by: Keith Owens Signed-off-by: Tony Luck --- include/linux/sched.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/linux/sched.h b/include/linux/sched.h index 4b83cb23000..ed3bb19d133 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -904,6 +904,8 @@ extern int task_curr(const task_t *p); extern int idle_cpu(int cpu); extern int sched_setscheduler(struct task_struct *, int, struct sched_param *); extern task_t *idle_task(int cpu); +extern task_t *curr_task(int cpu); +extern void set_curr_task(int cpu, task_t *p); void yield(void); -- cgit v1.2.3 From e619ae0b96b6ace6629a6a0c6a5db23861ddaa78 Mon Sep 17 00:00:00 2001 From: Keith Owens Date: Sun, 11 Sep 2005 17:20:14 +1000 Subject: [IA64] MCA/INIT: add an extra thread_info flag Add an extra thread_info flag to indicate the special MCA/INIT stacks. Mainly for debuggers. Signed-off-by: Keith Owens Signed-off-by: Tony Luck --- include/asm-ia64/ptrace.h | 2 +- include/asm-ia64/thread_info.h | 2 ++ 2 files changed, 3 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/asm-ia64/ptrace.h b/include/asm-ia64/ptrace.h index c8766def9ee..fc544929ac3 100644 --- a/include/asm-ia64/ptrace.h +++ b/include/asm-ia64/ptrace.h @@ -119,7 +119,7 @@ struct pt_regs { unsigned long ar_unat; /* interrupted task's NaT register (preserved) */ unsigned long ar_pfs; /* prev function state */ unsigned long ar_rsc; /* RSE configuration */ - /* The following two are valid only if cr_ipsr.cpl > 0: */ + /* The following two are valid only if cr_ipsr.cpl > 0 || ti->flags & _TIF_MCA_INIT */ unsigned long ar_rnat; /* RSE NaT */ unsigned long ar_bspstore; /* RSE bspstore */ diff --git a/include/asm-ia64/thread_info.h b/include/asm-ia64/thread_info.h index b2c79f0694f..cf4a950a0f4 100644 --- a/include/asm-ia64/thread_info.h +++ b/include/asm-ia64/thread_info.h @@ -76,6 +76,7 @@ struct thread_info { #define TIF_SIGDELAYED 5 /* signal delayed from MCA/INIT/NMI/PMI context */ #define TIF_POLLING_NRFLAG 16 /* true if poll_idle() is polling TIF_NEED_RESCHED */ #define TIF_MEMDIE 17 +#define TIF_MCA_INIT 18 /* this task is processing MCA or INIT */ #define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE) #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT) @@ -85,6 +86,7 @@ struct thread_info { #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) #define _TIF_SIGDELAYED (1 << TIF_SIGDELAYED) #define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG) +#define _TIF_MCA_INIT (1 << TIF_MCA_INIT) /* "work to do on user-return" bits */ #define TIF_ALLWORK_MASK (_TIF_NOTIFY_RESUME|_TIF_SIGPENDING|_TIF_NEED_RESCHED|_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SIGDELAYED) -- cgit v1.2.3 From 7f613c7d2203ae137d98fc1c38abc30fd7048637 Mon Sep 17 00:00:00 2001 From: Keith Owens Date: Sun, 11 Sep 2005 17:22:53 +1000 Subject: [PATCH] MCA/INIT: use per cpu stacks The bulk of the change. Use per cpu MCA/INIT stacks. Change the SAL to OS state (sos) to be per process. Do all the assembler work on the MCA/INIT stacks, leaving the original stack alone. Pass per cpu state data to the C handlers for MCA and INIT, which also means changing the mca_drv interfaces slightly. Lots of verification on whether the original stack is usable before converting it to a sleeping process. Signed-off-by: Keith Owens Signed-off-by: Tony Luck --- include/asm-ia64/mca.h | 102 ++++++++++++++++++++++-------------- include/asm-ia64/mca_asm.h | 125 ++++++++++----------------------------------- 2 files changed, 91 insertions(+), 136 deletions(-) (limited to 'include') diff --git a/include/asm-ia64/mca.h b/include/asm-ia64/mca.h index 149ad011845..97a28b8b2dd 100644 --- a/include/asm-ia64/mca.h +++ b/include/asm-ia64/mca.h @@ -11,8 +11,6 @@ #ifndef _ASM_IA64_MCA_H #define _ASM_IA64_MCA_H -#define IA64_MCA_STACK_SIZE 8192 - #if !defined(__ASSEMBLY__) #include @@ -48,7 +46,8 @@ typedef union cmcv_reg_u { enum { IA64_MCA_RENDEZ_CHECKIN_NOTDONE = 0x0, - IA64_MCA_RENDEZ_CHECKIN_DONE = 0x1 + IA64_MCA_RENDEZ_CHECKIN_DONE = 0x1, + IA64_MCA_RENDEZ_CHECKIN_INIT = 0x2, }; /* Information maintained by the MC infrastructure */ @@ -63,18 +62,42 @@ typedef struct ia64_mc_info_s { } ia64_mc_info_t; -typedef struct ia64_mca_sal_to_os_state_s { - u64 imsto_os_gp; /* GP of the os registered with the SAL */ - u64 imsto_pal_proc; /* PAL_PROC entry point - physical addr */ - u64 imsto_sal_proc; /* SAL_PROC entry point - physical addr */ - u64 imsto_sal_gp; /* GP of the SAL - physical */ - u64 imsto_rendez_state; /* Rendez state information */ - u64 imsto_sal_check_ra; /* Return address in SAL_CHECK while going - * back to SAL from OS after MCA handling. - */ - u64 pal_min_state; /* from PAL in r17 */ - u64 proc_state_param; /* from PAL in r18. See SDV 2:268 11.3.2.1 */ -} ia64_mca_sal_to_os_state_t; +/* Handover state from SAL to OS and vice versa, for both MCA and INIT events. + * Besides the handover state, it also contains some saved registers from the + * time of the event. + * Note: mca_asm.S depends on the precise layout of this structure. + */ + +struct ia64_sal_os_state { + /* SAL to OS, must be at offset 0 */ + u64 os_gp; /* GP of the os registered with the SAL, physical */ + u64 pal_proc; /* PAL_PROC entry point, physical */ + u64 sal_proc; /* SAL_PROC entry point, physical */ + u64 rv_rc; /* MCA - Rendezvous state, INIT - reason code */ + u64 proc_state_param; /* from R18 */ + u64 monarch; /* 1 for a monarch event, 0 for a slave */ + /* common, must follow SAL to OS */ + u64 sal_ra; /* Return address in SAL, physical */ + u64 sal_gp; /* GP of the SAL - physical */ + pal_min_state_area_t *pal_min_state; /* from R17. physical in asm, virtual in C */ + u64 prev_IA64_KR_CURRENT; /* previous value of IA64_KR(CURRENT) */ + struct task_struct *prev_task; /* previous task, NULL if it is not useful */ + /* Some interrupt registers are not saved in minstate, pt_regs or + * switch_stack. Because MCA/INIT can occur when interrupts are + * disabled, we need to save the additional interrupt registers over + * MCA/INIT and resume. + */ + u64 isr; + u64 ifa; + u64 itir; + u64 iipa; + u64 iim; + u64 iha; + /* OS to SAL, must follow common */ + u64 os_status; /* OS status to SAL, enum below */ + u64 context; /* 0 if return to same context + 1 if return to new context */ +}; enum { IA64_MCA_CORRECTED = 0x0, /* Error has been corrected by OS_MCA */ @@ -83,36 +106,22 @@ enum { IA64_MCA_HALT = -3 /* System to be halted by SAL */ }; +enum { + IA64_INIT_RESUME = 0x0, /* Resume after return from INIT */ + IA64_INIT_WARM_BOOT = -1, /* Warm boot of the system need from SAL */ +}; + enum { IA64_MCA_SAME_CONTEXT = 0x0, /* SAL to return to same context */ IA64_MCA_NEW_CONTEXT = -1 /* SAL to return to new context */ }; -typedef struct ia64_mca_os_to_sal_state_s { - u64 imots_os_status; /* OS status to SAL as to what happened - * with the MCA handling. - */ - u64 imots_sal_gp; /* GP of the SAL - physical */ - u64 imots_context; /* 0 if return to same context - 1 if return to new context */ - u64 *imots_new_min_state; /* Pointer to structure containing - * new values of registers in the min state - * save area. - */ - u64 imots_sal_check_ra; /* Return address in SAL_CHECK while going - * back to SAL from OS after MCA handling. - */ -} ia64_mca_os_to_sal_state_t; - /* Per-CPU MCA state that is too big for normal per-CPU variables. */ struct ia64_mca_cpu { - u64 stack[IA64_MCA_STACK_SIZE/8]; /* MCA memory-stack */ - u64 proc_state_dump[512]; - u64 stackframe[32]; - u64 rbstore[IA64_MCA_STACK_SIZE/8]; /* MCA reg.-backing store */ + u64 mca_stack[KERNEL_STACK_SIZE/8]; u64 init_stack[KERNEL_STACK_SIZE/8]; -} __attribute__ ((aligned(16))); +}; /* Array of physical addresses of each CPU's MCA area. */ extern unsigned long __per_cpu_mca[NR_CPUS]; @@ -121,12 +130,29 @@ extern void ia64_mca_init(void); extern void ia64_mca_cpu_init(void *); extern void ia64_os_mca_dispatch(void); extern void ia64_os_mca_dispatch_end(void); -extern void ia64_mca_ucmc_handler(void); +extern void ia64_mca_ucmc_handler(struct pt_regs *, struct ia64_sal_os_state *); +extern void ia64_init_handler(struct pt_regs *, + struct switch_stack *, + struct ia64_sal_os_state *); extern void ia64_monarch_init_handler(void); extern void ia64_slave_init_handler(void); extern void ia64_mca_cmc_vector_setup(void); -extern int ia64_reg_MCA_extension(void*); +extern int ia64_reg_MCA_extension(int (*fn)(void *, struct ia64_sal_os_state *)); extern void ia64_unreg_MCA_extension(void); +extern u64 ia64_get_rnat(u64 *); + +#else /* __ASSEMBLY__ */ + +#define IA64_MCA_CORRECTED 0x0 /* Error has been corrected by OS_MCA */ +#define IA64_MCA_WARM_BOOT -1 /* Warm boot of the system need from SAL */ +#define IA64_MCA_COLD_BOOT -2 /* Cold boot of the system need from SAL */ +#define IA64_MCA_HALT -3 /* System to be halted by SAL */ + +#define IA64_INIT_RESUME 0x0 /* Resume after return from INIT */ +#define IA64_INIT_WARM_BOOT -1 /* Warm boot of the system need from SAL */ + +#define IA64_MCA_SAME_CONTEXT 0x0 /* SAL to return to same context */ +#define IA64_MCA_NEW_CONTEXT -1 /* SAL to return to new context */ #endif /* !__ASSEMBLY__ */ #endif /* _ASM_IA64_MCA_H */ diff --git a/include/asm-ia64/mca_asm.h b/include/asm-ia64/mca_asm.h index 836953e0f91..27c9203d8ce 100644 --- a/include/asm-ia64/mca_asm.h +++ b/include/asm-ia64/mca_asm.h @@ -8,6 +8,8 @@ * Copyright (C) 2000 David Mosberger-Tang * Copyright (C) 2002 Intel Corp. * Copyright (C) 2002 Jenna Hall + * Copyright (C) 2005 Silicon Graphics, Inc + * Copyright (C) 2005 Keith Owens */ #ifndef _ASM_IA64_MCA_ASM_H #define _ASM_IA64_MCA_ASM_H @@ -207,106 +209,33 @@ ;; /* - * The following offsets capture the order in which the - * RSE related registers from the old context are - * saved onto the new stack frame. + * The MCA and INIT stacks in struct ia64_mca_cpu look like normal kernel + * stacks, except that the SAL/OS state and a switch_stack are stored near the + * top of the MCA/INIT stack. To support concurrent entry to MCA or INIT, as + * well as MCA over INIT, each event needs its own SAL/OS state. All entries + * are 16 byte aligned. * - * +-----------------------+ - * |NDIRTY [BSP - BSPSTORE]| - * +-----------------------+ - * | RNAT | - * +-----------------------+ - * | BSPSTORE | - * +-----------------------+ - * | IFS | - * +-----------------------+ - * | PFS | - * +-----------------------+ - * | RSC | - * +-----------------------+ <-------- Bottom of new stack frame + * +---------------------------+ + * | pt_regs | + * +---------------------------+ + * | switch_stack | + * +---------------------------+ + * | SAL/OS state | + * +---------------------------+ + * | 16 byte scratch area | + * +---------------------------+ <-------- SP at start of C MCA handler + * | ..... | + * +---------------------------+ + * | RBS for MCA/INIT handler | + * +---------------------------+ + * | struct task for MCA/INIT | + * +---------------------------+ <-------- Bottom of MCA/INIT stack */ -#define rse_rsc_offset 0 -#define rse_pfs_offset (rse_rsc_offset+0x08) -#define rse_ifs_offset (rse_pfs_offset+0x08) -#define rse_bspstore_offset (rse_ifs_offset+0x08) -#define rse_rnat_offset (rse_bspstore_offset+0x08) -#define rse_ndirty_offset (rse_rnat_offset+0x08) -/* - * rse_switch_context - * - * 1. Save old RSC onto the new stack frame - * 2. Save PFS onto new stack frame - * 3. Cover the old frame and start a new frame. - * 4. Save IFS onto new stack frame - * 5. Save the old BSPSTORE on the new stack frame - * 6. Save the old RNAT on the new stack frame - * 7. Write BSPSTORE with the new backing store pointer - * 8. Read and save the new BSP to calculate the #dirty registers - * NOTE: Look at pages 11-10, 11-11 in PRM Vol 2 - */ -#define rse_switch_context(temp,p_stackframe,p_bspstore) \ - ;; \ - mov temp=ar.rsc;; \ - st8 [p_stackframe]=temp,8;; \ - mov temp=ar.pfs;; \ - st8 [p_stackframe]=temp,8; \ - cover ;; \ - mov temp=cr.ifs;; \ - st8 [p_stackframe]=temp,8;; \ - mov temp=ar.bspstore;; \ - st8 [p_stackframe]=temp,8;; \ - mov temp=ar.rnat;; \ - st8 [p_stackframe]=temp,8; \ - mov ar.bspstore=p_bspstore;; \ - mov temp=ar.bsp;; \ - sub temp=temp,p_bspstore;; \ - st8 [p_stackframe]=temp,8;; - -/* - * rse_return_context - * 1. Allocate a zero-sized frame - * 2. Store the number of dirty registers RSC.loadrs field - * 3. Issue a loadrs to insure that any registers from the interrupted - * context which were saved on the new stack frame have been loaded - * back into the stacked registers - * 4. Restore BSPSTORE - * 5. Restore RNAT - * 6. Restore PFS - * 7. Restore IFS - * 8. Restore RSC - * 9. Issue an RFI - */ -#define rse_return_context(psr_mask_reg,temp,p_stackframe) \ - ;; \ - alloc temp=ar.pfs,0,0,0,0; \ - add p_stackframe=rse_ndirty_offset,p_stackframe;; \ - ld8 temp=[p_stackframe];; \ - shl temp=temp,16;; \ - mov ar.rsc=temp;; \ - loadrs;; \ - add p_stackframe=-rse_ndirty_offset+rse_bspstore_offset,p_stackframe;;\ - ld8 temp=[p_stackframe];; \ - mov ar.bspstore=temp;; \ - add p_stackframe=-rse_bspstore_offset+rse_rnat_offset,p_stackframe;;\ - ld8 temp=[p_stackframe];; \ - mov ar.rnat=temp;; \ - add p_stackframe=-rse_rnat_offset+rse_pfs_offset,p_stackframe;; \ - ld8 temp=[p_stackframe];; \ - mov ar.pfs=temp;; \ - add p_stackframe=-rse_pfs_offset+rse_ifs_offset,p_stackframe;; \ - ld8 temp=[p_stackframe];; \ - mov cr.ifs=temp;; \ - add p_stackframe=-rse_ifs_offset+rse_rsc_offset,p_stackframe;; \ - ld8 temp=[p_stackframe];; \ - mov ar.rsc=temp ; \ - mov temp=psr;; \ - or temp=temp,psr_mask_reg;; \ - mov cr.ipsr=temp;; \ - mov temp=ip;; \ - add temp=0x30,temp;; \ - mov cr.iip=temp;; \ - srlz.i;; \ - rfi;; +#define ALIGN16(x) ((x)&~15) +#define MCA_PT_REGS_OFFSET ALIGN16(KERNEL_STACK_SIZE-IA64_PT_REGS_SIZE) +#define MCA_SWITCH_STACK_OFFSET ALIGN16(MCA_PT_REGS_OFFSET-IA64_SWITCH_STACK_SIZE) +#define MCA_SOS_OFFSET ALIGN16(MCA_SWITCH_STACK_OFFSET-IA64_SAL_OS_STATE_SIZE) +#define MCA_SP_OFFSET ALIGN16(MCA_SOS_OFFSET-16) #endif /* _ASM_IA64_MCA_ASM_H */ -- cgit v1.2.3 From 49a28cc8fd26f5317c47a9aeb2bdd1c33e21738e Mon Sep 17 00:00:00 2001 From: Keith Owens Date: Sun, 11 Sep 2005 17:24:42 +1000 Subject: [IA64] MCA/INIT: remove obsolete unwind code Delete the special case unwind code that was only used by the old MCA/INIT handler. Signed-off-by: Keith Owens Signed-off-by: Tony Luck --- include/asm-ia64/unwind.h | 7 ------- 1 file changed, 7 deletions(-) (limited to 'include') diff --git a/include/asm-ia64/unwind.h b/include/asm-ia64/unwind.h index 61426ad3ecd..5df0276b049 100644 --- a/include/asm-ia64/unwind.h +++ b/include/asm-ia64/unwind.h @@ -114,13 +114,6 @@ extern void unw_remove_unwind_table (void *handle); */ extern void unw_init_from_blocked_task (struct unw_frame_info *info, struct task_struct *t); -/* - * Prepare to unwind from interruption. The pt-regs and switch-stack structures must have - * be "adjacent" (no state modifications between pt-regs and switch-stack). - */ -extern void unw_init_from_interruption (struct unw_frame_info *info, struct task_struct *t, - struct pt_regs *pt, struct switch_stack *sw); - extern void unw_init_frame_info (struct unw_frame_info *info, struct task_struct *t, struct switch_stack *sw); -- cgit v1.2.3