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502a0c775c
pt_regs->event was set with artificial values to identify the low level
system event (syscall trap / breakpoint trap / exceptions / interrupts)
With r8 saving out of the way, the full word can be used to save real
ECR (Exception Cause Register) which helps idenify the event naturally,
including additional info such as cause code, param.
Only for Interrupts, where ECR is not applicable, do we resort to
synthetic non ECR values.
SAVE_ALL_TRAP/EXCEPTIONS can now be merged as they both use ECR with
different runtime values.
The ptrace helpers now use the sub-fields of ECR to distinguish the
events (e.g. vector 0x25 is trap, param 0 is syscall...)
The following benefits will follow:
(1) This centralizes the location of where ECR is saved and will allow
the cleanup of task->thread.cause_code ECR placeholder which is set
in non-uniform way. Then ARC VM code can safely rely on it being
there for purpose of finer grained VM_EXEC dcache flush (based on
exec fault: I-TLB Miss)
(2) Further, ECR being passed around from low level handlers as arg can
be eliminated as it is part of standard reg-file in pt_regs
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
130 lines
2.9 KiB
C
130 lines
2.9 KiB
C
/*
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* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Amit Bhor, Sameer Dhavale: Codito Technologies 2004
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*/
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#ifndef __ASM_ARC_PTRACE_H
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#define __ASM_ARC_PTRACE_H
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#include <uapi/asm/ptrace.h>
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#ifndef __ASSEMBLY__
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/* THE pt_regs: Defines how regs are saved during entry into kernel */
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struct pt_regs {
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/* Real registers */
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long bta; /* bta_l1, bta_l2, erbta */
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long lp_start;
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long lp_end;
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long lp_count;
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long status32; /* status32_l1, status32_l2, erstatus */
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long ret; /* ilink1, ilink2 or eret */
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long blink;
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long fp;
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long r26; /* gp */
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long r12;
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long r11;
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long r10;
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long r9;
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long r8;
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long r7;
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long r6;
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long r5;
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long r4;
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long r3;
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long r2;
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long r1;
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long r0;
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long sp; /* user/kernel sp depending on where we came from */
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long orig_r0;
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/*
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* To distinguish bet excp, syscall, irq
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* For traps and exceptions, Exception Cause Register.
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* ECR: <00> <VV> <CC> <PP>
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* Last word used by Linux for extra state mgmt (syscall-restart)
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* For interrupts, use artificial ECR values to note current prio-level
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*/
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union {
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struct {
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#ifdef CONFIG_CPU_BIG_ENDIAN
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unsigned long state:8, ecr_vec:8,
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ecr_cause:8, ecr_param:8;
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#else
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unsigned long ecr_param:8, ecr_cause:8,
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ecr_vec:8, state:8;
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#endif
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};
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unsigned long event;
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};
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long user_r25;
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};
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/* Callee saved registers - need to be saved only when you are scheduled out */
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struct callee_regs {
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long r25;
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long r24;
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long r23;
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long r22;
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long r21;
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long r20;
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long r19;
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long r18;
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long r17;
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long r16;
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long r15;
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long r14;
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long r13;
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};
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#define instruction_pointer(regs) ((regs)->ret)
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#define profile_pc(regs) instruction_pointer(regs)
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/* return 1 if user mode or 0 if kernel mode */
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#define user_mode(regs) (regs->status32 & STATUS_U_MASK)
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#define user_stack_pointer(regs)\
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({ unsigned int sp; \
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if (user_mode(regs)) \
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sp = (regs)->sp;\
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else \
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sp = -1; \
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sp; \
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})
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/* return 1 if PC in delay slot */
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#define delay_mode(regs) ((regs->status32 & STATUS_DE_MASK) == STATUS_DE_MASK)
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#define in_syscall(regs) ((regs->ecr_vec == ECR_V_TRAP) && !regs->ecr_param)
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#define in_brkpt_trap(regs) ((regs->ecr_vec == ECR_V_TRAP) && regs->ecr_param)
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#define STATE_SCALL_RESTARTED 0x01
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#define syscall_wont_restart(reg) (reg->state |= STATE_SCALL_RESTARTED)
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#define syscall_restartable(reg) !(reg->state & STATE_SCALL_RESTARTED)
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#define current_pt_regs() \
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({ \
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/* open-coded current_thread_info() */ \
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register unsigned long sp asm ("sp"); \
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unsigned long pg_start = (sp & ~(THREAD_SIZE - 1)); \
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(struct pt_regs *)(pg_start + THREAD_SIZE) - 1; \
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})
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static inline long regs_return_value(struct pt_regs *regs)
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{
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return regs->r0;
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}
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#endif /* !__ASSEMBLY__ */
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#endif /* __ASM_PTRACE_H */
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