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dacbe41f77
While in theory user_enable_single_step/user_disable_single_step/
user_enable_blockstep could also be provided as an inline or macro there's
no good reason to do so, and having the prototype in one places keeps code
size and confusion down.
Roland said:
The original thought there was that user_enable_single_step() et al
might well be only an instruction or three on a sane machine (as if we
have any of those!), and since there is only one call site inlining
would be beneficial. But I agree that there is no strong reason to care
about inlining it.
As to the arch changes, there is only one thought I'd add to the
record. It was always my thinking that for an arch where
PTRACE_SINGLESTEP does text-modifying breakpoint insertion,
user_enable_single_step() should not be provided. That is,
arch_has_single_step()=>true means that there is an arch facility with
"pure" semantics that does not have any unexpected side effects.
Inserting a breakpoint might do very unexpected strange things in
multi-threaded situations. Aside from that, it is a peculiar side
effect that user_{enable,disable}_single_step() should cause COW
de-sharing of text pages and so forth. For PTRACE_SINGLESTEP, all these
peculiarities are the status quo ante for that arch, so having
arch_ptrace() itself do those is one thing. But for building other
things in the future, it is nicer to have a uniform "pure" semantics
that arch-independent code can expect.
OTOH, all such arch issues are really up to the arch maintainer. As
of today, there is nothing but ptrace using user_enable_single_step() et
al so it's a distinction without a practical difference. If/when there
are other facilities that use user_enable_single_step() and might care,
the affected arch's can revisit the question when someone cares about
the quality of the arch support for said new facility.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
65 lines
1.8 KiB
C
65 lines
1.8 KiB
C
#ifndef _PARISC_PTRACE_H
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#define _PARISC_PTRACE_H
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/* written by Philipp Rumpf, Copyright (C) 1999 SuSE GmbH Nuernberg
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** Copyright (C) 2000 Grant Grundler, Hewlett-Packard
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*/
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#include <linux/types.h>
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/* This struct defines the way the registers are stored on the
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* stack during a system call.
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*
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* N.B. gdb/strace care about the size and offsets within this
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* structure. If you change things, you may break object compatibility
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* for those applications.
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*/
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struct pt_regs {
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unsigned long gr[32]; /* PSW is in gr[0] */
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__u64 fr[32];
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unsigned long sr[ 8];
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unsigned long iasq[2];
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unsigned long iaoq[2];
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unsigned long cr27;
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unsigned long pad0; /* available for other uses */
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unsigned long orig_r28;
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unsigned long ksp;
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unsigned long kpc;
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unsigned long sar; /* CR11 */
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unsigned long iir; /* CR19 */
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unsigned long isr; /* CR20 */
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unsigned long ior; /* CR21 */
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unsigned long ipsw; /* CR22 */
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};
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/*
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* The numbers chosen here are somewhat arbitrary but absolutely MUST
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* not overlap with any of the number assigned in <linux/ptrace.h>.
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*
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* These ones are taken from IA-64 on the assumption that theirs are
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* the most correct (and we also want to support PTRACE_SINGLEBLOCK
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* since we have taken branch traps too)
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*/
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#define PTRACE_SINGLEBLOCK 12 /* resume execution until next branch */
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#ifdef __KERNEL__
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#define task_regs(task) ((struct pt_regs *) ((char *)(task) + TASK_REGS))
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#define arch_has_single_step() 1
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#define arch_has_block_step() 1
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/* XXX should we use iaoq[1] or iaoq[0] ? */
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#define user_mode(regs) (((regs)->iaoq[0] & 3) ? 1 : 0)
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#define user_space(regs) (((regs)->iasq[1] != 0) ? 1 : 0)
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#define instruction_pointer(regs) ((regs)->iaoq[0] & ~3)
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#define user_stack_pointer(regs) ((regs)->gr[30])
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unsigned long profile_pc(struct pt_regs *);
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extern void show_regs(struct pt_regs *);
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#endif /* __KERNEL__ */
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#endif
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