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>
98 lines
2.1 KiB
C
98 lines
2.1 KiB
C
#ifndef _M68K_PTRACE_H
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#define _M68K_PTRACE_H
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#define PT_D1 0
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#define PT_D2 1
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#define PT_D3 2
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#define PT_D4 3
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#define PT_D5 4
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#define PT_D6 5
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#define PT_D7 6
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#define PT_A0 7
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#define PT_A1 8
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#define PT_A2 9
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#define PT_A3 10
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#define PT_A4 11
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#define PT_A5 12
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#define PT_A6 13
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#define PT_D0 14
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#define PT_USP 15
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#define PT_ORIG_D0 16
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#define PT_SR 17
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#define PT_PC 18
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#ifndef __ASSEMBLY__
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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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struct pt_regs {
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long d1;
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long d2;
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long d3;
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long d4;
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long d5;
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long a0;
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long a1;
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long a2;
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long d0;
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long orig_d0;
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long stkadj;
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#ifdef CONFIG_COLDFIRE
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unsigned format : 4; /* frame format specifier */
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unsigned vector : 12; /* vector offset */
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unsigned short sr;
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unsigned long pc;
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#else
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unsigned short sr;
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unsigned long pc;
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unsigned format : 4; /* frame format specifier */
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unsigned vector : 12; /* vector offset */
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#endif
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};
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/*
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* This is the extended stack used by signal handlers and the context
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* switcher: it's pushed after the normal "struct pt_regs".
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*/
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struct switch_stack {
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unsigned long d6;
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unsigned long d7;
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unsigned long a3;
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unsigned long a4;
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unsigned long a5;
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unsigned long a6;
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unsigned long retpc;
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};
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/* Arbitrarily choose the same ptrace numbers as used by the Sparc code. */
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#define PTRACE_GETREGS 12
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#define PTRACE_SETREGS 13
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#define PTRACE_GETFPREGS 14
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#define PTRACE_SETFPREGS 15
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#define PTRACE_GET_THREAD_AREA 25
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#define PTRACE_SINGLEBLOCK 33 /* resume execution until next branch */
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#ifdef __KERNEL__
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#ifndef PS_S
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#define PS_S (0x2000)
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#define PS_M (0x1000)
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#endif
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#define user_mode(regs) (!((regs)->sr & PS_S))
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#define instruction_pointer(regs) ((regs)->pc)
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#define profile_pc(regs) instruction_pointer(regs)
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extern void show_regs(struct pt_regs *);
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#define arch_has_single_step() (1)
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#ifdef CONFIG_MMU
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#define arch_has_block_step() (1)
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#endif
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#endif /* __KERNEL__ */
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#endif /* __ASSEMBLY__ */
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#endif /* _M68K_PTRACE_H */
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