[PATCH] ptrace(2): note SPARC deviation wrt get/set regs

[PATCH] ptrace(2): note SPARC deviation wrt get/set regs

[Mike Frysinger]

Unfortunately the SPARC ptrace port handles the addr/data args the opposite
of every other arch.  It expects the struct to be in addr and the data is
ignored.

Signed-off-by: Mike Frysinger <vapier-aBrp7R+bbdUdnm+yROfE0A@public.gmane.org>
---
 man2/ptrace.2 |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/man2/ptrace.2 b/man2/ptrace.2
index 68601df..7cce955 100644
--- a/man2/ptrace.2
+++ b/man2/ptrace.2
@@ -168,6 +168,8 @@ respectively, to location \fIdata\fP in the parent.
 See \fI<sys/user.h>\fP for information on
 the format of this data.
 (\fIaddr\fP is ignored.)
+
+Note that SPARC systems have the meaning of \fIdata\fP and \fIaddr\fP reversed.
 .TP
 .BR PTRACE_GETSIGINFO " (since Linux 2.3.99-pre6)"
 Retrieve information about the signal that caused the stop.
@@ -184,6 +186,8 @@ As for
 some general
 purpose register modifications may be disallowed.
 (\fIaddr\fP is ignored.)
+
+Note that SPARC systems have the meaning of \fIdata\fP and \fIaddr\fP reversed.
 .TP
 .BR PTRACE_SETSIGINFO " (since Linux 2.3.99-pre6)"
 Set signal information.
-- 
1.6.5.1

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Re: [PATCH] ptrace(2): note SPARC deviation wrt get/set regs

[Michael Kerrisk (man-pages)]

[Adding some ptrace-knowledgeable people to CC]

Mike,

You long ago sent the patch below, but I didn't respond. I'm just
pulling up a few old ptrace pieces now for review.

Your patch below relates to PTRACE_GETREGS, PTRACE_GETFPREGS,
PTRACE_SETREGS, PTRACE_SETFPREGS. (The patch below no longer is
current, but is easy to fix)

Looking at arch/sparc/kernel/ptrace_32.c, I think I see what the point
of the patch is. However, the text is a bit cryptic. Would it not be
better to say something like

[[
Note that SPARC systems have the meaning of \fIdata\fP and \fIaddr\fP reversed;
that is, \fIdata\fP is ignored and the registers are copied to [from]
\fIaddr\fP.
]]

Cheers,

Michael


---------- Forwarded message ----------
From: Mike Frysinger <vapier-aBrp7R+bbdUdnm+yROfE0A@public.gmane.org>
Date: Sun, Oct 25, 2009 at 8:15 PM
Subject: [PATCH] ptrace(2): note SPARC deviation wrt get/set regs
To: Michael Kerrisk <mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org


Unfortunately the SPARC ptrace port handles the addr/data args the opposite
of every other arch.  It expects the struct to be in addr and the data is
ignored.

Signed-off-by: Mike Frysinger <vapier-aBrp7R+bbdUdnm+yROfE0A@public.gmane.org>
---
 man2/ptrace.2 |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/man2/ptrace.2 b/man2/ptrace.2
index 68601df..7cce955 100644
--- a/man2/ptrace.2
+++ b/man2/ptrace.2
@@ -168,6 +168,8 @@ respectively, to location \fIdata\fP in the parent.
 See \fI<sys/user.h>\fP for information on
 the format of this data.
 (\fIaddr\fP is ignored.)
+
+Note that SPARC systems have the meaning of \fIdata\fP and \fIaddr\fP reversed.
 .TP
 .BR PTRACE_GETSIGINFO " (since Linux 2.3.99-pre6)"
 Retrieve information about the signal that caused the stop.
@@ -184,6 +186,8 @@ As for
 some general
 purpose register modifications may be disallowed.
 (\fIaddr\fP is ignored.)
+
+Note that SPARC systems have the meaning of \fIdata\fP and \fIaddr\fP reversed.
 .TP
 .BR PTRACE_SETSIGINFO " (since Linux 2.3.99-pre6)"
 Set signal information.
--
1.6.5.1



-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Author of "The Linux Programming Interface"; http://man7.org/tlpi/
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Re: [PATCH] ptrace(2): note SPARC deviation wrt get/set regs

[Mike Frysinger]

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On Sunday 22 April 2012 14:56:14 Michael Kerrisk (man-pages) wrote:
> You long ago sent the patch below, but I didn't respond. I'm just
> pulling up a few old ptrace pieces now for review.
> 
> Your patch below relates to PTRACE_GETREGS, PTRACE_GETFPREGS,
> PTRACE_SETREGS, PTRACE_SETFPREGS. (The patch below no longer is
> current, but is easy to fix)
> 
> Looking at arch/sparc/kernel/ptrace_32.c, I think I see what the point
> of the patch is. However, the text is a bit cryptic. Would it not be
> better to say something like

seemed clear to me, but i wrote it ;)

> [[
> Note that SPARC systems have the meaning of \fIdata\fP and \fIaddr\fP
> reversed; that is, \fIdata\fP is ignored and the registers are copied to
> [from] \fIaddr\fP.
> ]]

i'd suggest "via" rather than "to [from]"
-mike

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Re: [PATCH] ptrace(2): note SPARC deviation wrt get/set regs

[Michael Kerrisk (man-pages)]

On Tue, Apr 24, 2012 at 3:55 PM, Mike Frysinger <vapier-aBrp7R+bbdUdnm+yROfE0A@public.gmane.org> wrote:
> On Sunday 22 April 2012 14:56:14 Michael Kerrisk (man-pages) wrote:
>> You long ago sent the patch below, but I didn't respond. I'm just
>> pulling up a few old ptrace pieces now for review.
>>
>> Your patch below relates to PTRACE_GETREGS, PTRACE_GETFPREGS,
>> PTRACE_SETREGS, PTRACE_SETFPREGS. (The patch below no longer is
>> current, but is easy to fix)
>>
>> Looking at arch/sparc/kernel/ptrace_32.c, I think I see what the point
>> of the patch is. However, the text is a bit cryptic. Would it not be
>> better to say something like
>
> seemed clear to me, but i wrote it ;)
>
>> [[
>> Note that SPARC systems have the meaning of \fIdata\fP and \fIaddr\fP
>> reversed; that is, \fIdata\fP is ignored and the registers are copied to
>> [from] \fIaddr\fP.
>> ]]
>
> i'd suggest "via" rather than "to [from]"

Thanks Mike. I've applied the patch below for 3.40.

Cheers,

Michael

--- a/man2/ptrace.2
+++ b/man2/ptrace.2
@@ -213,24 +213,32 @@ some modifications to the USER area are disallowed.
 .\" and when they are disallowed, how does userspace discover that fact?
 .TP
 .BR PTRACE_GETREGS ", " PTRACE_GETFPREGS
 Copy the tracee's general-purpose or floating-point registers,
 respectively, to the address
 .I data
 in the tracer.
 See
 .I <sys/user.h>
 for information on the format of this data.
 .RI ( addr
 is ignored.)
+Note that SPARC systems have the meaning of
+.I data
+and
+.I addr
+reversed; that is,
+.I data
+is ignored and the registers are copied to the address
+.IR addr .
 .TP
 .BR PTRACE_GETSIGINFO " (since Linux 2.3.99-pre6)"
 Retrieve information about the signal that caused the stop.
 Copy a
 .I siginfo_t
 structure (see
 .BR sigaction (2))
 from the tracee to the address
 .I data
 in the tracer.
 .RI ( addr
 is ignored.)
@@ -238,24 +246,32 @@ is ignored.)
 .BR PTRACE_SETREGS ", " PTRACE_SETFPREGS
 Copy the tracee's general-purpose or floating-point registers,
 respectively, from the address
 .I data
 in the tracer.
 As for
 .BR PTRACE_POKEUSER ,
 some general-purpose register modifications may be disallowed.
 .\" FIXME In the preceding sentence, which modifications are disallowed,
 .\" and when they are disallowed, how does userspace discover that fact?
 .RI ( addr
 is ignored.)
+Note that SPARC systems have the meaning of
+.I data
+and
+.I addr
+reversed; that is,
+.I data
+is ignored and the registers are copied from the address
+.IR addr .
 .TP
 .BR PTRACE_SETSIGINFO " (since Linux 2.3.99-pre6)"
 Set signal information:
 copy a
 .I siginfo_t
 structure from the address
 .I data
 in the tracer to the tracee.
 This will affect only signals that would normally be delivered to
 the tracee and were caught by the tracer.
 It may be difficult to tell
 these normal signals from synthetic signals generated by



-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Author of "The Linux Programming Interface"; http://man7.org/tlpi/
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