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

["Michael Kerrisk (man-pages)" <mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

[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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