Messages in this thread |  | | | Date | Fri, 19 Feb 2010 16:34:03 +0100 | | Subject | Re: [PATCH 2/2] hw-breakpoint: Keep track of dr7 local enable bits | | From | Frederic Weisbecker <> |
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2010/2/19 K.Prasad <prasad@linux.vnet.ibm.com>: > So, the thread's copy of DR7 (in thread->ptrace_dr7) stores the > requested data even if the 'write' onto DR7 i.e. ptrace_write_dr7() > failed. This can be the other way round i.e. populate the thread's copy > of DR7 only if the write was successful.
No. We store the new dr7 value only if ptrace_set_dr7() didn't fail.
> I think it will be in consonance with the v2.6.32 behaviour as well. For > instance, in the code snippet from ptrace_set_debugreg() in v2.6.32 > below: > for (i = 0; i < 4; i++) > if ((DR7_MASK >> ((data >> (16 + 4*i)) & 0xf)) & 1) > return -EIO; > child->thread.debugreg7 = data; > > The thread's copy of DR7 is populated only if the incoming data is > found to be valid.
This is also what does this patch. thread->ptrace_dr7 is only changed if ptrace_set_dr7() succeeded.
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