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powerpc/ptrace: Add DAWR debug feature info for userspace

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This adds new debug feature information so that the DAWR can be
identified by userspace tools like GDB.

Unfortunately the DAWR doesn't sit nicely into the current description
that ptrace provides to userspace via struct ppc_debug_info.  It doesn't
allow for specifying that only some ranges are possible or even the end
alignment constraints (DAWR only allows 512 byte wide ranges which can't
cross a 512 byte boundary).

After talking to Edjunior Machado (GDB ppc developer), it was decided
this was the best approach.  Just mark it as debug feature DAWR and
tools like GDB can internally decide the constraints.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
This commit is contained in:
Michael Neuling 2013-03-21 20:12:33 +00:00 committed by Michael Ellerman
parent a6a058e52a
commit 517b731477
3 changed files with 4 additions and 0 deletions
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1
Documentation/powerpc/ptrace.txt
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@ -40,6 +40,7 @@ features will have bits indicating whether there is support for:
#define PPC_DEBUG_FEATURE_INSN_BP_MASK 0x2
#define PPC_DEBUG_FEATURE_DATA_BP_RANGE 0x4
#define PPC_DEBUG_FEATURE_DATA_BP_MASK 0x8
#define PPC_DEBUG_FEATURE_DATA_BP_DAWR 0x10
2. PTRACE_SETHWDEBUG

1
arch/powerpc/include/uapi/asm/ptrace.h
View File

@ -211,6 +211,7 @@ struct ppc_debug_info {
#define PPC_DEBUG_FEATURE_INSN_BP_MASK 0x0000000000000002
#define PPC_DEBUG_FEATURE_DATA_BP_RANGE 0x0000000000000004
#define PPC_DEBUG_FEATURE_DATA_BP_MASK 0x0000000000000008
#define PPC_DEBUG_FEATURE_DATA_BP_DAWR 0x0000000000000010
#ifndef __ASSEMBLY__

2
arch/powerpc/kernel/ptrace.c
View File

@ -1644,6 +1644,8 @@ long arch_ptrace(struct task_struct *child, long request,
dbginfo.sizeof_condition = 0;
#ifdef CONFIG_HAVE_HW_BREAKPOINT
dbginfo.features = PPC_DEBUG_FEATURE_DATA_BP_RANGE;
if (cpu_has_feature(CPU_FTR_DAWR))
dbginfo.features |= PPC_DEBUG_FEATURE_DATA_BP_DAWR;
#else
dbginfo.features = 0;
#endif /* CONFIG_HAVE_HW_BREAKPOINT */