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powerpc: Hardware breakpoints rewrite to handle non DABR breakpoint registers

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This is a rewrite so that we don't assume we are using the DABR throughout the
code.  We now use the arch_hw_breakpoint to store the breakpoint in a generic
manner in the thread_struct, rather than storing the raw DABR value.

The ptrace GET/SET_DEBUGREG interface currently passes the raw DABR in from
userspace.  We keep this functionality, so that future changes (like the POWER8
DAWR), will still fake the DABR to userspace.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Michael Neuling
2012-12-20 14:06:44 +00:00
committed by Benjamin Herrenschmidt
parent a8190a59e7
commit 9422de3e95
14 changed files with 187 additions and 129 deletions
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75
arch/powerpc/kernel/process.c
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@@ -271,7 +271,7 @@ void do_send_trap(struct pt_regs *regs, unsigned long address,
force_sig_info(SIGTRAP, &info, current);
}
#else /* !CONFIG_PPC_ADV_DEBUG_REGS */
void do_dabr(struct pt_regs *regs, unsigned long address,
void do_break (struct pt_regs *regs, unsigned long address,
unsigned long error_code)
{
siginfo_t info;
@@ -281,11 +281,11 @@ void do_dabr(struct pt_regs *regs, unsigned long address,
11, SIGSEGV) == NOTIFY_STOP)
return;
if (debugger_dabr_match(regs))
if (debugger_break_match(regs))
return;
/* Clear the DABR */
set_dabr(0, 0);
/* Clear the breakpoint */
hw_breakpoint_disable();
/* Deliver the signal to userspace */
info.si_signo = SIGTRAP;
@@ -296,7 +296,7 @@ void do_dabr(struct pt_regs *regs, unsigned long address,
}
#endif /* CONFIG_PPC_ADV_DEBUG_REGS */
static DEFINE_PER_CPU(unsigned long, current_dabr);
static DEFINE_PER_CPU(struct arch_hw_breakpoint, current_brk);
#ifdef CONFIG_PPC_ADV_DEBUG_REGS
/*
@@ -364,39 +364,72 @@ static void switch_booke_debug_regs(struct thread_struct *new_thread)
#ifndef CONFIG_HAVE_HW_BREAKPOINT
static void set_debug_reg_defaults(struct thread_struct *thread)
{
if (thread->dabr) {
thread->dabr = 0;
thread->dabrx = 0;
set_dabr(0, 0);
}
thread->hw_brk.address = 0;
thread->hw_brk.type = 0;
set_break(&thread->hw_brk);
}
#endif /* !CONFIG_HAVE_HW_BREAKPOINT */
#endif /* CONFIG_PPC_ADV_DEBUG_REGS */
int set_dabr(unsigned long dabr, unsigned long dabrx)
{
__get_cpu_var(current_dabr) = dabr;
if (ppc_md.set_dabr)
return ppc_md.set_dabr(dabr, dabrx);
/* XXX should we have a CPU_FTR_HAS_DABR ? */
#ifdef CONFIG_PPC_ADV_DEBUG_REGS
static inline int __set_dabr(unsigned long dabr, unsigned long dabrx)
{
mtspr(SPRN_DAC1, dabr);
#ifdef CONFIG_PPC_47x
isync();
#endif
return 0;
}
#elif defined(CONFIG_PPC_BOOK3S)
static inline int __set_dabr(unsigned long dabr, unsigned long dabrx)
{
mtspr(SPRN_DABR, dabr);
mtspr(SPRN_DABRX, dabrx);
#endif
return 0;
}
#else
static inline int __set_dabr(unsigned long dabr, unsigned long dabrx)
{
return -EINVAL;
}
#endif
static inline int set_dabr(struct arch_hw_breakpoint *brk)
{
unsigned long dabr, dabrx;
dabr = brk->address | (brk->type & HW_BRK_TYPE_DABR);
dabrx = ((brk->type >> 3) & 0x7);
if (ppc_md.set_dabr)
return ppc_md.set_dabr(dabr, dabrx);
return __set_dabr(dabr, dabrx);
}
int set_break(struct arch_hw_breakpoint *brk)
{
__get_cpu_var(current_brk) = *brk;
return set_dabr(brk);
}
#ifdef CONFIG_PPC64
DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
#endif
static inline bool hw_brk_match(struct arch_hw_breakpoint *a,
struct arch_hw_breakpoint *b)
{
if (a->address != b->address)
return false;
if (a->type != b->type)
return false;
if (a->len != b->len)
return false;
return true;
}
struct task_struct *__switch_to(struct task_struct *prev,
struct task_struct *new)
{
@@ -481,8 +514,8 @@ struct task_struct *__switch_to(struct task_struct *prev,
* schedule DABR
*/
#ifndef CONFIG_HAVE_HW_BREAKPOINT
if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr))
set_dabr(new->thread.dabr, new->thread.dabrx);
if (unlikely(hw_brk_match(&__get_cpu_var(current_brk), &new->thread.hw_brk)))
set_break(&new->thread.hw_brk);
#endif /* CONFIG_HAVE_HW_BREAKPOINT */
#endif