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[PATCH] ppc64: Add ptrace data breakpoint support
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Add hardware data breakpoint support.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Anton Blanchard authored and Paul Mackerras committed Sep 12, 2005
1 parent a94d308 commit fd9648d
Showing 14 changed files with 145 additions and 25 deletions.
34 changes: 34 additions & 0 deletions arch/ppc64/kernel/process.c
Original file line number Diff line number Diff line change
@@ -54,6 +54,7 @@
#include <asm/sections.h>
#include <asm/tlbflush.h>
#include <asm/time.h>
#include <asm/plpar_wrappers.h>

#ifndef CONFIG_SMP
struct task_struct *last_task_used_math = NULL;
@@ -163,7 +164,30 @@ int dump_task_altivec(struct pt_regs *regs, elf_vrregset_t *vrregs)

#endif /* CONFIG_ALTIVEC */

static void set_dabr_spr(unsigned long val)
{
mtspr(SPRN_DABR, val);
}

int set_dabr(unsigned long dabr)
{
int ret = 0;

if (firmware_has_feature(FW_FEATURE_XDABR)) {
/* We want to catch accesses from kernel and userspace */
unsigned long flags = H_DABRX_KERNEL|H_DABRX_USER;
ret = plpar_set_xdabr(dabr, flags);
} else if (firmware_has_feature(FW_FEATURE_DABR)) {
ret = plpar_set_dabr(dabr);
} else {
set_dabr_spr(dabr);
}

return ret;
}

DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
static DEFINE_PER_CPU(unsigned long, current_dabr);

struct task_struct *__switch_to(struct task_struct *prev,
struct task_struct *new)
@@ -198,6 +222,11 @@ struct task_struct *__switch_to(struct task_struct *prev,
new->thread.regs->msr |= MSR_VEC;
#endif /* CONFIG_ALTIVEC */

if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr)) {
set_dabr(new->thread.dabr);
__get_cpu_var(current_dabr) = new->thread.dabr;
}

flush_tlb_pending();

new_thread = &new->thread;
@@ -334,6 +363,11 @@ void flush_thread(void)
last_task_used_altivec = NULL;
#endif /* CONFIG_ALTIVEC */
#endif /* CONFIG_SMP */

if (current->thread.dabr) {
current->thread.dabr = 0;
set_dabr(0);
}
}

void
13 changes: 13 additions & 0 deletions arch/ppc64/kernel/ptrace.c
Original file line number Diff line number Diff line change
@@ -207,6 +207,19 @@ int sys_ptrace(long request, long pid, long addr, long data)
break;
}

case PTRACE_GET_DEBUGREG: {
ret = -EINVAL;
/* We only support one DABR and no IABRS at the moment */
if (addr > 0)
break;
ret = put_user(child->thread.dabr,
(unsigned long __user *)data);
break;
}

case PTRACE_SET_DEBUGREG:
ret = ptrace_set_debugreg(child, addr, data);

case PTRACE_DETACH:
ret = ptrace_detach(child, data);
break;
13 changes: 13 additions & 0 deletions arch/ppc64/kernel/ptrace32.c
Original file line number Diff line number Diff line change
@@ -338,6 +338,19 @@ int sys32_ptrace(long request, long pid, unsigned long addr, unsigned long data)
break;
}

case PTRACE_GET_DEBUGREG: {
ret = -EINVAL;
/* We only support one DABR and no IABRS at the moment */
if (addr > 0)
break;
ret = put_user(child->thread.dabr, (u32 __user *)data);
break;
}

case PTRACE_SET_DEBUGREG:
ret = ptrace_set_debugreg(child, addr, data);
break;

case PTRACE_DETACH:
ret = ptrace_detach(child, data);
break;
2 changes: 0 additions & 2 deletions arch/ppc64/kernel/ras.c
Original file line number Diff line number Diff line change
@@ -59,8 +59,6 @@ char mce_data_buf[RTAS_ERROR_LOG_MAX]
/* This is true if we are using the firmware NMI handler (typically LPAR) */
extern int fwnmi_active;

extern void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr);

static int ras_get_sensor_state_token;
static int ras_check_exception_token;

9 changes: 9 additions & 0 deletions arch/ppc64/kernel/signal.c
Original file line number Diff line number Diff line change
@@ -550,6 +550,15 @@ int do_signal(sigset_t *oldset, struct pt_regs *regs)
/* Whee! Actually deliver the signal. */
if (TRAP(regs) == 0x0C00)
syscall_restart(regs, &ka);

/*
* Reenable the DABR before delivering the signal to
* user space. The DABR will have been cleared if it
* triggered inside the kernel.
*/
if (current->thread.dabr)
set_dabr(current->thread.dabr);

return handle_signal(signr, &ka, &info, oldset, regs);
}

8 changes: 8 additions & 0 deletions arch/ppc64/kernel/signal32.c
Original file line number Diff line number Diff line change
@@ -970,6 +970,14 @@ int do_signal32(sigset_t *oldset, struct pt_regs *regs)
newsp = regs->gpr[1];
newsp &= ~0xfUL;

/*
* Reenable the DABR before delivering the signal to
* user space. The DABR will have been cleared if it
* triggered inside the kernel.
*/
if (current->thread.dabr)
set_dabr(current->thread.dabr);

/* Whee! Actually deliver the signal. */
if (ka.sa.sa_flags & SA_SIGINFO)
ret = handle_rt_signal32(signr, &ka, &info, oldset, regs, newsp);
31 changes: 25 additions & 6 deletions arch/ppc64/mm/fault.c
Original file line number Diff line number Diff line change
@@ -77,6 +77,28 @@ static int store_updates_sp(struct pt_regs *regs)
return 0;
}

static void do_dabr(struct pt_regs *regs, unsigned long error_code)
{
siginfo_t info;

if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
11, SIGSEGV) == NOTIFY_STOP)
return;

if (debugger_dabr_match(regs))
return;

/* Clear the DABR */
set_dabr(0);

/* Deliver the signal to userspace */
info.si_signo = SIGTRAP;
info.si_errno = 0;
info.si_code = TRAP_HWBKPT;
info.si_addr = (void __user *)regs->nip;
force_sig_info(SIGTRAP, &info, current);
}

/*
* The error_code parameter is
* - DSISR for a non-SLB data access fault,
@@ -111,12 +133,9 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
if (!user_mode(regs) && (address >= TASK_SIZE))
return SIGSEGV;

if (error_code & DSISR_DABRMATCH) {
if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
11, SIGSEGV) == NOTIFY_STOP)
return 0;
if (debugger_dabr_match(regs))
return 0;
if (error_code & DSISR_DABRMATCH) {
do_dabr(regs, error_code);
return 0;
}

if (in_atomic() || mm == NULL) {
1 change: 0 additions & 1 deletion arch/ppc64/xmon/privinst.h
Original file line number Diff line number Diff line change
@@ -46,7 +46,6 @@ GSETSPR(287, pvr)
GSETSPR(1008, hid0)
GSETSPR(1009, hid1)
GSETSPR(1010, iabr)
GSETSPR(1013, dabr)
GSETSPR(1023, pir)

static inline void store_inst(void *p)
20 changes: 4 additions & 16 deletions arch/ppc64/xmon/xmon.c
Original file line number Diff line number Diff line change
@@ -586,6 +586,8 @@ int xmon_dabr_match(struct pt_regs *regs)
{
if ((regs->msr & (MSR_IR|MSR_PR|MSR_SF)) != (MSR_IR|MSR_SF))
return 0;
if (dabr.enabled == 0)
return 0;
xmon_core(regs, 0);
return 1;
}
@@ -628,20 +630,6 @@ int xmon_fault_handler(struct pt_regs *regs)
return 0;
}

/* On systems with a hypervisor, we can't set the DABR
(data address breakpoint register) directly. */
static void set_controlled_dabr(unsigned long val)
{
#ifdef CONFIG_PPC_PSERIES
if (systemcfg->platform == PLATFORM_PSERIES_LPAR) {
int rc = plpar_hcall_norets(H_SET_DABR, val);
if (rc != H_Success)
xmon_printf("Warning: setting DABR failed (%d)\n", rc);
} else
#endif
set_dabr(val);
}

static struct bpt *at_breakpoint(unsigned long pc)
{
int i;
@@ -728,7 +716,7 @@ static void insert_bpts(void)
static void insert_cpu_bpts(void)
{
if (dabr.enabled)
set_controlled_dabr(dabr.address | (dabr.enabled & 7));
set_dabr(dabr.address | (dabr.enabled & 7));
if (iabr && cpu_has_feature(CPU_FTR_IABR))
set_iabr(iabr->address
| (iabr->enabled & (BP_IABR|BP_IABR_TE)));
@@ -756,7 +744,7 @@ static void remove_bpts(void)

static void remove_cpu_bpts(void)
{
set_controlled_dabr(0);
set_dabr(0);
if (cpu_has_feature(CPU_FTR_IABR))
set_iabr(0);
}
6 changes: 6 additions & 0 deletions include/asm-ppc64/hvcall.h
Original file line number Diff line number Diff line change
@@ -56,6 +56,11 @@
#define H_PP1 (1UL<<(63-62))
#define H_PP2 (1UL<<(63-63))

/* DABRX flags */
#define H_DABRX_HYPERVISOR (1UL<<(63-61))
#define H_DABRX_KERNEL (1UL<<(63-62))
#define H_DABRX_USER (1UL<<(63-63))

/* pSeries hypervisor opcodes */
#define H_REMOVE 0x04
#define H_ENTER 0x08
@@ -101,6 +106,7 @@
#define H_VIO_SIGNAL 0x104
#define H_SEND_CRQ 0x108
#define H_COPY_RDMA 0x110
#define H_SET_XDABR 0x134
#define H_STUFF_TCE 0x138
#define H_PUT_TCE_INDIRECT 0x13C
#define H_VTERM_PARTNER_INFO 0x150
9 changes: 9 additions & 0 deletions include/asm-ppc64/plpar_wrappers.h
Original file line number Diff line number Diff line change
@@ -107,5 +107,14 @@ static inline long plpar_put_term_char(unsigned long termno,
lbuf[1]);
}

static inline long plpar_set_xdabr(unsigned long address, unsigned long flags)
{
return plpar_hcall_norets(H_SET_XDABR, address, flags);
}

static inline long plpar_set_dabr(unsigned long val)
{
return plpar_hcall_norets(H_SET_DABR, val);
}

#endif /* _PPC64_PLPAR_WRAPPERS_H */
1 change: 1 addition & 0 deletions include/asm-ppc64/processor.h
Original file line number Diff line number Diff line change
@@ -433,6 +433,7 @@ struct thread_struct {
unsigned long start_tb; /* Start purr when proc switched in */
unsigned long accum_tb; /* Total accumilated purr for process */
unsigned long vdso_base; /* base of the vDSO library */
unsigned long dabr; /* Data address breakpoint register */
#ifdef CONFIG_ALTIVEC
/* Complete AltiVec register set */
vector128 vr[32] __attribute((aligned(16)));
20 changes: 20 additions & 0 deletions include/asm-ppc64/ptrace-common.h
Original file line number Diff line number Diff line change
@@ -13,6 +13,7 @@
#define _PPC64_PTRACE_COMMON_H

#include <linux/config.h>
#include <asm/system.h>

/*
* Set of msr bits that gdb can change on behalf of a process.
@@ -141,4 +142,23 @@ static inline int set_vrregs(struct task_struct *task,
}
#endif

static inline int ptrace_set_debugreg(struct task_struct *task,
unsigned long addr, unsigned long data)
{
/* We only support one DABR and no IABRS at the moment */
if (addr > 0)
return -EINVAL;

/* The bottom 3 bits are flags */
if ((data & ~0x7UL) >= TASK_SIZE)
return -EIO;

/* Ensure translation is on */
if (data && !(data & DABR_TRANSLATION))
return -EIO;

task->thread.dabr = data;
return 0;
}

#endif /* _PPC64_PTRACE_COMMON_H */
3 changes: 3 additions & 0 deletions include/asm-ppc64/system.h
Original file line number Diff line number Diff line change
@@ -101,6 +101,9 @@ static inline int debugger_dabr_match(struct pt_regs *regs) { return 0; }
static inline int debugger_fault_handler(struct pt_regs *regs) { return 0; }
#endif

extern int set_dabr(unsigned long dabr);
extern void _exception(int signr, struct pt_regs *regs, int code,
unsigned long addr);
extern int fix_alignment(struct pt_regs *regs);
extern void bad_page_fault(struct pt_regs *regs, unsigned long address,
int sig);

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