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Commit 1f8870ed authored by Miles Bader's avatar Miles Bader Committed by Arnaldo Carvalho de Melo
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[PATCH] Add v850 support for hardware single-step (via ptrace)

parent 7d136361
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Showing with 310 additions and 94 deletions
arch/v850/kernel/entry.S
View file @ 1f8870ed
......@@ -235,25 +235,30 @@
sst.w syscall_num, PTO+PT_CUR_SYSCALL[ep]
/* Save register state not normally saved by PUSH_STATE for TYPE. */
/* Save register state not normally saved by PUSH_STATE for TYPE, to the
state-save-frame on the stack; also copies SP to EP. r19 may be trashed. */
#define SAVE_EXTRA_STATE(type) \
mov sp, ep; \
mov sp, ep; \
type ## _EXTRA_STATE_SAVER
/* Restore register state not normally restored by POP_STATE for TYPE. */
/* Restore register state not normally restored by POP_STATE for TYPE,
from the state-save-frame on the stack; also copies SP to EP.
r19 may be trashed. */
#define RESTORE_EXTRA_STATE(type) \
mov sp, ep; \
mov sp, ep; \
type ## _EXTRA_STATE_RESTORER
/* Save any call-clobbered registers not normally saved by PUSH_STATE
for TYPE. */
#define SAVE_EXTRA_STATE_FOR_FUNCALL(type) \
mov sp, ep; \
type ## _FUNCALL_EXTRA_STATE_SAVER
/* Restore any call-clobbered registers not normally restored by POP_STATE for
TYPE. */
#define RESTORE_EXTRA_STATE_FOR_FUNCALL(type) \
mov sp, ep; \
type ## _FUNCALL_EXTRA_STATE_RESTORER
/* Save any call-clobbered registers not normally saved by PUSH_STATE for
TYPE, to the state-save-frame on the stack.
EP may be trashed, but is not guaranteed to contain a copy of SP
(unlike after most SAVE_... macros). r19 may be trashed. */
#define SAVE_EXTRA_STATE_FOR_SCHEDULE(type) \
type ## _SCHEDULE_EXTRA_STATE_SAVER
/* Restore any call-clobbered registers not normally restored by
POP_STATE for TYPE, to the state-save-frame on the stack.
EP may be trashed, but is not guaranteed to contain a copy of SP
(unlike after most RESTORE_... macros). r19 may be trashed. */
#define RESTORE_EXTRA_STATE_FOR_SCHEDULE(type) \
type ## _SCHEDULE_EXTRA_STATE_RESTORER
/* These are extra_state_saver/restorer values for a user trap. Note
......@@ -264,36 +269,48 @@
caller of the syscall function should have saved them. */
#define TRAP_RET reti
/* Traps don't save call-clobbered registers (but do still save arg regs). */
/* Traps don't save call-clobbered registers (but do still save arg regs).
We preserve PSw to keep long-term state, namely interrupt status (for traps
from kernel-mode), and the single-step flag (for user traps). */
#define TRAP_STATE_SAVER \
SAVE_ARG_REGS; \
SAVE_PC(EIPC)
SAVE_PC(EIPC); \
SAVE_PSW(EIPSW)
/* When traps return, they just leave call-clobbered registers (except for arg
regs) with whatever value they have from the kernel. */
regs) with whatever value they have from the kernel. Traps don't preserve
the PSW, but we zero EIPSW to ensure it doesn't contain anything dangerous
(in particular, the single-step flag). */
#define TRAP_STATE_RESTORER \
RESTORE_ARG_REGS; \
RESTORE_PC(EIPC)
RESTORE_PC(EIPC); \
RESTORE_PSW(EIPSW)
/* Save registers not normally saved by traps. We need to save r12, even
though it's nominally call-clobbered, because it's used when restarting
a system call (the signal-handling path uses SAVE_EXTRA_STATE, and
expects r12 to be restored when the trap returns). Similarly, we must
save the PSW, so that it's at least in a known state in the the pt_regs
structure. */
expects r12 to be restored when the trap returns). */
#define TRAP_EXTRA_STATE_SAVER \
SAVE_RVAL_REGS; \
sst.w r12, PTO+PT_GPR(12)[ep]; \
SAVE_CALL_SAVED_REGS; \
SAVE_PSW(EIPSW); \
SAVE_CT_REGS
#define TRAP_EXTRA_STATE_RESTORER \
RESTORE_RVAL_REGS; \
sld.w PTO+PT_GPR(12)[ep], r12; \
RESTORE_CALL_SAVED_REGS; \
RESTORE_PSW(EIPSW); \
RESTORE_CT_REGS
#define TRAP_FUNCALL_EXTRA_STATE_SAVER \
/* Save registers prior to calling scheduler (just before trap returns).
We have to save the return-value registers to preserve the trap's return
value. Note that ..._SCHEDULE_EXTRA_STATE_SAVER, unlike most ..._SAVER
macros, is required to setup EP itself if EP is needed (this is because
in many cases, the macro is empty). */
#define TRAP_SCHEDULE_EXTRA_STATE_SAVER \
mov sp, ep; \
SAVE_RVAL_REGS
#define TRAP_FUNCALL_EXTRA_STATE_RESTORER \
/* Note that ..._SCHEDULE_EXTRA_STATE_RESTORER, unlike most ..._RESTORER
macros, is required to setup EP itself if EP is needed (this is because
in many cases, the macro is empty). */
#define TRAP_SCHEDULE_EXTRA_STATE_RESTORER \
mov sp, ep; \
RESTORE_RVAL_REGS
/* Register saving/restoring for maskable interrupts. */
......@@ -391,33 +408,34 @@
ld.w TI_FLAGS[r18], r19; \
andi _TIF_NEED_RESCHED, r19, r0; \
bnz 3f; /* Call the scheduler. */ \
andi _TIF_SIGPENDING, r19, r0; \
bnz 4f; /* Signals to handle, handle them */ \
5: andi _TIF_SIGPENDING, r19, r18; \
ld.w TASK_PTRACE[CURRENT_TASK], r19; /* ptrace flags */ \
or r18, r19; /* see if either is non-zero */ \
bnz 4f; /* if so, handle them */ \
\
/* Return to user state. */ \
/* Return to user state. */ \
1: st.b r0, KM; /* Now officially in user state. */ \
\
/* Final return. The stack-pointer fiddling is not needed when returning \
to kernel-mode, but they don't hurt, and this way we can share the \
(somtimes rather lengthy) POP_STATE macro. */ \
(sometimes rather lengthy) POP_STATE macro. */ \
2: POP_STATE(type); \
st.w sp, KSP; /* Save the kernel stack pointer. */ \
ld.w PT_GPR(GPR_SP)-PT_SIZE[sp], sp; /* Restore stack pointer. */ \
ld.w PT_GPR(GPR_SP)-PT_SIZE[sp], sp; /* Restore stack pointer. */ \
type ## _RET; /* Return from the trap/interrupt. */ \
\
/* Call the scheduler before returning from a syscall/trap. */ \
3: SAVE_EXTRA_STATE_FOR_FUNCALL(type); /* Prepare for funcall. */ \
jarl CSYM(schedule), lp; /* Call scheduler */ \
3: SAVE_EXTRA_STATE_FOR_SCHEDULE(type); /* Prepare to call scheduler. */ \
jarl call_scheduler, lp; /* Call scheduler */ \
di; /* The scheduler enables interrupts */\
RESTORE_EXTRA_STATE_FOR_FUNCALL(type); \
RESTORE_EXTRA_STATE_FOR_SCHEDULE(type); \
GET_CURRENT_THREAD(r18); \
ld.w TI_FLAGS[r18], r19; \
andi _TIF_SIGPENDING, r19, r0; \
bz 1b; /* No signals, return. */ \
/* Signals to handle, fall through to handle them. */ \
br 5b; /* Continue with return path. */ \
\
/* Handle a signal return. */ \
4: /* Not all registers are saved by the normal trap/interrupt entry \
/* Handle a signal or ptraced process return. \
r18 should be non-zero if there are pending signals. */ \
4: /* Not all registers are saved by the normal trap/interrupt entry \
points (for instance, call-saved registers (because the normal \
C-compiler calling sequence in the kernel makes sure they're \
preserved), and call-clobbered registers in the case of \
......@@ -425,12 +443,9 @@
complete register state. Here we save anything not saved by \
the normal entry sequence, so that it may be safely restored \
(in a possibly modified form) after do_signal returns. */ \
SAVE_EXTRA_STATE(type); /* Save state not saved by entry. */ \
movea PTO, sp, r6; /* Arg 1: struct pt_regs *regs */ \
mov r0, r7; /* Arg 2: sigset_t *oldset */ \
jarl CSYM(do_signal), lp; /* Handle any signals */ \
di; /* sig handling enables interrupts */ \
RESTORE_EXTRA_STATE(type); /* Restore extra regs. */ \
SAVE_EXTRA_STATE(type); /* Save state not saved by entry. */ \
jarl handle_signal_or_ptrace_return, lp; \
RESTORE_EXTRA_STATE(type); /* Restore extra regs. */ \
br 1b
......@@ -678,22 +693,50 @@ END(irq)
* indirect jump).
*/
G_ENTRY(dbtrap):
SAVE_STATE (DBTRAP, r0, ENTRY_SP)// Save registers.
SAVE_STATE (DBTRAP, r0, ENTRY_SP)// Save registers.
/* First see if we came from kernel mode; if so, the dbtrap
instruction has a special meaning, to set the DIR (`debug
information register') register. This is because the DIR register
can _only_ be manipulated/read while in `debug mode,' and debug
mode is only active while we're inside the dbtrap handler. The
exact functionality is: { DIR = (DIR | r6) & ~r7; return DIR; }. */
ld.b PTO+PT_KERNEL_MODE[sp], r19
cmp r19, r0
bz 1f
stsr SR_DIR, r10
or r6, r10
not r7, r7
and r7, r10
ldsr r10, SR_DIR
stsr SR_DIR, r10 // Confirm the value we set
st.w r10, PTO+PT_GPR(10)[sp] // return it
br 3f
1: ei // Enable interrupts.
/* The default signal type we raise. */
mov SIGTRAP, r6
/* See if it's a single-step trap. */
stsr SR_DBPSW, r19
andi 0x0800, r19, r19
bnz 2f
/* Look to see if the preceding instruction was is a dbtrap or not,
to decide which signal we should use. */
stsr SR_DBPC, r19 // PC following trapping insn
ld.hu -2[r19], r19
mov SIGTRAP, r6
ori 0xf840, r0, r20 // DBTRAP insn
cmp r19, r20 // Was this trap caused by DBTRAP?
cmov ne, SIGILL, r6, r6 // Choose signal appropriately
/* Raise the desired signal. */
mov CURRENT_TASK, r7 // Arg 1: task
jarl CSYM(force_sig), lp // tail call
2: mov CURRENT_TASK, r7 // Arg 1: task
jarl CSYM(send_sig), lp // tail call
RETURN(DBTRAP)
3: RETURN(DBTRAP)
END(dbtrap)
......@@ -734,10 +777,94 @@ L_ENTRY(bad_trap_wrapper):
END(bad_trap_wrapper)
/*
* Invoke the scheduler, called from the trap/irq kernel exit path.
*
* This basically just calls `schedule', but also arranges for extra
* registers to be saved for ptrace'd processes, so ptrace can modify them.
*/
L_ENTRY(call_scheduler):
ld.w TASK_PTRACE[CURRENT_TASK], r19 // See if task is ptrace'd
cmp r19, r0
bnz 1f // ... yes, do special stuff
jr CSYM(schedule) // ... no, just tail-call scheduler
// Save extra regs for ptrace'd task. We want to save anything
// that would otherwise only be `implicitly' saved by the normal
// compiler calling-convention.
1: mov sp, ep // Setup EP for SAVE_CALL_SAVED_REGS
SAVE_CALL_SAVED_REGS // Save call-saved registers to stack
mov lp, r20 // Save LP in a callee-saved register
jarl CSYM(schedule), lp // Call scheduler
mov r20, lp
mov sp, ep // We can't rely on EP after return
RESTORE_CALL_SAVED_REGS // Restore (possibly modified) regs
jmp [lp] // Return to the return path
END(call_scheduler)
/*
* This is an out-of-line handler for two special cases during the kernel
* trap/irq exit sequence:
*
* (1) If r18 is non-zero then a signal needs to be handled, which is
* done, and then the caller returned to.
*
* (2) If r18 is non-zero then we're returning to a ptraced process, which
* has several special cases -- single-stepping and trap tracing, both
* of which require using the `dbret' instruction to exit the kernel
* instead of the normal `reti' (this is because the CPU not correctly
* single-step after a reti). In this case, of course, this handler
* never returns to the caller.
*
* In either case, all registers should have been saved to the current
* state-save-frame on the stack, except for callee-saved registers.
*
* [These two different cases are combined merely to avoid bloating the
* macro-inlined code, not because they really make much sense together!]
*/
L_ENTRY(handle_signal_or_ptrace_return):
cmp r18, r0 // See if handling a signal
bz 1f // ... nope, go do ptrace return
// Handle a signal
mov lp, r20 // Save link-pointer
mov r10, r21 // Save return-values (for trap)
mov r11, r22
movea PTO, sp, r6 // Arg 1: struct pt_regs *regs
mov r0, r7 // Arg 2: sigset_t *oldset
jarl CSYM(do_signal), lp // Handle the signal
di // sig handling enables interrupts
mov r20, lp // Restore link-pointer
mov r21, r10 // Restore return-values (for trap)
mov r22, r11
ld.w TASK_PTRACE[CURRENT_TASK], r19 // check ptrace flags too
cmp r19, r0
bnz 1f // ... some set, so look more
2: jmp [lp] // ... none set, so return normally
// ptrace return
1: ld.w PTO+PT_PSW[sp], r19 // Look at user-processes's flags
andi 0x0800, r19, r19 // See if single-step flag is set
bz 2b // ... nope, return normally
// Return as if from a dbtrap insn
st.b r0, KM // Now officially in user state.
POP_STATE(DBTRAP) // Restore regs
st.w sp, KSP // Save the kernel stack pointer.
ld.w PT_GPR(GPR_SP)-PT_SIZE[sp], sp // Restore user stack pointer.
DBTRAP_RET // Return from the trap/interrupt.
END(handle_signal_or_ptrace_return)
/*
* This is where we switch between two threads. The arguments are:
* r6 -- pointer to the struct thread for the `current' process
* r7 -- pointer to the struct thread for the `new' process.
* r7 -- pointer to the struct thread for the `new' process.
* when this function returns, it will return to the new thread.
*/
C_ENTRY(switch_thread):
......
arch/v850/kernel/ptrace.c
View file @ 1f8870ed
/*
* arch/v850/kernel/ptrace.c -- `ptrace' system call
*
* Copyright (C) 2002 NEC Corporation
* Copyright (C) 2002 Miles Bader <miles@gnu.org>
* Copyright (C) 2002,03 NEC Electronics Corporation
* Copyright (C) 2002,03 Miles Bader <miles@gnu.org>
*
* Derived from arch/mips/kernel/ptrace.c:
*
......@@ -29,6 +29,89 @@
#include <asm/processor.h>
#include <asm/uaccess.h>
/* Returns the address where the register at REG_OFFS in P is stashed away. */
static v850_reg_t *reg_save_addr (unsigned reg_offs, struct task_struct *t)
{
struct pt_regs *regs;
/* Three basic cases:
(1) A register normally saved before calling the scheduler, is
available in the kernel entry pt_regs structure at the top
of the kernel stack. The kernel trap/irq exit path takes
care to save/restore almost all registers for ptrace'd
processes.
(2) A call-clobbered register, where the process P entered the
kernel via [syscall] trap, is not stored anywhere; that's
OK, because such registers are not expected to be preserved
when the trap returns anyway (so we don't actually bother to
test for this case).
(3) A few registers not used at all by the kernel, and so
normally never saved except by context-switches, are in the
context switch state. */
if (reg_offs == PT_CTPC || reg_offs == PT_CTPSW || reg_offs == PT_CTBP)
/* Register saved during context switch. */
regs = thread_saved_regs (t);
else
/* Register saved during kernel entry (or not available). */
regs = task_regs (t);
return (v850_reg_t *)((char *)regs + reg_offs);
}
/* Set the bits SET and clear the bits CLEAR in the v850e DIR
(`debug information register'). Returns the new value of DIR. */
static inline v850_reg_t set_dir (v850_reg_t set, v850_reg_t clear)
{
register v850_reg_t rval asm ("r10");
register v850_reg_t arg0 asm ("r6") = set;
register v850_reg_t arg1 asm ("r7") = clear;
/* The dbtrap handler has exactly this functionality when called
from kernel mode. 0xf840 is a `dbtrap' insn. */
asm (".short 0xf840" : "=r" (rval) : "r" (arg0), "r" (arg1));
return rval;
}
/* Makes sure hardware single-stepping is (globally) enabled.
Returns true if successful. */
static inline int enable_single_stepping (void)
{
static int enabled = 0; /* Remember whether we already did it. */
if (! enabled) {
/* Turn on the SE (`single-step enable') bit, 0x100, in the
DIR (`debug information register'). This may fail if a
processor doesn't support it or something. We also try
to clear bit 0x40 (`INI'), which is necessary to use the
debug stuff on the v850e2; on the v850e, clearing 0x40
shouldn't cause any problem. */
v850_reg_t dir = set_dir (0x100, 0x40);
/* Make sure it really got set. */
if (dir & 0x100)
enabled = 1;
}
return enabled;
}
/* Try to set CHILD's single-step flag to VAL. Returns true if successful. */
static int set_single_step (struct task_struct *t, int val)
{
v850_reg_t *psw_addr = reg_save_addr(PT_PSW, t);
if (val) {
/* Make sure single-stepping is enabled. */
if (! enable_single_stepping ())
return 0;
/* Set T's single-step flag. */
*psw_addr |= 0x800;
} else
*psw_addr &= ~0x800;
return 1;
}
int sys_ptrace(long request, long pid, long addr, long data)
{
struct task_struct *child;
......@@ -36,12 +119,6 @@ int sys_ptrace(long request, long pid, long addr, long data)
lock_kernel();
#if 0
printk("ptrace(r=%d,pid=%d,addr=%08lx,data=%08lx)\n",
(int) request, (int) pid, (unsigned long) addr,
(unsigned long) data);
#endif
if (request == PTRACE_TRACEME) {
/* are we already being traced? */
if (current->ptrace & PT_PTRACED) {
......@@ -81,31 +158,15 @@ int sys_ptrace(long request, long pid, long addr, long data)
goto out_tsk;
switch (request) {
case PTRACE_PEEKTEXT: /* read word at location addr. */
case PTRACE_PEEKDATA:{
unsigned long tmp;
int copied;
unsigned long val, copied;
copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
case PTRACE_PEEKTEXT: /* read word at location addr. */
case PTRACE_PEEKDATA:
copied = access_process_vm(child, addr, &val, sizeof(val), 0);
rval = -EIO;
if (copied != sizeof(tmp))
if (copied != sizeof(val))
break;
rval = put_user(tmp,(unsigned long *) data);
goto out;
}
/* Read the word at location addr in the USER area. */
case PTRACE_PEEKUSR:
if (addr >= 0 && addr < PT_SIZE && (addr & 0x3) == 0) {
struct pt_regs *regs = task_regs (child);
unsigned long val =
*(unsigned long *)((char *)regs + addr);
rval = put_user (val, (unsigned long *)data);
} else {
rval = 0;
rval = -EIO;
}
rval = put_user(val, (unsigned long *)data);
goto out;
case PTRACE_POKETEXT: /* write the word at location addr. */
......@@ -117,35 +178,62 @@ int sys_ptrace(long request, long pid, long addr, long data)
rval = -EIO;
goto out;
/* Read/write the word at location ADDR in the registers. */
case PTRACE_PEEKUSR:
case PTRACE_POKEUSR:
if (addr >= 0 && addr < PT_SIZE && (addr & 0x3) == 0) {
struct pt_regs *regs = task_regs (child);
unsigned long *loc =
(unsigned long *)((char *)regs + addr);
*loc = data;
} else {
rval = 0;
rval = -EIO;
}
rval = 0;
if (addr >= PT_SIZE && request == PTRACE_PEEKUSR) {
/* Special requests that don't actually correspond
to offsets in struct pt_regs. */
if (addr == PT_TEXT_ADDR)
val = child->mm->start_code;
else if (addr == PT_DATA_ADDR)
val = child->mm->start_data;
else if (addr == PT_TEXT_LEN)
val = child->mm->end_code
- child->mm->start_code;
else
rval = -EIO;
} else if (addr >= 0 && addr < PT_SIZE && (addr & 0x3) == 0) {
v850_reg_t *reg_addr = reg_save_addr(addr, child);
if (request == PTRACE_PEEKUSR)
val = *reg_addr;
else
*reg_addr = data;
} else
rval = -EIO;
if (rval == 0 && request == PTRACE_PEEKUSR)
rval = put_user (val, (unsigned long *)data);
goto out;
case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
case PTRACE_CONT: /* rvaltart after signal. */
/* Continue and stop at next (return from) syscall */
case PTRACE_SYSCALL:
/* Restart after a signal. */
case PTRACE_CONT:
/* Execute a single instruction. */
case PTRACE_SINGLESTEP:
rval = -EIO;
if ((unsigned long) data > _NSIG)
break;
/* Turn CHILD's single-step flag on or off. */
if (! set_single_step (child, request == PTRACE_SINGLESTEP))
break;
if (request == PTRACE_SYSCALL)
set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
else
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
child->exit_code = data;
wake_up_process(child);
rval = 0;
break;
/*
* make the child exit. Best I can do is send it a sigkill.
* perhaps it should be put in the status that it wants to
* make the child exit. Best I can do is send it a sigkill.
* perhaps it should be put in the status that it wants to
* exit.
*/
case PTRACE_KILL:
......@@ -157,6 +245,7 @@ int sys_ptrace(long request, long pid, long addr, long data)
break;
case PTRACE_DETACH: /* detach a process that was attached. */
set_single_step (child, 0); /* Clear single-step flag */
rval = ptrace_detach(child, data);
break;
......@@ -181,7 +270,7 @@ asmlinkage void syscall_trace(void)
/* The 0x80 provides a way for the tracing parent to distinguish
between a syscall stop and SIGTRAP delivery */
current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
? 0x80 : 0);
? 0x80 : 0);
current->state = TASK_STOPPED;
notify_parent(current, SIGCHLD);
schedule();
......
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