Commit 547f1125 authored by Vineet Gupta's avatar Vineet Gupta

ARC: ptrace support

Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
parent 080c3747
......@@ -22,6 +22,7 @@ config ARC
select GENERIC_PENDING_IRQ if SMP
select GENERIC_SIGALTSTACK
select GENERIC_SMP_IDLE_THREAD
select HAVE_ARCH_TRACEHOOK
select HAVE_GENERIC_HARDIRQS
select HAVE_MEMBLOCK
select IRQ_DOMAIN
......
......@@ -5,6 +5,9 @@
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.
# Pass UTS_MACHINE for user_regset definition
CFLAGS_ptrace.o += -DUTS_MACHINE='"$(UTS_MACHINE)"'
obj-y := arcksyms.o setup.o irq.o time.o reset.o ptrace.o entry.o process.o
obj-y += signal.o traps.o sys.o troubleshoot.o stacktrace.o clk.o
obj-y += devtree.o
......
......@@ -7,6 +7,13 @@
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* vineetg: Feb 2011 (ptrace low level code fixes)
* -traced syscall return code (r0) was not saved into pt_regs for restoring
* into user reg-file when traded task rets to user space.
* -syscalls needing arch-wrappers (mainly for passing sp as pt_regs)
* were not invoking post-syscall trace hook (jumping directly into
* ret_from_system_call)
*
* vineetg: Nov 2010:
* -Vector table jumps (@8 bytes) converted into branches (@4 bytes)
* -To maintain the slot size of 8 bytes/vector, added nop, which is
......@@ -347,6 +354,50 @@ ARC_ENTRY EV_Extension
b ret_from_exception
ARC_EXIT EV_Extension
;######################### System Call Tracing #########################
tracesys:
; save EFA in case tracer wants the PC of traced task
; using ERET won't work since next-PC has already committed
lr r12, [efa]
GET_CURR_TASK_FIELD_PTR TASK_THREAD, r11
st r12, [r11, THREAD_FAULT_ADDR]
; PRE Sys Call Ptrace hook
mov r0, sp ; pt_regs needed
bl @syscall_trace_entry
; Tracing code now returns the syscall num (orig or modif)
mov r8, r0
; Do the Sys Call as we normally would.
; Validate the Sys Call number
cmp r8, NR_syscalls
mov.hi r0, -ENOSYS
bhi tracesys_exit
; Restore the sys-call args. Mere invocation of the hook abv could have
; clobbered them (since they are in scratch regs). The tracer could also
; have deliberately changed the syscall args: r0-r7
ld r0, [sp, PT_r0]
ld r1, [sp, PT_r1]
ld r2, [sp, PT_r2]
ld r3, [sp, PT_r3]
ld r4, [sp, PT_r4]
ld r5, [sp, PT_r5]
ld r6, [sp, PT_r6]
ld r7, [sp, PT_r7]
ld.as r9, [sys_call_table, r8]
jl [r9] ; Entry into Sys Call Handler
tracesys_exit:
st r0, [sp, PT_r0] ; sys call return value in pt_regs
;POST Sys Call Ptrace Hook
bl @syscall_trace_exit
b ret_from_exception ; NOT ret_from_system_call at is saves r0 which
; we'd done before calling post hook above
;################### Break Point TRAP ##########################
; ======= (5b) Trap is due to Break-Point =========
......@@ -412,6 +463,11 @@ ARC_ENTRY EV_Trap
; Before doing anything, return from CPU Exception Mode
FAKE_RET_FROM_EXCPN r11
; If syscall tracing ongoing, invoke pre-pos-hooks
GET_CURR_THR_INFO_FLAGS r10
btst r10, TIF_SYSCALL_TRACE
bnz tracesys ; this never comes back
;============ This is normal System Call case ==========
; Sys-call num shd not exceed the total system calls avail
cmp r8, NR_syscalls
......@@ -608,6 +664,10 @@ ARC_ENTRY sys_fork_wrapper
bl @sys_fork
DISCARD_CALLEE_SAVED_USER
GET_CURR_THR_INFO_FLAGS r10
btst r10, TIF_SYSCALL_TRACE
bnz tracesys_exit
b ret_from_system_call
ARC_EXIT sys_fork_wrapper
......@@ -616,6 +676,10 @@ ARC_ENTRY sys_vfork_wrapper
bl @sys_vfork
DISCARD_CALLEE_SAVED_USER
GET_CURR_THR_INFO_FLAGS r10
btst r10, TIF_SYSCALL_TRACE
bnz tracesys_exit
b ret_from_system_call
ARC_EXIT sys_vfork_wrapper
......@@ -624,5 +688,9 @@ ARC_ENTRY sys_clone_wrapper
bl @sys_clone
DISCARD_CALLEE_SAVED_USER
GET_CURR_THR_INFO_FLAGS r10
btst r10, TIF_SYSCALL_TRACE
bnz tracesys_exit
b ret_from_system_call
ARC_EXIT sys_clone_wrapper
......@@ -7,6 +7,122 @@
*/
#include <linux/ptrace.h>
#include <linux/tracehook.h>
#include <linux/regset.h>
#include <linux/unistd.h>
#include <linux/elf.h>
static struct callee_regs *task_callee_regs(struct task_struct *tsk)
{
struct callee_regs *tmp = (struct callee_regs *)tsk->thread.callee_reg;
return tmp;
}
static int genregs_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
const struct pt_regs *ptregs = task_pt_regs(target);
const struct callee_regs *cregs = task_callee_regs(target);
int ret = 0;
unsigned int stop_pc_val;
#define REG_O_CHUNK(START, END, PTR) \
if (!ret) \
ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, PTR, \
offsetof(struct user_regs_struct, START), \
offsetof(struct user_regs_struct, END));
#define REG_O_ONE(LOC, PTR) \
if (!ret) \
ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, PTR, \
offsetof(struct user_regs_struct, LOC), \
offsetof(struct user_regs_struct, LOC) + 4);
REG_O_CHUNK(scratch, callee, ptregs);
REG_O_CHUNK(callee, efa, cregs);
REG_O_CHUNK(efa, stop_pc, &target->thread.fault_address);
if (!ret) {
if (in_brkpt_trap(ptregs)) {
stop_pc_val = target->thread.fault_address;
pr_debug("\t\tstop_pc (brk-pt)\n");
} else {
stop_pc_val = ptregs->ret;
pr_debug("\t\tstop_pc (others)\n");
}
REG_O_ONE(stop_pc, &stop_pc_val);
}
return ret;
}
static int genregs_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
const struct pt_regs *ptregs = task_pt_regs(target);
const struct callee_regs *cregs = task_callee_regs(target);
int ret = 0;
#define REG_IN_CHUNK(FIRST, NEXT, PTR) \
if (!ret) \
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, \
(void *)(PTR), \
offsetof(struct user_regs_struct, FIRST), \
offsetof(struct user_regs_struct, NEXT));
#define REG_IN_ONE(LOC, PTR) \
if (!ret) \
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, \
(void *)(PTR), \
offsetof(struct user_regs_struct, LOC), \
offsetof(struct user_regs_struct, LOC) + 4);
#define REG_IGNORE_ONE(LOC) \
if (!ret) \
ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, \
offsetof(struct user_regs_struct, LOC), \
offsetof(struct user_regs_struct, LOC) + 4);
/* TBD: disallow updates to STATUS32, orig_r8 etc*/
REG_IN_CHUNK(scratch, callee, ptregs); /* pt_regs[bta..orig_r8] */
REG_IN_CHUNK(callee, efa, cregs); /* callee_regs[r25..r13] */
REG_IGNORE_ONE(efa); /* efa update invalid */
REG_IN_ONE(stop_pc, &ptregs->ret); /* stop_pc: PC update */
return ret;
}
enum arc_getset {
REGSET_GENERAL,
};
static const struct user_regset arc_regsets[] = {
[REGSET_GENERAL] = {
.core_note_type = NT_PRSTATUS,
.n = ELF_NGREG,
.size = sizeof(unsigned long),
.align = sizeof(unsigned long),
.get = genregs_get,
.set = genregs_set,
}
};
static const struct user_regset_view user_arc_view = {
.name = UTS_MACHINE,
.e_machine = EM_ARCOMPACT,
.regsets = arc_regsets,
.n = ARRAY_SIZE(arc_regsets)
};
const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
return &user_arc_view;
}
void ptrace_disable(struct task_struct *child)
{
......@@ -16,11 +132,27 @@ long arch_ptrace(struct task_struct *child, long request,
unsigned long addr, unsigned long data)
{
int ret = -EIO;
pr_debug("REQ=%ld: ADDR =0x%lx, DATA=0x%lx)\n", request, addr, data);
switch (request) {
default:
ret = ptrace_request(child, request, addr, data);
break;
}
return ret;
}
asmlinkage int syscall_trace_entry(struct pt_regs *regs)
{
if (tracehook_report_syscall_entry(regs))
return ULONG_MAX;
const struct user_regset_view *task_user_regset_view(struct task_struct *task)
return regs->r8;
}
asmlinkage void syscall_trace_exit(struct pt_regs *regs)
{
return (const struct user_regset_view *)NULL;
tracehook_report_syscall_exit(regs, 0);
}
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