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Commit 9f319191 authored by Keith Owens's avatar Keith Owens Committed by David Mosberger
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[PATCH] ia64: fix scratch-regs handling in kernel unwinder 

This patch has been running inside SGI for 2 months.  It
handles kernel stacks with multiple struct pt_regs, as found
while debugging the kernel.
parent c88f9da4
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Showing with 44 additions and 30 deletions
arch/ia64/kernel/unwind.c
View file @ 9f319191
......@@ -227,12 +227,21 @@ pt_regs_off (unsigned long reg)
return off;
}
static void
dump_info_pt(struct unw_frame_info *info, const char *func)
{
/* WAR for no struct pt_regs, may be caused by bad unwind data. KAO */
if (!info->pt) {
dprintk("unwind.%s: sp 0x%lx pt 0x%lx, set to 0x%lx\n", func, info->sp, info->pt, info->sp - 16);
info->pt = info->sp - 16;
}
}
int
unw_access_gr (struct unw_frame_info *info, int regnum, unsigned long *val, char *nat, int write)
{
unsigned long *addr, *nat_addr, nat_mask = 0, dummy_nat;
struct unw_ireg *ireg;
struct pt_regs *pt;
if ((unsigned) regnum - 1 >= 127) {
dprintk("unwind: trying to access non-existent r%u\n", regnum);
......@@ -298,11 +307,8 @@ unw_access_gr (struct unw_frame_info *info, int regnum, unsigned long *val, char
}
} else {
/* access a scratch register */
if (info->flags & UNW_FLAG_INTERRUPT_FRAME)
pt = (struct pt_regs *) info->psp - 1;
else
pt = (struct pt_regs *) info->sp - 1;
addr = (unsigned long *) ((long) pt + pt_regs_off(regnum));
dump_info_pt(info, __FUNCTION__);
addr = (unsigned long *) (info->pt + pt_regs_off(regnum));
if (info->pri_unat_loc)
nat_addr = info->pri_unat_loc;
else
......@@ -348,10 +354,8 @@ unw_access_br (struct unw_frame_info *info, int regnum, unsigned long *val, int
unsigned long *addr;
struct pt_regs *pt;
if (info->flags & UNW_FLAG_INTERRUPT_FRAME)
pt = (struct pt_regs *) info->psp - 1;
else
pt = (struct pt_regs *) info->sp - 1;
dump_info_pt(info, __FUNCTION__);
pt = (struct pt_regs *)info->pt;
switch (regnum) {
/* scratch: */
case 0: addr = &pt->b0; break;
......@@ -387,10 +391,8 @@ unw_access_fr (struct unw_frame_info *info, int regnum, struct ia64_fpreg *val,
return -1;
}
if (info->flags & UNW_FLAG_INTERRUPT_FRAME)
pt = (struct pt_regs *) info->psp - 1;
else
pt = (struct pt_regs *) info->sp - 1;
dump_info_pt(info, __FUNCTION__);
pt = (struct pt_regs *)info->pt;
if (regnum <= 5) {
addr = *(&info->f2_loc + (regnum - 2));
......@@ -428,10 +430,8 @@ unw_access_ar (struct unw_frame_info *info, int regnum, unsigned long *val, int
unsigned long *addr;
struct pt_regs *pt;
if (info->flags & UNW_FLAG_INTERRUPT_FRAME)
pt = (struct pt_regs *) info->psp - 1;
else
pt = (struct pt_regs *) info->sp - 1;
dump_info_pt(info, __FUNCTION__);
pt = (struct pt_regs *)info->pt;
switch (regnum) {
case UNW_AR_BSP:
......@@ -1339,8 +1339,9 @@ compile_reg (struct unw_state_record *sr, int i, struct unw_script *script)
}
val = unw.preg_index[UNW_REG_R4 + (rval - 4)];
} else {
opc = UNW_INSN_ADD_SP;
val = -sizeof(struct pt_regs) + pt_regs_off(rval);
/* register got spilled to a scratch register */
opc = UNW_INSN_MOVE_SCRATCH;
val = pt_regs_off(rval);
}
break;
......@@ -1350,10 +1351,9 @@ compile_reg (struct unw_state_record *sr, int i, struct unw_script *script)
else if (rval >= 16 && rval <= 31)
val = unw.preg_index[UNW_REG_F16 + (rval - 16)];
else {
opc = UNW_INSN_ADD_SP;
val = -sizeof(struct pt_regs);
opc = UNW_INSN_MOVE_SCRATCH;
if (rval <= 9)
val += struct_offset(struct pt_regs, f6) + 16*(rval - 6);
val = struct_offset(struct pt_regs, f6) + 16*(rval - 6);
else
dprintk("unwind: kernel may not touch f%lu\n", rval);
}
......@@ -1363,14 +1363,13 @@ compile_reg (struct unw_state_record *sr, int i, struct unw_script *script)
if (rval >= 1 && rval <= 5)
val = unw.preg_index[UNW_REG_B1 + (rval - 1)];
else {
opc = UNW_INSN_ADD_SP;
val = -sizeof(struct pt_regs);
opc = UNW_INSN_MOVE_SCRATCH;
if (rval == 0)
val += struct_offset(struct pt_regs, b0);
val = struct_offset(struct pt_regs, b0);
else if (rval == 6)
val += struct_offset(struct pt_regs, b6);
val = struct_offset(struct pt_regs, b6);
else
val += struct_offset(struct pt_regs, b7);
val = struct_offset(struct pt_regs, b7);
}
break;
......@@ -1642,6 +1641,17 @@ run_script (struct unw_script *script, struct unw_frame_info *state)
s[dst] = s[val];
break;
case UNW_INSN_MOVE_SCRATCH:
if (state->pt) {
dump_info_pt(state, __FUNCTION__);
s[dst] = state->pt+val;
}
else {
s[dst] = 0;
dprintk("unwind.%s: no state->pt, dst=%ld, val=%ld\n", __FUNCTION__, dst, val);
}
break;
case UNW_INSN_MOVE_STACKED:
s[dst] = (unsigned long) ia64_rse_skip_regs((unsigned long *)state->bsp,
val);
......@@ -1774,10 +1784,11 @@ unw_unwind (struct unw_frame_info *info)
pr = info->pr;
num_regs = 0;
if ((info->flags & UNW_FLAG_INTERRUPT_FRAME)) {
info->pt = info->sp + 16;
if ((pr & (1UL << pNonSys)) != 0)
num_regs = *info->cfm_loc & 0x7f; /* size of frame */
info->pfs_loc =
(unsigned long *) (info->sp + 16 + struct_offset(struct pt_regs, ar_pfs));
(unsigned long *) (info->pt + struct_offset(struct pt_regs, ar_pfs));
} else
num_regs = (*info->cfm_loc >> 7) & 0x7f; /* size of locals */
info->bsp = (unsigned long) ia64_rse_skip_regs((unsigned long *) info->bsp, -num_regs);
......@@ -1874,6 +1885,7 @@ unw_init_frame_info (struct unw_frame_info *info, struct task_struct *t, struct
info->task = t;
info->sw = sw;
info->sp = info->psp = (unsigned long) (sw + 1) - 16;
info->pt = 0;
info->cfm_loc = &sw->ar_pfs;
sol = (*info->cfm_loc >> 7) & 0x7f;
info->bsp = (unsigned long) ia64_rse_skip_regs((unsigned long *) info->regstk.top, -sol);
......
arch/ia64/kernel/unwind_i.h
View file @ 9f319191
......@@ -137,7 +137,8 @@ enum unw_insn_opcode {
UNW_INSN_SETNAT_MEMSTK, /* s[dst+1].nat.type = MEMSTK;
s[dst+1].nat.off = *s.pri_unat - s[dst] */
UNW_INSN_SETNAT_TYPE, /* s[dst+1].nat.type = val */
UNW_INSN_LOAD /* s[dst] = *s[val] */
UNW_INSN_LOAD, /* s[dst] = *s[val] */
UNW_INSN_MOVE_SCRATCH, /* s[dst] = scratch reg "val" */
};
struct unw_insn {
......
include/asm-ia64/unwind.h
View file @ 9f319191
......@@ -60,6 +60,7 @@ struct unw_frame_info {
unsigned long ip; /* instruction pointer value */
unsigned long pr; /* current predicate values */
unsigned long *cfm_loc; /* cfm save location (or NULL) */
unsigned long pt; /* struct pt_regs location */
struct task_struct *task;
struct switch_stack *sw;
......
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