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Fix for the "bt" command to properly pull the stack and frame pointer

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registers from the NT_PRSTATUS notes of 32-bit tasks running in
user-mode on ARM64.  Without the patch, the "bt" command utilizes
ptregs->sp and ptregs->regs[29] for 32-bit tasks instead of the
architecturally-mapped ptregs->regs[13] and ptregs->regs[11], which
yields unpredictable/invalid results, and possibly a segmentation
violation.
(drjones@redhat.com)
This commit is contained in:
Dave Anderson 2016-01-05 15:56:34 -05:00
parent e2a2ed3406
commit 4641ea1f61
1 changed files with 36 additions and 6 deletions
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42
arm64.c
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@ -993,6 +993,25 @@ arm64_stackframe_init(void)
#define PSR_MODE_EL3h 0x0000000d
#define PSR_MODE_MASK 0x0000000f
/* Architecturally defined mapping between AArch32 and AArch64 registers */
#define compat_usr(x) regs[(x)]
#define compat_fp regs[11]
#define compat_sp regs[13]
#define compat_lr regs[14]
#define user_mode(ptregs) \
(((ptregs)->pstate & PSR_MODE_MASK) == PSR_MODE_EL0t)
#define compat_user_mode(ptregs) \
(((ptregs)->pstate & (PSR_MODE32_BIT | PSR_MODE_MASK)) == \
(PSR_MODE32_BIT | PSR_MODE_EL0t))
#define user_stack_pointer(ptregs) \
(!compat_user_mode(ptregs) ? (ptregs)->sp : (ptregs)->compat_sp)
#define user_frame_pointer(ptregs) \
(!compat_user_mode(ptregs) ? (ptregs)->regs[29] : (ptregs)->compat_fp)
static int
arm64_is_kernel_exception_frame(struct bt_info *bt, ulong stkptr)
{
@ -1348,13 +1367,22 @@ arm64_get_dumpfile_stackframe(struct bt_info *bt, struct arm64_stackframe *frame
}
ptregs = &ms->panic_task_regs[bt->tc->processor];
frame->sp = ptregs->sp;
frame->pc = ptregs->pc;
frame->fp = ptregs->regs[29];
if (!is_kernel_text(frame->pc) &&
in_user_stack(bt->tc->task, frame->sp))
if (user_mode(ptregs)) {
frame->sp = user_stack_pointer(ptregs);
frame->fp = user_frame_pointer(ptregs);
if (is_kernel_text(frame->pc) ||
!in_user_stack(bt->tc->task, frame->sp)) {
error(WARNING, "Corrupt prstatus? pstate=0x%lx, but no user frame found\n",
ptregs->pstate);
bt->flags |= BT_REGS_NOT_FOUND;
return FALSE;
}
bt->flags |= BT_USER_SPACE;
} else {
frame->sp = ptregs->sp;
frame->fp = ptregs->regs[29];
}
if (arm64_in_kdump_text(bt, frame))
bt->flags |= BT_KDUMP_ADJUST;
@ -1473,7 +1501,9 @@ arm64_print_exception_frame(struct bt_info *bt, ulong pt_regs, int mode, FILE *o
i < 10 ? " " : "", i);
fprintf(ofp, is_64_bit ? "%016lx" : "%08lx",
(ulong)regs->regs[i]);
if ((i == 0) || ((r % rows) == 0))
if ((i == 0) && !is_64_bit)
fprintf(ofp, "\n");
else if ((i == 0) || ((r % rows) == 0))
fprintf(ofp, "\n ");
else
fprintf(ofp, "%s", is_64_bit ? " " : " ");