sh: Add support for DWARF GNU extensions
Also, remove the "fix" to DW_CFA_def_cfa_register where we reset the
frame's cfa_offset to 0. This action is incorrect when handling
DW_CFA_def_cfa_register as the DWARF spec specifically states that the
previous contents of cfa_offset should be used with the new
register. The reason that I thought cfa_offset should be reset to 0 was
because it was being assigned a bogus value prior to executing the
DW_CFA_def_cfa_register op. It turns out that the bogus cfa_offset value
came from interpreting .cfi_escape pseudo-ops (those used by the GNU
extensions) as CFA_DW_def_cfa ops.
Signed-off-by: Matt Fleming <matt@console-pimps.org>
diff --git a/arch/sh/kernel/dwarf.c b/arch/sh/kernel/dwarf.c
index 44e674e..5fd6e60 100644
--- a/arch/sh/kernel/dwarf.c
+++ b/arch/sh/kernel/dwarf.c
@@ -429,7 +429,6 @@
count = dwarf_read_uleb128(current_insn,
&frame->cfa_register);
current_insn += count;
- frame->cfa_offset = 0;
frame->flags |= DWARF_FRAME_CFA_REG_OFFSET;
break;
case DW_CFA_def_cfa_offset:
@@ -465,6 +464,19 @@
frame->regs[reg].flags |= DWARF_REG_OFFSET;
frame->regs[reg].addr = offset;
break;
+ case DW_CFA_GNU_args_size:
+ count = dwarf_read_uleb128(current_insn, &offset);
+ current_insn += count;
+ break;
+ case DW_CFA_GNU_negative_offset_extended:
+ count = dwarf_read_uleb128(current_insn, ®);
+ current_insn += count;
+ count = dwarf_read_uleb128(current_insn, &offset);
+ offset *= cie->data_alignment_factor;
+ dwarf_frame_alloc_regs(frame, reg);
+ frame->regs[reg].flags |= DWARF_REG_OFFSET;
+ frame->regs[reg].addr = -offset;
+ break;
default:
pr_debug("unhandled DWARF instruction 0x%x\n", insn);
break;