On Mon, Aug 11, 2014 at 5:40 PM, Jan Beulich <jbeul...@suse.com> wrote: >>>> On 11.08.14 at 02:46, <fweis...@gmail.com> wrote: >> On Mon, Aug 04, 2014 at 05:03:42AM +0200, Denys Vlasenko wrote: >>> On Sat, Aug 2, 2014 at 1:19 AM, Frederic Weisbecker <fweis...@gmail.com> >> wrote: >>> >> CFI_ESCAPE 0x0f /* DW_CFA_def_cfa_expression */, 6, \ >>> >> 0x77 /* DW_OP_breg7 */, 0, \ >>> >> 0x06 /* DW_OP_deref */, \ >>> >> - 0x08 /* DW_OP_const1u */, SS+8-RBP, \ >>> >> + 0x08 /* DW_OP_const1u */, SS+8, \ >>> >> 0x22 /* DW_OP_plus */ >>> >> /* We entered an interrupt context - irqs are off: */ >>> >> TRACE_IRQS_OFF >>> >> - >>> >> call \func >>> >> .endm >>> >> >>> >> @@ -749,10 +719,9 @@ ret_from_intr: >>> >> >>> >> /* Restore saved previous stack */ >>> >> popq %rsi >>> > >>> > And then you pop to rsi. Ok that indeed works but perhaps we should keep >>> > it symetrical >>> > just for clarity? Any reason why we can't reuse rdi here? >>> >>> I changed this entire area in v2: basically, I will not change the logic, >>> but will add comments explaining what are we doing here, and why. >>> (Some minor code changes will be done, not affecting the logic). >>> >>> While we are at it, what this CFI_ESCAPE thing does here? >>> As usual, it has no comment :/ > > Each of its lines has a comment; with other CFI annotations not > each having comments, I don't see what else is needed here. > >> I don't know, only Jan Beulich understands those CFI black magic. > > That would be very said if true. > > In any case: This needs to be a CFI_ESCAPE because there's no > other way I know of to emit the DW_CFA_def_cfa_expression. > And the change to it looks correct to me. >
How does one test the entry CFI annotations? The best that I know of is to single-step through using gdb attached to qemu and see whether backtraces seem to work. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
