Messages in this thread | | | Date | Mon, 11 Aug 2014 15:26:14 +0200 | From | Denys Vlasenko <> | Subject | Re: [PATCH 4/5] x86: entry_64.S: always allocate complete "struct pt_regs" |
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On 08/11/2014 10:40 AM, Jan Beulich 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 ... ... >>> 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.
The existing comments explain what every byte means. They are useful if CFI-literate reader wants to check correctness of the encoding of this annotation.
There is no overall comment what this CFI annotation *achieves*. In human language, what do we say to DWARF decoder here?
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