On Fri, Aug 01, 2014 at 04:48:17PM +0200, Denys Vlasenko wrote: > > /* 0(%rsp): ~(interrupt number) */ > .macro interrupt func > - /* reserve pt_regs for scratch regs and rbp */ > - subq $ORIG_RAX-RBP, %rsp > - CFI_ADJUST_CFA_OFFSET ORIG_RAX-RBP > - cld > - /* start from rbp in pt_regs and jump over */ > - movq_cfi rdi, (RDI-RBP) > - movq_cfi rsi, (RSI-RBP) > - movq_cfi rdx, (RDX-RBP) > - movq_cfi rcx, (RCX-RBP) > - movq_cfi rax, (RAX-RBP) > - movq_cfi r8, (R8-RBP) > - movq_cfi r9, (R9-RBP) > - movq_cfi r10, (R10-RBP) > - movq_cfi r11, (R11-RBP) > - > - /* Save rbp so that we can unwind from get_irq_regs() */ > - movq_cfi rbp, 0
Hmm SAVEE_C_REGS below doesn't seem to save rbp like we did before. Perhaps it's implicitely saved somewhere? > - > - /* Save previous stack value */ > - movq %rsp, %rsi Also rsp isn't saved in %rsi like before. Maybe that's because we already save it in rdi? Makes sense since now arg1 == rsp. More on that later. > - > - leaq -RBP(%rsp),%rdi /* arg1 for handler */ > - testl $3, CS-RBP(%rsi) > + ALLOC_PTREGS_ON_STACK > + SAVE_C_REGS > + movq %rsp, %rdi /* arg1 for handler */ > + testl $3, CS(%rsp) > je 1f > SWAPGS > - /* > +1: /* > * irq_count is used to check if a CPU is already on an interrupt stack > * or not. While this is essentially redundant with preempt_count it is > * a little cheaper to use a separate counter in the PDA (short of > * moving irq_enter into assembly, which would be too much work) > */ > -1: incl PER_CPU_VAR(irq_count) > + incl PER_CPU_VAR(irq_count) > cmovzq PER_CPU_VAR(irq_stack_ptr),%rsp > - CFI_DEF_CFA_REGISTER rsi > + CFI_DEF_CFA_REGISTER rdi > > /* Store previous stack value */ > - pushq %rsi > + pushq %rdi So you push rdi instead... > 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? > - CFI_DEF_CFA rsi,SS+8-RBP /* reg/off reset after def_cfa_expr */ > - leaq ARGOFFSET-RBP(%rsi), %rsp > + CFI_DEF_CFA rsi,SS+8 /* reg/off reset after def_cfa_expr */ > + movq %rsi, %rsp > CFI_DEF_CFA_REGISTER rsp > - CFI_ADJUST_CFA_OFFSET RBP-ARGOFFSET Thanks. -- 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/
