[Bug other/67552] New: [meta] x86 interrupt attribute

[Bug other/67552] New: [meta] x86 interrupt attribute

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67552

            Bug ID: 67552
           Summary: [meta] x86 interrupt attribute
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: other
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hjl.tools at gmail dot com
                CC: julia.koval at intel dot com
  Target Milestone: ---

This meta bug covers all interrupt attribute issues on jkoval/interrupt/master
branch in GCC git repo.

[Bug other/67552] [meta] x86 interrupt attribute

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67552

--- Comment #1 from H.J. Lu <hjl.tools at gmail dot com> ---
Created attachment 36324
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36324&action=edit
A patch to remove railing whitespaces in interrupt-switch-abi.c

[Bug other/67552] [meta] x86 interrupt attribute

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67552

--- Comment #2 from H.J. Lu <hjl.tools at gmail dot com> ---
Red zone isn't supported in interrupt handler:

'interrupt'
     Use this attribute to indicate that the specified void function
     without arguments is an interrupt handler.  The compiler generates
     function entry and exit sequences suitable for use in an interrupt
     handler when this attribute is present.  The 'IRET' instruction,
     instead of the 'RET' instruction, is used to return from interrupt
     handlers.  All registers, except for the EFLAGS register which is
     restored by the 'IRET' instruction, are preserved by the compiler.
     The red zone isn't supported in an interrupt handler; that is an
     interrupt handler can't access stack beyond the current stack
     pointer.

It is wrong to do

-  if (crtl->args.pops_args && crtl->args.size)
+  if (ix86_is_interrupt_p ())
+    {
+      if (ix86_using_red_zone ())
+          emit_insn (gen_adddi3 (
+                   gen_rtx_REG (DImode, SP_REG),
+                   gen_rtx_REG (DImode, SP_REG),
+                   GEN_INT (128)));

GCC should assume that red zone isn't used in interrupt handler.

[Bug other/67552] [meta] x86 interrupt attribute

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67552

--- Comment #3 from H.J. Lu <hjl.tools at gmail dot com> ---
X87 instructions should be disallowed in interrupt handler:

[hjl@gnu-6 interrupt-1]$ cat f.i
extern long double y, x;

void
__attribute__((interrupt))
fn1 (void)
{
  x += y;
}
[hjl@gnu-6 interrupt-1]$ make f.s
/export/build/gnu/gcc-5/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc-5/build-x86_64-linux/gcc/ -O2 -S -o f.s f.i
[hjl@gnu-6 interrupt-1]$ cat f.s
        .file   "f.i"
        .section        .text.unlikely,"ax",@progbits
.LCOLDB1:
        .text
.LHOTB1:
        .p2align 4,,15
        .globl  fn1
        .type   fn1, @function
fn1:
.LFB0:
        .cfi_startproc
        fldt    y(%rip)
        addq    $-128, %rsp
        fldt    x(%rip)
        faddp   %st, %st(1)
        fstpt   x(%rip)
        ret
        .cfi_endproc
.LFE0:
        .size   fn1, .-fn1
        .section        .text.unlikely
.LCOLDE1:
        .text
.LHOTE1:
        .ident  "GCC: (GNU) 5.2.1 20150911"
        .section        .note.GNU-stack,"",@progbits
[hjl@gnu-6 interrupt-1]$

[Bug other/67552] [meta] x86 interrupt attribute

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67552

--- Comment #4 from H.J. Lu <hjl.tools at gmail dot com> ---
MMX instructions should be disallowed in interrupt handler:

[hjl@gnu-6 interrupt-1]$ cat m.i 
typedef short __v4hi __attribute__ ((__vector_size__ (8)));
typedef int __m64 __attribute__ ((__vector_size__ (8), __may_alias__));

extern __m64 y, x;

void
__attribute__((interrupt))
fn1 (void)
{
  x = (__m64) __builtin_ia32_packsswb ((__v4hi) x, (__v4hi) y);
}
[hjl@gnu-6 interrupt-1]$ make m.s
/export/build/gnu/gcc-5/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc-5/build-x86_64-linux/gcc/ -O2 -S -o m.s m.i
[hjl@gnu-6 interrupt-1]$ cat m.s
        .file   "m.i"
        .section        .text.unlikely,"ax",@progbits
.LCOLDB0:
        .text
.LHOTB0:
        .p2align 4,,15
        .globl  fn1
        .type   fn1, @function
fn1:
.LFB0:
        .cfi_startproc
        movq    x(%rip), %mm0
        addq    $-128, %rsp
        packsswb        y(%rip), %mm0
        movq    %mm0, x(%rip)
        ret
        .cfi_endproc
.LFE0:
        .size   fn1, .-fn1
        .section        .text.unlikely
.LCOLDE0:
        .text
.LHOTE0:
        .ident  "GCC: (GNU) 5.2.1 20150911"
        .section        .note.GNU-stack,"",@progbits
[hjl@gnu-6 interrupt-1]$

[Bug other/67552] [meta] x86 interrupt attribute

[julia.koval at intel dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67552

--- Comment #5 from Yulia Koval <julia.koval at intel dot com> ---
Sorry, I don't understand why we shouldn't preserve the red zone. The function
"foo", executing before the interrupt was called, used its red zone. If the
interrupt does not adjust the stack pointer, who control that "foo" function's
red zone would not be overwritten?

[Bug other/67552] [meta] x86 interrupt attribute

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67552

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-09-14
     Ever confirmed|0                           |1

--- Comment #6 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Yulia Koval from comment #5)
> Sorry, I don't understand why we shouldn't preserve the red zone. The
> function "foo", executing before the interrupt was called, used its red
> zone. If the interrupt does not adjust the stack pointer, who control that
> "foo" function's red zone would not be overwritten?

Please take a look at Exception- or Interrupt-Handler Procedures in
Intel64 and IA-32 Architectures Software Developer’s Manual vol 3.
There is no red zone on stack of interrupt handler, which is controlled
by processor, independent of any calling conventions.
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Subject: [Bug lto/67548] [5/6 Regression] LTO drops weak binding with "ld -r"
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idg548

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
I thought we do nothing in an incremental link but concat the LTO input
sections?
That's why we put that $ID suffix on the section names.  So maybe with plugin
auto-loading (and thus slim objects?) the LTO plugin shouldn't claim any files
with LDPO_REL mode.

[Bug other/67552] [meta] x86 interrupt attribute

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67552
Bug 67552 depends on bug 67634, which changed state.

Bug 67634 Summary: Can't preserve bound register in interrupt handler
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67634

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |FIXED

[Bug other/67552] [meta] x86 interrupt attribute

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67552
Bug 67552 depends on bug 67630, which changed state.

Bug 67630 Summary: ymm and zmm register aren't preserved in interrupt handler
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67630

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

[Bug other/67552] [meta] x86 interrupt attribute

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67552
Bug 67552 depends on bug 67698, which changed state.

Bug 67698 Summary: internal compiler error: in maybe_record_trace_start, at dwarf2cfi.c:2297
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67698

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

[Bug other/67552] [meta] x86 interrupt attribute

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67552
Bug 67552 depends on bug 67855, which changed state.

Bug 67855 Summary: -g doesn't with x86 interrupt handler
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67855

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

[Bug other/67552] [meta] x86 interrupt attribute

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67552
Bug 67552 depends on bug 67850, which changed state.

Bug 67850 Summary: Wrong call_used_regs used in aggregate_value_p
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67850

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |FIXED