[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793
Bug 79793 depends on bug 81570, which changed state.

Bug 81570 Summary: create_pseudo_cfg assumes that INCOMING_FRAME_SP_OFFSET is a 
constant
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81570

   What|Removed |Added

 Status|NEW |RESOLVED
 Resolution|--- |DUPLICATE

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[aldyh at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

--- Comment #21 from Aldy Hernandez  ---
Author: aldyh
Date: Wed Sep 13 16:05:20 2017
New Revision: 252181

URL: https://gcc.gnu.org/viewcvs?rev=252181=gcc=rev
Log:
i386: Update INCOMING_FRAME_SP_OFFSET for exception handler

Since there is an extra error code passed to the exception handler,
INCOMING_FRAME_SP_OFFSET is return address plus error code for the
exception handler.  This patch updates INCOMING_FRAME_SP_OFFSET to
the correct value for the exception handler.

This patch exposed a bug in DWARF stack frame CFI generation, which
assumes that INCOMING_FRAME_SP_OFFSET is the same for all functions:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81570

It sets and caches the incoming stack frame offset with the same
INCOMING_FRAME_SP_OFFSET for all functions.  When there are both
exception handler and normal function in the same input, the wrong
incoming stack frame offset is used for exception handler or normal
function, which leads to

FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 error == 0x12345670
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->ip == 0x12345671
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->cs == 0x12345672
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->flags == 0x12345673
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->sp == 0x12345674
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->ss == 0x12345675

With the patch for PR 81570:

https://gcc.gnu.org/ml/gcc-patches/2017-07/msg01851.html

applied, there are no regressions on i686 and x86-64.

gcc/

PR target/79793
* config/i386/i386.c (ix86_function_arg): Update arguments for
exception handler.
(ix86_compute_frame_layout): Set the initial stack offset to
INCOMING_FRAME_SP_OFFSET.  Update red-zone offset with
INCOMING_FRAME_SP_OFFSET.
(ix86_expand_epilogue): Don't pop the 'ERROR_CODE' off the
stack before exception handler returns.
* config/i386/i386.h (INCOMING_FRAME_SP_OFFSET): Add the
the 'ERROR_CODE' for exception handler.

gcc/testsuite/

PR target/79793
* gcc.dg/guality/pr68037-1.c: Update gdb breakpoints.
* gcc.target/i386/interrupt-5.c (interrupt_frame): New struct.
(foo): Check the builtin return address against the return address
in interrupt frame.
* gcc.target/i386/pr79793-1.c: New test.
* gcc.target/i386/pr79793-2.c: Likewise.

Added:
branches/range-gen2/gcc/testsuite/gcc.target/i386/pr79793-1.c
branches/range-gen2/gcc/testsuite/gcc.target/i386/pr79793-2.c
Modified:
branches/range-gen2/gcc/ChangeLog
branches/range-gen2/gcc/config/i386/i386.c
branches/range-gen2/gcc/config/i386/i386.h
branches/range-gen2/gcc/testsuite/ChangeLog
branches/range-gen2/gcc/testsuite/gcc.dg/guality/pr68037-1.c
branches/range-gen2/gcc/testsuite/gcc.target/i386/interrupt-5.c

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

H.J. Lu  changed:

   What|Removed |Added

 Status|NEW |RESOLVED
 Resolution|--- |FIXED

--- Comment #20 from H.J. Lu  ---
Fixed for GCC 8.

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[hjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

--- Comment #19 from hjl at gcc dot gnu.org  ---
Author: hjl
Date: Sun Jul 30 14:10:32 2017
New Revision: 250721

URL: https://gcc.gnu.org/viewcvs?rev=250721=gcc=rev
Log:
i386: Update INCOMING_FRAME_SP_OFFSET for exception handler

Since there is an extra error code passed to the exception handler,
INCOMING_FRAME_SP_OFFSET is return address plus error code for the
exception handler.  This patch updates INCOMING_FRAME_SP_OFFSET to
the correct value for the exception handler.

This patch exposed a bug in DWARF stack frame CFI generation, which
assumes that INCOMING_FRAME_SP_OFFSET is the same for all functions:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81570

It sets and caches the incoming stack frame offset with the same
INCOMING_FRAME_SP_OFFSET for all functions.  When there are both
exception handler and normal function in the same input, the wrong
incoming stack frame offset is used for exception handler or normal
function, which leads to

FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 error == 0x12345670
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->ip == 0x12345671
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->cs == 0x12345672
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->flags == 0x12345673
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->sp == 0x12345674
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->ss == 0x12345675

With the patch for PR 81570:

https://gcc.gnu.org/ml/gcc-patches/2017-07/msg01851.html

applied, there are no regressions on i686 and x86-64.

gcc/

PR target/79793
* config/i386/i386.c (ix86_function_arg): Update arguments for
exception handler.
(ix86_compute_frame_layout): Set the initial stack offset to
INCOMING_FRAME_SP_OFFSET.  Update red-zone offset with
INCOMING_FRAME_SP_OFFSET.
(ix86_expand_epilogue): Don't pop the 'ERROR_CODE' off the
stack before exception handler returns.
* config/i386/i386.h (INCOMING_FRAME_SP_OFFSET): Add the
the 'ERROR_CODE' for exception handler.

gcc/testsuite/

PR target/79793
* gcc.dg/guality/pr68037-1.c: Update gdb breakpoints.
* gcc.target/i386/interrupt-5.c (interrupt_frame): New struct.
(foo): Check the builtin return address against the return address
in interrupt frame.
* gcc.target/i386/pr79793-1.c: New test.
* gcc.target/i386/pr79793-2.c: Likewise.

Added:
trunk/gcc/testsuite/gcc.target/i386/pr79793-1.c
trunk/gcc/testsuite/gcc.target/i386/pr79793-2.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/config/i386/i386.c
trunk/gcc/config/i386/i386.h
trunk/gcc/testsuite/ChangeLog
trunk/gcc/testsuite/gcc.dg/guality/pr68037-1.c
trunk/gcc/testsuite/gcc.target/i386/interrupt-5.c

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

H.J. Lu  changed:

   What|Removed |Added

 Status|REOPENED|NEW
 Depends on||81570

--- Comment #18 from H.J. Lu  ---
(In reply to H.J. Lu from comment #17)
> 
> We didn't lose the info. The problem is that create_pseudo_cfg assumes
> INCOMING_FRAME_SP_OFFSET is a constant.

I opened PR 81570.


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81570
[Bug 81570] create_pseudo_cfg assumes that INCOMING_FRAME_SP_OFFSET is a
constant

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

--- Comment #17 from H.J. Lu  ---
(In reply to H.J. Lu from comment #16)
> The problem is in create_cie_data:
> 
>  /* On entry, the Canonical Frame Address is at SP.  */
>   memset (, 0, sizeof (loc));
>   loc.reg = dw_stack_pointer_regnum;
>   loc.offset = INCOMING_FRAME_SP_OFFSET;
>   def_cfa_1 ();
> 
> We lost the function type info with LTO.

We didn't lose the info. The problem is that create_pseudo_cfg assumes
INCOMING_FRAME_SP_OFFSET is a constant.

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

--- Comment #16 from H.J. Lu  ---
The problem is in create_cie_data:

 /* On entry, the Canonical Frame Address is at SP.  */
  memset (, 0, sizeof (loc));
  loc.reg = dw_stack_pointer_regnum;
  loc.offset = INCOMING_FRAME_SP_OFFSET;
  def_cfa_1 ();

We lost the function type info with LTO.

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

H.J. Lu  changed:

   What|Removed |Added

  Attachment #41834|0   |1
is obsolete||

--- Comment #15 from H.J. Lu  ---
Created attachment 41839
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41839=edit
A patch

-g -O2 -flto generates:

Dump of assembler code for function fn:
   0x00400550 <+0>: push   %rdi
   0x00400551 <+1>: sub$0x8,%rsp
   0x00400555 <+5>: cmpq   $0x12345670,0x10(%rsp)
   0x0040055e <+14>:jne0x400430 
=> 0x00400564 <+20>:cmpq   $0x12345671,0x18(%rsp)

with debug info:

0084 0018 0058 FDE cie=0030
pc=00400550..004005b7
  DW_CFA_advance_loc: 1 to 00400551
  DW_CFA_def_cfa_offset: 16
  DW_CFA_offset: r5 (rdi) at cfa-16
  DW_CFA_advance_loc: 4 to 00400555
  DW_CFA_def_cfa_offset: 24
  DW_CFA_nop
  DW_CFA_nop
  DW_CFA_nop

-g -O2 generates:

   0x00400550 <+0>: push   %rdi
   0x00400551 <+1>: sub$0x8,%rsp
   0x00400555 <+5>: cmpq   $0x12345670,0x10(%rsp)
   0x0040055e <+14>:jne0x400430 
   0x00400564 <+20>:cmpq   $0x12345671,0x18(%rsp)

with debug info:

0070 0018 0044 FDE cie=0030
pc=00400550..004005b7
  DW_CFA_advance_loc: 1 to 00400551
  DW_CFA_def_cfa_offset: 24 
  DW_CFA_offset: r5 (rdi) at cfa-24
  DW_CFA_advance_loc: 4 to 00400555
  DW_CFA_def_cfa_offset: 32 
  DW_CFA_nop
  DW_CFA_nop
  DW_CFA_nop

Somehow -flto -O2 generates the incorrect debug info.

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

H.J. Lu  changed:

   What|Removed |Added

  Attachment #41830|0   |1
is obsolete||

--- Comment #14 from H.J. Lu  ---
Created attachment 41834
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41834=edit
An untested patch

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

H.J. Lu  changed:

   What|Removed |Added

  Attachment #41826|0   |1
is obsolete||
  Attachment #41828|0   |1
is obsolete||

--- Comment #13 from H.J. Lu  ---
Created attachment 41830
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41830=edit
An untested patch

The only interrupt failures are

FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 error == 0x12345670
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->ip == 0x12345671
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->cs == 0x12345672
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->flags == 0x12345673
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->sp == 0x12345674
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->ss == 0x12345675

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

--- Comment #12 from H.J. Lu  ---
Created attachment 41828
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41828=edit
An updated patch

Update gcc.dg/guality/pr68037-1.c.  I got

FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 error == 0x12345670
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->ip == 0x12345671
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->cs == 0x12345672
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->flags == 0x12345673
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->sp == 0x12345674
FAIL: gcc.dg/guality/pr68037-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 33 frame->ss == 0x12345675

and

Running target unix/-m32
Using /usr/share/dejagnu/baseboards/unix.exp as board description file for
target.
Using /usr/share/dejagnu/config/unix.exp as generic interface file for target.
Using /export/gnu/import/git/sources/gcc/gcc/testsuite/config/default.exp as
tool-and-target-specific interface file.
Running
/export/gnu/import/git/sources/gcc/gcc/testsuite/gcc.target/i386/i386.exp ...
FAIL: gcc.target/i386/interrupt-12.c scan-assembler-times movl[\\t
]*-4\\(%ebp\\),[\\t ]*%eax 1
FAIL: gcc.target/i386/interrupt-13.c scan-assembler-times movl[\\t
]*-4\\(%ebp\\),[\\t ]*%eax 1
FAIL: gcc.target/i386/interrupt-15.c scan-assembler-times movl[\\t
]*-4\\(%ebp\\),[\\t ]*%eax 2

=== gcc Summary for unix/-m32 ===

# of expected passes211
# of unexpected failures3
# of unsupported tests  2

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

--- Comment #11 from H.J. Lu  ---
(In reply to Uroš Bizjak from comment #9)
> Created attachment 41826 [details]
> Adjust INCOMING_FRAME_SP_OFFSET for TYPE_EXCEPTION functions
> 
> How about something like attached patch? The patch adjusts
> INCOMING_FRAME_SP_OFFSET of an exception handler to 2 * UNITS_PER_WORD.
> 
> The resulting code reads:
> 
> .cfi_startproc
> subq$392, %rsp
> .cfi_def_cfa_offset 400
> fxsave64-120(%rsp)
> addq$400, %rsp
> .cfi_def_cfa_offset 0
> iretq
> .cfi_endproc
> 
> Patch is otherwise untested. Probably, function argument parsing code has to
> be adjusted as well. I'm also not sure if all .cfi directives are correct.

Our patches are very similar.  Mine passed most of interrupt tests.

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

--- Comment #10 from H.J. Lu  ---
Created attachment 41827
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41827=edit
An untested patch

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

--- Comment #9 from Uroš Bizjak  ---
Created attachment 41826
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41826=edit
Adjust INCOMING_FRAME_SP_OFFSET for TYPE_EXCEPTION functions

How about something like attached patch? The patch adjusts
INCOMING_FRAME_SP_OFFSET of an exception handler to 2 * UNITS_PER_WORD.

The resulting code reads:

.cfi_startproc
subq$392, %rsp
.cfi_def_cfa_offset 400
fxsave64-120(%rsp)
addq$400, %rsp
.cfi_def_cfa_offset 0
iretq
.cfi_endproc

Patch is otherwise untested. Probably, function argument parsing code has to be
adjusted as well. I'm also not sure if all .cfi directives are correct.

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

--- Comment #8 from H.J. Lu  ---
clang 5.0 handles stack alignment correctly:

[hjl@gnu-skl-1 pr79793]$ cat x.c
typedef unsigned int uword_t __attribute__ ((mode (__word__)));

__attribute__((interrupt))
void
fn (void *frame)
{
  char fxsave_region [512] __attribute__((aligned(16)));
  __builtin_ia32_fxsave (fxsave_region);
}
[hjl@gnu-skl-1 pr79793]$ cat y.c
typedef unsigned int uword_t __attribute__ ((mode (__word__)));

__attribute__((interrupt))
void
fn (void *frame, uword_t error)
{
  char fxsave_region [512] __attribute__((aligned(16)));
  __builtin_ia32_fxsave (fxsave_region);
}
[hjl@gnu-skl-1 pr79793]$ make 
/export/build/gnu/llvm-clang/build-x86_64-linux/bin/clang -O2
-mgeneral-regs-only -S -o y.s y.c
clang-5.0: warning: argument unused during compilation: '-mgeneral-regs-only'
[-Wunused-command-line-argument]
[hjl@gnu-skl-1 pr79793]$ cat x.s
.text
.file   "x.c"
.globl  fn  # -- Begin function fn
.p2align4, 0x90
.type   fn,@function
fn: # @fn
.cfi_startproc
# BB#0: # %entry
subq$392, %rsp  # imm = 0x188
.Lcfi0:
.cfi_def_cfa_offset 400
cld
fxsave  -128(%rsp)
addq$392, %rsp  # imm = 0x188
iretq
.Lfunc_end0:
.size   fn, .Lfunc_end0-fn
.cfi_endproc
# -- End function

.ident  "clang version 5.0.0 (http://llvm.org/git/clang.git
f53edbb006df3bc205bf38008d96de510b2a) (http://llvm.org/git/llvm.git
9889fe2290766430b99a2d4fadbc5ba92f8004b6)"
.section".note.GNU-stack","",@progbits
[hjl@gnu-skl-1 pr79793]$ cat y.s
.text
.file   "y.c"
.globl  fn  # -- Begin function fn
.p2align4, 0x90
.type   fn,@function
fn: # @fn
.cfi_startproc
# BB#0: # %entry
pushq   %rax
subq$400, %rsp  # imm = 0x190
.Lcfi0:
.cfi_def_cfa_offset 408
cld
fxsave  -120(%rsp)
addq$400, %rsp  # imm = 0x190
addq$16, %rsp
iretq
.Lfunc_end0:
.size   fn, .Lfunc_end0-fn
.cfi_endproc
# -- End function

.ident  "clang version 5.0.0 (http://llvm.org/git/clang.git
f53edbb006df3bc205bf38008d96de510b2a) (http://llvm.org/git/llvm.git
9889fe2290766430b99a2d4fadbc5ba92f8004b6)"
.section".note.GNU-stack","",@progbits
[hjl@gnu-skl-1 pr79793]$

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

--- Comment #7 from H.J. Lu  ---
(In reply to H.J. Lu from comment #5)
> In 64-bit mode, stack is 16-byte aligned when entering handler.  But if
> there is error code
> 
> SS
> RSP
> FLAGS
> CS
> RIP
> Error Code
> 
> the stack alignment is off by 8 bytes.  That is %rsp + 8 isn't multiple
> of 16 at the start of handler.

A testcase:

[hjl@gnu-skl-1 pr79793]$ cat y.c
#include 

typedef unsigned int uword_t __attribute__ ((mode (__word__)));

struct interrupt_frame
{
  uword_t ip;
  uword_t cs;
  uword_t flags;
  uword_t sp;
  uword_t ss;
};

__attribute__((interrupt))
void
fn (struct interrupt_frame *frame, uword_t error)
{
  char fxsave_region [512] __attribute__((aligned(16)));
  _fxsave64 (fxsave_region);
}
[hjl@gnu-skl-1 pr79793]$ make y.s
/export/build/gnu/gcc-x32-7/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc-x32-7/build-x86_64-linux/gcc/ -O2 -mgeneral-regs-only
-S -o y.s y.c
[hjl@gnu-skl-1 pr79793]$ cat y.s
.file   "y.c"
.text
.p2align 4,,15
.globl  fn
.type   fn, @function
fn:
.LFB4:
.cfi_startproc
subq$400, %rsp
.cfi_def_cfa_offset 408
fxsave64-120(%rsp)
addq$408, %rsp
iretq
.cfi_endproc
.LFE4:
.size   fn, .-fn
.ident  "GCC: (GNU) 7.1.1 20170724"
.section.note.GNU-stack,"",@progbits
[hjl@gnu-skl-1 pr79793]$ 

-120(%rsp) isn't aligned at 16 bytes.

For

[hjl@gnu-skl-1 pr79793]$ cat x.c
#include 

typedef unsigned int uword_t __attribute__ ((mode (__word__)));

struct interrupt_frame
{
  uword_t ip;
  uword_t cs;
  uword_t flags;
  uword_t sp;
  uword_t ss;
};

__attribute__((interrupt))
void
fn (struct interrupt_frame *frame)
{
  char fxsave_region [512] __attribute__((aligned(16)));
  _fxsave64 (fxsave_region);
}
[hjl@gnu-skl-1 pr79793]$ make x.s
/export/build/gnu/gcc-x32-7/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc-x32-7/build-x86_64-linux/gcc/ -O2 -mgeneral-regs-only
-S -o x.s x.c
[hjl@gnu-skl-1 pr79793]$ cat x.s
.file   "x.c"
.text
.p2align 4,,15
.globl  fn
.type   fn, @function
fn:
.LFB4:
.cfi_startproc
subq$400, %rsp
.cfi_def_cfa_offset 408
fxsave64-120(%rsp)
addq$400, %rsp
.cfi_def_cfa_offset 8
iretq
.cfi_endproc
.LFE4:
.size   fn, .-fn
.ident  "GCC: (GNU) 7.1.1 20170724"
.section.note.GNU-stack,"",@progbits
[hjl@gnu-skl-1 pr79793]$ 

-120(%rsp) is aligned at 16 bytes.

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

Jakub Jelinek  changed:

   What|Removed |Added

   Target Milestone|7.0 |7.2

--- Comment #6 from Jakub Jelinek  ---
GCC 7.1 has been released.

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

H.J. Lu  changed:

   What|Removed |Added

 Status|RESOLVED|REOPENED
   Last reconfirmed||2017-03-13
 Resolution|FIXED   |---
 Ever confirmed|0   |1

--- Comment #5 from H.J. Lu  ---
In 64-bit mode, stack is 16-byte aligned when entering handler.  But if
there is error code

SS
RSP
FLAGS
CS
RIP
Error Code

the stack alignment is off by 8 bytes.  That is %rsp + 8 isn't multiple
of 16 at the start of handler.

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

H.J. Lu  changed:

   What|Removed |Added

 Status|UNCONFIRMED |RESOLVED
 Resolution|--- |FIXED
   Target Milestone|--- |7.0

--- Comment #4 from H.J. Lu  ---
Fixed for GCC 7.

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[hjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

--- Comment #3 from hjl at gcc dot gnu.org  ---
Author: hjl
Date: Mon Mar  6 16:08:59 2017
New Revision: 245926

URL: https://gcc.gnu.org/viewcvs?rev=245926=gcc=rev
Log:
Set incoming stack boundary to 128 for 64-bit targets

For 64-bit targets, the incoming stack of interrupt handler is aligned
to 16 bytes.  Update ix86_minimum_incoming_stack_boundary to set the
incoming stack boundary of interrupt handler to 128 for 64-bit targets.

gcc/

2017-03-06  Julia Koval  

PR target/79793
* config/i386/i386.c (ix86_minimum_incoming_stack_boundary): Set
incoming stack boundary to 128 for 64-bit targets.

gcc/testsuite/

2017-03-06  Julia Koval  

PR target/79793
 * gcc.target/i386/interrupt-12.c: Update scan-assembler-times
 directives.
 * gcc.target/i386/interrupt-13.c: Ditto.
 * gcc.target/i386/interrupt-14.c: Ditto.
 * gcc.target/i386/interrupt-15.c: Ditto.


Modified:
trunk/gcc/ChangeLog
trunk/gcc/config/i386/i386.c
trunk/gcc/testsuite/ChangeLog
trunk/gcc/testsuite/gcc.target/i386/interrupt-12.c
trunk/gcc/testsuite/gcc.target/i386/interrupt-13.c
trunk/gcc/testsuite/gcc.target/i386/interrupt-14.c
trunk/gcc/testsuite/gcc.target/i386/interrupt-15.c

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[julia.koval at intel dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

--- Comment #2 from Yulia Koval  ---
Patch posted at
https://gcc.gnu.org/ml/gcc-patches/2017-03/msg00178.html

[Bug target/79793] Incorrect stack alignment for interrupt handler in 64-bit

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79793

--- Comment #1 from Richard Biener  ---
Well, not "incorrect" but too conservative.