* Re: [PATCH] x86/entry: add compatibility with IAS
2020-07-13 1:24 [PATCH] x86/entry: add compatibility with IAS Jian Cai
@ 2020-07-13 2:33 ` Brian Gerst
2020-07-13 2:54 ` Arvind Sankar
` (3 subsequent siblings)
4 siblings, 0 replies; 12+ messages in thread
From: Brian Gerst @ 2020-07-13 2:33 UTC (permalink / raw)
To: Jian Cai
Cc: jiancai, Nick Desaulniers, manojgupta, Sedat Dilek,
Thomas Gleixner, Ingo Molnar, Borislav Petkov,
the arch/x86 maintainers, H. Peter Anvin, Andy Lutomirski,
Peter Zijlstra, Alexandre Chartre, Linux Kernel Mailing List,
clang-built-linux
On Sun, Jul 12, 2020 at 9:26 PM Jian Cai <caij2003@gmail.com> wrote:
>
> Clang's integrated assembler does not allow symbols with non-absolute
> values to be reassigned. This patch allows the affected code to be
> compatible with IAS.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1043
> Reported-by: Nick Desaulniers <ndesaulniers@google.com>
> Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
> Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
> Signed-off-by: Jian Cai <caij2003@gmail.com>
> ---
> arch/x86/include/asm/idtentry.h | 22 ++++++++++------------
> 1 file changed, 10 insertions(+), 12 deletions(-)
>
> diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
> index f3d70830bf2a..77beed2cd6d9 100644
> --- a/arch/x86/include/asm/idtentry.h
> +++ b/arch/x86/include/asm/idtentry.h
> @@ -468,34 +468,32 @@ __visible noinstr void func(struct pt_regs *regs, \
> */
> .align 8
> SYM_CODE_START(irq_entries_start)
> - vector=FIRST_EXTERNAL_VECTOR
> - pos = .
> + i = 1
Start with index 0.
> + pos1 = .
pos1 is unnecessary, as it's equal to irq_entries_start.
> .rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)
> UNWIND_HINT_IRET_REGS
> - .byte 0x6a, vector
> + .byte 0x6a, FIRST_EXTERNAL_VECTOR + i - 1
> jmp asm_common_interrupt
> nop
> /* Ensure that the above is 8 bytes max */
> - . = pos + 8
> - pos=pos+8
> - vector=vector+1
> + . = pos1 + 8 * i
> + i = i + 1
If you swap these two lines then the index will be correct for the
next stub if you start at 0..
> .endr
> SYM_CODE_END(irq_entries_start)
>
> #ifdef CONFIG_X86_LOCAL_APIC
> .align 8
> SYM_CODE_START(spurious_entries_start)
> - vector=FIRST_SYSTEM_VECTOR
> - pos = .
> + i = 1
> + pos2 = .
> .rept (NR_VECTORS - FIRST_SYSTEM_VECTOR)
> UNWIND_HINT_IRET_REGS
> - .byte 0x6a, vector
> + .byte 0x6a, FIRST_SYSTEM_VECTOR + i - 1
> jmp asm_spurious_interrupt
> nop
> /* Ensure that the above is 8 bytes max */
> - . = pos + 8
> - pos=pos+8
> - vector=vector+1
> + . = pos2 + 8 * i
> + i = i + 1
> .endr
> SYM_CODE_END(spurious_entries_start)
> #endif
--
Brian Gerst
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [PATCH] x86/entry: add compatibility with IAS
2020-07-13 1:24 [PATCH] x86/entry: add compatibility with IAS Jian Cai
2020-07-13 2:33 ` Brian Gerst
@ 2020-07-13 2:54 ` Arvind Sankar
2020-07-13 3:57 ` Arvind Sankar
2020-07-13 21:38 ` Jian Cai
` (2 subsequent siblings)
4 siblings, 1 reply; 12+ messages in thread
From: Arvind Sankar @ 2020-07-13 2:54 UTC (permalink / raw)
To: Jian Cai
Cc: jiancai, ndesaulniers, manojgupta, sedat.dilek, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, x86, H. Peter Anvin,
Andy Lutomirski, Peter Zijlstra, Alexandre Chartre, linux-kernel,
clang-built-linux
On Sun, Jul 12, 2020 at 06:24:22PM -0700, Jian Cai wrote:
> Clang's integrated assembler does not allow symbols with non-absolute
> values to be reassigned. This patch allows the affected code to be
> compatible with IAS.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1043
> Reported-by: Nick Desaulniers <ndesaulniers@google.com>
> Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
> Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
> Signed-off-by: Jian Cai <caij2003@gmail.com>
> ---
> arch/x86/include/asm/idtentry.h | 22 ++++++++++------------
> 1 file changed, 10 insertions(+), 12 deletions(-)
>
> diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
> index f3d70830bf2a..77beed2cd6d9 100644
> --- a/arch/x86/include/asm/idtentry.h
> +++ b/arch/x86/include/asm/idtentry.h
> @@ -468,34 +468,32 @@ __visible noinstr void func(struct pt_regs *regs, \
> */
> .align 8
> SYM_CODE_START(irq_entries_start)
> - vector=FIRST_EXTERNAL_VECTOR
> - pos = .
> + i = 1
> + pos1 = .
> .rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)
> UNWIND_HINT_IRET_REGS
> - .byte 0x6a, vector
> + .byte 0x6a, FIRST_EXTERNAL_VECTOR + i - 1
> jmp asm_common_interrupt
> nop
> /* Ensure that the above is 8 bytes max */
> - . = pos + 8
> - pos=pos+8
> - vector=vector+1
> + . = pos1 + 8 * i
> + i = i + 1
> .endr
> SYM_CODE_END(irq_entries_start)
I think it would be a little cleaner to initialize i to 0, and drop pos.
i.e. couldn't we do
i = 0
...
.byte 0x6a, FIRST_EXTERNAL_VECTOR + i
...
i = i + 1
. = irq_entries_start + 8 * i
>
> #ifdef CONFIG_X86_LOCAL_APIC
> .align 8
> SYM_CODE_START(spurious_entries_start)
> - vector=FIRST_SYSTEM_VECTOR
> - pos = .
> + i = 1
> + pos2 = .
> .rept (NR_VECTORS - FIRST_SYSTEM_VECTOR)
> UNWIND_HINT_IRET_REGS
> - .byte 0x6a, vector
> + .byte 0x6a, FIRST_SYSTEM_VECTOR + i - 1
> jmp asm_spurious_interrupt
> nop
> /* Ensure that the above is 8 bytes max */
> - . = pos + 8
> - pos=pos+8
> - vector=vector+1
> + . = pos2 + 8 * i
> + i = i + 1
> .endr
> SYM_CODE_END(spurious_entries_start)
> #endif
> --
> 2.27.0.383.g050319c2ae-goog
>
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [PATCH] x86/entry: add compatibility with IAS
2020-07-13 2:54 ` Arvind Sankar
@ 2020-07-13 3:57 ` Arvind Sankar
0 siblings, 0 replies; 12+ messages in thread
From: Arvind Sankar @ 2020-07-13 3:57 UTC (permalink / raw)
To: Arvind Sankar
Cc: Jian Cai, jiancai, ndesaulniers, manojgupta, sedat.dilek,
Thomas Gleixner, Ingo Molnar, Borislav Petkov, x86,
H. Peter Anvin, Andy Lutomirski, Peter Zijlstra,
Alexandre Chartre, linux-kernel, clang-built-linux
On Sun, Jul 12, 2020 at 10:54:29PM -0400, Arvind Sankar wrote:
> On Sun, Jul 12, 2020 at 06:24:22PM -0700, Jian Cai wrote:
> > Clang's integrated assembler does not allow symbols with non-absolute
> > values to be reassigned. This patch allows the affected code to be
> > compatible with IAS.
> >
> > Link: https://github.com/ClangBuiltLinux/linux/issues/1043
> > Reported-by: Nick Desaulniers <ndesaulniers@google.com>
> > Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
> > Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> > Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
> > Signed-off-by: Jian Cai <caij2003@gmail.com>
> > ---
> > arch/x86/include/asm/idtentry.h | 22 ++++++++++------------
> > 1 file changed, 10 insertions(+), 12 deletions(-)
> >
> > diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
> > index f3d70830bf2a..77beed2cd6d9 100644
> > --- a/arch/x86/include/asm/idtentry.h
> > +++ b/arch/x86/include/asm/idtentry.h
> > @@ -468,34 +468,32 @@ __visible noinstr void func(struct pt_regs *regs, \
> > */
> > .align 8
> > SYM_CODE_START(irq_entries_start)
> > - vector=FIRST_EXTERNAL_VECTOR
> > - pos = .
> > + i = 1
> > + pos1 = .
> > .rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)
> > UNWIND_HINT_IRET_REGS
> > - .byte 0x6a, vector
> > + .byte 0x6a, FIRST_EXTERNAL_VECTOR + i - 1
> > jmp asm_common_interrupt
> > nop
> > /* Ensure that the above is 8 bytes max */
> > - . = pos + 8
> > - pos=pos+8
> > - vector=vector+1
> > + . = pos1 + 8 * i
> > + i = i + 1
> > .endr
> > SYM_CODE_END(irq_entries_start)
>
> I think it would be a little cleaner to initialize i to 0, and drop pos.
> i.e. couldn't we do
> i = 0
> ...
> .byte 0x6a, FIRST_EXTERNAL_VECTOR + i
> ...
> i = i + 1
> . = irq_entries_start + 8 * i
>
Or maybe just:
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index eeac6dc2adaa..c774039d130b 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -469,15 +469,14 @@ __visible noinstr void func(struct pt_regs *regs, \
.align 8
SYM_CODE_START(irq_entries_start)
vector=FIRST_EXTERNAL_VECTOR
- pos = .
.rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)
+ 0:
UNWIND_HINT_IRET_REGS
.byte 0x6a, vector
jmp asm_common_interrupt
nop
/* Ensure that the above is 8 bytes max */
- . = pos + 8
- pos=pos+8
+ . = 0b + 8
vector=vector+1
.endr
SYM_CODE_END(irq_entries_start)
@@ -486,15 +485,14 @@ SYM_CODE_END(irq_entries_start)
.align 8
SYM_CODE_START(spurious_entries_start)
vector=FIRST_SYSTEM_VECTOR
- pos = .
.rept (NR_VECTORS - FIRST_SYSTEM_VECTOR)
+ 0:
UNWIND_HINT_IRET_REGS
.byte 0x6a, vector
jmp asm_spurious_interrupt
nop
/* Ensure that the above is 8 bytes max */
- . = pos + 8
- pos=pos+8
+ . = 0b + 8
vector=vector+1
.endr
SYM_CODE_END(spurious_entries_start)
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH] x86/entry: add compatibility with IAS
2020-07-13 1:24 [PATCH] x86/entry: add compatibility with IAS Jian Cai
2020-07-13 2:33 ` Brian Gerst
2020-07-13 2:54 ` Arvind Sankar
@ 2020-07-13 21:38 ` Jian Cai
2020-07-13 22:17 ` Arvind Sankar
2020-07-13 22:40 ` Jian Cai
2020-07-14 23:30 ` [PATCH v2] " Jian Cai
4 siblings, 1 reply; 12+ messages in thread
From: Jian Cai @ 2020-07-13 21:38 UTC (permalink / raw)
Cc: caij2003, jiancai, ndesaulniers, manojgupta, sedat.dilek,
Brian Gerst, Arvind Sankar, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, x86, H. Peter Anvin, Andy Lutomirski,
Peter Zijlstra, Alexandre Chartre, linux-kernel,
clang-built-linux
Clang's integrated assembler does not allow symbols with non-absolute
values to be reassigned. This patch allows the affected code to be
compatible with IAS.
Link: https://github.com/ClangBuiltLinux/linux/issues/1043
Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Suggested-by: Brian Gerst <brgerst@gmail.com>
Suggested-by: Arvind Sankar <nivedita@alum.mit.edu>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Jian Cai <caij2003@gmail.com>
---
arch/x86/include/asm/idtentry.h | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index f3d70830bf2a..7d22684eafdf 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -469,16 +469,15 @@ __visible noinstr void func(struct pt_regs *regs, \
.align 8
SYM_CODE_START(irq_entries_start)
vector=FIRST_EXTERNAL_VECTOR
- pos = .
.rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)
+0 :
UNWIND_HINT_IRET_REGS
.byte 0x6a, vector
jmp asm_common_interrupt
nop
/* Ensure that the above is 8 bytes max */
- . = pos + 8
- pos=pos+8
- vector=vector+1
+ . = 0b + 8
+ vector = vector+1
.endr
SYM_CODE_END(irq_entries_start)
@@ -486,16 +485,15 @@ SYM_CODE_END(irq_entries_start)
.align 8
SYM_CODE_START(spurious_entries_start)
vector=FIRST_SYSTEM_VECTOR
- pos = .
.rept (NR_VECTORS - FIRST_SYSTEM_VECTOR)
+0 :
UNWIND_HINT_IRET_REGS
- .byte 0x6a, vector
+ .byte 0x6a, FIRST_SYSTEM_VECTOR + i
jmp asm_spurious_interrupt
nop
/* Ensure that the above is 8 bytes max */
- . = pos + 8
- pos=pos+8
- vector=vector+1
+ . = 0b + 8
+ vector = vector+1
.endr
SYM_CODE_END(spurious_entries_start)
#endif
--
2.27.0.383.g050319c2ae-goog
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [PATCH] x86/entry: add compatibility with IAS
2020-07-13 21:38 ` Jian Cai
@ 2020-07-13 22:17 ` Arvind Sankar
0 siblings, 0 replies; 12+ messages in thread
From: Arvind Sankar @ 2020-07-13 22:17 UTC (permalink / raw)
To: Jian Cai
Cc: jiancai, ndesaulniers, manojgupta, sedat.dilek, Brian Gerst,
Arvind Sankar, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
x86, H. Peter Anvin, Andy Lutomirski, Peter Zijlstra,
Alexandre Chartre, linux-kernel, clang-built-linux
On Mon, Jul 13, 2020 at 02:38:01PM -0700, Jian Cai wrote:
> Clang's integrated assembler does not allow symbols with non-absolute
> values to be reassigned. This patch allows the affected code to be
> compatible with IAS.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1043
> Reported-by: Nick Desaulniers <ndesaulniers@google.com>
> Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
> Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> Suggested-by: Brian Gerst <brgerst@gmail.com>
> Suggested-by: Arvind Sankar <nivedita@alum.mit.edu>
> Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
> Signed-off-by: Jian Cai <caij2003@gmail.com>
> ---
> arch/x86/include/asm/idtentry.h | 16 +++++++---------
> 1 file changed, 7 insertions(+), 9 deletions(-)
>
> diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
> index f3d70830bf2a..7d22684eafdf 100644
> --- a/arch/x86/include/asm/idtentry.h
> +++ b/arch/x86/include/asm/idtentry.h
> @@ -469,16 +469,15 @@ __visible noinstr void func(struct pt_regs *regs, \
> .align 8
> SYM_CODE_START(irq_entries_start)
> vector=FIRST_EXTERNAL_VECTOR
> - pos = .
> .rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)
> +0 :
> UNWIND_HINT_IRET_REGS
I know I had it this way, but I think it may be slightly safer to put
the label immediately after UNWIND_HINT_IRET_REGS instead of before,
just in case anyone adds a 0: inside that macro.
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH] x86/entry: add compatibility with IAS
2020-07-13 1:24 [PATCH] x86/entry: add compatibility with IAS Jian Cai
` (2 preceding siblings ...)
2020-07-13 21:38 ` Jian Cai
@ 2020-07-13 22:40 ` Jian Cai
2020-07-14 9:34 ` Sedat Dilek
2020-07-14 23:30 ` [PATCH v2] " Jian Cai
4 siblings, 1 reply; 12+ messages in thread
From: Jian Cai @ 2020-07-13 22:40 UTC (permalink / raw)
Cc: caij2003, jiancai, ndesaulniers, manojgupta, sedat.dilek,
Brian Gerst, Arvind Sankar, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, x86, H. Peter Anvin, Andy Lutomirski,
Peter Zijlstra, Alexandre Chartre, linux-kernel,
clang-built-linux
Clang's integrated assembler does not allow symbols with non-absolute
values to be reassigned. This patch allows the affected code to be
compatible with IAS.
Link: https://github.com/ClangBuiltLinux/linux/issues/1043
Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Suggested-by: Brian Gerst <brgerst@gmail.com>
Suggested-by: Arvind Sankar <nivedita@alum.mit.edu>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Jian Cai <caij2003@gmail.com>
---
arch/x86/include/asm/idtentry.h | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index f3d70830bf2a..5efaaed34eda 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -469,16 +469,15 @@ __visible noinstr void func(struct pt_regs *regs, \
.align 8
SYM_CODE_START(irq_entries_start)
vector=FIRST_EXTERNAL_VECTOR
- pos = .
.rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)
UNWIND_HINT_IRET_REGS
+0 :
.byte 0x6a, vector
jmp asm_common_interrupt
nop
/* Ensure that the above is 8 bytes max */
- . = pos + 8
- pos=pos+8
- vector=vector+1
+ . = 0b + 8
+ vector = vector+1
.endr
SYM_CODE_END(irq_entries_start)
@@ -486,16 +485,15 @@ SYM_CODE_END(irq_entries_start)
.align 8
SYM_CODE_START(spurious_entries_start)
vector=FIRST_SYSTEM_VECTOR
- pos = .
.rept (NR_VECTORS - FIRST_SYSTEM_VECTOR)
UNWIND_HINT_IRET_REGS
+0 :
.byte 0x6a, vector
jmp asm_spurious_interrupt
nop
/* Ensure that the above is 8 bytes max */
- . = pos + 8
- pos=pos+8
- vector=vector+1
+ . = 0b + 8
+ vector = vector+1
.endr
SYM_CODE_END(spurious_entries_start)
#endif
--
2.27.0.383.g050319c2ae-goog
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [PATCH] x86/entry: add compatibility with IAS
2020-07-13 22:40 ` Jian Cai
@ 2020-07-14 9:34 ` Sedat Dilek
2020-07-14 10:48 ` Sedat Dilek
0 siblings, 1 reply; 12+ messages in thread
From: Sedat Dilek @ 2020-07-14 9:34 UTC (permalink / raw)
To: Jian Cai
Cc: jiancai, Nick Desaulniers, manojgupta, Brian Gerst,
Arvind Sankar, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
x86, H. Peter Anvin, Andy Lutomirski, Peter Zijlstra,
Alexandre Chartre, linux-kernel, Clang-Built-Linux ML
On Tue, Jul 14, 2020 at 12:40 AM Jian Cai <caij2003@gmail.com> wrote:
>
> Clang's integrated assembler does not allow symbols with non-absolute
> values to be reassigned. This patch allows the affected code to be
> compatible with IAS.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1043
> Reported-by: Nick Desaulniers <ndesaulniers@google.com>
> Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
> Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> Suggested-by: Brian Gerst <brgerst@gmail.com>
> Suggested-by: Arvind Sankar <nivedita@alum.mit.edu>
> Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
> Signed-off-by: Jian Cai <caij2003@gmail.com>
Hi Jian,
thanks for the update!
I am glad to see that some Linux/x86 assembler "monsters" jumped on the train.
So, your patch with reviewer's comment got several iterations?
Not sure if you are aware of the process of submitting patches (see [1])?
It is common to add a ChangeLog below commit-message-body and diffstat
means add below "--".
Something like:
--
Changes v1 -> v2:
- I did some cool stuff to improve this
While at it... Please add your version-of-patch to the subject-line:
You can do this via "git format-patch --signoff --subject-prefix="PATCH v2".
There might be other cool git tricks I do not know.
Hope I was no "Uberlehrer".
- Sedat -
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst
> ---
> arch/x86/include/asm/idtentry.h | 14 ++++++--------
> 1 file changed, 6 insertions(+), 8 deletions(-)
>
> diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
> index f3d70830bf2a..5efaaed34eda 100644
> --- a/arch/x86/include/asm/idtentry.h
> +++ b/arch/x86/include/asm/idtentry.h
> @@ -469,16 +469,15 @@ __visible noinstr void func(struct pt_regs *regs, \
> .align 8
> SYM_CODE_START(irq_entries_start)
> vector=FIRST_EXTERNAL_VECTOR
> - pos = .
> .rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)
> UNWIND_HINT_IRET_REGS
> +0 :
> .byte 0x6a, vector
> jmp asm_common_interrupt
> nop
> /* Ensure that the above is 8 bytes max */
> - . = pos + 8
> - pos=pos+8
> - vector=vector+1
> + . = 0b + 8
> + vector = vector+1
> .endr
> SYM_CODE_END(irq_entries_start)
>
> @@ -486,16 +485,15 @@ SYM_CODE_END(irq_entries_start)
> .align 8
> SYM_CODE_START(spurious_entries_start)
> vector=FIRST_SYSTEM_VECTOR
> - pos = .
> .rept (NR_VECTORS - FIRST_SYSTEM_VECTOR)
> UNWIND_HINT_IRET_REGS
> +0 :
> .byte 0x6a, vector
> jmp asm_spurious_interrupt
> nop
> /* Ensure that the above is 8 bytes max */
> - . = pos + 8
> - pos=pos+8
> - vector=vector+1
> + . = 0b + 8
> + vector = vector+1
> .endr
> SYM_CODE_END(spurious_entries_start)
> #endif
> --
> 2.27.0.383.g050319c2ae-goog
>
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] x86/entry: add compatibility with IAS
2020-07-14 9:34 ` Sedat Dilek
@ 2020-07-14 10:48 ` Sedat Dilek
0 siblings, 0 replies; 12+ messages in thread
From: Sedat Dilek @ 2020-07-14 10:48 UTC (permalink / raw)
To: Jian Cai
Cc: jiancai, Nick Desaulniers, manojgupta, Brian Gerst,
Arvind Sankar, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
x86, H. Peter Anvin, Andy Lutomirski, Peter Zijlstra,
Alexandre Chartre, linux-kernel, Clang-Built-Linux ML
On Tue, Jul 14, 2020 at 11:34 AM Sedat Dilek <sedat.dilek@gmail.com> wrote:
>
> On Tue, Jul 14, 2020 at 12:40 AM Jian Cai <caij2003@gmail.com> wrote:
> >
> > Clang's integrated assembler does not allow symbols with non-absolute
> > values to be reassigned. This patch allows the affected code to be
> > compatible with IAS.
> >
> > Link: https://github.com/ClangBuiltLinux/linux/issues/1043
> > Reported-by: Nick Desaulniers <ndesaulniers@google.com>
> > Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
> > Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> > Suggested-by: Brian Gerst <brgerst@gmail.com>
> > Suggested-by: Arvind Sankar <nivedita@alum.mit.edu>
> > Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
> > Signed-off-by: Jian Cai <caij2003@gmail.com>
>
> Hi Jian,
>
> thanks for the update!
>
> I am glad to see that some Linux/x86 assembler "monsters" jumped on the train.
>
> So, your patch with reviewer's comment got several iterations?
> Not sure if you are aware of the process of submitting patches (see [1])?
>
> It is common to add a ChangeLog below commit-message-body and diffstat
> means add below "--".
> Something like:
> --
> Changes v1 -> v2:
> - I did some cool stuff to improve this
>
> While at it... Please add your version-of-patch to the subject-line:
> You can do this via "git format-patch --signoff --subject-prefix="PATCH v2".
> There might be other cool git tricks I do not know.
>
> Hope I was no "Uberlehrer".
>
> - Sedat -
>
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst
>
> > ---
> > arch/x86/include/asm/idtentry.h | 14 ++++++--------
> > 1 file changed, 6 insertions(+), 8 deletions(-)
> >
> > diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
> > index f3d70830bf2a..5efaaed34eda 100644
> > --- a/arch/x86/include/asm/idtentry.h
> > +++ b/arch/x86/include/asm/idtentry.h
> > @@ -469,16 +469,15 @@ __visible noinstr void func(struct pt_regs *regs, \
> > .align 8
> > SYM_CODE_START(irq_entries_start)
> > vector=FIRST_EXTERNAL_VECTOR
> > - pos = .
> > .rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)
> > UNWIND_HINT_IRET_REGS
> > +0 :
> > .byte 0x6a, vector
> > jmp asm_common_interrupt
> > nop
> > /* Ensure that the above is 8 bytes max */
> > - . = pos + 8
> > - pos=pos+8
> > - vector=vector+1
> > + . = 0b + 8
> > + vector = vector+1
> > .endr
> > SYM_CODE_END(irq_entries_start)
> >
> > @@ -486,16 +485,15 @@ SYM_CODE_END(irq_entries_start)
> > .align 8
> > SYM_CODE_START(spurious_entries_start)
> > vector=FIRST_SYSTEM_VECTOR
> > - pos = .
> > .rept (NR_VECTORS - FIRST_SYSTEM_VECTOR)
> > UNWIND_HINT_IRET_REGS
> > +0 :
> > .byte 0x6a, vector
> > jmp asm_spurious_interrupt
> > nop
> > /* Ensure that the above is 8 bytes max */
> > - . = pos + 8
> > - pos=pos+8
> > - vector=vector+1
> > + . = 0b + 8
> > + vector = vector+1
> > .endr
> > SYM_CODE_END(spurious_entries_start)
> > #endif
> > --
> > 2.27.0.383.g050319c2ae-goog
> >
Stolen the patch from [1].
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> #
Compile-/Assemble-tested against Linux v5.8-rc5 with LLVM/Clang
v11.0.0-git
- Sedat -
[1] https://lore.kernel.org/patchwork/patch/1272115/
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH v2] x86/entry: add compatibility with IAS
2020-07-13 1:24 [PATCH] x86/entry: add compatibility with IAS Jian Cai
` (3 preceding siblings ...)
2020-07-13 22:40 ` Jian Cai
@ 2020-07-14 23:30 ` Jian Cai
2020-07-16 15:30 ` [tip: x86/urgent] x86/entry: Add " tip-bot2 for Jian Cai
4 siblings, 1 reply; 12+ messages in thread
From: Jian Cai @ 2020-07-14 23:30 UTC (permalink / raw)
Cc: caij2003, jiancai, ndesaulniers, manojgupta, sedat.dilek,
Brian Gerst, Arvind Sankar, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, x86, H. Peter Anvin, Andy Lutomirski,
Peter Zijlstra, Alexandre Chartre, linux-kernel,
clang-built-linux
Clang's integrated assembler does not allow symbols with non-absolute
values to be reassigned. This patch allows the affected code to be
compatible with IAS.
Link: https://github.com/ClangBuiltLinux/linux/issues/1043
Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Suggested-by: Brian Gerst <brgerst@gmail.com>
Suggested-by: Arvind Sankar <nivedita@alum.mit.edu>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> #
Compile-/Assemble-tested against Linux v5.8-rc5 with LLVM/Clang
v11.0.0-git
Signed-off-by: Jian Cai <caij2003@gmail.com>
---
Thanks Nick and Sedat for explaining the process of submitting patches.
Include the changelog as follows,
Changes v1 -> v2:
Update the patch based on Arvind Sankar <nivedita@alum.mit.edu>'s
comments. Also include addtional information in the Tested-by tag.
arch/x86/include/asm/idtentry.h | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index f3d70830bf2a..5efaaed34eda 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -469,16 +469,15 @@ __visible noinstr void func(struct pt_regs *regs, \
.align 8
SYM_CODE_START(irq_entries_start)
vector=FIRST_EXTERNAL_VECTOR
- pos = .
.rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)
UNWIND_HINT_IRET_REGS
+0 :
.byte 0x6a, vector
jmp asm_common_interrupt
nop
/* Ensure that the above is 8 bytes max */
- . = pos + 8
- pos=pos+8
- vector=vector+1
+ . = 0b + 8
+ vector = vector+1
.endr
SYM_CODE_END(irq_entries_start)
@@ -486,16 +485,15 @@ SYM_CODE_END(irq_entries_start)
.align 8
SYM_CODE_START(spurious_entries_start)
vector=FIRST_SYSTEM_VECTOR
- pos = .
.rept (NR_VECTORS - FIRST_SYSTEM_VECTOR)
UNWIND_HINT_IRET_REGS
+0 :
.byte 0x6a, vector
jmp asm_spurious_interrupt
nop
/* Ensure that the above is 8 bytes max */
- . = pos + 8
- pos=pos+8
- vector=vector+1
+ . = 0b + 8
+ vector = vector+1
.endr
SYM_CODE_END(spurious_entries_start)
#endif
--
2.27.0.389.gc38d7665816-goog
^ permalink raw reply [flat|nested] 12+ messages in thread* [tip: x86/urgent] x86/entry: Add compatibility with IAS
2020-07-14 23:30 ` [PATCH v2] " Jian Cai
@ 2020-07-16 15:30 ` tip-bot2 for Jian Cai
0 siblings, 0 replies; 12+ messages in thread
From: tip-bot2 for Jian Cai @ 2020-07-16 15:30 UTC (permalink / raw)
To: linux-tip-commits
Cc: Nick Desaulniers, Sedat Dilek, Brian Gerst, Arvind Sankar,
Jian Cai, Thomas Gleixner, x86, LKML
The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: 6ee93f8df09c470da1a4af11e394c52d7b62418c
Gitweb: https://git.kernel.org/tip/6ee93f8df09c470da1a4af11e394c52d7b62418c
Author: Jian Cai <caij2003@gmail.com>
AuthorDate: Tue, 14 Jul 2020 16:30:21 -07:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Thu, 16 Jul 2020 17:25:09 +02:00
x86/entry: Add compatibility with IAS
Clang's integrated assembler does not allow symbols with non-absolute
values to be reassigned. Modify the interrupt entry loop macro to be
compatible with IAS by using a label and an offset.
Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Suggested-by: Brian Gerst <brgerst@gmail.com>
Suggested-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Jian Cai <caij2003@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> #
Link: https://github.com/ClangBuiltLinux/linux/issues/1043
Link: https://lkml.kernel.org/r/20200714233024.1789985-1-caij2003@gmail.com
---
arch/x86/include/asm/idtentry.h | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index f3d7083..5efaaed 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -469,16 +469,15 @@ __visible noinstr void func(struct pt_regs *regs, \
.align 8
SYM_CODE_START(irq_entries_start)
vector=FIRST_EXTERNAL_VECTOR
- pos = .
.rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)
UNWIND_HINT_IRET_REGS
+0 :
.byte 0x6a, vector
jmp asm_common_interrupt
nop
/* Ensure that the above is 8 bytes max */
- . = pos + 8
- pos=pos+8
- vector=vector+1
+ . = 0b + 8
+ vector = vector+1
.endr
SYM_CODE_END(irq_entries_start)
@@ -486,16 +485,15 @@ SYM_CODE_END(irq_entries_start)
.align 8
SYM_CODE_START(spurious_entries_start)
vector=FIRST_SYSTEM_VECTOR
- pos = .
.rept (NR_VECTORS - FIRST_SYSTEM_VECTOR)
UNWIND_HINT_IRET_REGS
+0 :
.byte 0x6a, vector
jmp asm_spurious_interrupt
nop
/* Ensure that the above is 8 bytes max */
- . = pos + 8
- pos=pos+8
- vector=vector+1
+ . = 0b + 8
+ vector = vector+1
.endr
SYM_CODE_END(spurious_entries_start)
#endif
^ permalink raw reply [flat|nested] 12+ messages in thread