Patch "arm64: vdso: remove commas between macro name and arguments" has been added to the 4.19-stable tree

[gregkh at linuxfoundation.org]

This is a note to let you know that I've just added the patch titled

    arm64: vdso: remove commas between macro name and arguments

to the 4.19-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     arm64-vdso-remove-commas-between-macro-name-and-arguments.patch
and it can be found in the queue-4.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable at vger.kernel.org> know about it.


>From jiancai at google.com  Mon May 10 10:02:08 2021
From: Jian Cai <jiancai at google.com>
Date: Wed,  5 May 2021 18:25:08 -0700
Subject: arm64: vdso: remove commas between macro name and arguments
To: gregkh at linuxfoundation.org, sashal at kernel.org, will at kernel.org, catalin.marinas at arm.com, nathan at kernel.org
Cc: stable at vger.kernel.org, ndesaulniers at google.com, manojgupta at google.com, llozano at google.com, clang-built-linux at googlegroups.com, Jian Cai <jiancai at google.com>, Will Deacon <will.deacon at arm.com>, linux-arm-kernel at lists.infradead.org, linux-kernel at vger.kernel.org
Message-ID: <20210506012508.3822221-1-jiancai at google.com>

From: Jian Cai <jiancai at google.com>

LLVM's integrated assembler appears to assume an argument with default
value is passed whenever it sees a comma right after the macro name.
It will be fine if the number of following arguments is one less than
the number of parameters specified in the macro definition. Otherwise,
it fails. For example, the following code works:

$ cat foo.s
.macro  foo arg1=2, arg2=4
        ldr r0, [r1, #\arg1]
        ldr r0, [r1, #\arg2]
.endm

foo, arg2=8

$ llvm-mc -triple=armv7a -filetype=obj foo.s -o ias.o
arm-linux-gnueabihf-objdump -dr ias.o

ias.o:     file format elf32-littlearm

Disassembly of section .text:

00000000 <.text>:
   0: e5910001 ldr r0, [r1, #2]
   4: e5910003 ldr r0, [r1, #8]

While the the following code would fail:

$ cat foo.s
.macro  foo arg1=2, arg2=4
        ldr r0, [r1, #\arg1]
        ldr r0, [r1, #\arg2]
.endm

foo, arg1=2, arg2=8

$ llvm-mc -triple=armv7a -filetype=obj foo.s -o ias.o
foo.s:6:14: error: too many positional arguments
foo, arg1=2, arg2=8

This causes build failures as follows:

arch/arm64/kernel/vdso/gettimeofday.S:230:24: error: too many positional
arguments
 clock_gettime_return, shift=1
                       ^
arch/arm64/kernel/vdso/gettimeofday.S:253:24: error: too many positional
arguments
 clock_gettime_return, shift=1
                       ^
arch/arm64/kernel/vdso/gettimeofday.S:274:24: error: too many positional
arguments
 clock_gettime_return, shift=1

This error is not in mainline because commit 28b1a824a4f4 ("arm64: vdso:
Substitute gettimeofday() with C implementation") rewrote this assembler
file in C as part of a 25 patch series that is unsuitable for stable.
Just remove the comma in the clock_gettime_return invocations in 4.19 so
that GNU as and LLVM's integrated assembler work the same.

Link:
https://github.com/ClangBuiltLinux/linux/issues/1349

Suggested-by: Nathan Chancellor <nathan at kernel.org>
Reviewed-by: Nathan Chancellor <nathan at kernel.org>
Signed-off-by: Jian Cai <jiancai at google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
---
Changes v1 -> v2:
  Keep the comma in the macro definition to be consistent with other
  definitions.

Changes v2 -> v3:
  Edit tags.

Changes v3 -> v4:
  Update the commit message based on Nathan's comments.

 arch/arm64/kernel/vdso/gettimeofday.S |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/arch/arm64/kernel/vdso/gettimeofday.S
+++ b/arch/arm64/kernel/vdso/gettimeofday.S
@@ -227,7 +227,7 @@ realtime:
 	seqcnt_check fail=realtime
 	get_ts_realtime res_sec=x10, res_nsec=x11, \
 		clock_nsec=x15, xtime_sec=x13, xtime_nsec=x14, nsec_to_sec=x9
-	clock_gettime_return, shift=1
+	clock_gettime_return shift=1
 
 	ALIGN
 monotonic:
@@ -250,7 +250,7 @@ monotonic:
 		clock_nsec=x15, xtime_sec=x13, xtime_nsec=x14, nsec_to_sec=x9
 
 	add_ts sec=x10, nsec=x11, ts_sec=x3, ts_nsec=x4, nsec_to_sec=x9
-	clock_gettime_return, shift=1
+	clock_gettime_return shift=1
 
 	ALIGN
 monotonic_raw:
@@ -271,7 +271,7 @@ monotonic_raw:
 		clock_nsec=x15, nsec_to_sec=x9
 
 	add_ts sec=x10, nsec=x11, ts_sec=x13, ts_nsec=x14, nsec_to_sec=x9
-	clock_gettime_return, shift=1
+	clock_gettime_return shift=1
 
 	ALIGN
 realtime_coarse:


Patches currently in stable-queue which might be from jiancai at google.com are

queue-4.19/arm64-vdso-remove-commas-between-macro-name-and-arguments.patch