Re: [PATCH v2 06/29] ARM: add migrate_pages() system call

[Catalin Marinas]

On Fri, Jan 18, 2019 at 05:18:12PM +0100, Arnd Bergmann wrote:
> The migrate_pages system call has an assigned number on all architectures
> except ARM. When it got added initially in commit d80ade7b3231 ("ARM:
> Fix warning: #warning syscall migrate_pages not implemented"), it was
> intentionally left out based on the observation that there are no 32-bit
> ARM NUMA systems.
> 
> However, there are now arm64 NUMA machines that can in theory run 32-bit
> kernels (actually enabling NUMA there would require additional work)
> as well as 32-bit user space on 64-bit kernels, so that argument is no
> longer very strong.
> 
> Assigning the number lets us use the system call on 64-bit kernels as well
> as providing a more consistent set of syscalls across architectures.
> 
> Signed-off-by: Arnd Bergmann 

For the arm64 part:

Acked-by: Catalin Marinas 

[PATCH v2 06/29] ARM: add migrate_pages() system call

[Arnd Bergmann]

The migrate_pages system call has an assigned number on all architectures
except ARM. When it got added initially in commit d80ade7b3231 ("ARM:
Fix warning: #warning syscall migrate_pages not implemented"), it was
intentionally left out based on the observation that there are no 32-bit
ARM NUMA systems.

However, there are now arm64 NUMA machines that can in theory run 32-bit
kernels (actually enabling NUMA there would require additional work)
as well as 32-bit user space on 64-bit kernels, so that argument is no
longer very strong.

Assigning the number lets us use the system call on 64-bit kernels as well
as providing a more consistent set of syscalls across architectures.

Signed-off-by: Arnd Bergmann 
---
 arch/arm/include/asm/unistd.h | 1 -
 arch/arm/tools/syscall.tbl| 1 +
 arch/arm64/include/asm/unistd.h   | 2 +-
 arch/arm64/include/asm/unistd32.h | 2 ++
 4 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/arm/include/asm/unistd.h b/arch/arm/include/asm/unistd.h
index 88ef2ce1f69a..d713587dfcf4 100644
--- a/arch/arm/include/asm/unistd.h
+++ b/arch/arm/include/asm/unistd.h
@@ -45,7 +45,6 @@
  * Unimplemented (or alternatively implemented) syscalls
  */
 #define __IGNORE_fadvise64_64
-#define __IGNORE_migrate_pages
 
 #ifdef __ARM_EABI__
 /*
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index 8edf93b4490f..86de9eb34296 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -414,3 +414,4 @@
 397common  statx   sys_statx
 398common  rseqsys_rseq
 399common  io_pgetevents   sys_io_pgetevents
+400common  migrate_pages   sys_migrate_pages
diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h
index a7b1fc58ffdf..261216c3336e 100644
--- a/arch/arm64/include/asm/unistd.h
+++ b/arch/arm64/include/asm/unistd.h
@@ -44,7 +44,7 @@
 #define __ARM_NR_compat_set_tls(__ARM_NR_COMPAT_BASE + 5)
 #define __ARM_NR_COMPAT_END(__ARM_NR_COMPAT_BASE + 0x800)
 
-#define __NR_compat_syscalls   400
+#define __NR_compat_syscalls   401
 #endif
 
 #define __ARCH_WANT_SYS_CLONE
diff --git a/arch/arm64/include/asm/unistd32.h 
b/arch/arm64/include/asm/unistd32.h
index 04ee190b90fe..f15bcbacb8f6 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -821,6 +821,8 @@ __SYSCALL(__NR_statx, sys_statx)
 __SYSCALL(__NR_rseq, sys_rseq)
 #define __NR_io_pgetevents 399
 __SYSCALL(__NR_io_pgetevents, compat_sys_io_pgetevents)
+#define __NR_migrate_pages 400
+__SYSCALL(__NR_migrate_pages, compat_sys_migrate_pages)
 
 /*
  * Please add new compat syscalls above this comment and update
-- 
2.20.0