[RFC v2 6/7] mm/powerpc: Use generic VDSO remap and unmap functions

The PowerPC VDSO remap and unmap code was copied to a generic location,
only modifying the variable name expected in mm->context (vdso instead of
vdso_base) to match most other architectures. Having adopted this generic
naming, drop the code in arch/powerpc and use the generic version.

Signed-off-by: Christopher Covington <redacted>
---
 arch/powerpc/Kconfig                     |  1 +
 arch/powerpc/include/asm/Kbuild          |  1 +
 arch/powerpc/include/asm/mm-arch-hooks.h | 28 -------------------------
 arch/powerpc/include/asm/mmu_context.h   | 35 +-------------------------------
 4 files changed, 3 insertions(+), 62 deletions(-)
 delete mode 100644 arch/powerpc/include/asm/mm-arch-hooks.h

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 65fba4c..f4a1cb9 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig

@@ -134,6 +134,7 @@ config PPC
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
 	select GENERIC_STRNCPY_FROM_USER
 	select GENERIC_STRNLEN_USER
+	select GENERIC_VDSO
 	select HAVE_MOD_ARCH_SPECIFIC
 	select MODULES_USE_ELF_RELA
 	select CLONE_BACKWARDS

diff --git a/arch/powerpc/include/asm/Kbuild b/arch/powerpc/include/asm/Kbuild
index 5c4fbc8..4d89ec6 100644
--- a/arch/powerpc/include/asm/Kbuild
+++ b/arch/powerpc/include/asm/Kbuild

@@ -8,3 +8,4 @@ generic-y += mcs_spinlock.h
 generic-y += preempt.h
 generic-y += rwsem.h
 generic-y += vtime.h
+generic-y += mm-arch-hooks.h

diff --git a/arch/powerpc/include/asm/mm-arch-hooks.h b/arch/powerpc/include/asm/mm-arch-hooks.h
deleted file mode 100644
index ea6da89..0000000
--- a/arch/powerpc/include/asm/mm-arch-hooks.h
+++ /dev/null

@@ -1,28 +0,0 @@
-/*
- * Architecture specific mm hooks
- *
- * Copyright (C) 2015, IBM Corporation
- * Author: Laurent Dufour <ldufour@linux.vnet.ibm.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-
-#ifndef _ASM_POWERPC_MM_ARCH_HOOKS_H
-#define _ASM_POWERPC_MM_ARCH_HOOKS_H
-
-static inline void arch_remap(struct mm_struct *mm,
-			      unsigned long old_start, unsigned long old_end,
-			      unsigned long new_start, unsigned long new_end)
-{
-	/*
-	 * mremap() doesn't allow moving multiple vmas so we can limit the
-	 * check to old_start == vdso.
-	 */
-	if (old_start == mm->context.vdso)
-		mm->context.vdso = new_start;
-}
-#define arch_remap arch_remap
-
-#endif /* _ASM_POWERPC_MM_ARCH_HOOKS_H */

diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index c907478..d8dcf45 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h

@@ -8,6 +8,7 @@
 #include <linux/spinlock.h>
 #include <asm/mmu.h>	
 #include <asm/cputable.h>
+#include <asm-generic/mm_hooks.h>
 #include <asm/cputhreads.h>
 
 /*

@@ -133,39 +134,5 @@ static inline void enter_lazy_tlb(struct mm_struct *mm,
 #endif
 }
 
-static inline void arch_dup_mmap(struct mm_struct *oldmm,
-				 struct mm_struct *mm)
-{
-}
-
-static inline void arch_exit_mmap(struct mm_struct *mm)
-{
-}
-
-static inline void arch_unmap(struct mm_struct *mm,
-			      struct vm_area_struct *vma,
-			      unsigned long start, unsigned long end)
-{
-	if (start <= mm->context.vdso && mm->context.vdso < end)
-		mm->context.vdso = 0;
-}
-
-static inline void arch_bprm_mm_init(struct mm_struct *mm,
-				     struct vm_area_struct *vma)
-{
-}
-
-static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
-		bool write, bool execute, bool foreign)
-{
-	/* by default, allow everything */
-	return true;
-}
-
-static inline bool arch_pte_access_permitted(pte_t pte, bool write)
-{
-	/* by default, allow everything */
-	return true;
-}
 #endif /* __KERNEL__ */
 #endif /* __ASM_POWERPC_MMU_CONTEXT_H */

-- 
Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.

Christopher Covington [off-list ref] writes:

The PowerPC VDSO remap and unmap code was copied to a generic location,
only modifying the variable name expected in mm->context (vdso instead of
vdso_base) to match most other architectures. Having adopted this generic
naming, drop the code in arch/powerpc and use the generic version.

Signed-off-by: Christopher Covington <redacted>
---
 arch/powerpc/Kconfig                     |  1 +
 arch/powerpc/include/asm/Kbuild          |  1 +
 arch/powerpc/include/asm/mm-arch-hooks.h | 28 -------------------------
 arch/powerpc/include/asm/mmu_context.h   | 35 +-------------------------------
 4 files changed, 3 insertions(+), 62 deletions(-)
 delete mode 100644 arch/powerpc/include/asm/mm-arch-hooks.h

This looks OK.

Have you tested it on powerpc? I could but I don't know how to actually
trigger these paths, I assume I need a CRIU setup?

Can you flip the subject to "powerpc/mm: ...".

cheers

On 04/11/2016 05:59, Michael Ellerman wrote:

Christopher Covington [off-list ref] writes:

quoted

The PowerPC VDSO remap and unmap code was copied to a generic location,
only modifying the variable name expected in mm->context (vdso instead of
vdso_base) to match most other architectures. Having adopted this generic
naming, drop the code in arch/powerpc and use the generic version.

Signed-off-by: Christopher Covington <redacted>
---
 arch/powerpc/Kconfig                     |  1 +
 arch/powerpc/include/asm/Kbuild          |  1 +
 arch/powerpc/include/asm/mm-arch-hooks.h | 28 -------------------------
 arch/powerpc/include/asm/mmu_context.h   | 35 +-------------------------------
 4 files changed, 3 insertions(+), 62 deletions(-)
 delete mode 100644 arch/powerpc/include/asm/mm-arch-hooks.h

This looks OK.

Have you tested it on powerpc? I could but I don't know how to actually
trigger these paths, I assume I need a CRIU setup?

FWIW, tested on ppc64le using a sample test process moving its VDSO and
then catching a signal on 4.9-rc4 and using CRIU on top of 4.8 with
sightly changes to due minor upstream changes.

Reviewed-by: Laurent Dufour <redacted>
Tested-by: Laurent Dufour <redacted>

Laurent Dufour [off-list ref] writes:

On 04/11/2016 05:59, Michael Ellerman wrote:

quoted

Christopher Covington [off-list ref] writes:

quoted

The PowerPC VDSO remap and unmap code was copied to a generic location,
only modifying the variable name expected in mm->context (vdso instead of
vdso_base) to match most other architectures. Having adopted this generic
naming, drop the code in arch/powerpc and use the generic version.

Signed-off-by: Christopher Covington <redacted>
---
 arch/powerpc/Kconfig                     |  1 +
 arch/powerpc/include/asm/Kbuild          |  1 +
 arch/powerpc/include/asm/mm-arch-hooks.h | 28 -------------------------
 arch/powerpc/include/asm/mmu_context.h   | 35 +-------------------------------
 4 files changed, 3 insertions(+), 62 deletions(-)
 delete mode 100644 arch/powerpc/include/asm/mm-arch-hooks.h

This looks OK.

Have you tested it on powerpc? I could but I don't know how to actually
trigger these paths, I assume I need a CRIU setup?

FWIW, tested on ppc64le using a sample test process moving its VDSO and
then catching a signal on 4.9-rc4 and using CRIU on top of 4.8 with
sightly changes to due minor upstream changes.

Reviewed-by: Laurent Dufour <redacted>
Tested-by: Laurent Dufour <redacted>

Thanks, in that case:

Acked-by: Michael Ellerman <mpe@ellerman.id.au>

cheers