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Groups > linux.kernel > #1652600 > unrolled thread

[PATCH 0/7] powerpc/mm: Fix kernel protection and implement STRICT_KERNEL_RWX on PPC32

Started byChristophe Leroy <christophe.leroy@c-s.fr>
First post2017-05-29 17:40 +0200
Last post2017-05-30 14:50 +0200
Articles 8 — 4 participants

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Contents

  [PATCH 0/7] powerpc/mm: Fix kernel protection and implement STRICT_KERNEL_RWX on PPC32 Christophe Leroy <christophe.leroy@c-s.fr> - 2017-05-29 17:40 +0200
    [PATCH 3/7] powerpc/mm: Fix kernel RAM protection after freeing  unused memory on PPC32 Christophe Leroy <christophe.leroy@c-s.fr> - 2017-05-29 17:40 +0200
      Re: [PATCH 3/7] powerpc/mm: Fix kernel RAM protection after freeing  unused memory on PPC32 Balbir Singh <bsingharora@gmail.com> - 2017-05-30 04:00 +0200
    [PATCH 4/7] powerpc/mm: Implement STRICT_KERNEL_RWX on PPC32 Christophe Leroy <christophe.leroy@c-s.fr> - 2017-05-29 17:40 +0200
    [PATCH 1/7] powerpc/mm: rename map_page() to map_kernel_page() on  PPC32 Christophe Leroy <christophe.leroy@c-s.fr> - 2017-05-29 17:40 +0200
      Re: [PATCH 1/7] powerpc/mm: rename map_page() to map_kernel_page()  on PPC32 Balbir Singh <bsingharora@gmail.com> - 2017-05-30 03:40 +0200
      Re: [PATCH 1/7] powerpc/mm: rename map_page() to map_kernel_page() on PPC32 Michael Ellerman <mpe@ellerman.id.au> - 2017-05-30 13:00 +0200
        Re: [PATCH 1/7] powerpc/mm: rename map_page() to map_kernel_page() on  PPC32 Christophe LEROY <christophe.leroy@c-s.fr> - 2017-05-30 14:50 +0200

#1652600 — [PATCH 0/7] powerpc/mm: Fix kernel protection and implement STRICT_KERNEL_RWX on PPC32

FromChristophe Leroy <christophe.leroy@c-s.fr>
Date2017-05-29 17:40 +0200
Subject[PATCH 0/7] powerpc/mm: Fix kernel protection and implement STRICT_KERNEL_RWX on PPC32
Message-ID<tMuVX-1P8-11@gated-at.bofh.it>
This patch set implements STRICT_KERNEL_RWX on Powerpc32
after fixing a few issues related to kernel code page protection.

It superseeds the previous patch set identified "Fix kernel protection
and implement CONFIG_DEBUG_RODATA on PPC32"

This set is based on Balbir Singh <bsingharora@gmail.com> set identified
"Enable STRICT_KERNEL_RWX" and applies on top of it.

At the end we take the opportunity to get rid of some unneccessary/outdated
fixmap stuff.

Christophe Leroy (7):
  powerpc/mm: rename map_page() to map_kernel_page() on PPC32
  powerpc/mm: Ensure change_page_attr() doesn't invalidate pinned TLBs
  powerpc/mm: Fix kernel RAM protection after freeing unused memory on
    PPC32
  powerpc/mm: Implement STRICT_KERNEL_RWX on PPC32
  powerpc/mm: declare some local functions static
  powerpc/mm: remove __this_fixmap_does_not_exist()
  powerpc/mm: Simplify __set_fixmap()

 arch/powerpc/Kconfig                         |  3 +-
 arch/powerpc/include/asm/book3s/32/pgtable.h |  3 +-
 arch/powerpc/include/asm/fixmap.h            | 10 ++--
 arch/powerpc/include/asm/nohash/32/pgtable.h |  3 +-
 arch/powerpc/kernel/vmlinux.lds.S            |  2 +-
 arch/powerpc/mm/8xx_mmu.c                    |  2 +-
 arch/powerpc/mm/dma-noncoherent.c            |  2 +-
 arch/powerpc/mm/init_32.c                    |  6 +++
 arch/powerpc/mm/mem.c                        |  5 +-
 arch/powerpc/mm/mmu_decl.h                   |  4 +-
 arch/powerpc/mm/pgtable_32.c                 | 73 ++++++++++++++++------------
 11 files changed, 69 insertions(+), 44 deletions(-)

-- 
2.12.0

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#1652601 — [PATCH 3/7] powerpc/mm: Fix kernel RAM protection after freeing unused memory on PPC32

FromChristophe Leroy <christophe.leroy@c-s.fr>
Date2017-05-29 17:40 +0200
Subject[PATCH 3/7] powerpc/mm: Fix kernel RAM protection after freeing unused memory on PPC32
Message-ID<tMuVY-1P8-37@gated-at.bofh.it>
In reply to#1652600
As seen below, allthough the init sections have been freed, the
associated memory area is still marked as executable in the
page tables.

~ dmesg
[    5.860093] Freeing unused kernel memory: 592K (c0570000 - c0604000)

~ cat /sys/kernel/debug/kernel_page_tables
---[ Start of kernel VM ]---
0xc0000000-0xc0497fff        4704K  rw  X  present dirty accessed shared
0xc0498000-0xc056ffff         864K  rw     present dirty accessed shared
0xc0570000-0xc059ffff         192K  rw  X  present dirty accessed shared
0xc05a0000-0xc7ffffff      125312K  rw     present dirty accessed shared
---[ vmalloc() Area ]---

This patch fixes that.

The implementation is done by reusing the change_page_attr()
function implemented for CONFIG_DEBUG_PAGEALLOC

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 arch/powerpc/mm/mem.c        |  1 +
 arch/powerpc/mm/mmu_decl.h   |  3 +++
 arch/powerpc/mm/pgtable_32.c | 13 ++++++++++---
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 8e9bef964dbf..250601ccc907 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -393,6 +393,7 @@ void free_initmem(void)
 {
 	ppc_md.progress = ppc_printk_progress;
 	free_initmem_default(POISON_FREE_INITMEM);
+	remap_init_ram();
 }
 
 #ifdef CONFIG_BLK_DEV_INITRD
diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h
index d46128b22150..207af7ad3bda 100644
--- a/arch/powerpc/mm/mmu_decl.h
+++ b/arch/powerpc/mm/mmu_decl.h
@@ -94,6 +94,7 @@ extern void _tlbia(void);
 #ifdef CONFIG_PPC32
 
 extern void mapin_ram(void);
+void remap_init_ram(void);
 extern void setbat(int index, unsigned long virt, phys_addr_t phys,
 		   unsigned int size, pgprot_t prot);
 
@@ -105,6 +106,8 @@ struct hash_pte;
 extern struct hash_pte *Hash, *Hash_end;
 extern unsigned long Hash_size, Hash_mask;
 
+#else
+static inline void remap_init_ram(void) {}
 #endif /* CONFIG_PPC32 */
 
 extern unsigned long ioremap_bot;
diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index bdfee8e62a6a..0dc9c9d8fafb 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -323,8 +323,6 @@ get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
         return(retval);
 }
 
-#ifdef CONFIG_DEBUG_PAGEALLOC
-
 static int __change_page_attr_noflush(struct page *page, pgprot_t prot)
 {
 	pte_t *kpte;
@@ -347,7 +345,7 @@ static int __change_page_attr_noflush(struct page *page, pgprot_t prot)
 /*
  * Change the page attributes of an page in the linear mapping.
  *
- * THIS CONFLICTS WITH BAT MAPPINGS, DEBUG USE ONLY
+ * THIS DOES NOTHING WITH BAT MAPPINGS, DEBUG USE ONLY
  */
 static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
 {
@@ -368,7 +366,16 @@ static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
 	return err;
 }
 
+void remap_init_ram(void)
+{
+	struct page *page = virt_to_page(_sinittext);
+	unsigned long numpages = PFN_UP((unsigned long)_einittext) -
+				 PFN_DOWN((unsigned long)_sinittext);
+
+	change_page_attr(page, numpages, PAGE_KERNEL);
+}
 
+#ifdef CONFIG_DEBUG_PAGEALLOC
 void __kernel_map_pages(struct page *page, int numpages, int enable)
 {
 	if (PageHighMem(page))
-- 
2.12.0

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#1652767 — Re: [PATCH 3/7] powerpc/mm: Fix kernel RAM protection after freeing unused memory on PPC32

FromBalbir Singh <bsingharora@gmail.com>
Date2017-05-30 04:00 +0200
SubjectRe: [PATCH 3/7] powerpc/mm: Fix kernel RAM protection after freeing unused memory on PPC32
Message-ID<tMEBX-go-1@gated-at.bofh.it>
In reply to#1652601
On Mon, 29 May 2017 17:32:00 +0200 (CEST)
Christophe Leroy <christophe.leroy@c-s.fr> wrote:

> As seen below, allthough the init sections have been freed, the
> associated memory area is still marked as executable in the
> page tables.

Good catch!

Acked-by: Balbir Singh <bsingharora@gmail.com>

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#1652602 — [PATCH 4/7] powerpc/mm: Implement STRICT_KERNEL_RWX on PPC32

FromChristophe Leroy <christophe.leroy@c-s.fr>
Date2017-05-29 17:40 +0200
Subject[PATCH 4/7] powerpc/mm: Implement STRICT_KERNEL_RWX on PPC32
Message-ID<tMuVY-1P8-41@gated-at.bofh.it>
In reply to#1652600
This patch implements STRICT_KERNEL_RWX on PPC32.

As for CONFIG_DEBUG_PAGEALLOC, it deactivates BAT and LTLB mappings
in order to allow page protection setup at the level of each page.

As BAT/LTLB mappings are deactivated, there might be a performance
impact. For this reason, we make it optional and keep it OFF by default.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 arch/powerpc/Kconfig              |  3 ++-
 arch/powerpc/kernel/vmlinux.lds.S |  2 +-
 arch/powerpc/mm/init_32.c         |  6 ++++++
 arch/powerpc/mm/pgtable_32.c      | 24 ++++++++++++++++++++++++
 4 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 8b3f03b88a3a..2f40fa79c759 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -171,7 +171,8 @@ config PPC
 	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if COMPAT
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_ARCH_TRACEHOOK
-	select ARCH_HAS_STRICT_KERNEL_RWX	if PPC64 && PPC_BOOK3S
+	select ARCH_HAS_STRICT_KERNEL_RWX	if PPC32 || (PPC64 && PPC_BOOK3S)
+	select ARCH_OPTIONAL_KERNEL_RWX		if PPC32
 	select HAVE_CBPF_JIT			if !PPC64
 	select HAVE_CONTEXT_TRACKING		if PPC64
 	select HAVE_DEBUG_KMEMLEAK
diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index 397382936c78..029d256bfb20 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -8,7 +8,7 @@
 #include <asm/cache.h>
 #include <asm/thread_info.h>
 
-#ifdef CONFIG_STRICT_KERNEL_RWX
+#if defined(CONFIG_STRICT_KERNEL_RWX) && !defined(CONFIG_PPC32)
 #define STRICT_ALIGN_SIZE	(1 << 24)
 #else
 #define STRICT_ALIGN_SIZE	PAGE_SIZE
diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c
index 8a7c38b8d335..7d5fee1bb116 100644
--- a/arch/powerpc/mm/init_32.c
+++ b/arch/powerpc/mm/init_32.c
@@ -113,6 +113,12 @@ void __init MMU_setup(void)
 		__map_without_bats = 1;
 		__map_without_ltlbs = 1;
 	}
+#ifdef CONFIG_STRICT_KERNEL_RWX
+	if (rodata_enabled) {
+		__map_without_bats = 1;
+		__map_without_ltlbs = 1;
+	}
+#endif
 }
 
 /*
diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index 0dc9c9d8fafb..46b02fe33864 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -34,6 +34,7 @@
 #include <asm/fixmap.h>
 #include <asm/io.h>
 #include <asm/setup.h>
+#include <asm/sections.h>
 
 #include "mmu_decl.h"
 
@@ -375,6 +376,29 @@ void remap_init_ram(void)
 	change_page_attr(page, numpages, PAGE_KERNEL);
 }
 
+#ifdef CONFIG_STRICT_KERNEL_RWX
+void mark_rodata_ro(void)
+{
+	struct page *page;
+	unsigned long numpages;
+
+	page = virt_to_page(_stext);
+	numpages = PFN_UP((unsigned long)_etext) -
+		   PFN_DOWN((unsigned long)_stext);
+
+	change_page_attr(page, numpages, PAGE_KERNEL_ROX);
+	/*
+	 * mark .rodata as read only. Use __init_begin rather than __end_rodata
+	 * to cover NOTES and EXCEPTION_TABLE.
+	 */
+	page = virt_to_page(__start_rodata);
+	numpages = PFN_UP((unsigned long)__init_begin) -
+		   PFN_DOWN((unsigned long)__start_rodata);
+
+	change_page_attr(page, numpages, PAGE_KERNEL_RO);
+}
+#endif
+
 #ifdef CONFIG_DEBUG_PAGEALLOC
 void __kernel_map_pages(struct page *page, int numpages, int enable)
 {
-- 
2.12.0

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#1652604 — [PATCH 1/7] powerpc/mm: rename map_page() to map_kernel_page() on PPC32

FromChristophe Leroy <christophe.leroy@c-s.fr>
Date2017-05-29 17:40 +0200
Subject[PATCH 1/7] powerpc/mm: rename map_page() to map_kernel_page() on PPC32
Message-ID<tMuVY-1P8-43@gated-at.bofh.it>
In reply to#1652600
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 arch/powerpc/include/asm/book3s/32/pgtable.h | 2 ++
 arch/powerpc/include/asm/nohash/32/pgtable.h | 2 ++
 arch/powerpc/mm/8xx_mmu.c                    | 2 +-
 arch/powerpc/mm/dma-noncoherent.c            | 2 +-
 arch/powerpc/mm/mem.c                        | 4 ++--
 arch/powerpc/mm/mmu_decl.h                   | 1 -
 arch/powerpc/mm/pgtable_32.c                 | 8 ++++----
 7 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h
index 26ed228d4dc6..7fb755880409 100644
--- a/arch/powerpc/include/asm/book3s/32/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/32/pgtable.h
@@ -297,6 +297,8 @@ static inline void __ptep_set_access_flags(struct mm_struct *mm,
 extern int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep,
 		      pmd_t **pmdp);
 
+int map_kernel_page(unsigned long va, phys_addr_t pa, int flags);
+
 /* Generic accessors to PTE bits */
 static inline int pte_write(pte_t pte)		{ return !!(pte_val(pte) & _PAGE_RW);}
 static inline int pte_dirty(pte_t pte)		{ return !!(pte_val(pte) & _PAGE_DIRTY); }
diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h b/arch/powerpc/include/asm/nohash/32/pgtable.h
index 5134ade2e850..91314268f04f 100644
--- a/arch/powerpc/include/asm/nohash/32/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/32/pgtable.h
@@ -340,6 +340,8 @@ static inline void __ptep_set_access_flags(struct mm_struct *mm,
 extern int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep,
 		      pmd_t **pmdp);
 
+int map_kernel_page(unsigned long va, phys_addr_t pa, int flags);
+
 #endif /* !__ASSEMBLY__ */
 
 #endif /* __ASM_POWERPC_NOHASH_32_PGTABLE_H */
diff --git a/arch/powerpc/mm/8xx_mmu.c b/arch/powerpc/mm/8xx_mmu.c
index 6c5025e81236..f4c6472f2fc4 100644
--- a/arch/powerpc/mm/8xx_mmu.c
+++ b/arch/powerpc/mm/8xx_mmu.c
@@ -88,7 +88,7 @@ static void mmu_mapin_immr(void)
 	int offset;
 
 	for (offset = 0; offset < IMMR_SIZE; offset += PAGE_SIZE)
-		map_page(v + offset, p + offset, f);
+		map_kernel_page(v + offset, p + offset, f);
 }
 
 /* Address of instructions to patch */
diff --git a/arch/powerpc/mm/dma-noncoherent.c b/arch/powerpc/mm/dma-noncoherent.c
index 2dc74e5c6458..382528475433 100644
--- a/arch/powerpc/mm/dma-noncoherent.c
+++ b/arch/powerpc/mm/dma-noncoherent.c
@@ -227,7 +227,7 @@ __dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, gfp_t
 
 		do {
 			SetPageReserved(page);
-			map_page(vaddr, page_to_phys(page),
+			map_kernel_page(vaddr, page_to_phys(page),
 				 pgprot_val(pgprot_noncached(PAGE_KERNEL)));
 			page++;
 			vaddr += PAGE_SIZE;
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index de5a90e1ceaa..8e9bef964dbf 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -305,11 +305,11 @@ void __init paging_init(void)
 	unsigned long end = __fix_to_virt(FIX_HOLE);
 
 	for (; v < end; v += PAGE_SIZE)
-		map_page(v, 0, 0); /* XXX gross */
+		map_kernel_page(v, 0, 0); /* XXX gross */
 #endif
 
 #ifdef CONFIG_HIGHMEM
-	map_page(PKMAP_BASE, 0, 0);	/* XXX gross */
+	map_kernel_page(PKMAP_BASE, 0, 0);	/* XXX gross */
 	pkmap_page_table = virt_to_kpte(PKMAP_BASE);
 
 	kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h
index f988db655e5b..d46128b22150 100644
--- a/arch/powerpc/mm/mmu_decl.h
+++ b/arch/powerpc/mm/mmu_decl.h
@@ -94,7 +94,6 @@ extern void _tlbia(void);
 #ifdef CONFIG_PPC32
 
 extern void mapin_ram(void);
-extern int map_page(unsigned long va, phys_addr_t pa, int flags);
 extern void setbat(int index, unsigned long virt, phys_addr_t phys,
 		   unsigned int size, pgprot_t prot);
 
diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index a65c0b4c0669..9c23c0965566 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -189,7 +189,7 @@ __ioremap_caller(phys_addr_t addr, unsigned long size, unsigned long flags,
 
 	err = 0;
 	for (i = 0; i < size && err == 0; i += PAGE_SIZE)
-		err = map_page(v+i, p+i, flags);
+		err = map_kernel_page(v+i, p+i, flags);
 	if (err) {
 		if (slab_is_available())
 			vunmap((void *)v);
@@ -215,7 +215,7 @@ void iounmap(volatile void __iomem *addr)
 }
 EXPORT_SYMBOL(iounmap);
 
-int map_page(unsigned long va, phys_addr_t pa, int flags)
+int map_kernel_page(unsigned long va, phys_addr_t pa, int flags)
 {
 	pmd_t *pd;
 	pte_t *pg;
@@ -255,7 +255,7 @@ void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
 		ktext = ((char *)v >= _stext && (char *)v < etext) ||
 			((char *)v >= _sinittext && (char *)v < _einittext);
 		f = ktext ? pgprot_val(PAGE_KERNEL_TEXT) : pgprot_val(PAGE_KERNEL);
-		map_page(v, p, f);
+		map_kernel_page(v, p, f);
 #ifdef CONFIG_PPC_STD_MMU_32
 		if (ktext)
 			hash_preload(&init_mm, v, 0, 0x300);
@@ -387,7 +387,7 @@ void __set_fixmap (enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
 		return;
 	}
 
-	map_page(address, phys, pgprot_val(flags));
+	map_kernel_page(address, phys, pgprot_val(flags));
 	fixmaps++;
 }
 
-- 
2.12.0

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#1652763 — Re: [PATCH 1/7] powerpc/mm: rename map_page() to map_kernel_page() on PPC32

FromBalbir Singh <bsingharora@gmail.com>
Date2017-05-30 03:40 +0200
SubjectRe: [PATCH 1/7] powerpc/mm: rename map_page() to map_kernel_page() on PPC32
Message-ID<tMEiB-7P-9@gated-at.bofh.it>
In reply to#1652604
On Mon, 29 May 2017 17:31:56 +0200 (CEST)
Christophe Leroy <christophe.leroy@c-s.fr> wrote:

> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
...

> diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
> index de5a90e1ceaa..8e9bef964dbf 100644
> --- a/arch/powerpc/mm/mem.c
> +++ b/arch/powerpc/mm/mem.c
> @@ -305,11 +305,11 @@ void __init paging_init(void)
>  	unsigned long end = __fix_to_virt(FIX_HOLE);
>  
>  	for (; v < end; v += PAGE_SIZE)
> -		map_page(v, 0, 0); /* XXX gross */
> +		map_kernel_page(v, 0, 0); /* XXX gross */

What is 0, 0? Everything maps to physical address 0 with 0 permissions?


Thanks for doing this

Acked-by: Balbir Singh <bsingharora@gmail.com>

Balbir

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#1653112 — Re: [PATCH 1/7] powerpc/mm: rename map_page() to map_kernel_page() on PPC32

FromMichael Ellerman <mpe@ellerman.id.au>
Date2017-05-30 13:00 +0200
SubjectRe: [PATCH 1/7] powerpc/mm: rename map_page() to map_kernel_page() on PPC32
Message-ID<tMN2x-6he-7@gated-at.bofh.it>
In reply to#1652604
Christophe Leroy <christophe.leroy@c-s.fr> writes:

...

Please tell me why.

You also moved the declaration from mmu_decl.h to book3s/32/pgtable.h,
but didn't update any includes, presumably we're confident everything
gets pgtable.h somehow?

cheers

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#1653192 — Re: [PATCH 1/7] powerpc/mm: rename map_page() to map_kernel_page() on PPC32

FromChristophe LEROY <christophe.leroy@c-s.fr>
Date2017-05-30 14:50 +0200
SubjectRe: [PATCH 1/7] powerpc/mm: rename map_page() to map_kernel_page() on PPC32
Message-ID<tMOL0-7oW-13@gated-at.bofh.it>
In reply to#1653112

Le 30/05/2017 à 12:50, Michael Ellerman a écrit :
> Christophe Leroy <christophe.leroy@c-s.fr> writes:
> 
> ...
> 
> Please tell me why.

Because of patch https://patchwork.ozlabs.org/patch/766777/ which 
modifies patch_instruction() to use an alternative mapping.
Compilation fails on PPC32 because map_kernel_page() only exists on 
PPC64. However we have map_page() which does the same on PPC32, hence 
the renaming.

> 
> You also moved the declaration from mmu_decl.h to book3s/32/pgtable.h,
> but didn't update any includes, presumably we're confident everything
> gets pgtable.h somehow?

Yes I did that so that lib/code_patching.c sees it.
All users of map_page() already include pgtable in a way or another.

Christophe

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