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From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	alex@ghiti.fr
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>,
	linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-mm@kvack.org
Subject: [PATCH v2 6/9] mm: Allow arch specific arch_randomize_brk() with CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
Date: Thu, 25 Nov 2021 09:23:28 +0100	[thread overview]
Message-ID: <e059e83c12b01ba7c3352162828046504e586c0c.1637828367.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1637828367.git.christophe.leroy@csgroup.eu>

Commit e7142bf5d231 ("arm64, mm: make randomization selected by
generic topdown mmap layout") introduced a default version of
arch_randomize_brk() provided when
CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT is selected.

powerpc could select CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
but needs to provide its own arch_randomize_brk().

In order to allow that, define generic version of arch_randomize_brk()
as a __weak symbol.

Cc: Alexandre Ghiti <alex@ghiti.fr>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v2: Make the generic version of it a __weak symbol instead of a messy play with CONFIG_ items.
---
 mm/util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/util.c b/mm/util.c
index e58151a61255..7eb69f697b38 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -344,7 +344,7 @@ unsigned long randomize_stack_top(unsigned long stack_top)
 }
 
 #ifdef CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
-unsigned long arch_randomize_brk(struct mm_struct *mm)
+unsigned long __weak arch_randomize_brk(struct mm_struct *mm)
 {
 	/* Is the current task 32bit ? */
 	if (!IS_ENABLED(CONFIG_64BIT) || is_compat_task())
-- 
2.33.1


  parent reply	other threads:[~2021-11-25  8:27 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-25  8:23 [PATCH v2 0/9] Convert powerpc to default topdown mmap layout Christophe Leroy
2021-11-25  8:23 ` [PATCH v2 1/9] powerpc/mm: Make slice specific to book3s/64 Christophe Leroy
2021-11-25  8:23 ` [PATCH v2 2/9] powerpc/mm: Move vma_mmu_pagesize() and hugetlb_get_unmapped_area() to slice.c Christophe Leroy
2021-11-25  8:23 ` [PATCH v2 3/9] powerpc/mm: Remove CONFIG_PPC_MM_SLICES Christophe Leroy
2021-11-25  8:23 ` [PATCH v2 4/9] powerpc/mm: Remove asm/slice.h Christophe Leroy
2021-11-25  8:23 ` [PATCH v2 5/9] powerpc/mm: Call radix__arch_get_unmapped_area() from arch_get_unmapped_area() Christophe Leroy
2021-11-25  8:23 ` Christophe Leroy [this message]
2021-11-25  8:23 ` [PATCH v2 7/9] powerpc/mm: Convert to default topdown mmap layout Christophe Leroy
2021-11-25  8:23 ` [PATCH v2 8/9] powerpc/mm: Properly randomise mmap with slices Christophe Leroy
2021-11-25  8:23 ` [PATCH v2 9/9] powerpc: Simplify and move arch_randomize_brk() Christophe Leroy
2021-11-25 10:42   ` Christophe Leroy
2021-11-26  0:36   ` kernel test robot
2021-11-26 19:23   ` kernel test robot

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