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>,
akpm@linux-foundation.org
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-mm@kvack.org
Subject: [PATCH v10 13/13] powerpc: Simplify and move arch_randomize_brk()
Date: Sat, 9 Apr 2022 19:17:37 +0200 [thread overview]
Message-ID: <eafa4d18ec8ac7b98dd02b40181e61643707cc7c.1649523076.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1649523076.git.christophe.leroy@csgroup.eu>
arch_randomize_brk() is only needed for hash on book3s/64, for other
platforms the one provided by the default mmap layout is good enough.
Move it to hash_utils.c and use randomize_page() like the generic one.
And properly opt out the radix case instead of making an assumption
on mmu_highuser_ssize.
Also change to a 32M range like most other architectures instead of 8M.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/kernel/process.c | 41 ---------------------------
arch/powerpc/mm/book3s64/hash_utils.c | 19 +++++++++++++
2 files changed, 19 insertions(+), 41 deletions(-)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 984813a4d5dc..e7f809bdd433 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -34,10 +34,8 @@
#include <linux/ftrace.h>
#include <linux/kernel_stat.h>
#include <linux/personality.h>
-#include <linux/random.h>
#include <linux/hw_breakpoint.h>
#include <linux/uaccess.h>
-#include <linux/elf-randomize.h>
#include <linux/pkeys.h>
#include <linux/seq_buf.h>
@@ -2313,42 +2311,3 @@ unsigned long arch_align_stack(unsigned long sp)
sp -= get_random_int() & ~PAGE_MASK;
return sp & ~0xf;
}
-
-static inline unsigned long brk_rnd(void)
-{
- unsigned long rnd = 0;
-
- /* 8MB for 32bit, 1GB for 64bit */
- if (is_32bit_task())
- rnd = (get_random_long() % (1UL<<(23-PAGE_SHIFT)));
- else
- rnd = (get_random_long() % (1UL<<(30-PAGE_SHIFT)));
-
- return rnd << PAGE_SHIFT;
-}
-
-unsigned long arch_randomize_brk(struct mm_struct *mm)
-{
- unsigned long base = mm->brk;
- unsigned long ret;
-
-#ifdef CONFIG_PPC_BOOK3S_64
- /*
- * If we are using 1TB segments and we are allowed to randomise
- * the heap, we can put it above 1TB so it is backed by a 1TB
- * segment. Otherwise the heap will be in the bottom 1TB
- * which always uses 256MB segments and this may result in a
- * performance penalty.
- */
- if (!radix_enabled() && !is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T))
- base = max_t(unsigned long, mm->brk, 1UL << SID_SHIFT_1T);
-#endif
-
- ret = PAGE_ALIGN(base + brk_rnd());
-
- if (ret < mm->brk)
- return mm->brk;
-
- return ret;
-}
-
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
index 43ecad8f9564..72a3eca02449 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c
@@ -37,6 +37,8 @@
#include <linux/cpu.h>
#include <linux/pgtable.h>
#include <linux/debugfs.h>
+#include <linux/random.h>
+#include <linux/elf-randomize.h>
#include <asm/interrupt.h>
#include <asm/processor.h>
@@ -2133,3 +2135,20 @@ void __init print_system_hash_info(void)
if (htab_hash_mask)
pr_info("htab_hash_mask = 0x%lx\n", htab_hash_mask);
}
+
+unsigned long arch_randomize_brk(struct mm_struct *mm)
+{
+ /*
+ * If we are using 1TB segments and we are allowed to randomise
+ * the heap, we can put it above 1TB so it is backed by a 1TB
+ * segment. Otherwise the heap will be in the bottom 1TB
+ * which always uses 256MB segments and this may result in a
+ * performance penalty.
+ */
+ if (is_32bit_task())
+ return randomize_page(mm->brk, SZ_32M);
+ else if (!radix_enabled() && mmu_highuser_ssize == MMU_SEGSIZE_1T)
+ return randomize_page(max_t(unsigned long, mm->brk, SZ_1T), SZ_1G);
+ else
+ return randomize_page(mm->brk, SZ_1G);
+}
--
2.35.1
next prev parent reply other threads:[~2022-04-09 17:19 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-09 17:17 [PATCH v10 00/13] Convert powerpc to default topdown mmap layout (v10) Christophe Leroy
2022-04-09 17:17 ` [PATCH v10 01/13] mm, hugetlbfs: Allow for "high" userspace addresses Christophe Leroy
2022-05-03 16:29 ` Christophe Leroy
2022-04-09 17:17 ` [PATCH v10 02/13] mm: Allow arch specific arch_randomize_brk() with CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT Christophe Leroy
2022-04-09 17:17 ` [PATCH v10 03/13] mm, hugetlbfs: Allow an arch to always use generic versions of get_unmapped_area functions Christophe Leroy
2022-04-09 17:17 ` [PATCH v10 04/13] mm: Add len and flags parameters to arch_get_mmap_end() Christophe Leroy
2022-04-09 17:17 ` [PATCH v10 05/13] powerpc/mm: Move vma_mmu_pagesize() Christophe Leroy
2022-04-09 17:17 ` [PATCH v10 06/13] powerpc/mm: Make slice specific to book3s/64 Christophe Leroy
2022-04-09 17:17 ` [PATCH v10 07/13] powerpc/mm: Remove CONFIG_PPC_MM_SLICES Christophe Leroy
2022-04-09 17:17 ` [PATCH v10 08/13] powerpc/mm: Use generic_get_unmapped_area() and call it from arch_get_unmapped_area() Christophe Leroy
2022-04-09 17:17 ` [PATCH v10 09/13] powerpc/mm: Use generic_hugetlb_get_unmapped_area() Christophe Leroy
2022-04-09 17:17 ` [PATCH v10 10/13] powerpc/mm: Move get_unmapped_area functions to slice.c Christophe Leroy
2022-05-23 12:27 ` Laurent Dufour
2022-05-23 15:18 ` Christophe Leroy
2022-05-23 16:44 ` Laurent Dufour
2022-04-09 17:17 ` [PATCH v10 11/13] powerpc/mm: Enable full randomisation of memory mappings Christophe Leroy
2022-04-09 17:17 ` [PATCH v10 12/13] powerpc/mm: Convert to default topdown mmap layout Christophe Leroy
2022-04-09 17:17 ` Christophe Leroy [this message]
2022-05-15 10:28 ` [PATCH v10 00/13] Convert powerpc to default topdown mmap layout (v10) Michael Ellerman
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