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Message-ID: <20200306064033.3398-2-yanaijie@huawei.com>
Date: Fri, 6 Mar 2020 14:40:28 +0800
From: Jason Yan <yanaijie@...wei.com>
To: <mpe@...erman.id.au>, <linuxppc-dev@...ts.ozlabs.org>,
<diana.craciun@....com>, <christophe.leroy@....fr>,
<benh@...nel.crashing.org>, <paulus@...ba.org>, <npiggin@...il.com>,
<keescook@...omium.org>, <kernel-hardening@...ts.openwall.com>,
<oss@...error.net>
CC: <linux-kernel@...r.kernel.org>, <zhaohongjiang@...wei.com>,
<dja@...ens.net>, Jason Yan <yanaijie@...wei.com>
Subject: [PATCH v4 1/6] powerpc/fsl_booke/kaslr: refactor kaslr_legal_offset() and kaslr_early_init()
Some code refactor in kaslr_legal_offset() and kaslr_early_init(). No
functional change. This is a preparation for KASLR fsl_booke64.
Signed-off-by: Jason Yan <yanaijie@...wei.com>
Cc: Scott Wood <oss@...error.net>
Cc: Diana Craciun <diana.craciun@....com>
Cc: Michael Ellerman <mpe@...erman.id.au>
Cc: Christophe Leroy <christophe.leroy@....fr>
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Nicholas Piggin <npiggin@...il.com>
Cc: Kees Cook <keescook@...omium.org>
---
arch/powerpc/mm/nohash/kaslr_booke.c | 34 +++++++++++++++-------------
1 file changed, 18 insertions(+), 16 deletions(-)
diff --git a/arch/powerpc/mm/nohash/kaslr_booke.c b/arch/powerpc/mm/nohash/kaslr_booke.c
index 4a75f2d9bf0e..6ebff31fefcc 100644
--- a/arch/powerpc/mm/nohash/kaslr_booke.c
+++ b/arch/powerpc/mm/nohash/kaslr_booke.c
@@ -25,6 +25,7 @@ struct regions {
unsigned long pa_start;
unsigned long pa_end;
unsigned long kernel_size;
+ unsigned long linear_sz;
unsigned long dtb_start;
unsigned long dtb_end;
unsigned long initrd_start;
@@ -260,11 +261,23 @@ static __init void get_cell_sizes(const void *fdt, int node, int *addr_cells,
*size_cells = fdt32_to_cpu(*prop);
}
-static unsigned long __init kaslr_legal_offset(void *dt_ptr, unsigned long index,
- unsigned long offset)
+static unsigned long __init kaslr_legal_offset(void *dt_ptr, unsigned long random)
{
unsigned long koffset = 0;
unsigned long start;
+ unsigned long index;
+ unsigned long offset;
+
+ /*
+ * Decide which 64M we want to start
+ * Only use the low 8 bits of the random seed
+ */
+ index = random & 0xFF;
+ index %= regions.linear_sz / SZ_64M;
+
+ /* Decide offset inside 64M */
+ offset = random % (SZ_64M - regions.kernel_size);
+ offset = round_down(offset, SZ_16K);
while ((long)index >= 0) {
offset = memstart_addr + index * SZ_64M + offset;
@@ -289,10 +302,9 @@ static inline __init bool kaslr_disabled(void)
static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size,
unsigned long kernel_sz)
{
- unsigned long offset, random;
+ unsigned long random;
unsigned long ram, linear_sz;
u64 seed;
- unsigned long index;
kaslr_get_cmdline(dt_ptr);
if (kaslr_disabled())
@@ -333,22 +345,12 @@ static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size
regions.dtb_start = __pa(dt_ptr);
regions.dtb_end = __pa(dt_ptr) + fdt_totalsize(dt_ptr);
regions.kernel_size = kernel_sz;
+ regions.linear_sz = linear_sz;
get_initrd_range(dt_ptr);
get_crash_kernel(dt_ptr, ram);
- /*
- * Decide which 64M we want to start
- * Only use the low 8 bits of the random seed
- */
- index = random & 0xFF;
- index %= linear_sz / SZ_64M;
-
- /* Decide offset inside 64M */
- offset = random % (SZ_64M - kernel_sz);
- offset = round_down(offset, SZ_16K);
-
- return kaslr_legal_offset(dt_ptr, index, offset);
+ return kaslr_legal_offset(dt_ptr, random);
}
/*
--
2.17.2
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