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Message-ID: <20191115093209.26434-4-yanaijie@huawei.com>
Date: Fri, 15 Nov 2019 17:32:06 +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>
CC: <linux-kernel@...r.kernel.org>, <oss@...error.net>, Jason Yan
<yanaijie@...wei.com>
Subject: [PATCH 3/6] powerpc/fsl_booke/64: implement KASLR for fsl_booke64
The implementation for Freescale BookE64 is similar as BookE32. One
difference is that Freescale BookE64 set up a TLB mapping of 1G during
booting. Another difference is that ppc64 needs the kernel to be
64K-aligned. So we can randomize the kernel in this 1G mapping and make
it 64K-aligned. This can save some code to creat another TLB map at
early boot. The disadvantage is that we only have about 1G/64K = 16384
slots to put the kernel in.
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/Kconfig | 2 +-
arch/powerpc/kernel/setup_64.c | 4 +++-
arch/powerpc/mm/nohash/kaslr_booke.c | 29 ++++++++++++++++++++++++++--
3 files changed, 31 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 4c4a0fcd1674..3e563a07cb67 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -553,7 +553,7 @@ config RELOCATABLE
config RANDOMIZE_BASE
bool "Randomize the address of the kernel image"
- depends on (FSL_BOOKE && FLATMEM && PPC32)
+ depends on (PPC_FSL_BOOK3E && FLATMEM)
depends on RELOCATABLE
help
Randomizes the virtual address at which the kernel image is
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index d2af4c228970..b7e4f1e92c7e 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -65,7 +65,7 @@
#include <asm/hw_irq.h>
#include <asm/feature-fixups.h>
#include <asm/kup.h>
-
+#include <mm/mmu_decl.h>
#include "setup.h"
int spinning_secondaries;
@@ -299,6 +299,8 @@ void __init early_setup(unsigned long dt_ptr)
/* Enable early debugging if any specified (see udbg.h) */
udbg_early_init();
+ kaslr_early_init(__va(dt_ptr), 0);
+
udbg_printf(" -> %s(), dt_ptr: 0x%lx\n", __func__, dt_ptr);
/*
diff --git a/arch/powerpc/mm/nohash/kaslr_booke.c b/arch/powerpc/mm/nohash/kaslr_booke.c
index 07b036e98353..513f4616e92a 100644
--- a/arch/powerpc/mm/nohash/kaslr_booke.c
+++ b/arch/powerpc/mm/nohash/kaslr_booke.c
@@ -265,14 +265,14 @@ static unsigned long __init kaslr_legal_offset(void *dt_ptr, unsigned long rando
{
unsigned long koffset = 0;
unsigned long start;
- unsigned long index;
unsigned long offset;
+#ifdef CONFIG_PPC32
/*
* Decide which 64M we want to start
* Only use the low 8 bits of the random seed
*/
- index = random & 0xFF;
+ unsigned long index = random & 0xFF;
index %= regions.linear_sz / SZ_64M;
/* Decide offset inside 64M */
@@ -287,6 +287,15 @@ static unsigned long __init kaslr_legal_offset(void *dt_ptr, unsigned long rando
break;
index--;
}
+#else
+ /* Decide kernel offset inside 1G */
+ offset = random % (SZ_1G - regions.kernel_size);
+ offset = round_down(offset, SZ_64K);
+
+ start = memstart_addr;
+ offset = memstart_addr + offset;
+ koffset = get_usable_address(dt_ptr, start, offset);
+#endif
if (koffset != 0)
koffset -= memstart_addr;
@@ -325,6 +334,7 @@ static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size
else
pr_warn("KASLR: No safe seed for randomizing the kernel base.\n");
+#ifdef CONFIG_PPC32
ram = min_t(phys_addr_t, __max_low_memory, size);
ram = map_mem_in_cams(ram, CONFIG_LOWMEM_CAM_NUM, true);
linear_sz = min_t(unsigned long, ram, SZ_512M);
@@ -332,6 +342,7 @@ static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size
/* If the linear size is smaller than 64M, do not randmize */
if (linear_sz < SZ_64M)
return 0;
+#endif
/* check for a reserved-memory node and record its cell sizes */
regions.reserved_mem = fdt_path_offset(dt_ptr, "/reserved-memory");
@@ -363,6 +374,18 @@ notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size)
unsigned long offset;
unsigned long kernel_sz;
+#ifdef CONFIG_PPC64
+ unsigned int *__run_at_load = (unsigned int *)(KERNELBASE + 0x5c);
+
+ if (*__run_at_load == 1)
+ return;
+
+ *__run_at_load = 1;
+
+ /* Setup flat device-tree pointer */
+ initial_boot_params = dt_ptr;
+#endif
+
kernel_sz = (unsigned long)_end - (unsigned long)_stext;
offset = kaslr_choose_location(dt_ptr, size, kernel_sz);
@@ -372,6 +395,7 @@ notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size)
kernstart_virt_addr += offset;
kernstart_addr += offset;
+#ifdef CONFIG_PPC32
is_second_reloc = 1;
if (offset >= SZ_64M) {
@@ -381,6 +405,7 @@ notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size)
/* Create kernel map to relocate in */
create_kaslr_tlb_entry(1, tlb_virt, tlb_phys);
}
+#endif
/* Copy the kernel to it's new location and run */
memcpy((void *)kernstart_virt_addr, (void *)_stext, kernel_sz);
--
2.17.2
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