On 2019/7/29 19:38, Christophe Leroy wrote:
Le 17/07/2019 à 10:06, Jason Yan a écrit :
One may want to disable kaslr when boot, so provide a cmdline parameter
'nokaslr' to support this.
Signed-off-by: Jason Yan <yanai...@huawei.com>
Cc: Diana Craciun <diana.crac...@nxp.com>
Cc: Michael Ellerman <m...@ellerman.id.au>
Cc: Christophe Leroy <christophe.le...@c-s.fr>
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Nicholas Piggin <npig...@gmail.com>
Cc: Kees Cook <keesc...@chromium.org>
---
arch/powerpc/kernel/kaslr_booke.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/arch/powerpc/kernel/kaslr_booke.c
b/arch/powerpc/kernel/kaslr_booke.c
index 00339c05879f..e65a5d9d2ff1 100644
--- a/arch/powerpc/kernel/kaslr_booke.c
+++ b/arch/powerpc/kernel/kaslr_booke.c
@@ -373,6 +373,18 @@ static unsigned long __init
kaslr_choose_location(void *dt_ptr, phys_addr_t size
return kaslr_offset;
}
+static inline __init bool kaslr_disabled(void)
+{
+ char *str;
+
+ str = strstr(early_command_line, "nokaslr");
Why using early_command_line instead of boot_command_line ?
Will switch to boot_command_line.
+ if ((str == early_command_line) ||
+ (str > early_command_line && *(str - 1) == ' '))
Is that stuff really needed ?
Why not just:
return strstr(early_command_line, "nokaslr") != NULL;
This code is derived from other arch such as arm64/mips. It's trying to
make sure that 'nokaslr' is a separate word but not part of other words
such as 'abcnokaslr'.
+ return true;
+
+ return false;
+}
+
/*
* To see if we need to relocate the kernel to a random offset
* void *dt_ptr - address of the device tree
@@ -388,6 +400,8 @@ notrace void __init kaslr_early_init(void *dt_ptr,
phys_addr_t size)
kernel_sz = (unsigned long)_end - KERNELBASE;
kaslr_get_cmdline(dt_ptr);
+ if (kaslr_disabled())
+ return;
offset = kaslr_choose_location(dt_ptr, size, kernel_sz);
Christophe
.
