[v5,09/10] powerpc/fsl_booke/kaslr: support nokaslr cmdline parameter
diff mbox series

Message ID 20190807065706.11411-10-yanaijie@huawei.com
State New
Headers show
Series
  • implement KASLR for powerpc/fsl_booke/32
Related show

Commit Message

Jason Yan Aug. 7, 2019, 6:57 a.m. UTC
One may want to disable kaslr when boot, so provide a cmdline parameter
'nokaslr' to support this.

Signed-off-by: Jason Yan <yanaijie@huawei.com>
Cc: Diana Craciun <diana.craciun@nxp.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Reviewed-by: Diana Craciun <diana.craciun@nxp.com>
Tested-by: Diana Craciun <diana.craciun@nxp.com>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 arch/powerpc/kernel/kaslr_booke.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

Comments

Michael Ellerman Aug. 7, 2019, 1:03 p.m. UTC | #1
Jason Yan <yanaijie@huawei.com> writes:
> diff --git a/arch/powerpc/kernel/kaslr_booke.c b/arch/powerpc/kernel/kaslr_booke.c
> index c6b326424b54..436f9a03f385 100644
> --- a/arch/powerpc/kernel/kaslr_booke.c
> +++ b/arch/powerpc/kernel/kaslr_booke.c
> @@ -361,6 +361,18 @@ 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(boot_command_line, "nokaslr");
> +	if (str == boot_command_line ||
> +	    (str > boot_command_line && *(str - 1) == ' '))
> +		return true;

This extra logic doesn't work for "nokaslrfoo". Is it worth it?

cheers
Jason Yan Aug. 8, 2019, 8:19 a.m. UTC | #2
On 2019/8/7 21:03, Michael Ellerman wrote:
> Jason Yan <yanaijie@huawei.com> writes:
>> diff --git a/arch/powerpc/kernel/kaslr_booke.c b/arch/powerpc/kernel/kaslr_booke.c
>> index c6b326424b54..436f9a03f385 100644
>> --- a/arch/powerpc/kernel/kaslr_booke.c
>> +++ b/arch/powerpc/kernel/kaslr_booke.c
>> @@ -361,6 +361,18 @@ 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(boot_command_line, "nokaslr");
>> +	if (str == boot_command_line ||
>> +	    (str > boot_command_line && *(str - 1) == ' '))
>> +		return true;
> 
> This extra logic doesn't work for "nokaslrfoo". Is it worth it?
> 

Seems nobody likes this logic. Maybe I can delete this logic for now and
see if anyone has any objections.

> cheers
> 
> .
>

Patch
diff mbox series

diff --git a/arch/powerpc/kernel/kaslr_booke.c b/arch/powerpc/kernel/kaslr_booke.c
index c6b326424b54..436f9a03f385 100644
--- a/arch/powerpc/kernel/kaslr_booke.c
+++ b/arch/powerpc/kernel/kaslr_booke.c
@@ -361,6 +361,18 @@  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(boot_command_line, "nokaslr");
+	if (str == boot_command_line ||
+	    (str > boot_command_line && *(str - 1) == ' '))
+		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
@@ -376,6 +388,8 @@  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);