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SubjectRe: [PATCH] of/kexec: Omit kaslr-seed when kexecing with nokaslr
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在 2023/9/8 22:58, Rob Herring 写道:
> On Fri, Sep 8, 2023 at 5:45 AM Song Shuai <songshuaishuai@tinylab.org> wrote:
>>
>> The chosen node always adds the kaslr-seed property which is needless
>> for the kernels kexeced with the cmdline contained "nokaslr".
>>
>> So omit the kaslr-seed when kexecing with nokaslr.
>
> The kexec'ed kernel can ignore bootargs with CONFIG_CMDLINE_FORCE. So
> you don't know if kaslr-seed will be used or not.
>
You are correct. In addition, unlike the EFI Stub, Kexec is unable to
determine whether the kexec'ed kernel supports RANDOMIZE_BASE,
hence it is appropriate to emit the kaslr-seed unconditionally like
those out-of-linux bootloaders.

Apologies for bothering you with this incorrect patch.

>> Signed-off-by: Song Shuai <songshuaishuai@tinylab.org>
>> ---
>> drivers/of/kexec.c | 15 ++++++++++++---
>> 1 file changed, 12 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
>> index f26d2ba8a371..c0d53b10cb70 100644
>> --- a/drivers/of/kexec.c
>> +++ b/drivers/of/kexec.c
>> @@ -19,6 +19,7 @@
>> #include <linux/random.h>
>> #include <linux/slab.h>
>> #include <linux/types.h>
>> +#include <linux/string.h>
>>
>> #define RNG_SEED_SIZE 128
>>
>> @@ -263,6 +264,14 @@ static inline int setup_ima_buffer(const struct kimage *image, void *fdt,
>> }
>> #endif /* CONFIG_IMA_KEXEC */
>>
>> +static bool is_nokaslr_cmdline(const char *cmdline)
>> +{
>> + char *str;
>> +
>> + str = strstr(cmdline, "nokaslr");
>> + return str == cmdline || (str > cmdline && *(str - 1) == ' ');
>
> Yet another copy of the same code. That's a clue to refactor into a
> common function.
>
> Rob
>

--
Thanks
Song Shuai

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