powerpc: Randomise lower bits of stack address

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Randomise the lower bits of the stack address. More randomisation is good for
security but the scatter can also help with SMT threads that share an L1. A
quick test case shows this working:

int main()
{
	int sp;
	printf("%x\n", (unsigned long)&sp & 4095);
}

before:
80
80
80
80
80

after:
610
490
300
6b0
d80

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

...

This commit is contained in:

Anton Blanchard 2009-02-22 01:50:03 +00:00 • committed by Benjamin Herrenschmidt

parent 2dadb987e0

commit d839088cae

2 changed files with 10 additions and 1 deletions

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2

arch/powerpc/include/asm/system.h

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9

arch/powerpc/kernel/process.c

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