On Thu, Dec 14, 2023 at 12:24:48AM +0100, Ilya Leoshkevich wrote: > The pages for the KMSAN metadata associated with most kernel mappings > are taken from memblock by the common code. However, vmalloc and module > metadata needs to be defined by the architectures. > > Be a little bit more careful than x86: allocate exactly MODULES_LEN > for the module shadow and origins, and then take 2/3 of vmalloc for > the vmalloc shadow and origins. This ensures that users passing small > vmalloc= values on the command line do not cause module metadata > collisions. > > Reviewed-by: Alexander Potapenko <glider@xxxxxxxxxx> > Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx> > --- > arch/s390/boot/startup.c | 8 ++++++++ > arch/s390/include/asm/pgtable.h | 10 ++++++++++ > 2 files changed, 18 insertions(+) > > diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c > index 8104e0e3d188..e37e7ffda430 100644 > --- a/arch/s390/boot/startup.c > +++ b/arch/s390/boot/startup.c > @@ -253,9 +253,17 @@ static unsigned long setup_kernel_memory_layout(void) > MODULES_END = round_down(__abs_lowcore, _SEGMENT_SIZE); > MODULES_VADDR = MODULES_END - MODULES_LEN; > VMALLOC_END = MODULES_VADDR; > +#ifdef CONFIG_KMSAN > + VMALLOC_END -= MODULES_LEN * 2; > +#endif > > /* allow vmalloc area to occupy up to about 1/2 of the rest virtual space left */ > vmalloc_size = min(vmalloc_size, round_down(VMALLOC_END / 2, _REGION3_SIZE)); > +#ifdef CONFIG_KMSAN > + /* take 2/3 of vmalloc area for KMSAN shadow and origins */ > + vmalloc_size = round_down(vmalloc_size / 3, _REGION3_SIZE); > + VMALLOC_END -= vmalloc_size * 2; > +#endif Please use if (IS_ENABLED(CONFIG_KMSAN)) above, since this way we get more compile time checks. > +#ifdef CONFIG_KMSAN > +#define KMSAN_VMALLOC_SIZE (VMALLOC_END - VMALLOC_START) > +#define KMSAN_VMALLOC_SHADOW_START VMALLOC_END > +#define KMSAN_VMALLOC_ORIGIN_START (KMSAN_VMALLOC_SHADOW_START + \ > + KMSAN_VMALLOC_SIZE) > +#define KMSAN_MODULES_SHADOW_START (KMSAN_VMALLOC_ORIGIN_START + \ > + KMSAN_VMALLOC_SIZE) Long single lines for these, please :) With that, and Alexander Gordeev's comments addressed: Acked-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
