Re: [PATCH v3 1/6] powerpc/fsl_booke/kaslr: refactor kaslr_legal_offset() and kaslr_early_init()

[Jason Yan]

å 2020/2/20 21:40, Christophe Leroy åé:
> Le 06/02/2020 Ã 03:58, Jason Yan a ÃcritÂ:
> > Some code refactor in kaslr_legal_offset() and kaslr_early_init(). No
> > functional change. This is a preparation for KASLR fsl_booke64.
> >
> > Signed-off-by: Jason Yan <yanaijie@xxxxxxxxxx>
> > Cc: Scott Wood <oss@xxxxxxxxxxxx>
> > Cc: Diana Craciun <diana.craciun@xxxxxxx>
> > Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> > Cc: Christophe Leroy <christophe.leroy@xxxxxx>
> > Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> > Cc: Paul Mackerras <paulus@xxxxxxxxx>
> > Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
> > Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> > ---
> > Â arch/powerpc/mm/nohash/kaslr_booke.c | 40 ++++++++++++++--------------
> > Â 1 file changed, 20 insertions(+), 20 deletions(-)
> >
> > diff --git a/arch/powerpc/mm/nohash/kaslr_booke.c 
> > b/arch/powerpc/mm/nohash/kaslr_booke.c
> > index 4a75f2d9bf0e..07b036e98353 100644
> > --- a/arch/powerpc/mm/nohash/kaslr_booke.c
> > +++ b/arch/powerpc/mm/nohash/kaslr_booke.c
> > @@ -25,6 +25,7 @@ struct regions {
> > ÂÂÂÂÂ unsigned long pa_start;
> > ÂÂÂÂÂ unsigned long pa_end;
> > ÂÂÂÂÂ unsigned long kernel_size;
> > +ÂÂÂ unsigned long linear_sz;
> > ÂÂÂÂÂ unsigned long dtb_start;
> > ÂÂÂÂÂ unsigned long dtb_end;
> > ÂÂÂÂÂ unsigned long initrd_start;
> > @@ -260,11 +261,23 @@ static __init void get_cell_sizes(const void 
> > *fdt, int node, int *addr_cells,
> > ÂÂÂÂÂÂÂÂÂ *size_cells = fdt32_to_cpu(*prop);
> > Â }
> > -static unsigned long __init kaslr_legal_offset(void *dt_ptr, unsigned 
> > long index,
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ unsigned long offset)
> > +static unsigned long __init kaslr_legal_offset(void *dt_ptr, unsigned 
> > long random)
> > Â {
> > ÂÂÂÂÂ unsigned long koffset = 0;
> > ÂÂÂÂÂ unsigned long start;
> > +ÂÂÂ unsigned long index;
> > +ÂÂÂ unsigned long offset;
> > +
> > +ÂÂÂ /*
> > +ÂÂÂÂ * Decide which 64M we want to start
> > +ÂÂÂÂ * Only use the low 8 bits of the random seed
> > +ÂÂÂÂ */
> > +ÂÂÂ index = random & 0xFF;
> > +ÂÂÂ index %= regions.linear_sz / SZ_64M;
> > +
> > +ÂÂÂ /* Decide offset inside 64M */
> > +ÂÂÂ offset = random % (SZ_64M - regions.kernel_size);
> > +ÂÂÂ offset = round_down(offset, SZ_16K);
> > ÂÂÂÂÂ while ((long)index >= 0) {
> > ÂÂÂÂÂÂÂÂÂ offset = memstart_addr + index * SZ_64M + offset;
> > @@ -289,10 +302,9 @@ static inline __init bool kaslr_disabled(void)
> > Â static unsigned long __init kaslr_choose_location(void *dt_ptr, 
> > phys_addr_t size,
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ unsigned long kernel_sz)
> > Â {
> > -ÂÂÂ unsigned long offset, random;
> > +ÂÂÂ unsigned long random;
> > ÂÂÂÂÂ unsigned long ram, linear_sz;
> > ÂÂÂÂÂ u64 seed;
> > -ÂÂÂ unsigned long index;
> > ÂÂÂÂÂ kaslr_get_cmdline(dt_ptr);
> > ÂÂÂÂÂ if (kaslr_disabled())
> > @@ -333,22 +345,12 @@ static unsigned long __init 
> > kaslr_choose_location(void *dt_ptr, phys_addr_t size
> > ÂÂÂÂÂ regions.dtb_start = __pa(dt_ptr);
> > ÂÂÂÂÂ regions.dtb_end = __pa(dt_ptr) + fdt_totalsize(dt_ptr);
> > ÂÂÂÂÂ regions.kernel_size = kernel_sz;
> > +ÂÂÂ regions.linear_sz = linear_sz;
> > ÂÂÂÂÂ get_initrd_range(dt_ptr);
> > ÂÂÂÂÂ get_crash_kernel(dt_ptr, ram);
> > -ÂÂÂ /*
> > -ÂÂÂÂ * Decide which 64M we want to start
> > -ÂÂÂÂ * Only use the low 8 bits of the random seed
> > -ÂÂÂÂ */
> > -ÂÂÂ index = random & 0xFF;
> > -ÂÂÂ index %= linear_sz / SZ_64M;
> > -
> > -ÂÂÂ /* Decide offset inside 64M */
> > -ÂÂÂ offset = random % (SZ_64M - kernel_sz);
> > -ÂÂÂ offset = round_down(offset, SZ_16K);
> > -
> > -ÂÂÂ return kaslr_legal_offset(dt_ptr, index, offset);
> > +ÂÂÂ return kaslr_legal_offset(dt_ptr, random);
> > Â }
> > Â /*
> > @@ -358,8 +360,6 @@ static unsigned long __init 
> > kaslr_choose_location(void *dt_ptr, phys_addr_t size
> > ÂÂ */
> > Â notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size)
> > Â {
> > -ÂÂÂ unsigned long tlb_virt;
> > -ÂÂÂ phys_addr_t tlb_phys;
> > ÂÂÂÂÂ unsigned long offset;
> > ÂÂÂÂÂ unsigned long kernel_sz;
> > @@ -375,8 +375,8 @@ notrace void __init kaslr_early_init(void *dt_ptr, 
> > phys_addr_t size)
> > ÂÂÂÂÂ is_second_reloc = 1;
> > ÂÂÂÂÂ if (offset >= SZ_64M) {
> > -ÂÂÂÂÂÂÂ tlb_virt = round_down(kernstart_virt_addr, SZ_64M);
> > -ÂÂÂÂÂÂÂ tlb_phys = round_down(kernstart_addr, SZ_64M);
> > +ÂÂÂÂÂÂÂ unsigned long tlb_virt = round_down(kernstart_virt_addr, 
> > SZ_64M);
> > +ÂÂÂÂÂÂÂ phys_addr_t tlb_phys = round_down(kernstart_addr, SZ_64M);
>
> That looks like cleanup unrelated to the patch itself.

Hi, Christophe

These two variables is only for the booke32 code, so I moved the
definition here so that I can save a "#ifdef CONFIG_PPC32" for them.

Thanks,
Jason

> > ÂÂÂÂÂÂÂÂÂ /* Create kernel map to relocate in */
> > ÂÂÂÂÂÂÂÂÂ create_kaslr_tlb_entry(1, tlb_virt, tlb_phys);
>
> Christophe
>
> .