lkml.org 
[lkml]   [2020]   [Feb]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v3 1/6] powerpc/fsl_booke/kaslr: refactor kaslr_legal_offset() and kaslr_early_init()
    Date
    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@huawei.com>
    Cc: Scott Wood <oss@buserror.net>
    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>
    ---
    arch/powerpc/mm/nohash/kaslr_booke.c | 40 ++++++++++++++--------------
    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 {
    unsigned long pa_start;
    unsigned long pa_end;
    unsigned long kernel_size;
    + unsigned long linear_sz;
    unsigned long dtb_start;
    unsigned long dtb_end;
    unsigned long initrd_start;
    @@ -260,11 +261,23 @@ static __init void get_cell_sizes(const void *fdt, int node, int *addr_cells,
    *size_cells = fdt32_to_cpu(*prop);
    }

    -static unsigned long __init kaslr_legal_offset(void *dt_ptr, unsigned long index,
    - unsigned long offset)
    +static unsigned long __init kaslr_legal_offset(void *dt_ptr, unsigned long random)
    {
    unsigned long koffset = 0;
    unsigned long start;
    + unsigned long index;
    + unsigned long offset;
    +
    + /*
    + * Decide which 64M we want to start
    + * Only use the low 8 bits of the random seed
    + */
    + index = random & 0xFF;
    + index %= regions.linear_sz / SZ_64M;
    +
    + /* Decide offset inside 64M */
    + offset = random % (SZ_64M - regions.kernel_size);
    + offset = round_down(offset, SZ_16K);

    while ((long)index >= 0) {
    offset = memstart_addr + index * SZ_64M + offset;
    @@ -289,10 +302,9 @@ static inline __init bool kaslr_disabled(void)
    static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size,
    unsigned long kernel_sz)
    {
    - unsigned long offset, random;
    + unsigned long random;
    unsigned long ram, linear_sz;
    u64 seed;
    - unsigned long index;

    kaslr_get_cmdline(dt_ptr);
    if (kaslr_disabled())
    @@ -333,22 +345,12 @@ static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size
    regions.dtb_start = __pa(dt_ptr);
    regions.dtb_end = __pa(dt_ptr) + fdt_totalsize(dt_ptr);
    regions.kernel_size = kernel_sz;
    + regions.linear_sz = linear_sz;

    get_initrd_range(dt_ptr);
    get_crash_kernel(dt_ptr, ram);

    - /*
    - * Decide which 64M we want to start
    - * Only use the low 8 bits of the random seed
    - */
    - index = random & 0xFF;
    - index %= linear_sz / SZ_64M;
    -
    - /* Decide offset inside 64M */
    - offset = random % (SZ_64M - kernel_sz);
    - offset = round_down(offset, SZ_16K);
    -
    - return kaslr_legal_offset(dt_ptr, index, offset);
    + return kaslr_legal_offset(dt_ptr, random);
    }

    /*
    @@ -358,8 +360,6 @@ static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size
    */
    notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size)
    {
    - unsigned long tlb_virt;
    - phys_addr_t tlb_phys;
    unsigned long offset;
    unsigned long kernel_sz;

    @@ -375,8 +375,8 @@ notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size)
    is_second_reloc = 1;

    if (offset >= SZ_64M) {
    - tlb_virt = round_down(kernstart_virt_addr, SZ_64M);
    - tlb_phys = round_down(kernstart_addr, SZ_64M);
    + unsigned long tlb_virt = round_down(kernstart_virt_addr, SZ_64M);
    + phys_addr_t tlb_phys = round_down(kernstart_addr, SZ_64M);

    /* Create kernel map to relocate in */
    create_kaslr_tlb_entry(1, tlb_virt, tlb_phys);
    --
    2.17.2
    \
     
     \ /
      Last update: 2020-02-06 04:00    [W:4.134 / U:0.216 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site