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    Subject[PATCH v5 08/10] powerpc/fsl_booke/kaslr: clear the original kernel if randomized
    Date
    The original kernel still exists in the memory, clear it now.

    Signed-off-by: Jason Yan <yanaijie@huawei.com>
    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>
    Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
    Reviewed-by: Diana Craciun <diana.craciun@nxp.com>
    Tested-by: Diana Craciun <diana.craciun@nxp.com>
    ---
    arch/powerpc/kernel/kaslr_booke.c | 11 +++++++++++
    arch/powerpc/mm/mmu_decl.h | 2 ++
    arch/powerpc/mm/nohash/fsl_booke.c | 1 +
    3 files changed, 14 insertions(+)

    diff --git a/arch/powerpc/kernel/kaslr_booke.c b/arch/powerpc/kernel/kaslr_booke.c
    index 52b59b05f906..c6b326424b54 100644
    --- a/arch/powerpc/kernel/kaslr_booke.c
    +++ b/arch/powerpc/kernel/kaslr_booke.c
    @@ -400,3 +400,14 @@ notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size)

    reloc_kernel_entry(dt_ptr, kimage_vaddr);
    }
    +
    +void __init kaslr_late_init(void)
    +{
    + /* If randomized, clear the original kernel */
    + if (kimage_vaddr != KERNELBASE) {
    + unsigned long kernel_sz;
    +
    + kernel_sz = (unsigned long)_end - kimage_vaddr;
    + memzero_explicit((void *)KERNELBASE, kernel_sz);
    + }
    +}
    diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h
    index 9332772c8a66..f0a461482dba 100644
    --- a/arch/powerpc/mm/mmu_decl.h
    +++ b/arch/powerpc/mm/mmu_decl.h
    @@ -150,8 +150,10 @@ extern void loadcam_multi(int first_idx, int num, int tmp_idx);

    #ifdef CONFIG_RANDOMIZE_BASE
    void kaslr_early_init(void *dt_ptr, phys_addr_t size);
    +void kaslr_late_init(void);
    #else
    static inline void kaslr_early_init(void *dt_ptr, phys_addr_t size) {}
    +static inline void kaslr_late_init(void) {}
    #endif

    struct tlbcam {
    diff --git a/arch/powerpc/mm/nohash/fsl_booke.c b/arch/powerpc/mm/nohash/fsl_booke.c
    index 8d25a8dc965f..e88fcc367600 100644
    --- a/arch/powerpc/mm/nohash/fsl_booke.c
    +++ b/arch/powerpc/mm/nohash/fsl_booke.c
    @@ -269,6 +269,7 @@ notrace void __init relocate_init(u64 dt_ptr, phys_addr_t start)
    kernstart_addr = start;
    if (is_second_reloc) {
    virt_phys_offset = PAGE_OFFSET - memstart_addr;
    + kaslr_late_init();
    return;
    }

    --
    2.17.2
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