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Subject[PATCH v7 08/12] 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/mm/mmu_decl.h | 2 ++
arch/powerpc/mm/nohash/fsl_booke.c | 1 +
arch/powerpc/mm/nohash/kaslr_booke.c | 11 +++++++++++
3 files changed, 14 insertions(+)

diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h
index a3a4937c0496..565731475a07 100644
--- a/arch/powerpc/mm/mmu_decl.h
+++ b/arch/powerpc/mm/mmu_decl.h
@@ -151,8 +151,10 @@ 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 2dc27cf88add..b4eb06ceb189 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;
}

diff --git a/arch/powerpc/mm/nohash/kaslr_booke.c b/arch/powerpc/mm/nohash/kaslr_booke.c
index 7b238fc2c8a9..aa1b60c782e7 100644
--- a/arch/powerpc/mm/nohash/kaslr_booke.c
+++ b/arch/powerpc/mm/nohash/kaslr_booke.c
@@ -381,3 +381,14 @@ notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size)

reloc_kernel_entry(dt_ptr, kernstart_virt_addr);
}
+
+void __init kaslr_late_init(void)
+{
+ /* If randomized, clear the original kernel */
+ if (kernstart_virt_addr != KERNELBASE) {
+ unsigned long kernel_sz;
+
+ kernel_sz = (unsigned long)_end - kernstart_virt_addr;
+ memzero_explicit((void *)KERNELBASE, kernel_sz);
+ }
+}
--
2.17.2
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