[v6,08/12] powerpc/fsl_booke/kaslr: clear the original kernel if randomized

Commit Message

Jason Yan Aug. 9, 2019, 10:07 a.m. UTC

The original kernel still exists in the memory, clear it now.

Signed-off-by: Jason Yan <[e-mail]>
Cc: Diana Craciun <[e-mail]>
Cc: Michael Ellerman <[e-mail]>
Cc: Christophe Leroy <[e-mail]>
Cc: Benjamin Herrenschmidt <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Nicholas Piggin <[e-mail]>
Cc: Kees Cook <[e-mail]>
Reviewed-by: Christophe Leroy <[e-mail]>
Reviewed-by: Diana Craciun <[e-mail]>
Tested-by: Diana Craciun <[e-mail]>
---
 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(+)

Patch

diff --git a/arch/powerpc/kernel/kaslr_booke.c b/arch/powerpc/kernel/kaslr_booke.c
index 51a0b3749724..9a360b6124ed 100644
--- a/arch/powerpc/kernel/kaslr_booke.c
+++ b/arch/powerpc/kernel/kaslr_booke.c
@@ -373,3 +373,14 @@  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);
+	}
+}
diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h
index 213997d69729..64b2ac8a5343 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;
 	}