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Subject[PATCH v1 46/46] powerpc/32s: Implement dedicated kasan_init_region()
Date
Implement a kasan_init_region() dedicated to book3s/32 that
allocates KASAN regions using BATs.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/include/asm/kasan.h | 1 +
arch/powerpc/mm/kasan/Makefile | 1 +
arch/powerpc/mm/kasan/book3s_32.c | 57 +++++++++++++++++++++++++++
arch/powerpc/mm/kasan/kasan_init_32.c | 2 +-
4 files changed, 60 insertions(+), 1 deletion(-)
create mode 100644 arch/powerpc/mm/kasan/book3s_32.c

diff --git a/arch/powerpc/include/asm/kasan.h b/arch/powerpc/include/asm/kasan.h
index 107a24c3f7b3..be85c7005fb1 100644
--- a/arch/powerpc/include/asm/kasan.h
+++ b/arch/powerpc/include/asm/kasan.h
@@ -34,6 +34,7 @@ static inline void kasan_init(void) { }
static inline void kasan_late_init(void) { }
#endif

+void kasan_update_early_region(unsigned long k_start, unsigned long k_end, pte_t pte);
int kasan_init_shadow_page_tables(unsigned long k_start, unsigned long k_end);
int kasan_init_region(void *start, size_t size);

diff --git a/arch/powerpc/mm/kasan/Makefile b/arch/powerpc/mm/kasan/Makefile
index 440038ea79f1..bb1a5408b86b 100644
--- a/arch/powerpc/mm/kasan/Makefile
+++ b/arch/powerpc/mm/kasan/Makefile
@@ -4,3 +4,4 @@ KASAN_SANITIZE := n

obj-$(CONFIG_PPC32) += kasan_init_32.o
obj-$(CONFIG_PPC_8xx) += 8xx.o
+obj-$(CONFIG_PPC_BOOK3S_32) += book3s_32.o
diff --git a/arch/powerpc/mm/kasan/book3s_32.c b/arch/powerpc/mm/kasan/book3s_32.c
new file mode 100644
index 000000000000..4bc491a4a1fd
--- /dev/null
+++ b/arch/powerpc/mm/kasan/book3s_32.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define DISABLE_BRANCH_PROFILING
+
+#include <linux/kasan.h>
+#include <linux/memblock.h>
+#include <asm/pgalloc.h>
+#include <mm/mmu_decl.h>
+
+int __init kasan_init_region(void *start, size_t size)
+{
+ unsigned long k_start = (unsigned long)kasan_mem_to_shadow(start);
+ unsigned long k_end = (unsigned long)kasan_mem_to_shadow(start + size);
+ unsigned long k_cur = k_start;
+ int k_size = k_end - k_start;
+ int k_size_base = 1 << (ffs(k_size) - 1);
+ int ret;
+ void *block;
+
+ block = memblock_alloc(k_size, k_size_base);
+
+ if (block && k_size_base >= SZ_128K && k_start == ALIGN(k_start, k_size_base)) {
+ int k_size_more = 1 << (ffs(k_size - k_size_base) - 1);
+
+ setbat(-1, k_start, __pa(block), k_size_base, PAGE_KERNEL);
+ if (k_size_more >= SZ_128K)
+ setbat(-1, k_start + k_size_base, __pa(block) + k_size_base,
+ k_size_more, PAGE_KERNEL);
+ if (v_block_mapped(k_start))
+ k_cur = k_start + k_size_base;
+ if (v_block_mapped(k_start + k_size_base))
+ k_cur = k_start + k_size_base + k_size_more;
+
+ update_bats();
+ }
+
+ if (!block)
+ block = memblock_alloc(k_size, PAGE_SIZE);
+ if (!block)
+ return -ENOMEM;
+
+ ret = kasan_init_shadow_page_tables(k_start, k_end);
+ if (ret)
+ return ret;
+
+ kasan_update_early_region(k_start, k_cur, __pte(0));
+
+ for (; k_cur < k_end; k_cur += PAGE_SIZE) {
+ pmd_t *pmd = pmd_ptr_k(k_cur);
+ void *va = block + k_cur - k_start;
+ pte_t pte = pfn_pte(PHYS_PFN(__pa(va)), PAGE_KERNEL);
+
+ __set_pte_at(&init_mm, k_cur, pte_offset_kernel(pmd, k_cur), pte, 0);
+ }
+ flush_tlb_kernel_range(k_start, k_end);
+ return 0;
+}
diff --git a/arch/powerpc/mm/kasan/kasan_init_32.c b/arch/powerpc/mm/kasan/kasan_init_32.c
index 03d30ec7a858..e9fda8451718 100644
--- a/arch/powerpc/mm/kasan/kasan_init_32.c
+++ b/arch/powerpc/mm/kasan/kasan_init_32.c
@@ -79,7 +79,7 @@ int __init __weak kasan_init_region(void *start, size_t size)
return 0;
}

-static void __init
+void __init
kasan_update_early_region(unsigned long k_start, unsigned long k_end, pte_t pte)
{
unsigned long k_cur;
--
2.25.0
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