powerpc/32s: Implement dedicated kasan_init_region()

Implement a kasan_init_region() dedicated to book3s/32 that
allocates KASAN regions using BATs.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/709e821602b48a1d7c211a9b156da26db98c3e9d.1589866984.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/include/asm/kasan.h b/arch/powerpc/include/asm/kasan.h
index 107a24c3f7b38cd3bd53e1a34df5300d43be9c1a..be85c7005fb15011c946caba8b14317e2cfd38db 100644 (file)
--- 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 440038ea79f18d3bb03b1a21e4e8a017e047af25..bb1a5408b86b2cb3ca1af86c65c7f4355a0adbc6 100644 (file)
--- 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 (file)
index 0000000..4bc491a
--- /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 76d418af4ce84c18e739d5ad1f00e251373e05c8..c42085801c04c53cd14e75e818eab87311d0fb17 100644 (file)
--- 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;