KASAN requires early activation of hash table, before memblock()
functions are available.
This patch implements an early hash_table statically defined in
__initdata.
During early boot, a single page table is used. For hash32, when doing
the final init, one page table is allocated for each PGD entry because
of the _PAGE_HASHPTE flag which can't be common to several virt pages.
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
---
arch/powerpc/kernel/head_32.S | 40 ++++++++++++++++++++++++++---------
arch/powerpc/mm/kasan/kasan_init_32.c | 32 ++++++++++++++++++++++++----
arch/powerpc/mm/mmu_decl.h | 1 +
3 files changed, 59 insertions(+), 14 deletions(-)
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index e644aab2cf5b..65c9e8819da1 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -160,6 +160,10 @@ __after_mmu_off:
bl flush_tlbs
bl initial_bats
+ bl load_segment_registers
+#ifdef CONFIG_KASAN
+ bl early_hash_table
+#endif
#if defined(CONFIG_BOOTX_TEXT)
bl setup_disp_bat
#endif
@@ -205,7 +209,7 @@ __after_mmu_off:
*/
turn_on_mmu:
mfmsr r0
- ori r0,r0,MSR_DR|MSR_IR
+ ori r0,r0,MSR_DR|MSR_IR|MSR_RI
mtspr SPRN_SRR1,r0
lis r0,start_here@h
ori r0,r0,start_here@l
@@ -881,11 +885,24 @@ _ENTRY(__restore_cpu_setup)
blr
#endif /* !defined(CONFIG_PPC_BOOK3S_32) */
-
/*
* Load stuff into the MMU. Intended to be called with
* IR=0 and DR=0.
*/
+#ifdef CONFIG_KASAN
+early_hash_table:
+ sync /* Force all PTE updates to finish */
+ isync
+ tlbia /* Clear all TLB entries */
+ sync /* wait for tlbia/tlbie to finish */
+ TLBSYNC /* ... on all CPUs */
+ /* Load the SDR1 register (hash table base & size) */
+ lis r6, early_hash - PAGE_OFFSET@h
+ ori r6, r6, 3 /* 256kB table */
+ mtspr SPRN_SDR1, r6
+ blr
+#endif
+
load_up_mmu:
sync /* Force all PTE updates to finish */
isync
@@ -897,14 +914,6 @@ load_up_mmu:
tophys(r6,r6)
lwz r6,_SDR1@l(r6)
mtspr SPRN_SDR1,r6
- li r0,16 /* load up segment register values */
- mtctr r0 /* for context 0 */
- lis r3,0x2000 /* Ku = 1, VSID = 0 */
- li r4,0
-3: mtsrin r3,r4
- addi r3,r3,0x111 /* increment VSID */
- addis r4,r4,0x1000 /* address of next segment */
- bdnz 3b
/* Load the BAT registers with the values set up by MMU_init.
MMU_init takes care of whether we're on a 601 or not. */
@@ -926,6 +935,17 @@ BEGIN_MMU_FTR_SECTION
END_MMU_FTR_SECTION_IFSET(MMU_FTR_USE_HIGH_BATS)
blr
+load_segment_registers:
+ li r0, 16 /* load up segment register values */
+ mtctr r0 /* for context 0 */
+ lis r3, 0x2000 /* Ku = 1, VSID = 0 */
+ li r4, 0
+3: mtsrin r3, r4
+ addi r3, r3, 0x111 /* increment VSID */
+ addis r4, r4, 0x1000 /* address of next segment */
+ bdnz 3b
+ blr
+
/*
* This is where the main kernel code starts.
*/
diff --git a/arch/powerpc/mm/kasan/kasan_init_32.c b/arch/powerpc/mm/kasan/kasan_init_32.c
index 42f8534ce3ea..8c25c1e8c2c8 100644
--- a/arch/powerpc/mm/kasan/kasan_init_32.c
+++ b/arch/powerpc/mm/kasan/kasan_init_32.c
@@ -60,10 +60,13 @@ static int __ref kasan_init_region(void *start, size_t size)
unsigned long k_cur;
pmd_t *pmd;
void *block = NULL;
- int ret = kasan_init_shadow_page_tables(k_start, k_end);
- if (ret)
- return ret;
+ if (!early_mmu_has_feature(MMU_FTR_HPTE_TABLE)) {
+ int ret = kasan_init_shadow_page_tables(k_start, k_end);
+
+ if (ret)
+ return ret;
+ }
if (!slab_is_available())
block = memblock_alloc(k_end - k_start, PAGE_SIZE);
@@ -94,6 +97,13 @@ void __init kasan_init(void)
int ret;
struct memblock_region *reg;
+ if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE)) {
+ ret = kasan_init_shadow_page_tables(KASAN_SHADOW_START, KASAN_SHADOW_END);
+
+ if (ret)
+ panic("kasan: kasan_init_shadow_page_tables() failed");
+ }
+
for_each_memblock(memory, reg) {
phys_addr_t base = reg->base;
phys_addr_t top = min(base + reg->size, total_lowmem);
@@ -132,6 +142,20 @@ void *module_alloc(unsigned long size)
}
#endif
+#ifdef CONFIG_PPC_BOOK3S_32
+u8 __initdata early_hash[256 << 10] __aligned(256 << 10) = {0};
+
+static void __init kasan_early_hash_table(void)
+{
+ modify_instruction_site(&patch__hash_page_A0, 0xffff, __pa(early_hash) >> 16);
+ modify_instruction_site(&patch__flush_hash_A0, 0xffff, __pa(early_hash) >> 16);
+
+ Hash = (struct hash_pte *)early_hash;
+}
+#else
+static void __init kasan_early_hash_table(void) {}
+#endif
+
void __init kasan_early_init(void)
{
unsigned long addr = KASAN_SHADOW_START;
@@ -149,5 +173,5 @@ void __init kasan_early_init(void)
} while (pmd++, addr = next, addr != end);
if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE))
- WARN(1, "KASAN not supported on hash 6xx");
+ kasan_early_hash_table();
}
diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h
index d726ff776054..31fce3914ddc 100644
--- a/arch/powerpc/mm/mmu_decl.h
+++ b/arch/powerpc/mm/mmu_decl.h
@@ -106,6 +106,7 @@ extern unsigned int rtas_data, rtas_size;
struct hash_pte;
extern struct hash_pte *Hash, *Hash_end;
extern unsigned long Hash_size, Hash_mask;
+extern u8 early_hash[];
#endif /* CONFIG_PPC32 */
--
2.13.3
