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. This is done after memblock get
available but before switching to the final hash table, otherwise
there are issues with TLB flushing due to the shared entries.
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
---
arch/powerpc/kernel/head_32.S | 40 ++++++++++++++++++++++++++---------
arch/powerpc/mm/kasan/kasan_init_32.c | 23 +++++++++++++++++++-
arch/powerpc/mm/mmu_decl.h | 1 +
3 files changed, 53 insertions(+), 11 deletions(-)
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 0bfaf64e67ee..fd7c394bc77c 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
@@ -884,11 +888,24 @@ _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
@@ -900,14 +917,6 @@ 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. */
@@ -929,6 +938,17 @@ 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 42617fcad828..ba8361487075 100644
--- a/arch/powerpc/mm/kasan/kasan_init_32.c
+++ b/arch/powerpc/mm/kasan/kasan_init_32.c
@@ -94,6 +94,13 @@ void __init kasan_mmu_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);
@@ -135,6 +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;
@@ -152,5 +173,5 @@ void __init kasan_early_init(void)
} while (pmd++, addr = next, addr != end);
if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE))
- WARN(true, "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
