From c7b9ed7c34a9f5dbf8222d63e3e313cef9f3150b Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Tue, 28 Jun 2022 16:48:59 +0200 Subject: [PATCH] powerpc/64e: KASAN Full support for BOOK3E/64 We now have memory organised in a way that allows implementing KASAN. Unlike book3s/64, book3e always has translation active so the only thing needed to use KASAN is to setup an early zero shadow mapping just after setting a stack pointer and before calling early_setup(). The memory layout is now as follows +------------------------+ Kernel virtual map end (0xc000200000000000) | | | 16TB of KASAN map | | | +------------------------+ Kernel KASAN shadow map start | | | 16TB of IO map | | | +------------------------+ Kernel IO map start | | | 16TB of vmemmap | | | +------------------------+ Kernel vmemmap start | | | 16TB of vmap | | | +------------------------+ Kernel virt start (0xc000100000000000) | | | 64TB of linear mem | | | +------------------------+ Kernel linear (0xc.....) Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/0bef8beda27baf71e3b9e8b13e620fba6e19499b.1656427701.git.christophe.leroy@csgroup.eu --- arch/powerpc/Kconfig | 2 + arch/powerpc/Kconfig.debug | 3 +- arch/powerpc/include/asm/kasan.h | 13 +++- arch/powerpc/kernel/head_64.S | 3 + arch/powerpc/mm/kasan/Makefile | 1 + arch/powerpc/mm/kasan/init_book3e_64.c | 133 +++++++++++++++++++++++++++++++++ arch/powerpc/mm/kasan/init_book3s_64.c | 2 + arch/powerpc/platforms/Kconfig.cputype | 1 - 8 files changed, 155 insertions(+), 3 deletions(-) create mode 100644 arch/powerpc/mm/kasan/init_book3e_64.c diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index c2ce2e6..92e0cad 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -193,6 +193,7 @@ config PPC select HAVE_ARCH_JUMP_LABEL_RELATIVE select HAVE_ARCH_KASAN if PPC32 && PPC_PAGE_SHIFT <= 14 select HAVE_ARCH_KASAN if PPC_RADIX_MMU + select HAVE_ARCH_KASAN if PPC_BOOK3E_64 select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN select HAVE_ARCH_KFENCE if PPC_BOOK3S_32 || PPC_8xx || 40x select HAVE_ARCH_KGDB @@ -254,6 +255,7 @@ config PPC select IOMMU_HELPER if PPC64 select IRQ_DOMAIN select IRQ_FORCED_THREADING + select KASAN_VMALLOC if KASAN && MODULES select MMU_GATHER_PAGE_SIZE select MMU_GATHER_RCU_TABLE_FREE select MODULES_USE_ELF_RELA diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug index 9f363c1..6a8855d 100644 --- a/arch/powerpc/Kconfig.debug +++ b/arch/powerpc/Kconfig.debug @@ -375,4 +375,5 @@ config KASAN_SHADOW_OFFSET hex depends on KASAN default 0xe0000000 if PPC32 - default 0xa80e000000000000 if PPC64 + default 0xa80e000000000000 if PPC_BOOK3S_64 + default 0xa8001c0000000000 if PPC_BOOK3E_64 diff --git a/arch/powerpc/include/asm/kasan.h b/arch/powerpc/include/asm/kasan.h index a6be402..92a9682 100644 --- a/arch/powerpc/include/asm/kasan.h +++ b/arch/powerpc/include/asm/kasan.h @@ -19,7 +19,7 @@ #define KASAN_SHADOW_SCALE_SHIFT 3 -#ifdef CONFIG_MODULES +#if defined(CONFIG_MODULES) && defined(CONFIG_PPC32) #define KASAN_KERN_START ALIGN_DOWN(PAGE_OFFSET - SZ_256M, SZ_256M) #else #define KASAN_KERN_START PAGE_OFFSET @@ -39,6 +39,17 @@ * c00e000000000000 << 3 + a80e000000000000 = c00fc00000000000 */ #define KASAN_SHADOW_END 0xc00fc00000000000UL + +#else + +/* + * The shadow ends before the highest accessible address + * because we don't need a shadow for the shadow. + * But it doesn't hurt to have a shadow for the shadow, + * keep shadow end aligned eases things. + */ +#define KASAN_SHADOW_END 0xc000200000000000UL + #endif #ifdef CONFIG_KASAN diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S index d3eea63..cf2c089 100644 --- a/arch/powerpc/kernel/head_64.S +++ b/arch/powerpc/kernel/head_64.S @@ -965,6 +965,9 @@ start_here_multiplatform: * and SLB setup before we turn on relocation. */ +#ifdef CONFIG_KASAN + bl kasan_early_init +#endif /* Restore parameters passed from prom_init/kexec */ mr r3,r31 LOAD_REG_ADDR(r12, DOTSYM(early_setup)) diff --git a/arch/powerpc/mm/kasan/Makefile b/arch/powerpc/mm/kasan/Makefile index 4999aad..699eeff 100644 --- a/arch/powerpc/mm/kasan/Makefile +++ b/arch/powerpc/mm/kasan/Makefile @@ -6,3 +6,4 @@ obj-$(CONFIG_PPC32) += init_32.o obj-$(CONFIG_PPC_8xx) += 8xx.o obj-$(CONFIG_PPC_BOOK3S_32) += book3s_32.o obj-$(CONFIG_PPC_BOOK3S_64) += init_book3s_64.o +obj-$(CONFIG_PPC_BOOK3E_64) += init_book3e_64.o diff --git a/arch/powerpc/mm/kasan/init_book3e_64.c b/arch/powerpc/mm/kasan/init_book3e_64.c new file mode 100644 index 0000000..11519e8 --- /dev/null +++ b/arch/powerpc/mm/kasan/init_book3e_64.c @@ -0,0 +1,133 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KASAN for 64-bit Book3e powerpc + * + * Copyright 2022, Christophe Leroy, CS GROUP France + */ + +#define DISABLE_BRANCH_PROFILING + +#include +#include +#include +#include + +#include + +static inline bool kasan_pud_table(p4d_t p4d) +{ + return p4d_page(p4d) == virt_to_page(lm_alias(kasan_early_shadow_pud)); +} + +static inline bool kasan_pmd_table(pud_t pud) +{ + return pud_page(pud) == virt_to_page(lm_alias(kasan_early_shadow_pmd)); +} + +static inline bool kasan_pte_table(pmd_t pmd) +{ + return pmd_page(pmd) == virt_to_page(lm_alias(kasan_early_shadow_pte)); +} + +static int __init kasan_map_kernel_page(unsigned long ea, unsigned long pa, pgprot_t prot) +{ + pgd_t *pgdp; + p4d_t *p4dp; + pud_t *pudp; + pmd_t *pmdp; + pte_t *ptep; + + pgdp = pgd_offset_k(ea); + p4dp = p4d_offset(pgdp, ea); + if (kasan_pud_table(*p4dp)) { + pudp = memblock_alloc(PUD_TABLE_SIZE, PUD_TABLE_SIZE); + memcpy(pudp, kasan_early_shadow_pud, PUD_TABLE_SIZE); + p4d_populate(&init_mm, p4dp, pudp); + } + pudp = pud_offset(p4dp, ea); + if (kasan_pmd_table(*pudp)) { + pmdp = memblock_alloc(PMD_TABLE_SIZE, PMD_TABLE_SIZE); + memcpy(pmdp, kasan_early_shadow_pmd, PMD_TABLE_SIZE); + pud_populate(&init_mm, pudp, pmdp); + } + pmdp = pmd_offset(pudp, ea); + if (kasan_pte_table(*pmdp)) { + ptep = memblock_alloc(PTE_TABLE_SIZE, PTE_TABLE_SIZE); + memcpy(ptep, kasan_early_shadow_pte, PTE_TABLE_SIZE); + pmd_populate_kernel(&init_mm, pmdp, ptep); + } + ptep = pte_offset_kernel(pmdp, ea); + + __set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, prot), 0); + + return 0; +} + +static void __init kasan_init_phys_region(void *start, void *end) +{ + unsigned long k_start, k_end, k_cur; + void *va; + + if (start >= end) + return; + + k_start = ALIGN_DOWN((unsigned long)kasan_mem_to_shadow(start), PAGE_SIZE); + k_end = ALIGN((unsigned long)kasan_mem_to_shadow(end), PAGE_SIZE); + + va = memblock_alloc(k_end - k_start, PAGE_SIZE); + for (k_cur = k_start; k_cur < k_end; k_cur += PAGE_SIZE, va += PAGE_SIZE) + kasan_map_kernel_page(k_cur, __pa(va), PAGE_KERNEL); +} + +void __init kasan_early_init(void) +{ + int i; + unsigned long addr; + pgd_t *pgd = pgd_offset_k(KASAN_SHADOW_START); + pte_t zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL); + + BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE)); + BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE)); + + for (i = 0; i < PTRS_PER_PTE; i++) + __set_pte_at(&init_mm, (unsigned long)kasan_early_shadow_page, + &kasan_early_shadow_pte[i], zero_pte, 0); + + for (i = 0; i < PTRS_PER_PMD; i++) + pmd_populate_kernel(&init_mm, &kasan_early_shadow_pmd[i], + kasan_early_shadow_pte); + + for (i = 0; i < PTRS_PER_PUD; i++) + pud_populate(&init_mm, &kasan_early_shadow_pud[i], + kasan_early_shadow_pmd); + + for (addr = KASAN_SHADOW_START; addr != KASAN_SHADOW_END; addr += PGDIR_SIZE) + p4d_populate(&init_mm, p4d_offset(pgd++, addr), kasan_early_shadow_pud); +} + +void __init kasan_init(void) +{ + phys_addr_t start, end; + u64 i; + pte_t zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL_RO); + + for_each_mem_range(i, &start, &end) + kasan_init_phys_region((void *)start, (void *)end); + + if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) + kasan_remove_zero_shadow((void *)VMALLOC_START, VMALLOC_SIZE); + + for (i = 0; i < PTRS_PER_PTE; i++) + __set_pte_at(&init_mm, (unsigned long)kasan_early_shadow_page, + &kasan_early_shadow_pte[i], zero_pte, 0); + + flush_tlb_kernel_range(KASAN_SHADOW_START, KASAN_SHADOW_END); + + memset(kasan_early_shadow_page, 0, PAGE_SIZE); + + /* Enable error messages */ + init_task.kasan_depth = 0; + pr_info("KASAN init done\n"); +} + +void __init kasan_late_init(void) { } diff --git a/arch/powerpc/mm/kasan/init_book3s_64.c b/arch/powerpc/mm/kasan/init_book3s_64.c index 0da5566..9300d64 100644 --- a/arch/powerpc/mm/kasan/init_book3s_64.c +++ b/arch/powerpc/mm/kasan/init_book3s_64.c @@ -99,4 +99,6 @@ void __init kasan_init(void) pr_info("KASAN init done\n"); } +void __init kasan_early_init(void) { } + void __init kasan_late_init(void) { } diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype index 9e2df4b..383ed4f 100644 --- a/arch/powerpc/platforms/Kconfig.cputype +++ b/arch/powerpc/platforms/Kconfig.cputype @@ -2,7 +2,6 @@ config PPC32 bool default y if !PPC64 - select KASAN_VMALLOC if KASAN && MODULES config PPC64 bool "64-bit kernel" -- 2.7.4