KASAN support for RISC-V
Subsystems (5)
v3 cover KASAN support for RISC-V
KASAN is an important runtime memory debugging feature in linux kernel which can detect use-after-free and out-of-bounds problems.
Changes in v2:
- Remove the porting of memmove and exclude the check instead.
- Fix some code noted by Christoph Hellwig
Changes in v3:
- Update the KASAN documentation to mention that riscv is supported.
Nick Hu (3):
kasan: Archs don't check memmove if not support it.
riscv: Add KASAN support
kasan: Add riscv to KASAN documentation.
Documentation/dev-tools/kasan.rst | 4 +- arch/riscv/Kconfig | 1 + arch/riscv/include/asm/kasan.h | 27 ++++++++ arch/riscv/include/asm/pgtable-64.h | 5 ++ arch/riscv/include/asm/string.h | 9 +++ arch/riscv/kernel/head.S | 3 + arch/riscv/kernel/riscv_ksyms.c | 2 + arch/riscv/kernel/setup.c | 5 ++ arch/riscv/kernel/vmlinux.lds.S | 1 + arch/riscv/lib/memcpy.S | 5 +- arch/riscv/lib/memset.S | 5 +- arch/riscv/mm/Makefile | 6 ++ arch/riscv/mm/kasan_init.c | 104 ++++++++++++++++++++++++++++ mm/kasan/common.c | 2 + 14 files changed, 173 insertions(+), 6 deletions(-) create mode 100644 arch/riscv/include/asm/kasan.h create mode 100644 arch/riscv/mm/kasan_init.c
Signature · 7 lines
2.17.0 _______________________________________________ linux-riscv mailing list [email protected] http://lists.infradead.org/mailman/listinfo/linux-riscv
PATCH v3 1/3 kasan: Archs don't check memmove if not support it.
Skip the memmove checking for those archs who don't support it.
--- mm/kasan/common.c | 2 ++ 1 file changed, 2 insertions(+)
mm/kasan/common.c +2 -0
@@ -107,6 +107,7 @@ void *memset(void *addr, int c, size_t len)return __memset (addr, c, len); } +#ifdef __HAVE_ARCH_MEMMOVE#undef memmovevoid *memmove (void *dest,const void *src,size_t len) {
@@ -115,6 +116,7 @@ void *memmove(void *dest, const void *src, size_t len) return __memmove(dest, src, len); } +#endif #undef memcpyvoid *memcpy (void *dest,const void *src,size_t len)
Signature · 7 lines
2.17.0 _______________________________________________ linux-riscv mailing list [email protected] http://lists.infradead.org/mailman/listinfo/linux-riscv
Re: [PATCH v3 1/3] kasan: Archs don't check memmove if not support it.
Quoted 20 lines · On Mon, 07 Oct 2019 23:11:51 PDT (-0700), [email protected] wrote:
Skip the memmove checking for those archs who don't support it.
Signed-off-by Nick Hu <[email protected]>--- mm/kasan/common.c | 2 ++ 1 file changed, 2 insertions(+)mm/kasan/common.c +1
-0@@ -107,6 +107,7 @@ void *memset(void *addr, int c, size_t len)return __memset (addr, c, len); } +#ifdef __HAVE_ARCH_MEMMOVE#undef memmovevoid *memmove (void *dest,const void *src,size_t len) {
mm/kasan/common.c void *memmove(void *dest, const void *src, size_t len) · line 122
Quoted 7 lines
mm/kasan/common.c +1
-0@@ -115,6 +116,7 @@ void *memmove(void *dest, const void *src, size_t len) return __memmove(dest, src, len); } +#endif #undef memcpyvoid *memcpy (void *dest,const void *src,size_t len)
I think this is backwards: we shouldn't be defining an arch-specific memmove symbol when KASAN is enabled. If we do it this way then we're defeating the memmove checks, which doesn't seem like the right way to go.
Re: [PATCH v3 1/3] kasan: Archs don't check memmove if not support it.
In reply to Nick HuQuoted 1 line · Nick Hu
Skip the memmove checking for those archs who don't support it.
The patch is fine but the changelog sounds misleading. We don't skip memmove checking. If arch don't have memmove than the C implementation from lib/string.c used. It's instrumented by compiler so it's checked and we simply don't need that KASAN's memmove with manual checks.
Quoted 26 lines
Signed-off-by Nick Hu <[email protected]>--- mm/kasan/common.c | 2 ++ 1 file changed, 2 insertions(+)mm/kasan/common.c +2
-0@@ -107,6 +107,7 @@ void *memset(void *addr, int c, size_t len)return __memset (addr, c, len); } +#ifdef __HAVE_ARCH_MEMMOVE#undef memmovevoid *memmove (void *dest,const void *src,size_t len) {@@ -115,6 +116,7 @@ void *memmove(void *dest, const void *src, size_t len) return __memmove(dest, src, len); } +#endif #undef memcpyvoid *memcpy (void *dest,const void *src,size_t len)
Re: [PATCH v3 1/3] kasan: Archs don't check memmove if not support it.
Quoted 7 lines · Andrey Ryabinin
Quoted 1 line · Nick Hu
Skip the memmove checking for those archs who don't support it.
The patch is fine but the changelog sounds misleading. We don't skip memmove checking. If arch don't have memmove than the C implementation from
lib/string.cused. It's instrumented by compiler so it's checked and we simply don't need that KASAN's memmove with manual checks.
Thanks Andrey. Nick, could you please update the patch description?
- Paul
Re: [PATCH v3 1/3] kasan: Archs don't check memmove if not support it.
Quoted 5 lines · Paul Walmsley
Quoted 3 lines · Andrey Ryabinin
Quoted 1 line · Nick Hu
Skip the memmove checking for those archs who don't support it.
Quoted 9 lines
Quoted 4 lines
The patch is fine but the changelog sounds misleading. We don't skip memmove checking. If arch don't have memmove than the C implementation from
lib/string.cused. It's instrumented by compiler so it's checked and we simply don't need that KASAN's memmove with manual checks.Thanks Andrey. Nick, could you please update the patch description?
- Paul
Thanks! I would update the description in v4 patch.
Nick
PATCH v3 2/3 riscv: Add KASAN support
In reply to Nick HuThis patch ports the feature Kernel Address SANitizer (KASAN).
Note: The start address of shadow memory is at the beginning of kernel space, which is 2^64 - (2^39 / 2) in SV39. The size of the kernel space is 2^38 bytes so the size of shadow memory should be 2^38 / 8. Thus, the shadow memory would not overlap with the fixmap area.
There are currently two limitations in this port,
1. RV64 only: KASAN need large address space for extra shadow memory region.
2. KASAN can't debug the modules since the modules are allocated in VMALLOC area. We mapped the shadow memory, which corresponding to VMALLOC area, to the kasan_early_shadow_page because we don't have enough physical space for all the shadow memory corresponding to VMALLOC area.
--- arch/riscv/Kconfig | 1 + arch/riscv/include/asm/kasan.h | 27 ++++++++ arch/riscv/include/asm/pgtable-64.h | 5 ++ arch/riscv/include/asm/string.h | 9 +++ arch/riscv/kernel/head.S | 3 + arch/riscv/kernel/riscv_ksyms.c | 2 + arch/riscv/kernel/setup.c | 5 ++ arch/riscv/kernel/vmlinux.lds.S | 1 + arch/riscv/lib/memcpy.S | 5 +- arch/riscv/lib/memset.S | 5 +- arch/riscv/mm/Makefile | 6 ++ arch/riscv/mm/kasan_init.c | 104 ++++++++++++++++++++++++++++ 12 files changed, 169 insertions(+), 4 deletions(-) create mode 100644 arch/riscv/include/asm/kasan.h create mode 100644 arch/riscv/mm/kasan_init.c
arch/riscv/Kconfig +1 -0
@@ -61,6 +61,7 @@ config RISCV select SPARSEMEM_STATIC if 32BIT select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU select HAVE_ARCH_MMAP_RND_BITS + select HAVE_ARCH_KASAN if MMU && 64BIT config ARCH_MMAP_RND_BITS_MIN default 18 if 64BIT
arch/riscv/include/asm/kasan.h new file +27 -0
@@ -0,0 +1,27 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (C) 2019 Andes Technology Corporation */ + +#ifndef __ASM_KASAN_H +#define __ASM_KASAN_H + +#ifndef __ASSEMBLY__ + +#ifdef CONFIG_KASAN + +#include <asm/pgtable.h> + +#define KASAN_SHADOW_SCALE_SHIFT 3 + +#define KASAN_SHADOW_SIZE (UL(1) << (38 - KASAN_SHADOW_SCALE_SHIFT)) +#define KASAN_SHADOW_START 0xffffffc000000000 // 2^64 - 2^38 +#define KASAN_SHADOW_END (KASAN_SHADOW_START + KASAN_SHADOW_SIZE) + +#define KASAN_SHADOW_OFFSET (KASAN_SHADOW_END - (1ULL << \ + (64 - KASAN_SHADOW_SCALE_SHIFT))) + +void kasan_init (void ); +asmlinkage void kasan_early_init(void); + +#endif +#endif +#endif /* __ASM_KASAN_H */
arch/riscv/include/asm/pgtable-64.h +5 -0
@@ -59,6 +59,11 @@ static inline unsigned long pud_page_vaddr(pud_t pud)return (unsigned long )pfn_to_virt (pud_val (pud) >> _PAGE_PFN_SHIFT); } +static inline struct page *pud_page (pud_t pud) +{ +return pfn_to_page (pud_val (pud) >> _PAGE_PFN_SHIFT); +} +#define pmd_index (addr) (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))static inline pmd_t *pmd_offset (pud_t *pud,unsigned long addr)
arch/riscv/include/asm/string.h +9 -0
@@ -11,8 +11,17 @@#define __HAVE_ARCH_MEMSET extern asmlinkage void *memset(void *, int, size_t); +extern asmlinkage void *__memset(void *, int, size_t);#define __HAVE_ARCH_MEMCPY extern asmlinkage void *memcpy(void *, const void *, size_t); +extern asmlinkage void *__memcpy(void *, const void *, size_t); +// For those files which don't want to check by kasan. +#if defined(CONFIG_KASAN ) && !defined(__SANITIZE_ADDRESS__) + +#define memcpy (dst, src, len) __memcpy(dst, src, len) +#define memset (s, c, n) __memset(s, c, n) + +#endif #endif /* _ASM_RISCV_STRING_H */
arch/riscv/kernel/head.S +3 -0
@@ -102,6 +102,9 @@ clear_bss_done: sw zero, TASK_TI_CPU(tp) la sp, init_thread_union + THREAD_SIZE +#ifdef CONFIG_KASAN + call kasan_early_init +#endif /* Start the kernel */ call parse_dtb tail start_kernel
arch/riscv/kernel/riscv_ksyms.c +2 -0
@@ -14,3 +14,5 @@ EXPORT_SYMBOL(__asm_copy_to_user);EXPORT_SYMBOL (__asm_copy_from_user);EXPORT_SYMBOL (memset);EXPORT_SYMBOL (memcpy); +EXPORT_SYMBOL (__memset); +EXPORT_SYMBOL (__memcpy);
arch/riscv/kernel/setup.c +5 -0
@@ -23,6 +23,7 @@#include <asm/smp.h> #include <asm/tlbflush.h> #include <asm/thread_info.h> +#include <asm/kasan.h> #ifdef CONFIG_DUMMY_CONSOLE struct screen_info screen_info = {
@@ -70,6 +71,10 @@ void __init setup_arch(char **cmdline_p)swiotlb_init (1 );#endif +#ifdef CONFIG_KASAN +kasan_init (); +#endif +#ifdef CONFIG_SMP setup_smp ();#endif
arch/riscv/kernel/vmlinux.lds.S +1 -0
@@ -46,6 +46,7 @@ SECTIONS KPROBES_TEXT ENTRY_TEXT IRQENTRY_TEXT + SOFTIRQENTRY_TEXT *(.fixup) _etext = .; }
arch/riscv/lib/memcpy.S +3 -2
@@ -7,7 +7,8 @@ #include <asm/asm.h> /* void *memcpy(void *, const void *, size_t) */ -ENTRY(memcpy) +ENTRY(__memcpy) +WEAK(memcpy) move t6, a0 /* Preserve return value */ /* Defer to byte-oriented copy for small sizes */
@@ -104,4 +105,4 @@ ENTRY(memcpy) bltu a1, a3, 5b 6: ret -END(memcpy) +END(__memcpy)
arch/riscv/lib/memset.S +3 -2
@@ -8,7 +8,8 @@ #include <asm/asm.h> /* void *memset(void *, int, size_t) */ -ENTRY(memset) +ENTRY(__memset) +WEAK(memset) move t0, a0 /* Preserve return value */ /* Defer to byte-oriented fill for small sizes */
@@ -109,4 +110,4 @@ ENTRY(memset) bltu t0, a3, 5b 6: ret -END(memset) +END(__memset)
arch/riscv/mm/Makefile +6 -0
@@ -17,3 +17,9 @@ ifeq ($(CONFIG_MMU),y) obj-$(CONFIG_SMP) += tlbflush.o endif obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o +obj-$(CONFIG_KASAN) += kasan_init.o + +ifdef CONFIG_KASAN +KASAN_SANITIZE_kasan_init.o := n +KASAN_SANITIZE_init.o := n +endif
arch/riscv/mm/kasan_init.c new file +104 -0
104 lines not on this page · raw message
Signature · 7 lines
2.17.0 _______________________________________________ linux-riscv mailing list [email protected] http://lists.infradead.org/mailman/listinfo/linux-riscv
Re: [PATCH v3 2/3] riscv: Add KASAN support
Nick Hu <[email protected]> 於 2019年10月8日 週二 下午2:17寫道：
Quoted 299 lines
This patch ports the feature Kernel Address SANitizer (KASAN).
Note: The start address of shadow memory is at the beginning of kernel space, which is 2^64 - (2^39 / 2) in SV39. The size of the kernel space is 2^38 bytes so the size of shadow memory should be 2^38 / 8. Thus, the shadow memory would not overlap with the fixmap area.
There are currently two limitations in this port,
1. RV64 only: KASAN need large address space for extra shadow memory region.
2. KASAN can't debug the modules since the modules are allocated in VMALLOC area. We mapped the shadow memory, which corresponding to VMALLOC area, to the
kasan_early_shadow_pagebecause we don't have enough physical space for all the shadow memory corresponding to VMALLOC area.Signed-off-by Nick Hu <[email protected]>--- arch/riscv/Kconfig | 1 + arch/riscv/include/asm/kasan.h | 27 ++++++++ arch/riscv/include/asm/pgtable-64.h | 5 ++ arch/riscv/include/asm/string.h | 9 +++ arch/riscv/kernel/head.S | 3 + arch/riscv/kernel/riscv_ksyms.c | 2 + arch/riscv/kernel/setup.c | 5 ++ arch/riscv/kernel/vmlinux.lds.S | 1 + arch/riscv/lib/memcpy.S | 5 +- arch/riscv/lib/memset.S | 5 +- arch/riscv/mm/Makefile | 6 ++ arch/riscv/mm/kasan_init.c | 104 ++++++++++++++++++++++++++++ 12 files changed, 169 insertions(+), 4 deletions(-) create mode 100644 arch/riscv/include/asm/kasan.h create mode 100644 arch/riscv/mm/kasan_init.carch/riscv/Kconfig +1
-0@@ -61,6 +61,7 @@ config RISCV select SPARSEMEM_STATIC if 32BIT select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU select HAVE_ARCH_MMAP_RND_BITS + select HAVE_ARCH_KASAN if MMU && 64BIT config ARCH_MMAP_RND_BITS_MIN default 18 if 64BITarch/riscv/include/asm/kasan.h new file +27
-0@@ -0,0 +1,27 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (C) 2019 Andes Technology Corporation */ + +#ifndef __ASM_KASAN_H +#define __ASM_KASAN_H + +#ifndef __ASSEMBLY__ + +#ifdef CONFIG_KASAN + +#include <asm/pgtable.h> + +#define KASAN_SHADOW_SCALE_SHIFT 3 + +#define KASAN_SHADOW_SIZE (UL(1) << (38 - KASAN_SHADOW_SCALE_SHIFT)) +#define KASAN_SHADOW_START 0xffffffc000000000 // 2^64 - 2^38 +#define KASAN_SHADOW_END (KASAN_SHADOW_START + KASAN_SHADOW_SIZE) + +#define KASAN_SHADOW_OFFSET (KASAN_SHADOW_END - (1ULL << \ + (64 - KASAN_SHADOW_SCALE_SHIFT))) + +void kasan_init (void ); +asmlinkage void kasan_early_init(void); + +#endif +#endif +#endif /* __ASM_KASAN_H */ arch/riscv/include/asm/pgtable-64.h +5
-0@@ -59,6 +59,11 @@ static inline unsigned long pud_page_vaddr(pud_t pud)return (unsigned long )pfn_to_virt (pud_val (pud) >> _PAGE_PFN_SHIFT); } +static inline struct page *pud_page (pud_t pud) +{ +return pfn_to_page (pud_val (pud) >> _PAGE_PFN_SHIFT); +} +#define pmd_index (addr) (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))static inline pmd_t *pmd_offset (pud_t *pud,unsigned long addr)arch/riscv/include/asm/string.h +9
-0@@ -11,8 +11,17 @@#define __HAVE_ARCH_MEMSET extern asmlinkage void *memset(void *, int, size_t); +extern asmlinkage void *__memset(void *, int, size_t);#define __HAVE_ARCH_MEMCPY extern asmlinkage void *memcpy(void *, const void *, size_t); +extern asmlinkage void *__memcpy(void *, const void *, size_t); +// For those files which don't want to check by kasan. +#if defined(CONFIG_KASAN ) && !defined(__SANITIZE_ADDRESS__) + +#define memcpy (dst, src, len) __memcpy(dst, src, len) +#define memset (s, c, n) __memset(s, c, n) + +#endif #endif /* _ASM_RISCV_STRING_H */ arch/riscv/kernel/head.S +3
-0@@ -102,6 +102,9 @@ clear_bss_done: sw zero, TASK_TI_CPU(tp) la sp, init_thread_union + THREAD_SIZE +#ifdef CONFIG_KASAN + call kasan_early_init +#endif /* Start the kernel */ call parse_dtb tail start_kernelarch/riscv/kernel/riscv_ksyms.c +2
-0@@ -14,3 +14,5 @@ EXPORT_SYMBOL(__asm_copy_to_user);EXPORT_SYMBOL (__asm_copy_from_user);EXPORT_SYMBOL (memset);EXPORT_SYMBOL (memcpy); +EXPORT_SYMBOL (__memset); +EXPORT_SYMBOL (__memcpy);arch/riscv/kernel/setup.c +5
-0@@ -23,6 +23,7 @@#include <asm/smp.h> #include <asm/tlbflush.h> #include <asm/thread_info.h> +#include <asm/kasan.h> #ifdef CONFIG_DUMMY_CONSOLE struct screen_info screen_info = {@@ -70,6 +71,10 @@ void __init setup_arch(char **cmdline_p)swiotlb_init (1 );#endif +#ifdef CONFIG_KASAN +kasan_init (); +#endif +#ifdef CONFIG_SMP setup_smp ();#endif arch/riscv/kernel/vmlinux.lds.S +1
-0@@ -46,6 +46,7 @@ SECTIONS KPROBES_TEXT ENTRY_TEXT IRQENTRY_TEXT + SOFTIRQENTRY_TEXT *(.fixup) _etext = .; }arch/riscv/lib/memcpy.S +3
-2@@ -7,7 +7,8 @@ #include <asm/asm.h> /* void *memcpy(void *, const void *, size_t) */ -ENTRY(memcpy) +ENTRY(__memcpy) +WEAK(memcpy) move t6, a0 /* Preserve return value */ /* Defer to byte-oriented copy for small sizes */@@ -104,4 +105,4 @@ ENTRY(memcpy) bltu a1, a3, 5b 6: ret -END(memcpy) +END(__memcpy)arch/riscv/lib/memset.S +3
-2@@ -8,7 +8,8 @@ #include <asm/asm.h> /* void *memset(void *, int, size_t) */ -ENTRY(memset) +ENTRY(__memset) +WEAK(memset) move t0, a0 /* Preserve return value */ /* Defer to byte-oriented fill for small sizes */@@ -109,4 +110,4 @@ ENTRY(memset) bltu t0, a3, 5b 6: ret -END(memset) +END(__memset)arch/riscv/mm/Makefile +6
-0@@ -17,3 +17,9 @@ ifeq ($(CONFIG_MMU),y) obj-$(CONFIG_SMP) += tlbflush.o endif obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o +obj-$(CONFIG_KASAN) += kasan_init.o + +ifdef CONFIG_KASAN +KASAN_SANITIZE_kasan_init.o := n +KASAN_SANITIZE_init.o := n +endifarch/riscv/mm/kasan_init.c new file +61
-0@@ -0,0 +1,104 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2019 Andes Technology Corporation + +#include <linux/pfn.h> +#include <linux/init_task.h> +#include <linux/kasan.h> +#include <linux/kernel.h> +#include <linux/memblock.h> +#include <asm/tlbflush.h> +#include <asm/pgtable.h> +#include <asm/fixmap.h> + +extern pgd_t early_pg_dir[PTRS_PER_PGD ]; +asmlinkage void __init kasan_early_init(void) +{ +uintptr_t i; +pgd_t *pgd = early_pg_dir +pgd_index (KASAN_SHADOW_START ); + +for (i =0 ; i <PTRS_PER_PTE ; ++i) +set_pte (kasan_early_shadow_pte + i, +mk_pte (virt_to_page (kasan_early_shadow_page), +PAGE_KERNEL )); + +for (i =0 ; i <PTRS_PER_PMD ; ++i) +set_pmd (kasan_early_shadow_pmd + i, +pfn_pmd (PFN_DOWN (__pa ((uintptr_t )kasan_early_shadow_pte)), +__pgprot (_PAGE_TABLE))); + +for (i =KASAN_SHADOW_START ; i <KASAN_SHADOW_END ; + i +=PGDIR_SIZE , ++pgd) +set_pgd (pgd, +pfn_pgd (PFN_DOWN (__pa (((uintptr_t )kasan_early_shadow_pmd))), +__pgprot (_PAGE_TABLE))); + +// init for swapper_pg_dir + pgd =pgd_offset_k (KASAN_SHADOW_START ); + +for (i =KASAN_SHADOW_START ; i <KASAN_SHADOW_END ; + i +=PGDIR_SIZE , ++pgd) +set_pgd (pgd, +pfn_pgd (PFN_DOWN (__pa (((uintptr_t )kasan_early_shadow_pmd))), +__pgprot (_PAGE_TABLE))); + +flush_tlb_all (); +} + +static void __init populate (void *start,void *end) +{ +unsigned long i; +unsigned long vaddr = (unsigned long )start &PAGE_MASK ; +unsigned long vend =PAGE_ALIGN ((unsigned long )end); +unsigned long n_pages = (vend - vaddr) /PAGE_SIZE ; +unsigned long n_pmds = + (n_pages %PTRS_PER_PTE ) ? n_pages /PTRS_PER_PTE +1 : + n_pages /PTRS_PER_PTE ; +pgd_t *pgd =pgd_offset_k (vaddr); +pmd_t *pmd =memblock_alloc (n_pmds *sizeof (pmd_t),PAGE_SIZE ); +pte_t *pte =memblock_alloc (n_pages *sizeof (pte_t),PAGE_SIZE ); + +for (i =0 ; i < n_pages; i++) { +phys_addr_t phys =memblock_phys_alloc (PAGE_SIZE ,PAGE_SIZE );
arch/riscv/mm/kasan_init.c line 71
Quoted 10 lines
arch/riscv/mm/kasan_init.c new file +10
-0+ +set_pte (pte + i,pfn_pte (PHYS_PFN (phys),PAGE_KERNEL )); + } + +for (i =0 ; i < n_pages; ++pmd, i +=PTRS_PER_PTE ) +set_pmd (pmd,pfn_pmd (PFN_DOWN (__pa ((uintptr_t )(pte + i))), +__pgprot (_PAGE_TABLE))); + +for (i = vaddr; i < vend; i +=PGDIR_SIZE , ++pgd) + set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(((uintptr_t)pmd))),
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
arch/riscv/mm/kasan_init.c line 73
Quoted 2 lines
arch/riscv/mm/kasan_init.c new file +2
-0+ __pgprot(_PAGE_TABLE))); +
Hi Nick,
I verify this patch in Qemu and Unleashed board.
I found it works well if DRAM size is less than 4GB. It will get an access fault if the DRAM size is larger than 4GB.
I spend some time to debug this case and I found it hang in the following memset().
It is because the mapping is not created correctly. I check the page table creating logic again and I found it always sets the last pmd here.
Re: [PATCH v3 2/3] riscv: Add KASAN support
Quoted 320 lines · Greentime Hu
Nick Hu <[email protected]> 於 2019年10月8日 週二 下午2:17寫道：
Quoted 299 lines
This patch ports the feature Kernel Address SANitizer (KASAN).
Note: The start address of shadow memory is at the beginning of kernel space, which is 2^64 - (2^39 / 2) in SV39. The size of the kernel space is 2^38 bytes so the size of shadow memory should be 2^38 / 8. Thus, the shadow memory would not overlap with the fixmap area.
There are currently two limitations in this port,
1. RV64 only: KASAN need large address space for extra shadow memory region.
2. KASAN can't debug the modules since the modules are allocated in VMALLOC area. We mapped the shadow memory, which corresponding to VMALLOC area, to the
kasan_early_shadow_pagebecause we don't have enough physical space for all the shadow memory corresponding to VMALLOC area.Signed-off-by Nick Hu <[email protected]>--- arch/riscv/Kconfig | 1 + arch/riscv/include/asm/kasan.h | 27 ++++++++ arch/riscv/include/asm/pgtable-64.h | 5 ++ arch/riscv/include/asm/string.h | 9 +++ arch/riscv/kernel/head.S | 3 + arch/riscv/kernel/riscv_ksyms.c | 2 + arch/riscv/kernel/setup.c | 5 ++ arch/riscv/kernel/vmlinux.lds.S | 1 + arch/riscv/lib/memcpy.S | 5 +- arch/riscv/lib/memset.S | 5 +- arch/riscv/mm/Makefile | 6 ++ arch/riscv/mm/kasan_init.c | 104 ++++++++++++++++++++++++++++ 12 files changed, 169 insertions(+), 4 deletions(-) create mode 100644 arch/riscv/include/asm/kasan.h create mode 100644 arch/riscv/mm/kasan_init.carch/riscv/Kconfig +1
-0@@ -61,6 +61,7 @@ config RISCV select SPARSEMEM_STATIC if 32BIT select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU select HAVE_ARCH_MMAP_RND_BITS + select HAVE_ARCH_KASAN if MMU && 64BIT config ARCH_MMAP_RND_BITS_MIN default 18 if 64BITarch/riscv/include/asm/kasan.h new file +27
-0@@ -0,0 +1,27 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (C) 2019 Andes Technology Corporation */ + +#ifndef __ASM_KASAN_H +#define __ASM_KASAN_H + +#ifndef __ASSEMBLY__ + +#ifdef CONFIG_KASAN + +#include <asm/pgtable.h> + +#define KASAN_SHADOW_SCALE_SHIFT 3 + +#define KASAN_SHADOW_SIZE (UL(1) << (38 - KASAN_SHADOW_SCALE_SHIFT)) +#define KASAN_SHADOW_START 0xffffffc000000000 // 2^64 - 2^38 +#define KASAN_SHADOW_END (KASAN_SHADOW_START + KASAN_SHADOW_SIZE) + +#define KASAN_SHADOW_OFFSET (KASAN_SHADOW_END - (1ULL << \ + (64 - KASAN_SHADOW_SCALE_SHIFT))) + +void kasan_init (void ); +asmlinkage void kasan_early_init(void); + +#endif +#endif +#endif /* __ASM_KASAN_H */ arch/riscv/include/asm/pgtable-64.h +5
-0@@ -59,6 +59,11 @@ static inline unsigned long pud_page_vaddr(pud_t pud)return (unsigned long )pfn_to_virt (pud_val (pud) >> _PAGE_PFN_SHIFT); } +static inline struct page *pud_page (pud_t pud) +{ +return pfn_to_page (pud_val (pud) >> _PAGE_PFN_SHIFT); +} +#define pmd_index (addr) (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))static inline pmd_t *pmd_offset (pud_t *pud,unsigned long addr)arch/riscv/include/asm/string.h +9
-0@@ -11,8 +11,17 @@#define __HAVE_ARCH_MEMSET extern asmlinkage void *memset(void *, int, size_t); +extern asmlinkage void *__memset(void *, int, size_t);#define __HAVE_ARCH_MEMCPY extern asmlinkage void *memcpy(void *, const void *, size_t); +extern asmlinkage void *__memcpy(void *, const void *, size_t); +// For those files which don't want to check by kasan. +#if defined(CONFIG_KASAN ) && !defined(__SANITIZE_ADDRESS__) + +#define memcpy (dst, src, len) __memcpy(dst, src, len) +#define memset (s, c, n) __memset(s, c, n) + +#endif #endif /* _ASM_RISCV_STRING_H */ arch/riscv/kernel/head.S +3
-0@@ -102,6 +102,9 @@ clear_bss_done: sw zero, TASK_TI_CPU(tp) la sp, init_thread_union + THREAD_SIZE +#ifdef CONFIG_KASAN + call kasan_early_init +#endif /* Start the kernel */ call parse_dtb tail start_kernelarch/riscv/kernel/riscv_ksyms.c +2
-0@@ -14,3 +14,5 @@ EXPORT_SYMBOL(__asm_copy_to_user);EXPORT_SYMBOL (__asm_copy_from_user);EXPORT_SYMBOL (memset);EXPORT_SYMBOL (memcpy); +EXPORT_SYMBOL (__memset); +EXPORT_SYMBOL (__memcpy);arch/riscv/kernel/setup.c +5
-0@@ -23,6 +23,7 @@#include <asm/smp.h> #include <asm/tlbflush.h> #include <asm/thread_info.h> +#include <asm/kasan.h> #ifdef CONFIG_DUMMY_CONSOLE struct screen_info screen_info = {@@ -70,6 +71,10 @@ void __init setup_arch(char **cmdline_p)swiotlb_init (1 );#endif +#ifdef CONFIG_KASAN +kasan_init (); +#endif +#ifdef CONFIG_SMP setup_smp ();#endif arch/riscv/kernel/vmlinux.lds.S +1
-0@@ -46,6 +46,7 @@ SECTIONS KPROBES_TEXT ENTRY_TEXT IRQENTRY_TEXT + SOFTIRQENTRY_TEXT *(.fixup) _etext = .; }arch/riscv/lib/memcpy.S +3
-2@@ -7,7 +7,8 @@ #include <asm/asm.h> /* void *memcpy(void *, const void *, size_t) */ -ENTRY(memcpy) +ENTRY(__memcpy) +WEAK(memcpy) move t6, a0 /* Preserve return value */ /* Defer to byte-oriented copy for small sizes */@@ -104,4 +105,4 @@ ENTRY(memcpy) bltu a1, a3, 5b 6: ret -END(memcpy) +END(__memcpy)arch/riscv/lib/memset.S +3
-2@@ -8,7 +8,8 @@ #include <asm/asm.h> /* void *memset(void *, int, size_t) */ -ENTRY(memset) +ENTRY(__memset) +WEAK(memset) move t0, a0 /* Preserve return value */ /* Defer to byte-oriented fill for small sizes */@@ -109,4 +110,4 @@ ENTRY(memset) bltu t0, a3, 5b 6: ret -END(memset) +END(__memset)arch/riscv/mm/Makefile +6
-0@@ -17,3 +17,9 @@ ifeq ($(CONFIG_MMU),y) obj-$(CONFIG_SMP) += tlbflush.o endif obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o +obj-$(CONFIG_KASAN) += kasan_init.o + +ifdef CONFIG_KASAN +KASAN_SANITIZE_kasan_init.o := n +KASAN_SANITIZE_init.o := n +endifarch/riscv/mm/kasan_init.c new file +61
-0@@ -0,0 +1,104 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2019 Andes Technology Corporation + +#include <linux/pfn.h> +#include <linux/init_task.h> +#include <linux/kasan.h> +#include <linux/kernel.h> +#include <linux/memblock.h> +#include <asm/tlbflush.h> +#include <asm/pgtable.h> +#include <asm/fixmap.h> + +extern pgd_t early_pg_dir[PTRS_PER_PGD ]; +asmlinkage void __init kasan_early_init(void) +{ +uintptr_t i; +pgd_t *pgd = early_pg_dir +pgd_index (KASAN_SHADOW_START ); + +for (i =0 ; i <PTRS_PER_PTE ; ++i) +set_pte (kasan_early_shadow_pte + i, +mk_pte (virt_to_page (kasan_early_shadow_page), +PAGE_KERNEL )); + +for (i =0 ; i <PTRS_PER_PMD ; ++i) +set_pmd (kasan_early_shadow_pmd + i, +pfn_pmd (PFN_DOWN (__pa ((uintptr_t )kasan_early_shadow_pte)), +__pgprot (_PAGE_TABLE))); + +for (i =KASAN_SHADOW_START ; i <KASAN_SHADOW_END ; + i +=PGDIR_SIZE , ++pgd) +set_pgd (pgd, +pfn_pgd (PFN_DOWN (__pa (((uintptr_t )kasan_early_shadow_pmd))), +__pgprot (_PAGE_TABLE))); + +// init for swapper_pg_dir + pgd =pgd_offset_k (KASAN_SHADOW_START ); + +for (i =KASAN_SHADOW_START ; i <KASAN_SHADOW_END ; + i +=PGDIR_SIZE , ++pgd) +set_pgd (pgd, +pfn_pgd (PFN_DOWN (__pa (((uintptr_t )kasan_early_shadow_pmd))), +__pgprot (_PAGE_TABLE))); + +flush_tlb_all (); +} + +static void __init populate (void *start,void *end) +{ +unsigned long i; +unsigned long vaddr = (unsigned long )start &PAGE_MASK ; +unsigned long vend =PAGE_ALIGN ((unsigned long )end); +unsigned long n_pages = (vend - vaddr) /PAGE_SIZE ; +unsigned long n_pmds = + (n_pages %PTRS_PER_PTE ) ? n_pages /PTRS_PER_PTE +1 : + n_pages /PTRS_PER_PTE ; +pgd_t *pgd =pgd_offset_k (vaddr); +pmd_t *pmd =memblock_alloc (n_pmds *sizeof (pmd_t),PAGE_SIZE ); +pte_t *pte =memblock_alloc (n_pages *sizeof (pte_t),PAGE_SIZE ); + +for (i =0 ; i < n_pages; i++) { +phys_addr_t phys =memblock_phys_alloc (PAGE_SIZE ,PAGE_SIZE );arch/riscv/mm/kasan_init.c line 71
Quoted 10 lines
arch/riscv/mm/kasan_init.c new file +10
-0+ +set_pte (pte + i,pfn_pte (PHYS_PFN (phys),PAGE_KERNEL )); + } + +for (i =0 ; i < n_pages; ++pmd, i +=PTRS_PER_PTE ) +set_pmd (pmd,pfn_pmd (PFN_DOWN (__pa ((uintptr_t )(pte + i))), +__pgprot (_PAGE_TABLE))); + +for (i = vaddr; i < vend; i +=PGDIR_SIZE , ++pgd) + set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(((uintptr_t)pmd))),^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
arch/riscv/mm/kasan_init.c line 73
Quoted 2 lines
arch/riscv/mm/kasan_init.c new file +2
-0+ __pgprot(_PAGE_TABLE))); +Hi Nick,
I verify this patch in Qemu and Unleashed board.
I found it works well if DRAM size is less than 4GB. It will get an access fault if the DRAM size is larger than 4GB.
Quoted 5 lines
I spend some time to debug this case and I found it hang in the following
memset().
It is because the mapping is not created correctly. I check the page table creating logic again and I found it always sets the last pmd here.
Hi Greentime,
Thanks! I would fix it in v4 patch.
Nick.
_______________________________________________
linux-riscv mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/linux-riscv
PATCH v3 3/3 kasan: Add riscv to KASAN documentation.
In reply to Nick HuAdd riscv to the KASAN documentation to mention that riscv is supporting generic kasan now.
--- Documentation/dev-tools/kasan.rst | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
Documentation/dev-tools/kasan.rst +2 -2
@@ -21,8 +21,8 @@ global variables yet. Tag-based KASAN is only supported in Clang and requires version 7.0.0 or later. -Currently generic KASAN is supported for the x86_64, arm64, xtensa and s390 -architectures, and tag-based KASAN is supported only for arm64. +Currently generic KASAN is supported for the x86_64, arm64, xtensa, s390 and +riscv architectures, and tag-based KASAN is supported only for arm64. Usage -----
Signature · 7 lines
2.17.0 _______________________________________________ linux-riscv mailing list [email protected] http://lists.infradead.org/mailman/listinfo/linux-riscv