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authorAndrey Konovalov <andreyknvl@google.com>2021-02-24 12:05:26 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-24 13:38:31 -0800
commitf05842cfb9ae25b5e78c618429c4716d9e4d5fc8 (patch)
tree903a626a0cf734d328721455ef8e8b49b9ceb47e /arch
parent573a48092313dec7b254d9dbcc2db62167f00456 (diff)
kasan, arm64: allow using KUnit tests with HW_TAGS mode
On a high level, this patch allows running KUnit KASAN tests with the hardware tag-based KASAN mode. Internally, this change reenables tag checking at the end of each KASAN test that triggers a tag fault and leads to tag checking being disabled. Also simplify is_write calculation in report_tag_fault. With this patch KASAN tests are still failing for the hardware tag-based mode; fixes come in the next few patches. [andreyknvl@google.com: export HW_TAGS symbols for KUnit tests] Link: https://lkml.kernel.org/r/e7eeb252da408b08f0c81b950a55fb852f92000b.1613155970.git.andreyknvl@google.com Link: https://linux-review.googlesource.com/id/Id94dc9eccd33b23cda4950be408c27f879e474c8 Link: https://lkml.kernel.org/r/51b23112cf3fd62b8f8e9df81026fa2b15870501.1610733117.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Marco Elver <elver@google.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/include/asm/memory.h1
-rw-r--r--arch/arm64/include/asm/mte-kasan.h12
-rw-r--r--arch/arm64/kernel/mte.c12
-rw-r--r--arch/arm64/mm/fault.c20
4 files changed, 39 insertions, 6 deletions
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index bc09af26c1b8..c759faf7a1ff 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -244,6 +244,7 @@ static inline const void *__tag_set(const void *addr, u8 tag)
#ifdef CONFIG_KASAN_HW_TAGS
#define arch_enable_tagging() mte_enable_kernel()
+#define arch_set_tagging_report_once(state) mte_set_report_once(state)
#define arch_init_tags(max_tag) mte_init_tags(max_tag)
#define arch_get_random_tag() mte_get_random_tag()
#define arch_get_mem_tag(addr) mte_get_mem_tag(addr)
diff --git a/arch/arm64/include/asm/mte-kasan.h b/arch/arm64/include/asm/mte-kasan.h
index 26349a4b5e2e..3748d5bb88c0 100644
--- a/arch/arm64/include/asm/mte-kasan.h
+++ b/arch/arm64/include/asm/mte-kasan.h
@@ -32,6 +32,9 @@ void *mte_set_mem_tag_range(void *addr, size_t size, u8 tag);
void mte_enable_kernel(void);
void mte_init_tags(u64 max_tag);
+void mte_set_report_once(bool state);
+bool mte_report_once(void);
+
#else /* CONFIG_ARM64_MTE */
static inline u8 mte_get_ptr_tag(void *ptr)
@@ -60,6 +63,15 @@ static inline void mte_init_tags(u64 max_tag)
{
}
+static inline void mte_set_report_once(bool state)
+{
+}
+
+static inline bool mte_report_once(void)
+{
+ return false;
+}
+
#endif /* CONFIG_ARM64_MTE */
#endif /* __ASSEMBLY__ */
diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c
index 80b62fe49dcf..2cfc850809ce 100644
--- a/arch/arm64/kernel/mte.c
+++ b/arch/arm64/kernel/mte.c
@@ -25,6 +25,8 @@
u64 gcr_kernel_excl __ro_after_init;
+static bool report_fault_once = true;
+
static void mte_sync_page_tags(struct page *page, pte_t *ptep, bool check_swap)
{
pte_t old_pte = READ_ONCE(*ptep);
@@ -158,6 +160,16 @@ void mte_enable_kernel(void)
isb();
}
+void mte_set_report_once(bool state)
+{
+ WRITE_ONCE(report_fault_once, state);
+}
+
+bool mte_report_once(void)
+{
+ return READ_ONCE(report_fault_once);
+}
+
static void update_sctlr_el1_tcf0(u64 tcf0)
{
/* ISB required for the kernel uaccess routines */
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 2e339f0bd958..dc9f96442edc 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -302,12 +302,24 @@ static void die_kernel_fault(const char *msg, unsigned long addr,
static void report_tag_fault(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
- bool is_write = ((esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT) != 0;
+ static bool reported;
+ bool is_write;
+
+ if (READ_ONCE(reported))
+ return;
+
+ /*
+ * This is used for KASAN tests and assumes that no MTE faults
+ * happened before running the tests.
+ */
+ if (mte_report_once())
+ WRITE_ONCE(reported, true);
/*
* SAS bits aren't set for all faults reported in EL1, so we can't
* find out access size.
*/
+ is_write = !!(esr & ESR_ELx_WNR);
kasan_report(addr, 0, is_write, regs->pc);
}
#else
@@ -319,12 +331,8 @@ static inline void report_tag_fault(unsigned long addr, unsigned int esr,
static void do_tag_recovery(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
- static bool reported;
- if (!READ_ONCE(reported)) {
- report_tag_fault(addr, esr, regs);
- WRITE_ONCE(reported, true);
- }
+ report_tag_fault(addr, esr, regs);
/*
* Disable MTE Tag Checking on the local CPU for the current EL.