diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-22 13:38:17 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-22 13:38:17 -0800 |
commit | 1375b9803e007842493c64d0d73d7dd0e385e17c (patch) | |
tree | bbdba09ad6c044f845a9dc553a88016417c8ad6b /arch/arm64/mm/fault.c | |
parent | c45647f9f562b52915b43b6bb447827cebf511bd (diff) | |
parent | 625d867347c9e84d1ac3c953e1b689f65b603bed (diff) |
Merge branch 'akpm' (patches from Andrew)
Merge KASAN updates from Andrew Morton.
This adds a new hardware tag-based mode to KASAN. The new mode is
similar to the existing software tag-based KASAN, but relies on arm64
Memory Tagging Extension (MTE) to perform memory and pointer tagging
(instead of shadow memory and compiler instrumentation).
By Andrey Konovalov and Vincenzo Frascino.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (60 commits)
kasan: update documentation
kasan, mm: allow cache merging with no metadata
kasan: sanitize objects when metadata doesn't fit
kasan: clarify comment in __kasan_kfree_large
kasan: simplify assign_tag and set_tag calls
kasan: don't round_up too much
kasan, mm: rename kasan_poison_kfree
kasan, mm: check kasan_enabled in annotations
kasan: add and integrate kasan boot parameters
kasan: inline (un)poison_range and check_invalid_free
kasan: open-code kasan_unpoison_slab
kasan: inline random_tag for HW_TAGS
kasan: inline kasan_reset_tag for tag-based modes
kasan: remove __kasan_unpoison_stack
kasan: allow VMAP_STACK for HW_TAGS mode
kasan, arm64: unpoison stack only with CONFIG_KASAN_STACK
kasan: introduce set_alloc_info
kasan: rename get_alloc/free_info
kasan: simplify quarantine_put call site
kselftest/arm64: check GCR_EL1 after context switch
...
Diffstat (limited to 'arch/arm64/mm/fault.c')
-rw-r--r-- | arch/arm64/mm/fault.c | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 2848952b178d..3c40da479899 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -14,6 +14,7 @@ #include <linux/mm.h> #include <linux/hardirq.h> #include <linux/init.h> +#include <linux/kasan.h> #include <linux/kprobes.h> #include <linux/uaccess.h> #include <linux/page-flags.h> @@ -33,6 +34,7 @@ #include <asm/debug-monitors.h> #include <asm/esr.h> #include <asm/kprobes.h> +#include <asm/mte.h> #include <asm/processor.h> #include <asm/sysreg.h> #include <asm/system_misc.h> @@ -296,6 +298,57 @@ static void die_kernel_fault(const char *msg, unsigned long addr, do_exit(SIGKILL); } +#ifdef CONFIG_KASAN_HW_TAGS +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; + + /* + * SAS bits aren't set for all faults reported in EL1, so we can't + * find out access size. + */ + kasan_report(addr, 0, is_write, regs->pc); +} +#else +/* Tag faults aren't enabled without CONFIG_KASAN_HW_TAGS. */ +static inline void report_tag_fault(unsigned long addr, unsigned int esr, + struct pt_regs *regs) { } +#endif + +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); + } + + /* + * Disable MTE Tag Checking on the local CPU for the current EL. + * It will be done lazily on the other CPUs when they will hit a + * tag fault. + */ + sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_NONE); + isb(); +} + +static bool is_el1_mte_sync_tag_check_fault(unsigned int esr) +{ + unsigned int ec = ESR_ELx_EC(esr); + unsigned int fsc = esr & ESR_ELx_FSC; + + if (ec != ESR_ELx_EC_DABT_CUR) + return false; + + if (fsc == ESR_ELx_FSC_MTE) + return true; + + return false; +} + static void __do_kernel_fault(unsigned long addr, unsigned int esr, struct pt_regs *regs) { @@ -312,6 +365,12 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr, "Ignoring spurious kernel translation fault at virtual address %016lx\n", addr)) return; + if (is_el1_mte_sync_tag_check_fault(esr)) { + do_tag_recovery(addr, esr, regs); + + return; + } + if (is_el1_permission_fault(addr, esr, regs)) { if (esr & ESR_ELx_WNR) msg = "write to read-only memory"; |