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| author |   Vincenzo Frascino <vincenzo.frascino@arm.com> | 2019-09-16 11:51:17 +0100 |
|---|---|---|
| committer |   Catalin Marinas <catalin.marinas@arm.com> | 2020-09-04 12:46:06 +0100 |
| commit | 637ec831ea4f09c7529ac4078399ce4e25b46341 (patch) | |
| tree | 7f8a21f46e15ffc6958c46a202ab8d578b23fb9c /arch/arm64/kernel/syscall.c | |
| parent | arm64: mte: Add specific SIGSEGV codes (diff) | |
| download | linux-dev-637ec831ea4f09c7529ac4078399ce4e25b46341.tar.xz linux-dev-637ec831ea4f09c7529ac4078399ce4e25b46341.zip | |
arm64: mte: Handle synchronous and asynchronous tag check faults
The Memory Tagging Extension has two modes of notifying a tag check
fault at EL0, configurable through the SCTLR_EL1.TCF0 field:
1. Synchronous raising of a Data Abort exception with DFSC 17.
2. Asynchronous setting of a cumulative bit in TFSRE0_EL1.
Add the exception handler for the synchronous exception and handling of
the asynchronous TFSRE0_EL1.TF0 bit setting via a new TIF flag in
do_notify_resume().
On a tag check failure in user-space, whether synchronous or
asynchronous, a SIGSEGV will be raised on the faulting thread.
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Co-developed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/kernel/syscall.c')
| -rw-r--r-- | arch/arm64/kernel/syscall.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index 5f0c04863d2c..e4c0dadf0d92 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -123,6 +123,16 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, local_daif_restore(DAIF_PROCCTX); user_exit(); + if (system_supports_mte() && (flags & _TIF_MTE_ASYNC_FAULT)) { + /* + * Process the asynchronous tag check fault before the actual + * syscall. do_notify_resume() will send a signal to userspace + * before the syscall is restarted. + */ + regs->regs[0] = -ERESTARTNOINTR; + return; + } + if (has_syscall_work(flags)) { /* * The de-facto standard way to skip a system call using ptrace |