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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/signal.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/signal.c')
| -rw-r--r-- | arch/arm64/kernel/signal.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 3b4f31f35e45..b27e87572ce3 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -748,6 +748,9 @@ static void setup_return(struct pt_regs *regs, struct k_sigaction *ka, regs->pstate |= PSR_BTYPE_C; } + /* TCO (Tag Check Override) always cleared for signal handlers */ + regs->pstate &= ~PSR_TCO_BIT; + if (ka->sa.sa_flags & SA_RESTORER) sigtramp = ka->sa.sa_restorer; else @@ -932,6 +935,12 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, if (thread_flags & _TIF_UPROBE) uprobe_notify_resume(regs); + if (thread_flags & _TIF_MTE_ASYNC_FAULT) { + clear_thread_flag(TIF_MTE_ASYNC_FAULT); + send_sig_fault(SIGSEGV, SEGV_MTEAERR, + (void __user *)NULL, current); + } + if (thread_flags & _TIF_SIGPENDING) do_signal(regs); |