[PATCH v5 6/9] task_isolation: arch/arm64: enable task isolation functionality

[Alex Belits <abelits@marvell.com>]

In do_notify_resume(), call task_isolation_before_pending_work_check()
first, to report isolation breaking, then after handling all pending
work, call task_isolation_start() for TIF_TASK_ISOLATION tasks.

Add _TIF_TASK_ISOLATION to _TIF_WORK_MASK, and _TIF_SYSCALL_WORK,
define local NOTIFY_RESUME_LOOP_FLAGS to check in the loop, since we
don't clear _TIF_TASK_ISOLATION in the loop.

Early kernel entry code calls task_isolation_kernel_enter(). In
particular:

Vectors:
el1_sync -> el1_sync_handler() -> task_isolation_kernel_enter()
el1_irq -> asm_nmi_enter(), handle_arch_irq()
el1_error -> do_serror()
el0_sync -> el0_sync_handler()
el0_irq -> handle_arch_irq()
el0_error -> do_serror()
el0_sync_compat -> el0_sync_compat_handler()
el0_irq_compat -> handle_arch_irq()
el0_error_compat -> do_serror()

SDEI entry:
__sdei_asm_handler -> __sdei_handler() -> nmi_enter()

Functions called from there:
asm_nmi_enter() -> nmi_enter() -> task_isolation_kernel_enter()
asm_nmi_exit() -> nmi_exit() -> task_isolation_kernel_return()

Handlers:
do_serror() -> nmi_enter() -> task_isolation_kernel_enter()
  or task_isolation_kernel_enter()
el1_sync_handler() -> task_isolation_kernel_enter()
el0_sync_handler() -> task_isolation_kernel_enter()
el0_sync_compat_handler() -> task_isolation_kernel_enter()

handle_arch_irq() is irqchip-specific, most call handle_domain_irq()
There is a separate patch for irqchips that do not follow this rule.

handle_domain_irq() -> task_isolation_kernel_enter()
do_handle_IPI() -> task_isolation_kernel_enter() (may be redundant)
nmi_enter() -> task_isolation_kernel_enter()

Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com>
[abelits@marvell.com: simplified to match kernel 5.10]
Signed-off-by: Alex Belits <abelits@marvell.com>
---
 arch/arm64/Kconfig                   |  1 +
 arch/arm64/include/asm/barrier.h     |  1 +
 arch/arm64/include/asm/thread_info.h |  7 +++++--
 arch/arm64/kernel/entry-common.c     |  7 +++++++
 arch/arm64/kernel/ptrace.c           | 10 ++++++++++
 arch/arm64/kernel/signal.c           | 13 ++++++++++++-
 arch/arm64/kernel/smp.c              |  3 +++
 7 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 1515f6f153a0..fc958d8d8945 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -141,6 +141,7 @@ config ARM64
 	select HAVE_ARCH_PREL32_RELOCATIONS
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_ARCH_STACKLEAK
+	select HAVE_ARCH_TASK_ISOLATION
 	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h
index c3009b0e5239..ad5a6dd380cf 100644
--- a/arch/arm64/include/asm/barrier.h
+++ b/arch/arm64/include/asm/barrier.h
@@ -49,6 +49,7 @@
 #define dma_rmb()	dmb(oshld)
 #define dma_wmb()	dmb(oshst)
 
+#define instr_sync()	isb()
 /*
  * Generate a mask for array_index__nospec() that is ~0UL when 0 <= idx < sz
  * and 0 otherwise.
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index 1fbab854a51b..3321c69c46fe 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -68,6 +68,7 @@ void arch_release_task_struct(struct task_struct *tsk);
 #define TIF_UPROBE		4	/* uprobe breakpoint or singlestep */
 #define TIF_FSCHECK		5	/* Check FS is USER_DS on return */
 #define TIF_MTE_ASYNC_FAULT	6	/* MTE Asynchronous Tag Check Fault */
+#define TIF_TASK_ISOLATION	7	/* task isolation enabled for task */
 #define TIF_SYSCALL_TRACE	8	/* syscall trace active */
 #define TIF_SYSCALL_AUDIT	9	/* syscall auditing */
 #define TIF_SYSCALL_TRACEPOINT	10	/* syscall tracepoint for ftrace */
@@ -87,6 +88,7 @@ void arch_release_task_struct(struct task_struct *tsk);
 #define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
 #define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
 #define _TIF_FOREIGN_FPSTATE	(1 << TIF_FOREIGN_FPSTATE)
+#define _TIF_TASK_ISOLATION	(1 << TIF_TASK_ISOLATION)
 #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
 #define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
 #define _TIF_SYSCALL_TRACEPOINT	(1 << TIF_SYSCALL_TRACEPOINT)
@@ -101,11 +103,12 @@ void arch_release_task_struct(struct task_struct *tsk);
 
 #define _TIF_WORK_MASK		(_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
 				 _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \
-				 _TIF_UPROBE | _TIF_FSCHECK | _TIF_MTE_ASYNC_FAULT)
+				 _TIF_UPROBE | _TIF_FSCHECK | \
+				 _TIF_MTE_ASYNC_FAULT | _TIF_TASK_ISOLATION)
 
 #define _TIF_SYSCALL_WORK	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
 				 _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \
-				 _TIF_SYSCALL_EMU)
+				 _TIF_SYSCALL_EMU | _TIF_TASK_ISOLATION)
 
 #ifdef CONFIG_SHADOW_CALL_STACK
 #define INIT_SCS							\
diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
index 43d4c329775f..8152760de683 100644
--- a/arch/arm64/kernel/entry-common.c
+++ b/arch/arm64/kernel/entry-common.c
@@ -8,6 +8,7 @@
 #include <linux/context_tracking.h>
 #include <linux/ptrace.h>
 #include <linux/thread_info.h>
+#include <linux/isolation.h>
 
 #include <asm/cpufeature.h>
 #include <asm/daifflags.h>
@@ -77,6 +78,8 @@ asmlinkage void notrace el1_sync_handler(struct pt_regs *regs)
 {
 	unsigned long esr = read_sysreg(esr_el1);
 
+	task_isolation_kernel_enter();
+
 	switch (ESR_ELx_EC(esr)) {
 	case ESR_ELx_EC_DABT_CUR:
 	case ESR_ELx_EC_IABT_CUR:
@@ -249,6 +252,8 @@ asmlinkage void notrace el0_sync_handler(struct pt_regs *regs)
 {
 	unsigned long esr = read_sysreg(esr_el1);
 
+	task_isolation_kernel_enter();
+
 	switch (ESR_ELx_EC(esr)) {
 	case ESR_ELx_EC_SVC64:
 		el0_svc(regs);
@@ -321,6 +326,8 @@ asmlinkage void notrace el0_sync_compat_handler(struct pt_regs *regs)
 {
 	unsigned long esr = read_sysreg(esr_el1);
 
+	task_isolation_kernel_enter();
+
 	switch (ESR_ELx_EC(esr)) {
 	case ESR_ELx_EC_SVC32:
 		el0_svc_compat(regs);
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index f49b349e16a3..2941f2b16796 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -29,6 +29,7 @@
 #include <linux/regset.h>
 #include <linux/tracehook.h>
 #include <linux/elf.h>
+#include <linux/isolation.h>
 
 #include <asm/compat.h>
 #include <asm/cpufeature.h>
@@ -1803,6 +1804,15 @@ int syscall_trace_enter(struct pt_regs *regs)
 			return NO_SYSCALL;
 	}
 
+	/*
+	 * In task isolation mode, we may prevent the syscall from
+	 * running, and if so we also deliver a signal to the process.
+	 */
+	if (test_thread_flag(TIF_TASK_ISOLATION)) {
+		if (task_isolation_syscall(regs->syscallno) == -1)
+			return NO_SYSCALL;
+	}
+
 	/* Do the secure computing after ptrace; failures should be fast. */
 	if (secure_computing() == -1)
 		return NO_SYSCALL;
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index a8184cad8890..e3a82b75e39d 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -20,6 +20,7 @@
 #include <linux/tracehook.h>
 #include <linux/ratelimit.h>
 #include <linux/syscalls.h>
+#include <linux/isolation.h>
 
 #include <asm/daifflags.h>
 #include <asm/debug-monitors.h>
@@ -911,6 +912,11 @@ static void do_signal(struct pt_regs *regs)
 	restore_saved_sigmask();
 }
 
+#define NOTIFY_RESUME_LOOP_FLAGS \
+	(_TIF_NEED_RESCHED | _TIF_SIGPENDING | _TIF_NOTIFY_RESUME | \
+	 _TIF_FOREIGN_FPSTATE | _TIF_UPROBE | _TIF_FSCHECK | \
+	 _TIF_MTE_ASYNC_FAULT)
+
 asmlinkage void do_notify_resume(struct pt_regs *regs,
 				 unsigned long thread_flags)
 {
@@ -921,6 +927,8 @@ asmlinkage void do_notify_resume(struct pt_regs *regs,
 	 */
 	trace_hardirqs_off();
 
+	task_isolation_before_pending_work_check();
+
 	do {
 		/* Check valid user FS if needed */
 		addr_limit_user_check();
@@ -956,7 +964,10 @@ asmlinkage void do_notify_resume(struct pt_regs *regs,
 
 		local_daif_mask();
 		thread_flags = READ_ONCE(current_thread_info()->flags);
-	} while (thread_flags & _TIF_WORK_MASK);
+	} while (thread_flags & NOTIFY_RESUME_LOOP_FLAGS);
+
+	if (thread_flags & _TIF_TASK_ISOLATION)
+		task_isolation_start();
 }
 
 unsigned long __ro_after_init signal_minsigstksz;
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 18e9727d3f64..4401eac4710c 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -33,6 +33,7 @@
 #include <linux/kernel_stat.h>
 #include <linux/kexec.h>
 #include <linux/kvm_host.h>
+#include <linux/isolation.h>
 
 #include <asm/alternative.h>
 #include <asm/atomic.h>
@@ -890,6 +891,8 @@ static void do_handle_IPI(int ipinr)
 {
 	unsigned int cpu = smp_processor_id();
 
+	task_isolation_kernel_enter();
+
 	if ((unsigned)ipinr < NR_IPI)
 		trace_ipi_entry_rcuidle(ipi_types[ipinr]);
 
-- 
2.20.1