[PATCH RFC v4 19/42] kmsan: x86/asm: softirq: add KMSAN IRQ entry hooks

[glider@google.com]

Add assembly helpers to entry_64.S that invoke hooks from kmsan_entry.c and
notify KMSAN about interrupts.
Also call these hooks from kernel/softirq.c
This is needed to switch between several KMSAN contexts holding function
parameter metadata.

Signed-off-by: Alexander Potapenko <glider@google.com>
To: Alexander Potapenko <glider@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: linux-mm@kvack.org
---

v4:
 - moved softirq changes to this patch

Change-Id: I3037d51672fe69d09e588b27adb2d9fdc6ad3a7d
---
 arch/x86/entry/entry_64.S | 16 ++++++++++++++++
 kernel/softirq.c          |  5 +++++
 2 files changed, 21 insertions(+)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 76942cbd95a1..293922680a39 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -35,6 +35,7 @@
 #include <asm/asm.h>
 #include <asm/smap.h>
 #include <asm/pgtable_types.h>
+#include <asm/kmsan.h>
 #include <asm/export.h>
 #include <asm/frame.h>
 #include <asm/nospec-branch.h>
@@ -575,6 +576,7 @@ SYM_CODE_START(interrupt_entry)
 
 1:
 	ENTER_IRQ_STACK old_rsp=%rdi save_ret=1
+	KMSAN_INTERRUPT_ENTER
 	/* We entered an interrupt context - irqs are off: */
 	TRACE_IRQS_OFF
 
@@ -604,12 +606,14 @@ SYM_CODE_START_LOCAL(common_interrupt)
 	addq	$-0x80, (%rsp)			/* Adjust vector to [-256, -1] range */
 	call	interrupt_entry
 	UNWIND_HINT_REGS indirect=1
+	KMSAN_UNPOISON_PT_REGS
 	call	do_IRQ	/* rdi points to pt_regs */
 	/* 0(%rsp): old RSP */
 ret_from_intr:
 	DISABLE_INTERRUPTS(CLBR_ANY)
 	TRACE_IRQS_OFF
 
+	KMSAN_INTERRUPT_EXIT
 	LEAVE_IRQ_STACK
 
 	testb	$3, CS(%rsp)
@@ -801,6 +805,7 @@ SYM_CODE_START(\sym)
 .Lcommon_\sym:
 	call	interrupt_entry
 	UNWIND_HINT_REGS indirect=1
+	KMSAN_UNPOISON_PT_REGS
 	call	\do_sym	/* rdi points to pt_regs */
 	jmp	ret_from_intr
 SYM_CODE_END(\sym)
@@ -908,15 +913,18 @@ apicinterrupt IRQ_WORK_VECTOR			irq_work_interrupt		smp_irq_work_interrupt
 
 	.if \shift_ist != -1
 	subq	$\ist_offset, CPU_TSS_IST(\shift_ist)
+	KMSAN_IST_ENTER(\shift_ist)
 	.endif
 
 	.if \read_cr2
 	movq	%r12, %rdx			/* Move CR2 into 3rd argument */
 	.endif
 
+	KMSAN_UNPOISON_PT_REGS
 	call	\do_sym
 
 	.if \shift_ist != -1
+	KMSAN_IST_EXIT(\shift_ist)
 	addq	$\ist_offset, CPU_TSS_IST(\shift_ist)
 	.endif
 
@@ -1079,7 +1087,9 @@ SYM_FUNC_START(do_softirq_own_stack)
 	pushq	%rbp
 	mov	%rsp, %rbp
 	ENTER_IRQ_STACK regs=0 old_rsp=%r11
+	KMSAN_SOFTIRQ_ENTER
 	call	__do_softirq
+	KMSAN_SOFTIRQ_EXIT
 	LEAVE_IRQ_STACK regs=0
 	leaveq
 	ret
@@ -1466,9 +1476,12 @@ SYM_CODE_START(nmi)
 	 * done with the NMI stack.
 	 */
 
+	KMSAN_NMI_ENTER
 	movq	%rsp, %rdi
 	movq	$-1, %rsi
+	KMSAN_UNPOISON_PT_REGS
 	call	do_nmi
+	KMSAN_NMI_EXIT
 
 	/*
 	 * Return back to user mode.  We must *not* do the normal exit
@@ -1678,10 +1691,13 @@ end_repeat_nmi:
 	call	paranoid_entry
 	UNWIND_HINT_REGS
 
+	KMSAN_NMI_ENTER
 	/* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */
 	movq	%rsp, %rdi
 	movq	$-1, %rsi
+	KMSAN_UNPOISON_PT_REGS
 	call	do_nmi
+	KMSAN_NMI_EXIT
 
 	/* Always restore stashed CR3 value (see paranoid_entry) */
 	RESTORE_CR3 scratch_reg=%r15 save_reg=%r14
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 0427a86743a4..98c5f4062cbf 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -11,6 +11,7 @@
 
 #include <linux/export.h>
 #include <linux/kernel_stat.h>
+#include <linux/kmsan.h>
 #include <linux/interrupt.h>
 #include <linux/init.h>
 #include <linux/mm.h>
@@ -370,7 +371,9 @@ static inline void invoke_softirq(void)
 		 * it is the irq stack, because it should be near empty
 		 * at this stage.
 		 */
+		kmsan_context_enter();
 		__do_softirq();
+		kmsan_context_exit();
 #else
 		/*
 		 * Otherwise, irq_exit() is called on the task stack that can
@@ -600,7 +603,9 @@ static void run_ksoftirqd(unsigned int cpu)
 		 * We can safely run softirq on inline stack, as we are not deep
 		 * in the task stack here.
 		 */
+		kmsan_context_enter();
 		__do_softirq();
+		kmsan_context_exit();
 		local_irq_enable();
 		cond_resched();
 		return;
-- 
2.24.1.735.g03f4e72817-goog