dtrace: add support for SMAP

Add support in dtrace for SMAP, so that actions like copyinstr() work.
It would be better if dtrace could use the SMAP_* hotpatch macros directly,
but the hotpatching code does not currently operate on kernel modules,
so we'll use some tiny functions in the base kernel for now.

external/cddl/osnet/dev/dtrace/amd64/dtrace_asm.S

@@ -1,4 +1,4 @@
-/*	$NetBSD: dtrace_asm.S,v 1.8 2018/05/28 21:05:03 chs Exp $	*/
+/*	$NetBSD: dtrace_asm.S,v 1.9 2023/11/03 09:07:56 chs Exp $	*/
 
 /*
  * CDDL HEADER START
@@ -39,6 +39,11 @@
 
 #include "assym.h"
 
+#define DTRACE_SMAP_DISABLE			\
+	call	dtrace_smap_disable
+#define DTRACE_SMAP_ENABLE			\
+	call	dtrace_smap_enable
+
 #define INTR_POP				\
 	MEXITCOUNT;				\
 	movq	TF_RDI(%rsp),%rdi;		\
@@ -217,8 +222,10 @@ dtrace_copy(uintptr_t src, uintptr_t dest, size_t size)
 
 	xchgq	%rdi, %rsi		/* make %rsi source, %rdi dest */
 	movq	%rdx, %rcx		/* load count */
+	DTRACE_SMAP_DISABLE
 	repz				/* repeat for count ... */
 	smovb				/*   move from %ds:rsi to %ed:rdi */
+	DTRACE_SMAP_ENABLE
 	leave
 	ret
 	END(dtrace_copy)
@@ -231,6 +238,7 @@ dtrace_copystr(uintptr_t uaddr, uintptr_t kaddr, size_t size,
 	ENTRY(dtrace_copystr)
 	pushq	%rbp
 	movq	%rsp, %rbp
+	DTRACE_SMAP_DISABLE
 
 0:
 	movb	(%rdi), %al		/* load from source */
@@ -248,6 +256,7 @@ dtrace_copystr(uintptr_t uaddr, uintptr_t kaddr, size_t size,
 	cmpq	$0, %rdx
 	jne	0b
 2:
+	DTRACE_SMAP_ENABLE
 	leave
 	ret
 
@@ -258,7 +267,9 @@ uintptr_t
 dtrace_fulword(void *addr)
 */
 	ENTRY(dtrace_fulword)
+	DTRACE_SMAP_DISABLE
 	movq	(%rdi), %rax
+	DTRACE_SMAP_ENABLE
 	ret
 	END(dtrace_fulword)
 
@@ -268,7 +279,9 @@ dtrace_fuword8_nocheck(void *addr)
 */
 	ENTRY(dtrace_fuword8_nocheck)
 	xorq	%rax, %rax
+	DTRACE_SMAP_DISABLE
 	movb	(%rdi), %al
+	DTRACE_SMAP_ENABLE
 	ret
 	END(dtrace_fuword8_nocheck)
 
@@ -278,7 +291,9 @@ dtrace_fuword16_nocheck(void *addr)
 */
 	ENTRY(dtrace_fuword16_nocheck)
 	xorq	%rax, %rax
+	DTRACE_SMAP_DISABLE
 	movw	(%rdi), %ax
+	DTRACE_SMAP_ENABLE
 	ret
 	END(dtrace_fuword16_nocheck)
 
@@ -288,7 +303,9 @@ dtrace_fuword32_nocheck(void *addr)
 */
 	ENTRY(dtrace_fuword32_nocheck)
 	xorq	%rax, %rax
+	DTRACE_SMAP_DISABLE
 	movl	(%rdi), %eax
+	DTRACE_SMAP_ENABLE
 	ret
 	END(dtrace_fuword32_nocheck)
 
@@ -297,7 +314,9 @@ uint64_t
 dtrace_fuword64_nocheck(void *addr)
 */
 	ENTRY(dtrace_fuword64_nocheck)
+	DTRACE_SMAP_DISABLE
 	movq	(%rdi), %rax
+	DTRACE_SMAP_ENABLE
 	ret
 	END(dtrace_fuword64_nocheck)
 

external/cddl/osnet/dev/dtrace/i386/dtrace_asm.S

@@ -1,4 +1,4 @@
-/*	$NetBSD: dtrace_asm.S,v 1.7 2018/05/28 21:05:03 chs Exp $	*/
+/*	$NetBSD: dtrace_asm.S,v 1.8 2023/11/03 09:07:57 chs Exp $	*/
 
 /*
  * CDDL HEADER START
@@ -38,6 +38,11 @@
 #include <machine/frameasm.h>
 #include <machine/trap.h>
 
+#define DTRACE_SMAP_DISABLE			\
+	call	dtrace_smap_disable
+#define DTRACE_SMAP_ENABLE			\
+	call	dtrace_smap_enable
+
 #define INTR_POP		\
 	addl	$16, %esp;	\
 	popl	%edi;		\
@@ -225,8 +230,10 @@ void dtrace_copy(uintptr_t src, uintptr_t dest, size_t size)
 	movl	8(%ebp), %esi		/* Load source address */
 	movl	12(%ebp), %edi		/* Load destination address */
 	movl	16(%ebp), %ecx		/* Load count */
+	DTRACE_SMAP_DISABLE
 	repz				/* Repeat for count... */
 	smovb				/*   move from %ds:si to %es:di */
+	DTRACE_SMAP_ENABLE
 
 	popl	%edi
 	popl	%esi
@@ -248,6 +255,7 @@ void dtrace_copystr(uintptr_t uaddr, uintptr_t kaddr, size_t size)
 	movl	8(%ebp), %ebx		/* Load source address */
 	movl	12(%ebp), %edx		/* Load destination address */
 	movl	16(%ebp), %ecx		/* Load count */
+	DTRACE_SMAP_DISABLE
 
 0:
 	movb	(%ebx), %al		/* Load from source */
@@ -261,6 +269,7 @@ void dtrace_copystr(uintptr_t uaddr, uintptr_t kaddr, size_t size)
 	jne	0b
 
 1:
+	DTRACE_SMAP_ENABLE
 	popl	%ebx
 	movl	%ebp, %esp
 	popl	%ebp
@@ -275,7 +284,9 @@ uintptr_t dtrace_fulword(void *addr)
 	ENTRY(dtrace_fulword)
 	movl	4(%esp), %ecx
 	xorl	%eax, %eax
+	DTRACE_SMAP_DISABLE
 	movl	(%ecx), %eax
+	DTRACE_SMAP_ENABLE
 	ret
 	END(dtrace_fulword)
 
@@ -286,7 +297,9 @@ uint8_t dtrace_fuword8_nocheck(void *addr)
 	ENTRY(dtrace_fuword8_nocheck)
 	movl	4(%esp), %ecx
 	xorl	%eax, %eax
+	DTRACE_SMAP_DISABLE
 	movzbl	(%ecx), %eax
+	DTRACE_SMAP_ENABLE
 	ret
 	END(dtrace_fuword8_nocheck)
 
@@ -297,7 +310,9 @@ uint16_t dtrace_fuword16_nocheck(void *addr)
 	ENTRY(dtrace_fuword16_nocheck)
 	movl	4(%esp), %ecx
 	xorl	%eax, %eax
+	DTRACE_SMAP_DISABLE
 	movzwl	(%ecx), %eax
+	DTRACE_SMAP_ENABLE
 	ret
 	END(dtrace_fuword16_nocheck)
 
@@ -308,7 +323,9 @@ uint32_t dtrace_fuword32_nocheck(void *addr)
 	ENTRY(dtrace_fuword32_nocheck)
 	movl	4(%esp), %ecx
 	xorl	%eax, %eax
+	DTRACE_SMAP_DISABLE
 	movl	(%ecx), %eax
+	DTRACE_SMAP_ENABLE
 	ret
 	END(dtrace_fuword32_nocheck)
 
@@ -320,8 +337,10 @@ uint64_t dtrace_fuword64_nocheck(void *addr)
 	movl	4(%esp), %ecx
 	xorl	%eax, %eax
 	xorl	%edx, %edx
+	DTRACE_SMAP_DISABLE
 	movl	(%ecx), %eax
 	movl	4(%ecx), %edx
+	DTRACE_SMAP_ENABLE
 	ret
 	END(dtrace_fuword64_nocheck)
 

sys/arch/amd64/amd64/cpufunc.S

@@ -1,4 +1,4 @@
-/*	$NetBSD: cpufunc.S,v 1.66 2023/10/04 20:28:05 ad Exp $	*/
+/*	$NetBSD: cpufunc.S,v 1.67 2023/11/03 09:07:56 chs Exp $	*/
 
 /*
  * Copyright (c) 1998, 2007, 2008, 2020, 2023 The NetBSD Foundation, Inc.
@@ -36,6 +36,7 @@
 #include <machine/specialreg.h>
 #include <machine/segments.h>
 
+#include "opt_dtrace.h"
 #include "opt_xen.h"
 #include "opt_svs.h"
 
@@ -177,6 +178,18 @@ ENTRY(smap_disable)
 	ret
 END(smap_disable)
 
+#ifdef KDTRACE_HOOKS
+ENTRY(dtrace_smap_enable)
+	SMAP_ENABLE
+	ret
+END(dtrace_smap_enable)
+
+ENTRY(dtrace_smap_disable)
+	SMAP_DISABLE
+	ret
+END(dtrace_smap_disable)
+#endif
+
 /*
  * %rdi = name
  * %rsi = sel

sys/arch/i386/i386/cpufunc.S

@@ -1,4 +1,4 @@
-/*	$NetBSD: cpufunc.S,v 1.50 2023/10/04 20:28:05 ad Exp $	*/
+/*	$NetBSD: cpufunc.S,v 1.51 2023/11/03 09:07:56 chs Exp $	*/
 
 /*-
  * Copyright (c) 1998, 2007, 2020, 2023 The NetBSD Foundation, Inc.
@@ -38,8 +38,10 @@
 #include <sys/errno.h>
 
 #include <machine/asm.h>
-__KERNEL_RCSID(0, "$NetBSD: cpufunc.S,v 1.50 2023/10/04 20:28:05 ad Exp $");
+#include <machine/frameasm.h>
+__KERNEL_RCSID(0, "$NetBSD: cpufunc.S,v 1.51 2023/11/03 09:07:56 chs Exp $");
 
+#include "opt_dtrace.h"
 #include "opt_xen.h"
 
 #include <machine/specialreg.h>
@@ -72,6 +74,18 @@ ENTRY(lidt)
 	ret
 END(lidt)
 
+#ifdef KDTRACE_HOOKS
+ENTRY(dtrace_smap_enable)
+	SMAP_ENABLE
+	ret
+END(dtrace_smap_enable)
+
+ENTRY(dtrace_smap_disable)
+	SMAP_DISABLE
+	ret
+END(dtrace_smap_disable)
+#endif
+
 ENTRY(x86_hotpatch)
 	/* save EFLAGS, and disable intrs */
 	pushfl