From: Alexander Bluhm <alexander.bluhm@gmx.net>
Subject: Re: ddb(4): db_read_bytes, db_write_bytes: change data parameter to void pointer
To: Scott Cheloha <scottcheloha@gmail.com>
Cc: tech@openbsd.org
Date: Thu, 8 Feb 2024 17:16:17 +0100

On Thu, Feb 08, 2024 at 10:01:43AM -0600, Scott Cheloha wrote:
> Almost all db_read_bytes/db_write_bytes callers cast the data
> parameter to a "char *", which suggests that the function prototypes
> don't match how the functions are actually used.
> 
> Change the data parameter to db_read_bytes/db_write/bytes from
> "char *" to "void *", update all implementations to use a "char *"
> internally, and update all callers to remove the casts.

Less casts is always good.

> While we're updating the callers, we can also change any magic sizes
> to sizeof.

Personally I like the sizeof() with parentheses more than without.

> ok?

OK bluhm@

> Index: ./ddb/db_access.h
> ===================================================================
> RCS file: /cvs/src/sys/ddb/db_access.h,v
> diff -u -p -r1.11 db_access.h
> --- ./ddb/db_access.h	20 Jan 2020 15:58:23 -0000	1.11
> +++ ./ddb/db_access.h	8 Feb 2024 15:43:26 -0000
> @@ -36,5 +36,5 @@
>  db_expr_t db_get_value(vaddr_t, size_t, int);
>  void db_put_value(vaddr_t, size_t, db_expr_t);
>  
> -void db_read_bytes(vaddr_t, size_t, char *);
> -void db_write_bytes(vaddr_t, size_t, char *);
> +void db_read_bytes(vaddr_t, size_t, void *);
> +void db_write_bytes(vaddr_t, size_t, void *);
> Index: ./arch/alpha/alpha/db_interface.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/alpha/alpha/db_interface.c,v
> diff -u -p -r1.28 db_interface.c
> --- ./arch/alpha/alpha/db_interface.c	14 Apr 2022 19:47:10 -0000	1.28
> +++ ./arch/alpha/alpha/db_interface.c	8 Feb 2024 15:43:26 -0000
> @@ -191,9 +191,9 @@ void
>  db_read_bytes(addr, size, data)
>  	vaddr_t		addr;
>  	register size_t	size;
> -	register char	*data;
> +	register void	*datap;
>  {
> -	register char	*src;
> +	register char	*data = datap, *src;
>  
>  	src = (char *)addr;
>  	while (size-- > 0)
> @@ -207,9 +207,9 @@ void
>  db_write_bytes(addr, size, data)
>  	vaddr_t		addr;
>  	register size_t	size;
> -	register char	*data;
> +	register void	*datap;
>  {
> -	register char	*dst;
> +	register char	*data = datap, *dst;
>  
>  	dst = (char *)addr;
>  	while (size-- > 0)
> Index: ./arch/amd64/amd64/db_memrw.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/amd64/amd64/db_memrw.c,v
> diff -u -p -r1.8 db_memrw.c
> --- ./arch/amd64/amd64/db_memrw.c	30 Apr 2017 13:04:49 -0000	1.8
> +++ ./arch/amd64/amd64/db_memrw.c	8 Feb 2024 15:43:26 -0000
> @@ -60,9 +60,9 @@
>   * Read bytes from kernel address space for debugger.
>   */
>  void
> -db_read_bytes(vaddr_t addr, size_t size, char *data)
> +db_read_bytes(vaddr_t addr, size_t size, void *datap)
>  {
> -	char *src;
> +	char *data = datap, *src;
>  
>  	src = (char *)addr;
>  
> @@ -90,12 +90,12 @@ db_read_bytes(vaddr_t addr, size_t size,
>   * pages writable temporarily.
>   */
>  static void
> -db_write_text(vaddr_t addr, size_t size, char *data)
> +db_write_text(vaddr_t addr, size_t size, void *datap)
>  {
>  	pt_entry_t *pte, oldpte, tmppte;
>  	vaddr_t pgva;
>  	size_t limit;
> -	char *dst;
> +	char *data = datap, *dst;
>  
>  	if (size == 0)
>  		return;
> Index: ./arch/arm/arm/db_interface.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/arm/arm/db_interface.c,v
> diff -u -p -r1.20 db_interface.c
> --- ./arch/arm/arm/db_interface.c	15 Oct 2022 08:04:02 -0000	1.20
> +++ ./arch/arm/arm/db_interface.c	8 Feb 2024 15:43:27 -0000
> @@ -182,9 +182,9 @@ db_validate_address(vaddr_t addr)
>   * Read bytes from kernel address space for debugger.
>   */
>  void
> -db_read_bytes(vaddr_t addr, size_t size, char *data)
> +db_read_bytes(vaddr_t addr, size_t size, void *datap)
>  {
> -	char	*src = (char *)addr;
> +	char *data = datap, *src = (char *)addr;
>  
>  	if (db_validate_address((u_int)src)) {
>  		db_printf("address %p is invalid\n", src);
> @@ -211,14 +211,14 @@ db_read_bytes(vaddr_t addr, size_t size,
>  }
>  
>  static void
> -db_write_text(vaddr_t addr, size_t size, char *data)
> +db_write_text(vaddr_t addr, size_t size, void *datap)
>  {        
>  	struct pmap *pmap = pmap_kernel();
>  	pd_entry_t *pde, oldpde, tmppde;
>  	pt_entry_t *pte, oldpte, tmppte;
>  	vaddr_t pgva;
>  	size_t limit, savesize;
> -	char *dst;
> +	char *data = datap, *dst;
>  
>  	/* XXX: gcc */
>  	oldpte = 0;
> @@ -434,7 +434,7 @@ db_branch_taken(u_int insn, vaddr_t pc, 
>  	case 0x7:	/* ldr pc, [pc, reg, lsl #2] */
>  		addr = db_fetch_reg(insn & 0xf, db_regs);
>  		addr = pc + 8 + (addr << 2);
> -		db_read_bytes(addr, 4, (char *)&addr);
> +		db_read_bytes(addr, sizeof addr, &addr);
>  		return (addr);
>  	case 0x1:	/* mov pc, reg */
>  		addr = db_fetch_reg(insn & 0xf, db_regs);
> @@ -460,7 +460,7 @@ db_branch_taken(u_int insn, vaddr_t pc, 
>  			addr = addr + 4 + ((nregs - 1) << 2);
>  			break;
>  		}
> -		db_read_bytes(addr, 4, (char *)&addr);
> +		db_read_bytes(addr, sizeof addr, &addr);
>  		return (addr);
>  	default:
>  		panic("branch_taken: botch");
> Index: ./arch/arm64/arm64/db_interface.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/arm64/arm64/db_interface.c,v
> diff -u -p -r1.14 db_interface.c
> --- ./arch/arm64/arm64/db_interface.c	7 Nov 2022 09:43:04 -0000	1.14
> +++ ./arch/arm64/arm64/db_interface.c	8 Feb 2024 15:43:26 -0000
> @@ -197,9 +197,9 @@ db_validate_address(vaddr_t addr)
>   * Read bytes from kernel address space for debugger.
>   */
>  void
> -db_read_bytes(vaddr_t addr, size_t size, char *data)
> +db_read_bytes(vaddr_t addr, size_t size, void *datap)
>  {
> -	char	*src = (char *)addr;
> +	char *data = datap, *src = (char *)addr;
>  
>  	if (db_validate_address((vaddr_t)src)) {
>  		db_printf("address %p is invalid\n", src);
> @@ -235,11 +235,11 @@ db_read_bytes(vaddr_t addr, size_t size,
>   * pages writable temporarily.
>   */
>  static void
> -db_write_text(vaddr_t addr, size_t size, char *data)
> +db_write_text(vaddr_t addr, size_t size, void *datap)
>  {
>  	vaddr_t pgva;
>  	size_t limit;
> -	char *dst;
> +	char *data = datap, *dst;
>  
>  	if (size == 0)
>  		return;
> Index: ./arch/hppa/hppa/db_interface.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/hppa/hppa/db_interface.c,v
> diff -u -p -r1.49 db_interface.c
> --- ./arch/hppa/hppa/db_interface.c	26 Apr 2023 16:53:58 -0000	1.49
> +++ ./arch/hppa/hppa/db_interface.c	8 Feb 2024 15:43:26 -0000
> @@ -134,8 +134,9 @@ db_enter(void)
>  }
>  
>  void
> -db_read_bytes(vaddr_t addr, size_t size, char *data)
> +db_read_bytes(vaddr_t addr, size_t size, void *datap)
>  {
> +	char *data = datap;
>  	register char *src = (char *)addr;
>  
>  	while (size--)
> @@ -143,8 +144,9 @@ db_read_bytes(vaddr_t addr, size_t size,
>  }
>  
>  void
> -db_write_bytes(vaddr_t addr, size_t size, char *data)
> +db_write_bytes(vaddr_t addr, size_t size, void *datap)
>  {
> +	char *data = datap;
>  	register char *dst = (char *)addr;
>  
>  	while (size--)
> Index: ./arch/i386/i386/db_memrw.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/i386/i386/db_memrw.c,v
> diff -u -p -r1.18 db_memrw.c
> --- ./arch/i386/i386/db_memrw.c	23 Sep 2020 15:13:26 -0000	1.18
> +++ ./arch/i386/i386/db_memrw.c	8 Feb 2024 15:43:26 -0000
> @@ -50,9 +50,9 @@
>   * Read bytes from kernel address space for debugger.
>   */
>  void
> -db_read_bytes(vaddr_t addr, size_t size, char *data)
> +db_read_bytes(vaddr_t addr, size_t size, void *datap)
>  {
> -	char	*src;
> +	char *data = datap, *src;
>  
>  	src = (char *)addr;
>  	while (size-- > 0)
> @@ -64,12 +64,12 @@ db_read_bytes(vaddr_t addr, size_t size,
>   * pages writable temporarily.
>   */
>  static void
> -db_write_text(vaddr_t addr, size_t size, char *data)
> +db_write_text(vaddr_t addr, size_t size, char *datap)
>  {
>  	vaddr_t pgva;
>  	size_t limit;
>  	uint32_t bits;
> -	char *dst;
> +	char *data = datap, *dst;
>  
>  	if (size == 0)
>  		return;
> Index: ./arch/m88k/m88k/db_interface.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/m88k/m88k/db_interface.c,v
> diff -u -p -r1.28 db_interface.c
> --- ./arch/m88k/m88k/db_interface.c	14 Apr 2022 19:47:11 -0000	1.28
> +++ ./arch/m88k/m88k/db_interface.c	8 Feb 2024 15:43:26 -0000
> @@ -487,9 +487,9 @@ ddb_entry_trap(level, eframe)
>   * Read bytes from kernel address space for debugger.
>   */
>  void
> -db_read_bytes(vaddr_t addr, size_t size, char *data)
> +db_read_bytes(vaddr_t addr, size_t size, void *datap)
>  {
> -	char *src;
> +	char *data = datap, *src;
>  
>  	src = (char *)addr;
>  
> @@ -502,10 +502,10 @@ db_read_bytes(vaddr_t addr, size_t size,
>   * Write bytes to kernel address space for debugger.
>   */
>  void
> -db_write_bytes(vaddr_t addr, size_t size, char *data)
> +db_write_bytes(vaddr_t addr, size_t size, void *datap)
>  {
>  	extern pt_entry_t *pmap_pte(pmap_t, vaddr_t);
> -	char *dst = (char *)addr;
> +	char *data = datap, *dst = (char *)addr;
>  	vaddr_t va;
>  	paddr_t pa;
>  	pt_entry_t *pte, opte, npte;
> Index: ./arch/mips64/mips64/db_machdep.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/mips64/mips64/db_machdep.c,v
> diff -u -p -r1.60 db_machdep.c
> --- ./arch/mips64/mips64/db_machdep.c	11 Jan 2023 03:17:56 -0000	1.60
> +++ ./arch/mips64/mips64/db_machdep.c	8 Feb 2024 15:43:26 -0000
> @@ -281,8 +281,10 @@ db_cpuinfo_cmd(db_expr_t addr, int have_
>  #endif
>  
>  void
> -db_read_bytes(vaddr_t addr, size_t size, char *data)
> +db_read_bytes(vaddr_t addr, size_t size, void *datap)
>  {
> +	char *data = datap;
> +
>  	while (size >= sizeof(uint32_t)) {
>  		*(uint32_t *)data = kdbpeek(addr);
>  		data += sizeof(uint32_t);
> @@ -302,8 +304,9 @@ db_read_bytes(vaddr_t addr, size_t size,
>  }
>  
>  void
> -db_write_bytes(vaddr_t addr, size_t size, char *data)
> +db_write_bytes(vaddr_t addr, size_t size, void *datap)
>  {
> +	char *data = datap;
>  	vaddr_t ptr = addr;
>  	size_t len = size;
>  
> Index: ./arch/powerpc/ddb/db_memrw.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/powerpc/ddb/db_memrw.c,v
> diff -u -p -r1.6 db_memrw.c
> --- ./arch/powerpc/ddb/db_memrw.c	15 Oct 2022 08:04:02 -0000	1.6
> +++ ./arch/powerpc/ddb/db_memrw.c	8 Feb 2024 15:43:26 -0000
> @@ -53,9 +53,9 @@
>   * Read bytes from kernel address space for debugger.
>   */
>  void
> -db_read_bytes(vaddr_t addr, size_t size, char *data)
> +db_read_bytes(vaddr_t addr, size_t size, void *datap)
>  {
> -	char	*src = (char *)addr;
> +	char *data = datap, *src = (char *)addr;
>  	faultbuf env;
>  	faultbuf *old_onfault = curpcb->pcb_onfault;
>  	if (setfault(&env)) {
> @@ -80,9 +80,9 @@ db_read_bytes(vaddr_t addr, size_t size,
>   * Write bytes to kernel address space for debugger.
>   */
>  void
> -db_write_bytes(vaddr_t addr, size_t size, char *data)
> +db_write_bytes(vaddr_t addr, size_t size, void *datap)
>  {
> -	char	*dst = (char *)addr;
> +	char *data = datap, *dst = (char *)addr;
>  	faultbuf env;
>  	faultbuf *old_onfault = curpcb->pcb_onfault;
>  
> Index: ./arch/powerpc64/powerpc64/db_memrw.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/powerpc64/powerpc64/db_memrw.c,v
> diff -u -p -r1.2 db_memrw.c
> --- ./arch/powerpc64/powerpc64/db_memrw.c	12 Jun 2020 22:01:01 -0000	1.2
> +++ ./arch/powerpc64/powerpc64/db_memrw.c	8 Feb 2024 15:43:26 -0000
> @@ -46,9 +46,9 @@
>   * Read bytes from kernel address space for debugger.
>   */
>  void
> -db_read_bytes(vaddr_t addr, size_t size, char *data)
> +db_read_bytes(vaddr_t addr, size_t size, void *datap)
>  {
> -	char *src;
> +	char *data = datap, *src;
>  
>  	src = (char *)addr;
>  
> @@ -76,13 +76,13 @@ db_read_bytes(vaddr_t addr, size_t size,
>   * pages writable temporarily.
>   */
>  void
> -db_write_text(vaddr_t addr, size_t size, char *data)
> +db_write_text(vaddr_t addr, size_t size, void *datap)
>  {
>  	struct pte *pte;
>  	uint64_t old_pte_lo;
>  	vaddr_t pgva;
>  	size_t limit;
> -	char *dst;
> +	char *data = datap, *dst;
>  
>  	if (size == 0)
>  		return;
> Index: ./arch/riscv64/riscv64/db_interface.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/riscv64/riscv64/db_interface.c,v
> diff -u -p -r1.8 db_interface.c
> --- ./arch/riscv64/riscv64/db_interface.c	14 Apr 2022 19:47:11 -0000	1.8
> +++ ./arch/riscv64/riscv64/db_interface.c	8 Feb 2024 15:43:27 -0000
> @@ -179,9 +179,9 @@ db_validate_address(vaddr_t addr)
>   * Read bytes from kernel address space for debugger.
>   */
>  void
> -db_read_bytes(vaddr_t addr, size_t size, char *data)
> +db_read_bytes(vaddr_t addr, size_t size, void *datap)
>  {
> -	char	*src = (char *)addr;
> +	char	*data = datap, *src = (char *)addr;
>  
>  	if (db_validate_address((vaddr_t)src)) {
>  		db_printf("address %p is invalid\n", src);
> @@ -217,7 +217,7 @@ db_read_bytes(vaddr_t addr, size_t size,
>   * Write bytes to kernel address space for debugger.
>   */
>  void
> -db_write_bytes(vaddr_t addr, size_t size, char *data)
> +db_write_bytes(vaddr_t addr, size_t size, void *datap)
>  {
>  	// XXX
>  }
> Index: ./arch/sh/sh/db_memrw.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/sh/sh/db_memrw.c,v
> diff -u -p -r1.1.1.1 db_memrw.c
> --- ./arch/sh/sh/db_memrw.c	6 Oct 2006 21:02:55 -0000	1.1.1.1
> +++ ./arch/sh/sh/db_memrw.c	8 Feb 2024 15:43:27 -0000
> @@ -49,9 +49,9 @@
>   * Read bytes from kernel address space for debugger.
>   */
>  void
> -db_read_bytes(vaddr_t addr, size_t size, char *data)
> +db_read_bytes(vaddr_t addr, size_t size, void *datap)
>  {
> -	char *src = (char *)addr;
> +	char *data = datap, *src = (char *)addr;
>  
>  	/* properly aligned 4-byte */
>  	if (size == 4 && ((addr & 3) == 0) && (((uintptr_t)data & 3) == 0)) {
> @@ -73,9 +73,9 @@ db_read_bytes(vaddr_t addr, size_t size,
>   * Write bytes to kernel address space for debugger.
>   */
>  void
> -db_write_bytes(vaddr_t addr, size_t size, char *data)
> +db_write_bytes(vaddr_t addr, size_t size, void *datap)
>  {
> -	char *dst = (char *)addr;
> +	char *data = datap, *dst = (char *)addr;
>  
>  	/* properly aligned 4-byte */
>  	if (size == 4 && ((addr & 3) == 0) && (((uintptr_t)data & 3) == 0)) {
> Index: ./arch/sparc64/sparc64/db_interface.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/sparc64/sparc64/db_interface.c,v
> diff -u -p -r1.61 db_interface.c
> --- ./arch/sparc64/sparc64/db_interface.c	31 Jan 2023 15:18:55 -0000	1.61
> +++ ./arch/sparc64/sparc64/db_interface.c	8 Feb 2024 15:43:27 -0000
> @@ -523,8 +523,9 @@ db_stopcpu(struct cpu_info *ci)
>   * Read bytes from kernel address space for debugger.
>   */
>  void
> -db_read_bytes(vaddr_t addr, size_t size, char *data)
> +db_read_bytes(vaddr_t addr, size_t size, void *datap)
>  {
> +	char *data = datap;
>  	register char	*src;
>  
>  	src = (char *)addr;
> @@ -541,8 +542,9 @@ db_read_bytes(vaddr_t addr, size_t size,
>   * Write bytes to kernel address space for debugger.
>   */
>  void
> -db_write_bytes(vaddr_t addr, size_t size, char *data)
> +db_write_bytes(vaddr_t addr, size_t size, void *datap)
>  {
> +	char *data = datap;
>  	register char	*dst;
>  	extern vaddr_t ktext;
>  	extern paddr_t ktextp;
> Index: arch/arm/arm/db_interface.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/arm/arm/db_interface.c,v
> diff -u -p -r1.20 db_interface.c
> --- arch/arm/arm/db_interface.c	15 Oct 2022 08:04:02 -0000	1.20
> +++ arch/arm/arm/db_interface.c	8 Feb 2024 15:43:27 -0000
> @@ -182,9 +182,9 @@ db_validate_address(vaddr_t addr)
>   * Read bytes from kernel address space for debugger.
>   */
>  void
> -db_read_bytes(vaddr_t addr, size_t size, char *data)
> +db_read_bytes(vaddr_t addr, size_t size, void *datap)
>  {
> -	char	*src = (char *)addr;
> +	char *data = datap, *src = (char *)addr;
>  
>  	if (db_validate_address((u_int)src)) {
>  		db_printf("address %p is invalid\n", src);
> @@ -211,14 +211,14 @@ db_read_bytes(vaddr_t addr, size_t size,
>  }
>  
>  static void
> -db_write_text(vaddr_t addr, size_t size, char *data)
> +db_write_text(vaddr_t addr, size_t size, void *datap)
>  {        
>  	struct pmap *pmap = pmap_kernel();
>  	pd_entry_t *pde, oldpde, tmppde;
>  	pt_entry_t *pte, oldpte, tmppte;
>  	vaddr_t pgva;
>  	size_t limit, savesize;
> -	char *dst;
> +	char *data = datap, *dst;
>  
>  	/* XXX: gcc */
>  	oldpte = 0;
> @@ -434,7 +434,7 @@ db_branch_taken(u_int insn, vaddr_t pc, 
>  	case 0x7:	/* ldr pc, [pc, reg, lsl #2] */
>  		addr = db_fetch_reg(insn & 0xf, db_regs);
>  		addr = pc + 8 + (addr << 2);
> -		db_read_bytes(addr, 4, (char *)&addr);
> +		db_read_bytes(addr, sizeof addr, &addr);
>  		return (addr);
>  	case 0x1:	/* mov pc, reg */
>  		addr = db_fetch_reg(insn & 0xf, db_regs);
> @@ -460,7 +460,7 @@ db_branch_taken(u_int insn, vaddr_t pc, 
>  			addr = addr + 4 + ((nregs - 1) << 2);
>  			break;
>  		}
> -		db_read_bytes(addr, 4, (char *)&addr);
> +		db_read_bytes(addr, sizeof addr, &addr);
>  		return (addr);
>  	default:
>  		panic("branch_taken: botch");
> Index: arch/arm64/arm64/db_trace.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/arm64/arm64/db_trace.c,v
> diff -u -p -r1.15 db_trace.c
> --- arch/arm64/arm64/db_trace.c	17 Jun 2023 08:13:56 -0000	1.15
> +++ arch/arm64/arm64/db_trace.c	8 Feb 2024 15:43:27 -0000
> @@ -86,10 +86,8 @@ db_stack_trace_print(db_expr_t addr, int
>  			lastlr =  p->p_addr->u_pcb.pcb_tf->tf_elr;
>  		} else {
>  			sp = addr;
> -			db_read_bytes(sp, sizeof(vaddr_t),
> -			    (char *)&frame);
> -			db_read_bytes(sp + 8, sizeof(vaddr_t),
> -			    (char *)&lr);
> +			db_read_bytes(sp, sizeof frame, &frame);
> +			db_read_bytes(sp + 8, sizeof lr, &lr);
>  			lastlr = 0;
>  		}
>  	}
> @@ -109,11 +107,11 @@ db_stack_trace_print(db_expr_t addr, int
>  		(*pr)("\n");
>  
>  		// can we detect traps ?
> -		db_read_bytes(frame, sizeof(vaddr_t), (char *)&frame);
> +		db_read_bytes(frame, sizeof frame, &frame);
>  		if (frame == 0)
>  			break;
>  		lastlr = lr;
> -		db_read_bytes(frame + 8, sizeof(vaddr_t), (char *)&lr);
> +		db_read_bytes(frame + 8, sizeof lr, &lr);
>  
>  		if (name != NULL) {
>  			if ((strcmp (name, "handle_el0_irq") == 0) ||
> Index: arch/m88k/m88k/db_sstep.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/m88k/m88k/db_sstep.c,v
> diff -u -p -r1.8 db_sstep.c
> --- arch/m88k/m88k/db_sstep.c	8 Nov 2019 15:01:15 -0000	1.8
> +++ arch/m88k/m88k/db_sstep.c	8 Feb 2024 15:43:27 -0000
> @@ -149,7 +149,7 @@ db_set_single_step(db_regs_t *regs)
>  		 * User was stopped at pc, e.g. the instruction
>  		 * at pc was not executed.
>  		 */
> -		db_read_bytes(pc, sizeof(inst), (caddr_t)&inst);
> +		db_read_bytes(pc, sizeof inst, &inst);
>  
>  		/*
>  		 * Find if this instruction may cause a branch, and set up a
> Index: arch/m88k/m88k/db_trace.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/m88k/m88k/db_trace.c,v
> diff -u -p -r1.19 db_trace.c
> --- arch/m88k/m88k/db_trace.c	11 Apr 2023 00:45:07 -0000	1.19
> +++ arch/m88k/m88k/db_trace.c	8 Feb 2024 15:43:27 -0000
> @@ -286,7 +286,7 @@ db_trace_get_val(vaddr_t addr, u_int *pt
>  		db_recover = prev;
>  		return 0;
>  	} else {
> -		db_read_bytes(addr, 4, (char *)ptr);
> +		db_read_bytes(addr, sizeof *ptr, ptr);
>  		db_recover = prev;
>  		return 1;
>  	}
> @@ -772,7 +772,7 @@ db_stack_trace_cmd2(db_regs_t *regs, int
>  		    badaddr((vaddr_t)(stack + 4), 4))
>  			break;
>  
> -		db_read_bytes((vaddr_t)stack, 2 * sizeof(int), (char *)pair);
> +		db_read_bytes((vaddr_t)stack, sizeof pair, pair);
>  
>  		/* the pairs should match and equal stack+8 */
>  		if (pair[0] == pair[1]) {
> Index: arch/powerpc/ddb/db_trace.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/powerpc/ddb/db_trace.c,v
> diff -u -p -r1.20 db_trace.c
> --- arch/powerpc/ddb/db_trace.c	26 Apr 2023 16:53:59 -0000	1.20
> +++ arch/powerpc/ddb/db_trace.c	8 Feb 2024 15:43:27 -0000
> @@ -158,7 +158,7 @@ db_stack_trace_print(db_expr_t addr, int
>  			addr = p->p_addr->u_pcb.pcb_sp;
>  		}
>  		sp = addr;
> -		db_read_bytes(sp + 4, sizeof(vaddr_t), (char *)&lr);
> +		db_read_bytes(sp + 4, sizeof lr, &lr);
>  	}
>  
>  	while (count && sp != 0) {
> @@ -213,11 +213,11 @@ db_stack_trace_print(db_expr_t addr, int
>  				(*pr)("--- trap (type 0x%x) ---\n", type);
>  		}
>  
> -		db_read_bytes(sp, sizeof(vaddr_t), (char *)&sp);
> +		db_read_bytes(sp, sizeof sp, &sp);
>  		if (sp == 0)
>  			break;
>  
> -		db_read_bytes(sp + 4, sizeof(vaddr_t), (char *)&lr);
> +		db_read_bytes(sp + 4, sizeof lr, &lr);
>  
>  		if (INKERNEL(sp)) {
>  			if (sp <= lastsp) {
> Index: arch/powerpc64/powerpc64/db_trace.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/powerpc64/powerpc64/db_trace.c,v
> diff -u -p -r1.9 db_trace.c
> --- arch/powerpc64/powerpc64/db_trace.c	26 Apr 2023 16:53:59 -0000	1.9
> +++ arch/powerpc64/powerpc64/db_trace.c	8 Feb 2024 15:43:27 -0000
> @@ -120,8 +120,8 @@ db_stack_trace_print(db_expr_t addr, int
>  		} else
>  			sp = addr;
>  		/* The 1st return address is in the 2nd frame. */
> -		db_read_bytes(sp, sizeof(vaddr_t), (char *)&sp);
> -		db_read_bytes(sp + 16, sizeof(vaddr_t), (char *)&lr);
> +		db_read_bytes(sp, sizeof sp, &sp);
> +		db_read_bytes(sp + 16, sizeof lr, &lr);
>  		callpc = lr - 4;
>  		has_frame = 1;
>  	}
> @@ -138,8 +138,7 @@ db_stack_trace_print(db_expr_t addr, int
>  			iaddr = sym->st_value;
>  			limit = MIN(iaddr + 0x100, callpc);
>  			for (; iaddr < limit; iaddr += 4) {
> -				db_read_bytes(iaddr, sizeof(ins),
> -				    (char *)&ins);
> +				db_read_bytes(iaddr, sizeof ins, &ins);
>  				if (inst_establish_frame(ins)) {
>  					has_frame = 1;
>  					break;
> @@ -178,14 +177,14 @@ db_stack_trace_print(db_expr_t addr, int
>  			lr = ddb_regs.lr;
>  			has_frame = 1;
>  		} else {
> -			db_read_bytes(sp, sizeof(vaddr_t), (char *)&sp);
> +			db_read_bytes(sp, sizeof sp, &sp);
>  			if (sp == 0)
>  				break;
>  			if (sp <= lastsp) {
>  				(*pr)("Bad frame pointer: 0x%lx\n", sp);
>  				break;
>  			}
> -			db_read_bytes(sp + 16, sizeof(vaddr_t), (char *)&lr);
> +			db_read_bytes(sp + 16, sizeof lr, &lr);
>  		}
>  		callpc = lr - 4;
>  
> Index: arch/riscv64/riscv64/db_trace.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/riscv64/riscv64/db_trace.c,v
> diff -u -p -r1.5 db_trace.c
> --- arch/riscv64/riscv64/db_trace.c	22 Feb 2022 07:46:04 -0000	1.5
> +++ arch/riscv64/riscv64/db_trace.c	8 Feb 2024 15:43:27 -0000
> @@ -74,8 +74,8 @@ db_stack_trace_print(db_expr_t addr, int
>  		ra = ddb_regs.tf_ra;
>  		frame = ddb_regs.tf_s[0];
>  	} else {
> -		db_read_bytes(addr - 16, sizeof(vaddr_t), (char *)&frame);
> -		db_read_bytes(addr - 8, sizeof(vaddr_t), (char *)&ra);
> +		db_read_bytes(addr - 16, sizeof frame, &frame);
> +		db_read_bytes(addr - 8, sizeof ra, &ra);
>  	}
>  
>  	while (count != 0 && frame != 0) {
> @@ -109,20 +109,18 @@ db_stack_trace_print(db_expr_t addr, int
>  		    subr == (vaddr_t)cpu_exception_handler_user) {
>  			struct trapframe *tf = (struct trapframe *)frame;
>  
> -			db_read_bytes((vaddr_t)&tf->tf_ra, sizeof(ra),
> -			    (char *)&ra);
> -			db_read_bytes((vaddr_t)&tf->tf_s[0], sizeof(frame),
> -			    (char *)&frame);
> +			db_read_bytes((vaddr_t)&tf->tf_ra, sizeof ra, &ra);
> +			db_read_bytes((vaddr_t)&tf->tf_s[0], sizeof frame,
> +			    &frame);
>  		} else {
> -			db_read_bytes(frame - 16, sizeof(frame),
> -			    (char *)&frame);
> +			db_read_bytes(frame - 16, sizeof frame, &frame);
>  			if (frame == 0)
>  				break;
>  			if ((frame & 0x7) != 0) {
>  				(*pr)("bad frame pointer: 0x%lx\n", frame);
>  				break;
>  			}
> -			db_read_bytes(frame - 8, sizeof(ra), (char *)&ra);
> +			db_read_bytes(frame - 8, sizeof ra, &ra);
>  		}
>  
>  		if (INKERNEL(frame)) {