USRTEXT used to be the address of the beginning of the a.out code segment. Today's world is ELF and PIE binaries, and USRTEXT has no meaning.
The following diff removes it, as well as trivial or no longer true comments. Index: sys/arch/alpha/include/vmparam.h =================================================================== RCS file: /OpenBSD/src/sys/arch/alpha/include/vmparam.h,v retrieving revision 1.27 diff -u -p -r1.27 vmparam.h --- sys/arch/alpha/include/vmparam.h 8 Feb 2015 03:48:25 -0000 1.27 +++ sys/arch/alpha/include/vmparam.h 25 Sep 2015 18:12:52 -0000 @@ -46,18 +46,6 @@ * Machine dependent constants for Alpha. */ -/* - * USRTEXT is the start of the user text/data space, while USRSTACK - * is the top (end) of the user stack. Immediately above the user stack - * resides the user structure, which is UPAGES long and contains the - * kernel stack. - * - * Digital UNIX (formerly DEC OSF/1) places the stack below the - * text segment (i.e. growing downward from 4G). We may want to - * consider doing that at some point, but it might require changes - * to the exec code. - */ -#define USRTEXT PAGE_SIZE #define USRSTACK ((vaddr_t)0x0000000200000000) /* 8G */ /* Index: sys/arch/arm/include/vmparam.h =================================================================== RCS file: /OpenBSD/src/sys/arch/arm/include/vmparam.h,v retrieving revision 1.15 diff -u -p -r1.15 vmparam.h --- sys/arch/arm/include/vmparam.h 10 May 2015 15:56:28 -0000 1.15 +++ sys/arch/arm/include/vmparam.h 25 Sep 2015 18:12:52 -0000 @@ -43,7 +43,6 @@ * Virtual Memory parameters common to all arm32 platforms. */ -#define USRTEXT VM_MIN_ADDRESS #define USRSTACK VM_MAXUSER_ADDRESS #define KERNBASE VM_MAXUSER_ADDRESS Index: sys/arch/hppa/include/vmparam.h =================================================================== RCS file: /OpenBSD/src/sys/arch/hppa/include/vmparam.h,v retrieving revision 1.46 diff -u -p -r1.46 vmparam.h --- sys/arch/hppa/include/vmparam.h 10 Feb 2015 10:02:55 -0000 1.46 +++ sys/arch/hppa/include/vmparam.h 25 Sep 2015 18:12:52 -0000 @@ -29,13 +29,8 @@ /* * Machine dependent constants for HP PA */ -/* - * USRTEXT is the start of the user text/data space, while USRSTACK - * is the bottm (start) of the user stack. - */ -#define USRTEXT PAGE_SIZE /* Start of user .text */ -#define USRSTACK 0x78000000UL /* Start of user stack */ -#define SYSCALLGATE 0xC0000000 /* syscall gateway page */ +#define USRSTACK 0x78000000UL /* start (bottom) of user stack */ +#define SYSCALLGATE 0xC0000000 /* syscall gateway page */ /* * Virtual memory related constants, all in bytes Index: sys/arch/hppa64/include/vmparam.h =================================================================== RCS file: /OpenBSD/src/sys/arch/hppa64/include/vmparam.h,v retrieving revision 1.14 diff -u -p -r1.14 vmparam.h --- sys/arch/hppa64/include/vmparam.h 10 Feb 2015 10:02:55 -0000 1.14 +++ sys/arch/hppa64/include/vmparam.h 25 Sep 2015 18:12:52 -0000 @@ -29,13 +29,8 @@ /* * Machine dependent constants for HP PA */ -/* - * USRTEXT is the start of the user text/data space, while USRSTACK - * is the bottm (start) of the user stack. - */ -#define USRTEXT PAGE_SIZE /* Start of user .text */ -#define USRSTACK 0x68FF3000 /* Start of user stack */ -#define SYSCALLGATE 0xC0000000 /* syscall gateway page */ +#define USRSTACK 0x68FF3000 /* start (bottom) of user stack */ +#define SYSCALLGATE 0xC0000000 /* syscall gateway page */ /* * Virtual memory related constants, all in bytes Index: sys/arch/i386/include/vmparam.h =================================================================== RCS file: /OpenBSD/src/sys/arch/i386/include/vmparam.h,v retrieving revision 1.54 diff -u -p -r1.54 vmparam.h --- sys/arch/i386/include/vmparam.h 26 Apr 2015 09:22:33 -0000 1.54 +++ sys/arch/i386/include/vmparam.h 25 Sep 2015 18:12:52 -0000 @@ -41,18 +41,6 @@ * Machine dependent constants for 386. */ -/* - * Virtual address space arrangement. On 386, both user and kernel - * share the address space, not unlike the vax. - * USRTEXT is the start of the user text/data space, while USRSTACK - * is the top (end) of the user stack. Immediately above the user stack - * resides the user structure, which is UPAGES long and contains the - * kernel stack. - * - * Immediately after the user structure is the page table map, and then - * kernel address space. - */ -#define USRTEXT PAGE_SIZE #define USRSTACK VM_MAXUSER_ADDRESS /* Index: sys/arch/m88k/include/vmparam.h =================================================================== RCS file: /OpenBSD/src/sys/arch/m88k/include/vmparam.h,v retrieving revision 1.19 diff -u -p -r1.19 vmparam.h --- sys/arch/m88k/include/vmparam.h 10 Feb 2015 10:02:55 -0000 1.19 +++ sys/arch/m88k/include/vmparam.h 25 Sep 2015 18:12:52 -0000 @@ -33,11 +33,6 @@ #ifndef _MACHINE_VM_PARAM_ #define _MACHINE_VM_PARAM_ -/* - * USRTEXT is the start of the user text/data space, while USRSTACK - * is the top (end) of the user stack. - */ -#define USRTEXT 0x1000 /* Start of user text */ #define USRSTACK VM_MAXUSER_ADDRESS /* Start of user stack */ /* Index: sys/arch/macppc/include/vmparam.h =================================================================== RCS file: /OpenBSD/src/sys/arch/macppc/include/vmparam.h,v retrieving revision 1.30 diff -u -p -r1.30 vmparam.h --- sys/arch/macppc/include/vmparam.h 10 Feb 2015 10:02:55 -0000 1.30 +++ sys/arch/macppc/include/vmparam.h 25 Sep 2015 18:12:52 -0000 @@ -35,7 +35,6 @@ #ifndef MACHINE_VMPARAM_H #define MACHINE_VMPARAM_H -#define USRTEXT PAGE_SIZE #define USRSTACK VM_MAXUSER_ADDRESS #ifndef MAXTSIZ Index: sys/arch/socppc/include/vmparam.h =================================================================== RCS file: /OpenBSD/src/sys/arch/socppc/include/vmparam.h,v retrieving revision 1.12 diff -u -p -r1.12 vmparam.h --- sys/arch/socppc/include/vmparam.h 10 Feb 2015 10:02:55 -0000 1.12 +++ sys/arch/socppc/include/vmparam.h 25 Sep 2015 18:12:52 -0000 @@ -35,7 +35,6 @@ #ifndef MACHINE_VMPARAM_H #define MACHINE_VMPARAM_H -#define USRTEXT PAGE_SIZE #define USRSTACK VM_MAXUSER_ADDRESS #ifndef MAXTSIZ Index: sys/arch/sparc64/include/vmparam.h =================================================================== RCS file: /OpenBSD/src/sys/arch/sparc64/include/vmparam.h,v retrieving revision 1.31 diff -u -p -r1.31 vmparam.h --- sys/arch/sparc64/include/vmparam.h 10 Feb 2015 10:02:55 -0000 1.31 +++ sys/arch/sparc64/include/vmparam.h 25 Sep 2015 18:12:52 -0000 @@ -48,11 +48,6 @@ #ifndef VMPARAM_H #define VMPARAM_H -/* - * USRTEXT is the start of the user text/data space, while USRSTACK - * is the top (end) of the user stack. - */ -#define USRTEXT 0x2000 /* Start of user text */ #define USRSTACK 0xffffffffffffe000L /* Index: sys/arch/vax/include/vmparam.h =================================================================== RCS file: /OpenBSD/src/sys/arch/vax/include/vmparam.h,v retrieving revision 1.36 diff -u -p -r1.36 vmparam.h --- sys/arch/vax/include/vmparam.h 30 Jan 2014 18:16:41 -0000 1.36 +++ sys/arch/vax/include/vmparam.h 25 Sep 2015 18:12:52 -0000 @@ -43,13 +43,6 @@ * Machine dependent constants for VAX. */ -/* - * USRTEXT is the start of the user text/data space, while USRSTACK - * is the top (end) of the user stack. Immediately above the user stack - * resides kernel. - */ - -#define USRTEXT PAGE_SIZE #define USRSTACK KERNBASE /*
