Date: Sat, 27 Jun 2020 15:51:10 +0000 From: adr@SDF.ORG To: freebsd-arm@freebsd.org Subject: calling mmap from assembly, invalid argument Message-ID: <20200627155110.GA22042@SDF.ORG>
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Hello,
I can't make a simple call to mmap.
I'm not using system calls because I've to use other c functions
in the real code, so there is not gain following the possible
changes on the syscalls.
I should be missing something.
I've used clang in openbsd without a problem.
I'll appreciate any help.
adr
============================================
% uname -a
FreeBSD fbsd 13.0-CURRENT FreeBSD 13.0-CURRENT #0 r362037: Thu Jun 11 05:06:50 UTC 2020
root@releng1.nyi.freebsd.org:/usr/obj/usr/src/arm.armv7/sys/GENERIC arm
It doesn't matter if I assemble the code with gas.
% clang -o test test.s
% ./test
Invalid argument
mmap addr: 0xffffffff
==============================
.syntax unified
@ /usr/include/sys/mman.h
PROT_READ = 1
PROT_WRITE = 2
MAP_PRIVATE = 2
MAP_ANONYMOUS = 0x1000
.data
ostr:
.string "mmap addr: %#x\n"
.align
.text
.global main
main:
mov r5, 0 @ offset
mov r4, -1 @ fd
push {r4, r5}
mov r3, MAP_ANONYMOUS|MAP_PRIVATE
mov r2, PROT_READ|PROT_WRITE
mov r1, 4096 @ len
mov r0, 0 @ addr
bl mmap
mov r5, r0
mov r0, 0
bl perror
ldr r0, =ostr
mov r1, r5
bl printf
mov r0, 0
bl fflush
b exit
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