If I won't make that change it gives me immediate error as follows: Taking exception 18 [v7M INVSTATE UsageFault] ...BusFault with BFSR.STKERR ...taking pending nonsecure exception 3 qemu: fatal: Lockup: can't take terminal derived exception (original exception priority -1)
BR. Abhijeet. On Thu, Dec 16, 2021 at 9:02 PM abhijeet inamdar < abhijeetinamdar3...@gmail.com> wrote: > I made some changes to the code in qemu : > https://github.com/qemu/qemu/blob/stable-6.0/target/arm/cpu.c#L339 . I > have commented out the variable vecbase and directly given the address of > my vector address(not zero) or where they are located in our binary file. > Is that a problem? > > BR. > Abhijeet. > > On Thu, Dec 16, 2021 at 7:47 PM Peter Maydell <peter.mayd...@linaro.org> > wrote: > >> On Thu, 16 Dec 2021 at 17:44, Philippe Mathieu-Daudé <f4...@amsat.org> >> wrote: >> > >> > Cc'ing qemu-arm developers. >> > >> > On 12/16/21 18:31, abhijeet inamdar wrote: >> > > Hi, >> > > >> > > I was running my .elf file on my custom machine(CM3) and was hit with >> > > this error when debugging and had the required -d flags and single >> stepping. >> > > >> > > IN: Hal_MemFault >> > > 0x7004e794: 4770 bx lr >> > > >> > > Trace 0: 0x7f4faa471100 [00000000/7004e794/0x312000c1] Hal_MemFault >> > > R00=7004938d R01=00000000 R02=7004938c R03=ffffffff >> > > R04=7005e410 R05=10020000 R06=e000eda0 R07=00000000 >> > > R08=00000010 R09=1003f8e0 R10=e000ed94 R11=00000000 >> > > R12=ffffffff R13=1003dbe0 R14=fffffff9 R15=7004e794 >> > > XPSR=01000003 ---- T handler >> > > Taking exception 8 [QEMU v7M exception exit] >> > > Exception return: magic PC fffffff9 previous exception 3 >> > > M profile return from interrupt with misaligned PC is UNPREDICTABLE >> on v7M >> > > ...successful exception return >> > > DRBAR[6]: 0xa0000000 misaligned to DRSR region size, mask = 0x3fffffff >> > > Taking exception 3 [Prefetch Abort] >> > > ...with CFSR.IACCVIOL >> > > ...taking pending nonsecure exception 3 >> >> The logging here tells you what happened: >> >> * we are in an exception handler >> * we do the bx lr to magic value which is M-profile's exception-return >> * ...but there's something wrong with the return address we pull >> off the stack, because it's not an aligned value (its least >> significant bit is set) >> * moreover, it's an address that corresponds to an MPU region >> that has been misprogrammed (the DRBAR value isn't right); >> the MPU treats such regions as not matching >> * and so we take an instruction access fault >> >> So you have two problems: >> (1) the PC value on the stack that you're trying to return to is wrong >> (2) you're programming the MPU wrong >> >> You need to investigate and fix both. >> >> -- PMM >> >
