From: Matthias Welwarsky Date: Thu, 11 Apr 2019 08:22:27 +0000 (+0200) Subject: cortex_a: warn on broken debug_base setting X-Git-Tag: v0.11.0-rc1~408 X-Git-Url: https://review.openocd.org/gitweb?p=openocd.git;a=commitdiff_plain;h=afe899f938a8edb3657c9455fc5caefcaef7e65f cortex_a: warn on broken debug_base setting A common problem with target configurations appears to be broken debug base address configuration. ARM DDI0406C.d specifies in App. D, 1.4.1, that bit 31 of the debug base address serves as identification of an external debugger, as opposed to an internal access to memory mapped debug registers by the CPU. External accesses are treated as privileged and require no debug authentification via the lock access register. Sometimes the base address of a debug component is wrong even in the targets' ROM table. In this case, the correct base address must be specified using the -dbgbase argument when creating the target. This patch adds a warning when bit 31 of the debug base address is not set, as a hint to the user. Change-Id: I9c41d85a138123c657ef655e3436a2aa39249dcc Signed-off-by: Matthias Welwarsky Reviewed-on: http://openocd.zylin.com/5105 Tested-by: jenkins Reviewed-by: Tommy Vestermark Reviewed-by: Antonio Borneo --- diff --git a/src/target/cortex_a.c b/src/target/cortex_a.c index 8773ea1607..a79b0b9061 100644 --- a/src/target/cortex_a.c +++ b/src/target/cortex_a.c @@ -2718,6 +2718,10 @@ static int cortex_a_examine_first(struct target *target) } else armv7a->debug_base = target->dbgbase; + if ((armv7a->debug_base & (1UL<<31)) == 0) + LOG_WARNING("Debug base address for target %s has bit 31 set to 0. Access to debug registers will likely fail!\n" + "Please fix the target configuration.", target_name(target)); + retval = mem_ap_read_atomic_u32(armv7a->debug_ap, armv7a->debug_base + CPUDBG_DIDR, &didr); if (retval != ERROR_OK) {