target:armv8: aarch32 do not try to restore same EL

While debugging a Cortex-R52 OpenOCD fail to restore context
on line
retval = dpm->instr_write_data_r0(dpm,
		ARMV8_MSR_GP_xPSR_T1(1, 0, 15), cpsr);

which trigger this exception:

aarch64.c:1206 aarch64_restore_context(): r8a779a0.r52
armv8_dpm.c:560 armv8_dpm_modeswitch(): restoring mode, cpsr = 0x0000011f
1262753 armv8_dpm.c:598 armv8_dpm_modeswitch(): target_el = 1, last_el = 1
armv8_dpm.c:611 armv8_dpm_modeswitch(): SPSR = 0x0000011f
armv8_dpm.c:260 dpmv8_exec_opcode(): Opcode 0x8f00f390, DSCR.ERR=1, DSCR.EL=1

and finally OpenOCD doesn't succeed to restore the processor.

This check 'dpm->last_el != target_el' exist for aarch64,
so might be correct for aarch32 too.

Signed-off-by: Julien Massot <julien.massot@iot.bzh>
Change-Id: I41d1006233251dcaf6d69bda580488b204b7eb63
Reviewed-on: https://review.openocd.org/c/openocd/+/6807
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

diff --git a/src/target/armv8_dpm.c b/src/target/armv8_dpm.c
index f40beb847dfb895c9675d91714bbc7b9be1140a8..fcd4d5971e9d87b2cba8d1312785a24642b5fe41 100644 (file)
--- a/src/target/armv8_dpm.c
+++ b/src/target/armv8_dpm.c
@@ -587,6 +587,9 @@ int armv8_dpm_modeswitch(struct arm_dpm *dpm, enum arm_mode mode)
        }
 
        LOG_DEBUG("target_el = %i, last_el = %i", target_el, dpm->last_el);
+       if (dpm->last_el == target_el)
+               return ERROR_OK; /* nothing to do */
+
        if (target_el > dpm->last_el) {
                retval = dpm->instr_execute(dpm,
                                armv8_opcode(armv8, ARMV8_OPC_DCPS) | target_el);