From b430d0a1520903213e0796e9fcbc5ab180f1fbe8 Mon Sep 17 00:00:00 2001 From: Matthias Welwarsky Date: Mon, 19 Sep 2016 17:04:03 +0200 Subject: [PATCH] aarch64: disable interrupts when stepping [WIP] On live hardware, interrupts will happen while the core is held for stepping. The next step will most of the time execute an interrupt service instead of the next line of code, which is not what you expect. Disable interrupts through DSCR before resuming for a step, and re-enable them again after the step happened. This should be made configurable, like on cortex_a target. Change-Id: I94d8ffb58cf7579dedb66bc756b7eb6828b6e8e4 Signed-off-by: Matthias Welwarsky --- src/target/aarch64.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/src/target/aarch64.c b/src/target/aarch64.c index d38e0428..88f9b5a4 100644 --- a/src/target/aarch64.c +++ b/src/target/aarch64.c @@ -1241,6 +1241,28 @@ static int aarch64_post_debug_entry(struct target *target) return ERROR_OK; } +static int aarch64_set_dscr_bits(struct target *target, unsigned long bit_mask, unsigned long value) +{ + struct armv8_common *armv8 = target_to_armv8(target); + uint32_t dscr; + + /* Read DSCR */ + int retval = mem_ap_read_atomic_u32(armv8->debug_ap, + armv8->debug_base + CPUV8_DBG_DSCR, &dscr); + if (ERROR_OK != retval) + return retval; + + /* clear bitfield */ + dscr &= ~bit_mask; + /* put new value */ + dscr |= value & bit_mask; + + /* write new DSCR */ + retval = mem_ap_write_atomic_u32(armv8->debug_ap, + armv8->debug_base + CPUV8_DBG_DSCR, dscr); + return retval; +} + static int aarch64_step(struct target *target, int current, target_addr_t address, int handle_breakpoints) { @@ -1267,6 +1289,11 @@ static int aarch64_step(struct target *target, int current, target_addr_t addres if (retval != ERROR_OK) return retval; + /* disable interrupts while stepping */ + retval = aarch64_set_dscr_bits(target, 0x3 << 22, 0x3 << 22); + if (retval != ERROR_OK) + return ERROR_OK; + /* resume the target */ retval = aarch64_resume(target, current, address, 0, 0); if (retval != ERROR_OK) @@ -1289,6 +1316,11 @@ static int aarch64_step(struct target *target, int current, target_addr_t addres if (retval != ERROR_OK) return retval; + /* restore interrupts */ + retval = aarch64_set_dscr_bits(target, 0x3 << 22, 0); + if (retval != ERROR_OK) + return ERROR_OK; + return ERROR_OK; } -- 2.39.5