From b551c62a7ff4e97a947486904f09a2356f27ced5 Mon Sep 17 00:00:00 2001 From: Matthias Welwarsky Date: Thu, 5 Oct 2017 14:50:16 +0200 Subject: [PATCH] cortex_a: fix handling of Thumb-2 32bit breakpoints When debugging Thumb-2 code, Gdb will at times send a breakpoint packet 'Z0,,3', the number 3 denoting that the instruction to break on is 32 bits long. Handle this by replacing it with two consecutive 16bit Thumb BKPTs and make sure to save and restore the full, original 32bit instruction. Note that this fix is only applicable if you debug a bare-metal program (like the linux kernel) with the 'wrong' gdb, e.g. use an "arm-linux" gdb instead of an "arm-eabi" gdb. But since most people may not know about the subtle differences between gdb configurations regarding thumb2 breakpoints it's still valid. Change-Id: Ib93025faf35b11f0dba747a8c1fc36fd09a4c0f8 Signed-off-by: Matthias Welwarsky Reviewed-on: http://openocd.zylin.com/4241 Reviewed-by: Matthias Welwarsky Tested-by: jenkins --- src/target/cortex_a.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/src/target/cortex_a.c b/src/target/cortex_a.c index 672a300e..9f7e38ef 100644 --- a/src/target/cortex_a.c +++ b/src/target/cortex_a.c @@ -1500,10 +1500,22 @@ static int cortex_a_set_breakpoint(struct target *target, brp_list[brp_i].value); } else if (breakpoint->type == BKPT_SOFT) { uint8_t code[4]; + /* length == 2: Thumb breakpoint */ if (breakpoint->length == 2) buf_set_u32(code, 0, 32, ARMV5_T_BKPT(0x11)); else + /* length == 3: Thumb-2 breakpoint, actual encoding is + * a regular Thumb BKPT instruction but we replace a + * 32bit Thumb-2 instruction, so fix-up the breakpoint + * length + */ + if (breakpoint->length == 3) { + buf_set_u32(code, 0, 32, ARMV5_T_BKPT(0x11)); + breakpoint->length = 4; + } else + /* length == 4, normal ARM breakpoint */ buf_set_u32(code, 0, 32, ARMV5_BKPT(0x11)); + retval = target_read_memory(target, breakpoint->address & 0xFFFFFFFE, breakpoint->length, 1, -- 2.39.5