Hi,
I think that there's a slight problem with this on BE systems.
On Sat, Nov 30, 2013 at 06:32:26AM +0000, vijay.kilari@gmail.com wrote:
From: Vijaya Kumar K Vijaya.Kumar@caviumnetworks.com
Add KGDB debug support for kernel debugging. With this patch, basic KGDB debugging is possible.GDB register layout is updated and GDB tool can establish connection with target and can set/clear breakpoints.
Signed-off-by: Vijaya Kumar K Vijaya.Kumar@caviumnetworks.com Reviewed-by: Will Deacon will.deacon@arm.com
arch/arm64/include/asm/debug-monitors.h | 47 +++++ arch/arm64/include/asm/kgdb.h | 86 +++++++++ arch/arm64/kernel/Makefile | 1 + arch/arm64/kernel/kgdb.c | 289 +++++++++++++++++++++++++++++++ 4 files changed, 423 insertions(+)
[...]
+struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
{ "x0", 8, offsetof(struct pt_regs, regs[0])},{ "x1", 8, offsetof(struct pt_regs, regs[1])},{ "x2", 8, offsetof(struct pt_regs, regs[2])},{ "x3", 8, offsetof(struct pt_regs, regs[3])},{ "x4", 8, offsetof(struct pt_regs, regs[4])},{ "x5", 8, offsetof(struct pt_regs, regs[5])},{ "x6", 8, offsetof(struct pt_regs, regs[6])},{ "x7", 8, offsetof(struct pt_regs, regs[7])},{ "x8", 8, offsetof(struct pt_regs, regs[8])},{ "x9", 8, offsetof(struct pt_regs, regs[9])},{ "x10", 8, offsetof(struct pt_regs, regs[10])},{ "x11", 8, offsetof(struct pt_regs, regs[11])},{ "x12", 8, offsetof(struct pt_regs, regs[12])},{ "x13", 8, offsetof(struct pt_regs, regs[13])},{ "x14", 8, offsetof(struct pt_regs, regs[14])},{ "x15", 8, offsetof(struct pt_regs, regs[15])},{ "x16", 8, offsetof(struct pt_regs, regs[16])},{ "x17", 8, offsetof(struct pt_regs, regs[17])},{ "x18", 8, offsetof(struct pt_regs, regs[18])},{ "x19", 8, offsetof(struct pt_regs, regs[19])},{ "x20", 8, offsetof(struct pt_regs, regs[20])},{ "x21", 8, offsetof(struct pt_regs, regs[21])},{ "x22", 8, offsetof(struct pt_regs, regs[22])},{ "x23", 8, offsetof(struct pt_regs, regs[23])},{ "x24", 8, offsetof(struct pt_regs, regs[24])},{ "x25", 8, offsetof(struct pt_regs, regs[25])},{ "x26", 8, offsetof(struct pt_regs, regs[26])},{ "x27", 8, offsetof(struct pt_regs, regs[27])},{ "x28", 8, offsetof(struct pt_regs, regs[28])},{ "x29", 8, offsetof(struct pt_regs, regs[29])},{ "x30", 8, offsetof(struct pt_regs, regs[30])},{ "sp", 8, offsetof(struct pt_regs, sp)},{ "pc", 8, offsetof(struct pt_regs, pc)},{ "pstate", 4, offsetof(struct pt_regs, pstate)},
As pt_regs::pstate is a u64, we're only describing half of the field here (to match GDB's expectations). While we happen to get the half we're interested in on an LE system, on a BE system this will point at the zeroed half.
[...]
+char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) +{
if (regno >= DBG_MAX_REG_NUM || regno < 0)return NULL;if (dbg_reg_def[regno].offset != -1)memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,dbg_reg_def[regno].size);
So here we'll read zeroes rather than the bits we're interested in.
elsememset(mem, 0, dbg_reg_def[regno].size);return dbg_reg_def[regno].name;+}
+int dbg_set_reg(int regno, void *mem, struct pt_regs *regs) +{
if (regno >= DBG_MAX_REG_NUM || regno < 0)return -EINVAL;if (dbg_reg_def[regno].offset != -1)memcpy((void *)regs + dbg_reg_def[regno].offset, mem,dbg_reg_def[regno].size);
And here we'll write to bits which should be zero, not the bits we're interested in.
[...]
+static struct notifier_block kgdb_notifier = {
.notifier_call = kgdb_notify,.priority = -INT_MAX,
On an unrelated note, is there a reason this isn't INT_MIN? This is one-off.
Thanks, Mark.