From 5bc98f3a29f134f7fb22c5b16cca8b227b41b9fd Mon Sep 17 00:00:00 2001 From: "Russell King (Oracle)" Date: Wed, 16 Feb 2022 15:37:38 +0000 Subject: [PATCH] ARM: Fix kgdb breakpoint for Thumb2 The kgdb code needs to register an undef hook for the Thumb UDF instruction that will fault in order to be functional on Thumb2 platforms. Reported-by: Johannes Stezenbach Tested-by: Johannes Stezenbach Fixes: 1f8c3295963e ("kgdb: support for ARCH=arm") Signed-off-by: Russell King (Oracle) --- arch/arm/kernel/kgdb.c | 36 ++++++++++++++++++++++++++++-------- 1 file changed, 28 insertions(+), 8 deletions(-) diff --git a/arch/arm/kernel/kgdb.c b/arch/arm/kernel/kgdb.c index 7bd30c0a4280d..22f937e6f3ffb 100644 --- a/arch/arm/kernel/kgdb.c +++ b/arch/arm/kernel/kgdb.c @@ -154,22 +154,38 @@ static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int instr) return 0; } -static struct undef_hook kgdb_brkpt_hook = { +static struct undef_hook kgdb_brkpt_arm_hook = { .instr_mask = 0xffffffff, .instr_val = KGDB_BREAKINST, - .cpsr_mask = MODE_MASK, + .cpsr_mask = PSR_T_BIT | MODE_MASK, .cpsr_val = SVC_MODE, .fn = kgdb_brk_fn }; -static struct undef_hook kgdb_compiled_brkpt_hook = { +static struct undef_hook kgdb_brkpt_thumb_hook = { + .instr_mask = 0xffff, + .instr_val = KGDB_BREAKINST & 0xffff, + .cpsr_mask = PSR_T_BIT | MODE_MASK, + .cpsr_val = PSR_T_BIT | SVC_MODE, + .fn = kgdb_brk_fn +}; + +static struct undef_hook kgdb_compiled_brkpt_arm_hook = { .instr_mask = 0xffffffff, .instr_val = KGDB_COMPILED_BREAK, - .cpsr_mask = MODE_MASK, + .cpsr_mask = PSR_T_BIT | MODE_MASK, .cpsr_val = SVC_MODE, .fn = kgdb_compiled_brk_fn }; +static struct undef_hook kgdb_compiled_brkpt_thumb_hook = { + .instr_mask = 0xffff, + .instr_val = KGDB_COMPILED_BREAK & 0xffff, + .cpsr_mask = PSR_T_BIT | MODE_MASK, + .cpsr_val = PSR_T_BIT | SVC_MODE, + .fn = kgdb_compiled_brk_fn +}; + static int __kgdb_notify(struct die_args *args, unsigned long cmd) { struct pt_regs *regs = args->regs; @@ -210,8 +226,10 @@ int kgdb_arch_init(void) if (ret != 0) return ret; - register_undef_hook(&kgdb_brkpt_hook); - register_undef_hook(&kgdb_compiled_brkpt_hook); + register_undef_hook(&kgdb_brkpt_arm_hook); + register_undef_hook(&kgdb_brkpt_thumb_hook); + register_undef_hook(&kgdb_compiled_brkpt_arm_hook); + register_undef_hook(&kgdb_compiled_brkpt_thumb_hook); return 0; } @@ -224,8 +242,10 @@ int kgdb_arch_init(void) */ void kgdb_arch_exit(void) { - unregister_undef_hook(&kgdb_brkpt_hook); - unregister_undef_hook(&kgdb_compiled_brkpt_hook); + unregister_undef_hook(&kgdb_brkpt_arm_hook); + unregister_undef_hook(&kgdb_brkpt_thumb_hook); + unregister_undef_hook(&kgdb_compiled_brkpt_arm_hook); + unregister_undef_hook(&kgdb_compiled_brkpt_thumb_hook); unregister_die_notifier(&kgdb_notifier); } -- 2.39.5