From: Ada Couprie Diaz Date: Mon, 7 Jul 2025 11:41:09 +0000 (+0100) Subject: arm64: debug: remove debug exception registration infrastructure X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a8b8cce9d96d65dfe3d89abf02033151f8b7d670;p=thirdparty%2Flinux.git arm64: debug: remove debug exception registration infrastructure Now that debug exceptions are handled individually and without the need for dynamic registration, remove the unused registration infrastructure. This removes the external caller for `debug_exception_enter()` and `debug_exception_exit()`. Make them static again and remove them from the header. Remove `early_brk64()` as it has been made redundant by (arm64: debug: split brk64 exception entry) and is not used anymore. Note : in `early_brk64()` `bug_brk_handler()` is called unconditionally as a fall-through, but now `call_break_hook()` only calls it if the immediate matches. This does not change the behaviour in early boot, as if `bug_brk_handler()` was called on a non-BUG immediate it would return DBG_HOOK_ERROR anyway, which `call_break_hook()` will do if no immediate matches. Remove `trap_init()`, as it would be empty and a weak definition already exists in `init/main.c`. Signed-off-by: Ada Couprie Diaz Tested-by: Luis Claudio R. Goncalves Reviewed-by: Will Deacon Acked-by: Mark Rutland Link: https://lore.kernel.org/r/20250707114109.35672-14-ada.coupriediaz@arm.com Signed-off-by: Will Deacon --- diff --git a/arch/arm64/include/asm/debug-monitors.h b/arch/arm64/include/asm/debug-monitors.h index 586290e95d874..4dfc37dd1d969 100644 --- a/arch/arm64/include/asm/debug-monitors.h +++ b/arch/arm64/include/asm/debug-monitors.h @@ -94,7 +94,5 @@ static inline bool try_step_suspended_breakpoints(struct pt_regs *regs) bool try_handle_aarch32_break(struct pt_regs *regs); -void debug_traps_init(void); - #endif /* __ASSEMBLY */ #endif /* __ASM_DEBUG_MONITORS_H */ diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h index cdce3c7137668..e3874c4fc399e 100644 --- a/arch/arm64/include/asm/exception.h +++ b/arch/arm64/include/asm/exception.h @@ -59,8 +59,6 @@ void do_el0_bti(struct pt_regs *regs); void do_el1_bti(struct pt_regs *regs, unsigned long esr); void do_el0_gcs(struct pt_regs *regs, unsigned long esr); void do_el1_gcs(struct pt_regs *regs, unsigned long esr); -void do_debug_exception(unsigned long addr_if_watchpoint, unsigned long esr, - struct pt_regs *regs); #ifdef CONFIG_HAVE_HW_BREAKPOINT void do_breakpoint(unsigned long esr, struct pt_regs *regs); void do_watchpoint(unsigned long addr, unsigned long esr, @@ -94,8 +92,4 @@ void do_serror(struct pt_regs *regs, unsigned long esr); void do_signal(struct pt_regs *regs); void __noreturn panic_bad_stack(struct pt_regs *regs, unsigned long esr, unsigned long far); - -void debug_exception_enter(struct pt_regs *regs); -void debug_exception_exit(struct pt_regs *regs); - #endif /* __ASM_EXCEPTION_H */ diff --git a/arch/arm64/include/asm/system_misc.h b/arch/arm64/include/asm/system_misc.h index c343442567625..344b1c1a4bbb6 100644 --- a/arch/arm64/include/asm/system_misc.h +++ b/arch/arm64/include/asm/system_misc.h @@ -25,10 +25,6 @@ void arm64_notify_die(const char *str, struct pt_regs *regs, int signo, int sicode, unsigned long far, unsigned long err); -void hook_debug_fault_code(int nr, int (*fn)(unsigned long, unsigned long, - struct pt_regs *), - int sig, int code, const char *name); - struct mm_struct; extern void __show_regs(struct pt_regs *); diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c index 43a612eaa7d2f..43f342a01fdff 100644 --- a/arch/arm64/kernel/debug-monitors.c +++ b/arch/arm64/kernel/debug-monitors.c @@ -316,9 +316,6 @@ bool try_handle_aarch32_break(struct pt_regs *regs) } NOKPROBE_SYMBOL(try_handle_aarch32_break); -void __init debug_traps_init(void) -{} - /* Re-enable single step for syscall restarting. */ void user_rewind_single_step(struct task_struct *task) { diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index bbf58fcab1427..4b67312a88ad6 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -448,7 +448,7 @@ static __always_inline void fpsimd_syscall_exit(void) * accidentally schedule in exception context and it will force a warning * if we somehow manage to schedule by accident. */ -void debug_exception_enter(struct pt_regs *regs) +static void debug_exception_enter(struct pt_regs *regs) { preempt_disable(); @@ -457,7 +457,7 @@ void debug_exception_enter(struct pt_regs *regs) } NOKPROBE_SYMBOL(debug_exception_enter); -void debug_exception_exit(struct pt_regs *regs) +static void debug_exception_exit(struct pt_regs *regs) { preempt_enable_no_resched(); } diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 654c8ea46ec65..98b11da5a5ade 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -1100,30 +1100,3 @@ int ubsan_brk_handler(struct pt_regs *regs, unsigned long esr) return DBG_HOOK_HANDLED; } #endif - -/* - * Initial handler for AArch64 BRK exceptions - * This handler only used until debug_traps_init(). - */ -int __init early_brk64(unsigned long addr, unsigned long esr, - struct pt_regs *regs) -{ -#ifdef CONFIG_CFI_CLANG - if (esr_is_cfi_brk(esr)) - return cfi_brk_handler(regs, esr) != DBG_HOOK_HANDLED; -#endif -#ifdef CONFIG_KASAN_SW_TAGS - if ((esr_brk_comment(esr) & ~KASAN_BRK_MASK) == KASAN_BRK_IMM) - return kasan_brk_handler(regs, esr) != DBG_HOOK_HANDLED; -#endif -#ifdef CONFIG_UBSAN_TRAP - if (esr_is_ubsan_brk(esr)) - return ubsan_brk_handler(regs, esr) != DBG_HOOK_HANDLED; -#endif - return bug_brk_handler(regs, esr) != DBG_HOOK_HANDLED; -} - -void __init trap_init(void) -{ - debug_traps_init(); -} diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index d451d7d834f1a..bc7f554dea9f2 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -53,18 +53,12 @@ struct fault_info { }; static const struct fault_info fault_info[]; -static struct fault_info debug_fault_info[]; static inline const struct fault_info *esr_to_fault_info(unsigned long esr) { return fault_info + (esr & ESR_ELx_FSC); } -static inline const struct fault_info *esr_to_debug_fault_info(unsigned long esr) -{ - return debug_fault_info + DBG_ESR_EVT(esr); -} - static void data_abort_decode(unsigned long esr) { unsigned long iss2 = ESR_ELx_ISS2(esr); @@ -938,53 +932,6 @@ void do_sp_pc_abort(unsigned long addr, unsigned long esr, struct pt_regs *regs) } NOKPROBE_SYMBOL(do_sp_pc_abort); -/* - * __refdata because early_brk64 is __init, but the reference to it is - * clobbered at arch_initcall time. - * See traps.c and debug-monitors.c:debug_traps_init(). - */ -static struct fault_info __refdata debug_fault_info[] = { - { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware breakpoint" }, - { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware single-step" }, - { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware watchpoint" }, - { do_bad, SIGKILL, SI_KERNEL, "unknown 3" }, - { do_bad, SIGTRAP, TRAP_BRKPT, "aarch32 BKPT" }, - { do_bad, SIGKILL, SI_KERNEL, "aarch32 vector catch" }, - { early_brk64, SIGTRAP, TRAP_BRKPT, "aarch64 BRK" }, - { do_bad, SIGKILL, SI_KERNEL, "unknown 7" }, -}; - -void __init hook_debug_fault_code(int nr, - int (*fn)(unsigned long, unsigned long, struct pt_regs *), - int sig, int code, const char *name) -{ - BUG_ON(nr < 0 || nr >= ARRAY_SIZE(debug_fault_info)); - - debug_fault_info[nr].fn = fn; - debug_fault_info[nr].sig = sig; - debug_fault_info[nr].code = code; - debug_fault_info[nr].name = name; -} - -void do_debug_exception(unsigned long addr_if_watchpoint, unsigned long esr, - struct pt_regs *regs) -{ - const struct fault_info *inf = esr_to_debug_fault_info(esr); - unsigned long pc = instruction_pointer(regs); - - debug_exception_enter(regs); - - if (user_mode(regs) && !is_ttbr0_addr(pc)) - arm64_apply_bp_hardening(); - - if (inf->fn(addr_if_watchpoint, esr, regs)) { - arm64_notify_die(inf->name, regs, inf->sig, inf->code, pc, esr); - } - - debug_exception_exit(regs); -} -NOKPROBE_SYMBOL(do_debug_exception); - /* * Used during anonymous page fault handling. */