[PATCH v3 13/13] arm64: debug: remove debug exception registration infrastructure
Ada Couprie Diaz
ada.coupriediaz at arm.com
Mon Jun 9 10:34:13 PDT 2025
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.
Signed-off-by: Ada Couprie Diaz <ada.coupriediaz at arm.com>
---
arch/arm64/include/asm/debug-monitors.h | 2 -
arch/arm64/include/asm/exception.h | 6 ---
arch/arm64/include/asm/system_misc.h | 4 --
arch/arm64/kernel/debug-monitors.c | 3 --
arch/arm64/kernel/entry-common.c | 4 +-
arch/arm64/kernel/traps.c | 26 +-----------
arch/arm64/mm/fault.c | 53 -------------------------
7 files changed, 3 insertions(+), 95 deletions(-)
diff --git a/arch/arm64/include/asm/debug-monitors.h b/arch/arm64/include/asm/debug-monitors.h
index 586290e95d87..4dfc37dd1d96 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 1c41b6e3d3be..f7f772d75860 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);
void do_breakpoint(unsigned long esr, struct pt_regs *regs);
void do_softstep(unsigned long esr, struct pt_regs *regs);
void do_watchpoint(unsigned long addr, unsigned long esr,
@@ -86,8 +84,4 @@ 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 c34344256762..344b1c1a4bbb 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 5490a4f32e85..172be6b367f8 100644
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -333,9 +333,6 @@ 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 90ee140052c5..879beba5c78b 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 654c8ea46ec6..d6c5268e6947 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -1101,29 +1101,5 @@ int ubsan_brk_handler(struct pt_regs *regs, unsigned long esr)
}
#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 d451d7d834f1..bc7f554dea9f 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.
*/
--
2.43.0
More information about the linux-arm-kernel
mailing list