In order to make early kgdb work properly we need early_brk64() to be
able to call into it. This is as easy as adding a call into
call_break_hook() just like we do later in the normal brk_handler().
Once we do this we can let kgdb know that it can break into the
debugger a little earlier (specifically when parsing early_param's).
NOTE: without this patch it turns out that arm64 can't do breakpoints
even at dbg_late_init(), so if we decide something about this patch is
wrong we might need to move dbg_late_init() a little later.
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
---
Changes in v4:
- Add "if KGDB" to "select ARCH_HAS_EARLY_DEBUG" in Kconfig.
Changes in v3:
- Change boolean weak function to KConfig.
Changes in v2: None
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/debug-monitors.h | 2 ++
arch/arm64/kernel/debug-monitors.c | 2 +-
arch/arm64/kernel/traps.c | 3 +++
4 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 40fb05d96c60..3d78f581269c 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -13,6 +13,7 @@ config ARM64
select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_DMA_PREP_COHERENT
select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
+ select ARCH_HAS_EARLY_DEBUG if KGDB
select ARCH_HAS_FAST_MULTIPLIER
select ARCH_HAS_FORTIFY_SOURCE
select ARCH_HAS_GCOV_PROFILE_ALL
diff --git a/arch/arm64/include/asm/debug-monitors.h b/arch/arm64/include/asm/debug-monitors.h
index 7619f473155f..2d82a0314d29 100644
--- a/arch/arm64/include/asm/debug-monitors.h
+++ b/arch/arm64/include/asm/debug-monitors.h
@@ -97,6 +97,8 @@ void unregister_user_break_hook(struct break_hook *hook);
void register_kernel_break_hook(struct break_hook *hook);
void unregister_kernel_break_hook(struct break_hook *hook);
+int call_break_hook(struct pt_regs *regs, unsigned int esr);
+
u8 debug_monitors_arch(void);
enum dbg_active_el {
diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index 48222a4760c2..59c353dfc8e9 100644
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -297,7 +297,7 @@ void unregister_kernel_break_hook(struct break_hook *hook)
unregister_debug_hook(&hook->node);
}
-static int call_break_hook(struct pt_regs *regs, unsigned int esr)
+int call_break_hook(struct pt_regs *regs, unsigned int esr)
{
struct break_hook *hook;
struct list_head *list;
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index cf402be5c573..a8173f0c1774 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -1044,6 +1044,9 @@ int __init early_brk64(unsigned long addr, unsigned int esr,
if ((comment & ~KASAN_BRK_MASK) == KASAN_BRK_IMM)
return kasan_handler(regs, esr) != DBG_HOOK_HANDLED;
#endif
+ if (call_break_hook(regs, esr) == DBG_HOOK_HANDLED)
+ return 0;
+
return bug_handler(regs, esr) != DBG_HOOK_HANDLED;
}
--
2.26.2.645.ge9eca65c58-goog
