[PATCH v2 09/16] LoongArch: Exception handling

[Simon Glass]

Hi Jiaxun,

On 2026-07-01T11:17:53, Yao Zi <me at ziyao.cc> wrote:
> LoongArch: Exception handling
>
> Add exception entry assembly code, import stackframe.h
> from Linux, provide debug prints when exception happens.
>
> Signed-off-by: Jiaxun Yang <jiaxun.yang at flygoat.com>
> Signed-off-by: Yao Zi <me at ziyao.cc>
>
> arch/loongarch/Kconfig                  |   3 +
>  arch/loongarch/cpu/Makefile             |   2 +-
>  arch/loongarch/cpu/genex.S              |  21 ++++
>  arch/loongarch/include/asm/stackframe.h | 175 +++++++++++++++++++++++++++++
>  arch/loongarch/lib/interrupts.c         | 189 ++++++++++++++++++++++++++++++++
>  5 files changed, 389 insertions(+), 1 deletion(-)

> diff --git a/arch/loongarch/lib/interrupts.c b/arch/loongarch/lib/interrupts.c
> @@ -0,0 +1,189 @@
> +static void show_regs(struct pt_regs *regs)
> +{
> +#if IS_ENABLED(CONFIG_SHOW_REGS)
> +     const int field = 2 * sizeof(unsigned long);

Please use 'if (CONFIG_IS_ENABLED(SHOW_REGS))' at the call site (as
you do for FRAMEPOINTER below) rather than wrapping the function
body in #if - that also lets you honour SPL_SHOW_REGS.

> diff --git a/arch/loongarch/lib/interrupts.c b/arch/loongarch/lib/interrupts.c
> @@ -0,0 +1,189 @@
> +static void __maybe_unused show_backtrace(struct pt_regs *regs)
> +{
> +     uintptr_t *fp = (uintptr_t *)regs->regs[0x16];

Magic 0x16 (= 22 = fp) is hard to read. Please use a named constant,
or add an fp accessor / use the regdef indices.

> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> @@ -30,6 +30,9 @@ config DMA_ADDR_T_64BIT
> +config SHOW_REGS
> +     bool "Show registers on unhandled exception"

Missing help text, and please follow the RISC-V pattern: default y
plus a matching SPL_SHOW_REGS entry. Otherwise the default on
LoongArch is to hide all GPRs on a crash, making triage harder.

Regards,
Simon