[PATCH v3 09/17] riscv: misaligned: factorize trap handling

Clément Léger
2025-03-10T15:14:03Z

misaligned accesses traps are not nmi and should be treated as normal
one using irqentry_enter()/exit(). Since both load/store and user/kernel
should use almost the same path and that we are going to add some code
around that, factorize it.

Signed-off-by: Clément Léger <cleger@rivosinc.com>
---
arch/riscv/kernel/traps.c | 49 ++++++++++++++++-----------------------
1 file changed, 20 insertions(+), 29 deletions(-)

diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index 8ff8e8b36524..55d9f3450398 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -198,47 +198,38 @@ asmlinkage __visible __trap_section void do_trap_insn_illegal(struct pt_regs *re
DO_ERROR_INFO(do_trap_load_fault,
SIGSEGV, SEGV_ACCERR, "load access fault");

-asmlinkage __visible __trap_section void do_trap_load_misaligned(struct pt_regs *regs)
+enum misaligned_access_type {
+ MISALIGNED_STORE,
+ MISALIGNED_LOAD,
+};
+
+static void do_trap_misaligned(struct pt_regs *regs, enum misaligned_access_type type)
{
- if (user_mode(regs)) {
- irqentry_enter_from_user_mode(regs);
+ irqentry_state_t state = irqentry_enter(regs);

+ if (type == MISALIGNED_LOAD) {
if (handle_misaligned_load(regs))
do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
- "Oops - load address misaligned");
-
- irqentry_exit_to_user_mode(regs);
+ "Oops - load address misaligned");
} else {
- irqentry_state_t state = irqentry_nmi_enter(regs);
-
- if (handle_misaligned_load(regs))
+ if (handle_misaligned_store(regs))
do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
- "Oops - load address misaligned");
-
- irqentry_nmi_exit(regs, state);
+ "Oops - store (or AMO) address misaligned");
}
+
+ irqentry_exit(regs, state);
}

-asmlinkage __visible __trap_section void do_trap_store_misaligned(struct pt_regs *regs)
+asmlinkage __visible __trap_section void do_trap_load_misaligned(struct pt_regs *regs)
{
- if (user_mode(regs)) {
- irqentry_enter_from_user_mode(regs);
-
- if (handle_misaligned_store(regs))
- do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
- "Oops - store (or AMO) address misaligned");
-
- irqentry_exit_to_user_mode(regs);
- } else {
- irqentry_state_t state = irqentry_nmi_enter(regs);
-
- if (handle_misaligned_store(regs))
- do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
- "Oops - store (or AMO) address misaligned");
+ do_trap_misaligned(regs, MISALIGNED_LOAD);
+}

- irqentry_nmi_exit(regs, state);
- }
+asmlinkage __visible __trap_section void do_trap_store_misaligned(struct pt_regs *regs)
+{
+ do_trap_misaligned(regs, MISALIGNED_STORE);
}
+
DO_ERROR_INFO(do_trap_store_fault,
SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault");
DO_ERROR_INFO(do_trap_ecall_s,
--
2.47.2