Re: [External] [PATCH v7 2/5] riscv: add support for SBI Supervisor Software Events extension

On 10/27/25 13:00, Xu Lu wrote:

quoted

+void do_sse(struct sse_event_arch_data *arch_evt, struct pt_regs *regs)
+{
+       nmi_enter();
+
+       /* Retrieve missing GPRs from SBI */
+       sbi_ecall(SBI_EXT_SSE, SBI_SSE_EVENT_ATTR_READ, arch_evt->evt_id,
+                 SBI_SSE_ATTR_INTERRUPTED_A6,
+                 (SBI_SSE_ATTR_INTERRUPTED_A7 - SBI_SSE_ATTR_INTERRUPTED_A6) + 1,
+                 arch_evt->interrupted_phys, 0, 0);
+
+       memcpy(&regs->a6, &arch_evt->interrupted, sizeof(arch_evt->interrupted));
+
+       sse_handle_event(arch_evt, regs);
+
+       /*
+        * The SSE delivery path does not uses the "standard" exception path
+        * (see sse_entry.S) and does not process any pending signal/softirqs
+        * due to being similar to a NMI.
+        * Some drivers (PMU, RAS) enqueue pending work that needs to be handled
+        * as soon as possible by bottom halves. For that purpose, set the SIP
+        * software interrupt pending bit which will force a software interrupt
+        * to be serviced once interrupts are reenabled in the interrupted
+        * context if they were masked or directly if unmasked.
+        */
+       csr_set(CSR_IP, IE_SIE);

IE_SIE may not always be enabled in CSR_IE(for example when we disable
CONFIG_ACLINT_SSWI and use imsic for ipi). Maybe we should send ipi to
the current cpu here.

Hi Xu,

Indeed, that's a good catch. Sending an IPI will be more generic.

Thanks,

Clément

Best regards,
Xu Lu