diff options
| author | Alastair D'Silva <alastair@d-silva.org> | 2019-06-20 14:12:01 +1000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-07-03 21:29:47 +0200 |
| commit | 60e8523e2ea18dc0c0cea69d6c1d69a065019062 (patch) | |
| tree | ff0c7696430960d500575631703f84e57f10ef37 /drivers/misc/ocxl | |
| parent | 7ce98fb6c53d2311b3e9faae90b1a9c1a96534db (diff) | |
ocxl: Allow contexts to be attached with a NULL mm
If an OpenCAPI context is to be used directly by a kernel driver, there
may not be a suitable mm to use.
The patch makes the mm parameter to ocxl_context_attach optional.
Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
Acked-by: Andrew Donnellan <ajd@linux.ibm.com>
Acked-by: Frederic Barrat <fbarrat@linux.ibm.com>
Acked-by: Nicholas Piggin <npiggin@gmail.com>
Link: https://lore.kernel.org/r/20190620041203.12274-1-alastair@au1.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/misc/ocxl')
| -rw-r--r-- | drivers/misc/ocxl/context.c | 9 | ||||
| -rw-r--r-- | drivers/misc/ocxl/link.c | 28 |
2 files changed, 30 insertions, 7 deletions
diff --git a/drivers/misc/ocxl/context.c b/drivers/misc/ocxl/context.c index bab9c9364184..994563a078eb 100644 --- a/drivers/misc/ocxl/context.c +++ b/drivers/misc/ocxl/context.c @@ -69,6 +69,7 @@ static void xsl_fault_error(void *data, u64 addr, u64 dsisr) int ocxl_context_attach(struct ocxl_context *ctx, u64 amr, struct mm_struct *mm) { int rc; + unsigned long pidr = 0; // Locks both status & tidr mutex_lock(&ctx->status_mutex); @@ -77,9 +78,11 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr, struct mm_struct *mm) goto out; } - rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid, - mm->context.id, ctx->tidr, amr, mm, - xsl_fault_error, ctx); + if (mm) + pidr = mm->context.id; + + rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid, pidr, ctx->tidr, + amr, mm, xsl_fault_error, ctx); if (rc) goto out; diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c index cce5b0d64505..58d111afd9f6 100644 --- a/drivers/misc/ocxl/link.c +++ b/drivers/misc/ocxl/link.c @@ -224,6 +224,17 @@ static irqreturn_t xsl_fault_handler(int irq, void *data) ack_irq(spa, ADDRESS_ERROR); return IRQ_HANDLED; } + + if (!pe_data->mm) { + /* + * translation fault from a kernel context - an OpenCAPI + * device tried to access a bad kernel address + */ + rcu_read_unlock(); + pr_warn("Unresolved OpenCAPI xsl fault in kernel context\n"); + ack_irq(spa, ADDRESS_ERROR); + return IRQ_HANDLED; + } WARN_ON(pe_data->mm->context.id != pid); if (mmget_not_zero(pe_data->mm)) { @@ -523,7 +534,13 @@ int ocxl_link_add_pe(void *link_handle, int pasid, u32 pidr, u32 tidr, pe->amr = cpu_to_be64(amr); pe->software_state = cpu_to_be32(SPA_PE_VALID); - mm_context_add_copro(mm); + /* + * For user contexts, register a copro so that TLBIs are seen + * by the nest MMU. If we have a kernel context, TLBIs are + * already global. + */ + if (mm) + mm_context_add_copro(mm); /* * Barrier is to make sure PE is visible in the SPA before it * is used by the device. It also helps with the global TLBI @@ -546,7 +563,8 @@ int ocxl_link_add_pe(void *link_handle, int pasid, u32 pidr, u32 tidr, * have a reference on mm_users. Incrementing mm_count solves * the problem. */ - mmgrab(mm); + if (mm) + mmgrab(mm); trace_ocxl_context_add(current->pid, spa->spa_mem, pasid, pidr, tidr); unlock: mutex_unlock(&spa->spa_lock); @@ -652,8 +670,10 @@ int ocxl_link_remove_pe(void *link_handle, int pasid) if (!pe_data) { WARN(1, "Couldn't find pe data when removing PE\n"); } else { - mm_context_remove_copro(pe_data->mm); - mmdrop(pe_data->mm); + if (pe_data->mm) { + mm_context_remove_copro(pe_data->mm); + mmdrop(pe_data->mm); + } kfree_rcu(pe_data, rcu); } unlock: |