powerpc/iommu: Do not immediately panic when failed IOMMU table allocation

Most platforms allocate IOMMU table structures (specifically it_map)
at the boot time and when this fails - it is a valid reason for panic().

However the powernv platform allocates it_map after a device is returned
to the host OS after being passed through and this happens long after
the host OS booted. It is quite possible to trigger the it_map allocation
panic() and kill the host even though it is not necessary - the host OS
can still use the DMA bypass mode (requires a tiny fraction of it_map's
memory) and even if that fails, the host OS is runnnable as it was without
the device for which allocating it_map causes the panic.

Instead of immediately crashing in a powernv/ioda2 system, this prints
an error and continues. All other platforms still call panic().

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Leonardo Bras <leobras.c@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210216033307.69863-3-aik@ozlabs.ru

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 91d0ba7559a629432d059a107eedab280e979e53..42e195aaf23a19723906a64895c475f9e8a7492b 100644 (file)
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -727,8 +727,10 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid,
        sz = BITS_TO_LONGS(tbl->it_size) * sizeof(unsigned long);
 
        tbl->it_map = vzalloc_node(sz, nid);
-       if (!tbl->it_map)
-               panic("iommu_init_table: Can't allocate %ld bytes\n", sz);
+       if (!tbl->it_map) {
+               pr_err("%s: Can't allocate %ld bytes\n", __func__, sz);
+               return NULL;
+       }
 
        iommu_table_reserve_pages(tbl, res_start, res_end);
 

diff --git a/arch/powerpc/platforms/cell/iommu.c b/arch/powerpc/platforms/cell/iommu.c
index 2124831cf57c081e7625be24fc25ea9c0e0ba286..fa08699aedeb8b7819603a276e730c56002df932 100644 (file)
--- a/arch/powerpc/platforms/cell/iommu.c
+++ b/arch/powerpc/platforms/cell/iommu.c
@@ -486,7 +486,8 @@ cell_iommu_setup_window(struct cbe_iommu *iommu, struct device_node *np,
        window->table.it_size = size >> window->table.it_page_shift;
        window->table.it_ops = &cell_iommu_ops;
 
-       iommu_init_table(&window->table, iommu->nid, 0, 0);
+       if (!iommu_init_table(&window->table, iommu->nid, 0, 0))
+               panic("Failed to initialize iommu table");
 
        pr_debug("\tioid      %d\n", window->ioid);
        pr_debug("\tblocksize %ld\n", window->table.it_blocksize);

diff --git a/arch/powerpc/platforms/pasemi/iommu.c b/arch/powerpc/platforms/pasemi/iommu.c
index b500a6e47e6b1181fee9da228edc3e919f0a0d43..5be7242fbd866cf5c3814b4509509eda68728e1c 100644 (file)
--- a/arch/powerpc/platforms/pasemi/iommu.c
+++ b/arch/powerpc/platforms/pasemi/iommu.c
@@ -146,7 +146,9 @@ static void iommu_table_iobmap_setup(void)
         */
        iommu_table_iobmap.it_blocksize = 4;
        iommu_table_iobmap.it_ops = &iommu_table_iobmap_ops;
-       iommu_init_table(&iommu_table_iobmap, 0, 0, 0);
+       if (!iommu_init_table(&iommu_table_iobmap, 0, 0, 0))
+               panic("Failed to initialize iommu table");
+
        pr_debug(" <- %s\n", __func__);
 }
 

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index f0f901683a2fe1056cc67190cccc09c76732640d..66c3c33373346815c23f0f0dac310d42eb7f945e 100644 (file)
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1762,7 +1762,8 @@ found:
        tbl->it_ops = &pnv_ioda1_iommu_ops;
        pe->table_group.tce32_start = tbl->it_offset << tbl->it_page_shift;
        pe->table_group.tce32_size = tbl->it_size << tbl->it_page_shift;
-       iommu_init_table(tbl, phb->hose->node, 0, 0);
+       if (!iommu_init_table(tbl, phb->hose->node, 0, 0))
+               panic("Failed to initialize iommu table");
 
        pe->dma_setup_done = true;
        return;
@@ -1930,16 +1931,16 @@ static long pnv_pci_ioda2_setup_default_config(struct pnv_ioda_pe *pe)
                res_start = pe->phb->ioda.m32_pci_base >> tbl->it_page_shift;
                res_end = min(window_size, SZ_4G) >> tbl->it_page_shift;
        }
-       iommu_init_table(tbl, pe->phb->hose->node, res_start, res_end);
 
-       rc = pnv_pci_ioda2_set_window(&pe->table_group, 0, tbl);
+       if (iommu_init_table(tbl, pe->phb->hose->node, res_start, res_end))
+               rc = pnv_pci_ioda2_set_window(&pe->table_group, 0, tbl);
+       else
+               rc = -ENOMEM;
        if (rc) {
-               pe_err(pe, "Failed to configure 32-bit TCE table, err %ld\n",
-                               rc);
+               pe_err(pe, "Failed to configure 32-bit TCE table, err %ld\n", rc);
                iommu_tce_table_put(tbl);
-               return rc;
+               tbl = NULL; /* This clears iommu_table_base below */
        }
-
        if (!pnv_iommu_bypass_disabled)
                pnv_pci_ioda2_set_bypass(pe, true);
 

diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 5b3050ff0c55ba11528c58ea44509ee20b854f1f..0c55b991f665b56c3473c91dc7924d9256bacb7f 100644 (file)
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -638,7 +638,8 @@ static void pci_dma_bus_setup_pSeries(struct pci_bus *bus)
 
        iommu_table_setparms(pci->phb, dn, tbl);
        tbl->it_ops = &iommu_table_pseries_ops;
-       iommu_init_table(tbl, pci->phb->node, 0, 0);
+       if (!iommu_init_table(tbl, pci->phb->node, 0, 0))
+               panic("Failed to initialize iommu table");
 
        /* Divide the rest (1.75GB) among the children */
        pci->phb->dma_window_size = 0x80000000ul;
@@ -720,7 +721,8 @@ static void pci_dma_bus_setup_pSeriesLP(struct pci_bus *bus)
                iommu_table_setparms_lpar(ppci->phb, pdn, tbl,
                                ppci->table_group, dma_window);
                tbl->it_ops = &iommu_table_lpar_multi_ops;
-               iommu_init_table(tbl, ppci->phb->node, 0, 0);
+               if (!iommu_init_table(tbl, ppci->phb->node, 0, 0))
+                       panic("Failed to initialize iommu table");
                iommu_register_group(ppci->table_group,
                                pci_domain_nr(bus), 0);
                pr_debug("  created table: %p\n", ppci->table_group);
@@ -749,7 +751,9 @@ static void pci_dma_dev_setup_pSeries(struct pci_dev *dev)
                tbl = PCI_DN(dn)->table_group->tables[0];
                iommu_table_setparms(phb, dn, tbl);
                tbl->it_ops = &iommu_table_pseries_ops;
-               iommu_init_table(tbl, phb->node, 0, 0);
+               if (!iommu_init_table(tbl, phb->node, 0, 0))
+                       panic("Failed to initialize iommu table");
+
                set_iommu_table_base(&dev->dev, tbl);
                return;
        }

diff --git a/arch/powerpc/sysdev/dart_iommu.c b/arch/powerpc/sysdev/dart_iommu.c
index 6b4a34b36d9879eb8973f45a12c230d0c0b30e4b..1d33b7a5ea83264c34a9465b35e2f6f37f60c7cb 100644 (file)
--- a/arch/powerpc/sysdev/dart_iommu.c
+++ b/arch/powerpc/sysdev/dart_iommu.c
@@ -344,7 +344,8 @@ static void iommu_table_dart_setup(void)
        iommu_table_dart.it_index = 0;
        iommu_table_dart.it_blocksize = 1;
        iommu_table_dart.it_ops = &iommu_dart_ops;
-       iommu_init_table(&iommu_table_dart, -1, 0, 0);
+       if (!iommu_init_table(&iommu_table_dart, -1, 0, 0))
+               panic("Failed to initialize iommu table");
 
        /* Reserve the last page of the DART to avoid possible prefetch
         * past the DART mapped area