From 1930bb5ccf77da3bf1483e2cd85a12ec9c0ed0f6 Mon Sep 17 00:00:00 2001 From: Scott Wood Date: Tue, 6 Oct 2015 22:48:08 -0500 Subject: [PATCH] powerpc/fsl_pci: Don't set up inbound windows in kdump crash kernel Otherwise, because the top end of the crash kernel is treated as the absolute top of memory rather than the beginning of a reserved region, in-flight DMA from the previous kernel that targets areas above the crash kernel can trigger a storm of PCI errors. We only do this for kdump, not normal kexec, in case kexec is being used to upgrade to a kernel that wants a different inbound memory map. Signed-off-by: Scott Wood Cc: Mingkai Hu --- arch/powerpc/sysdev/fsl_pci.c | 84 +++++++++++++++++++++++++---------- 1 file changed, 61 insertions(+), 23 deletions(-) diff --git a/arch/powerpc/sysdev/fsl_pci.c b/arch/powerpc/sysdev/fsl_pci.c index c42609dde8d2..1c65ef92768d 100644 --- a/arch/powerpc/sysdev/fsl_pci.c +++ b/arch/powerpc/sysdev/fsl_pci.c @@ -179,6 +179,19 @@ static int setup_one_atmu(struct ccsr_pci __iomem *pci, return i; } +static bool is_kdump(void) +{ + struct device_node *node; + + node = of_find_node_by_type(NULL, "memory"); + if (!node) { + WARN_ON_ONCE(1); + return false; + } + + return of_property_read_bool(node, "linux,usable-memory"); +} + /* atmu setup for fsl pci/pcie controller */ static void setup_pci_atmu(struct pci_controller *hose) { @@ -192,6 +205,16 @@ static void setup_pci_atmu(struct pci_controller *hose) const char *name = hose->dn->full_name; const u64 *reg; int len; + bool setup_inbound; + + /* + * If this is kdump, we don't want to trigger a bunch of PCI + * errors by closing the window on in-flight DMA. + * + * We still run most of the function's logic so that things like + * hose->dma_window_size still get set. + */ + setup_inbound = !is_kdump(); if (early_find_capability(hose, 0, 0, PCI_CAP_ID_EXP)) { if (in_be32(&pci->block_rev1) >= PCIE_IP_REV_2_2) { @@ -204,8 +227,11 @@ static void setup_pci_atmu(struct pci_controller *hose) /* Disable all windows (except powar0 since it's ignored) */ for(i = 1; i < 5; i++) out_be32(&pci->pow[i].powar, 0); - for (i = start_idx; i < end_idx; i++) - out_be32(&pci->piw[i].piwar, 0); + + if (setup_inbound) { + for (i = start_idx; i < end_idx; i++) + out_be32(&pci->piw[i].piwar, 0); + } /* Setup outbound MEM window */ for(i = 0, j = 1; i < 3; i++) { @@ -278,6 +304,7 @@ static void setup_pci_atmu(struct pci_controller *hose) /* Setup inbound mem window */ mem = memblock_end_of_DRAM(); + pr_info("%s: end of DRAM %llx\n", __func__, mem); /* * The msi-address-64 property, if it exists, indicates the physical @@ -320,12 +347,14 @@ static void setup_pci_atmu(struct pci_controller *hose) piwar |= ((mem_log - 1) & PIWAR_SZ_MASK); - /* Setup inbound memory window */ - out_be32(&pci->piw[win_idx].pitar, 0x00000000); - out_be32(&pci->piw[win_idx].piwbar, 0x00000000); - out_be32(&pci->piw[win_idx].piwar, piwar); - win_idx--; + if (setup_inbound) { + /* Setup inbound memory window */ + out_be32(&pci->piw[win_idx].pitar, 0x00000000); + out_be32(&pci->piw[win_idx].piwbar, 0x00000000); + out_be32(&pci->piw[win_idx].piwar, piwar); + } + win_idx--; hose->dma_window_base_cur = 0x00000000; hose->dma_window_size = (resource_size_t)sz; @@ -343,13 +372,15 @@ static void setup_pci_atmu(struct pci_controller *hose) piwar = (piwar & ~PIWAR_SZ_MASK) | (mem_log - 1); - /* Setup inbound memory window */ - out_be32(&pci->piw[win_idx].pitar, 0x00000000); - out_be32(&pci->piw[win_idx].piwbear, - pci64_dma_offset >> 44); - out_be32(&pci->piw[win_idx].piwbar, - pci64_dma_offset >> 12); - out_be32(&pci->piw[win_idx].piwar, piwar); + if (setup_inbound) { + /* Setup inbound memory window */ + out_be32(&pci->piw[win_idx].pitar, 0x00000000); + out_be32(&pci->piw[win_idx].piwbear, + pci64_dma_offset >> 44); + out_be32(&pci->piw[win_idx].piwbar, + pci64_dma_offset >> 12); + out_be32(&pci->piw[win_idx].piwar, piwar); + } /* * install our own dma_set_mask handler to fixup dma_ops @@ -362,12 +393,15 @@ static void setup_pci_atmu(struct pci_controller *hose) } else { u64 paddr = 0; - /* Setup inbound memory window */ - out_be32(&pci->piw[win_idx].pitar, paddr >> 12); - out_be32(&pci->piw[win_idx].piwbar, paddr >> 12); - out_be32(&pci->piw[win_idx].piwar, (piwar | (mem_log - 1))); - win_idx--; + if (setup_inbound) { + /* Setup inbound memory window */ + out_be32(&pci->piw[win_idx].pitar, paddr >> 12); + out_be32(&pci->piw[win_idx].piwbar, paddr >> 12); + out_be32(&pci->piw[win_idx].piwar, + (piwar | (mem_log - 1))); + } + win_idx--; paddr += 1ull << mem_log; sz -= 1ull << mem_log; @@ -375,11 +409,15 @@ static void setup_pci_atmu(struct pci_controller *hose) mem_log = ilog2(sz); piwar |= (mem_log - 1); - out_be32(&pci->piw[win_idx].pitar, paddr >> 12); - out_be32(&pci->piw[win_idx].piwbar, paddr >> 12); - out_be32(&pci->piw[win_idx].piwar, piwar); - win_idx--; + if (setup_inbound) { + out_be32(&pci->piw[win_idx].pitar, + paddr >> 12); + out_be32(&pci->piw[win_idx].piwbar, + paddr >> 12); + out_be32(&pci->piw[win_idx].piwar, piwar); + } + win_idx--; paddr += 1ull << mem_log; } -- 2.20.1