From 1446978d560fd708af4dfc10863109bc098e5b26 Mon Sep 17 00:00:00 2001 From: Jon Derrick Date: Mon, 11 May 2020 12:21:17 -0400 Subject: [PATCH] PCI: pci-bridge-emul: Eliminate the 'reserved' member Per PCIe 5.0 r1.0, Terms and Acronyms, Page 80: Reserved register fields must be read only and must return 0 (all 0's for multi-bit fields) when read. Reserved encodings for register and packet fields must not be used. Any implementation dependence on a Reserved field value or encoding will result in an implementation that is not PCI Express-compliant. This patch ensures reads will return 0 for any bit not in the Read-Only, Read-Write, or Write-1-to-Clear bitmasks. Link: https://lore.kernel.org/r/20200511162117.6674-5-jonathan.derrick@intel.com Signed-off-by: Jon Derrick Signed-off-by: Lorenzo Pieralisi Acked-by: Rob Herring --- drivers/pci/pci-bridge-emul.c | 30 +++++++++++++----------------- 1 file changed, 13 insertions(+), 17 deletions(-) diff --git a/drivers/pci/pci-bridge-emul.c b/drivers/pci/pci-bridge-emul.c index 6b1949995dee..ccf26d12ec61 100644 --- a/drivers/pci/pci-bridge-emul.c +++ b/drivers/pci/pci-bridge-emul.c @@ -24,6 +24,17 @@ #define PCI_CAP_PCIE_START PCI_BRIDGE_CONF_END #define PCI_CAP_PCIE_END (PCI_CAP_PCIE_START + PCI_EXP_SLTSTA2 + 2) +/** + * struct pci_bridge_reg_behavior - register bits behaviors + * @ro: Read-Only bits + * @rw: Read-Write bits + * @w1c: Write-1-to-Clear bits + * + * Reads and Writes will be filtered by specified behavior. All other bits not + * declared are assumed 'Reserved' and will return 0 on reads, per PCIe 5.0: + * "Reserved register fields must be read only and must return 0 (all 0's for + * multi-bit fields) when read". + */ struct pci_bridge_reg_behavior { /* Read-only bits */ u32 ro; @@ -33,9 +44,6 @@ struct pci_bridge_reg_behavior { /* Write-1-to-clear bits */ u32 w1c; - - /* Reserved bits (hardwired to 0) */ - u32 rsvd; }; static const struct pci_bridge_reg_behavior pci_regs_behavior[] = { @@ -49,7 +57,6 @@ static const struct pci_bridge_reg_behavior pci_regs_behavior[] = { PCI_COMMAND_FAST_BACK) | (PCI_STATUS_CAP_LIST | PCI_STATUS_66MHZ | PCI_STATUS_FAST_BACK | PCI_STATUS_DEVSEL_MASK) << 16), - .rsvd = GENMASK(15, 10) | ((BIT(6) | GENMASK(3, 0)) << 16), .w1c = PCI_STATUS_ERROR_BITS << 16, }, [PCI_CLASS_REVISION / 4] = { .ro = ~0 }, @@ -96,8 +103,6 @@ static const struct pci_bridge_reg_behavior pci_regs_behavior[] = { GENMASK(11, 8) | GENMASK(3, 0)), .w1c = PCI_STATUS_ERROR_BITS << 16, - - .rsvd = ((BIT(6) | GENMASK(4, 0)) << 16), }, [PCI_MEMORY_BASE / 4] = { @@ -130,12 +135,10 @@ static const struct pci_bridge_reg_behavior pci_regs_behavior[] = { [PCI_CAPABILITY_LIST / 4] = { .ro = GENMASK(7, 0), - .rsvd = GENMASK(31, 8), }, [PCI_ROM_ADDRESS1 / 4] = { .rw = GENMASK(31, 11) | BIT(0), - .rsvd = GENMASK(10, 1), }, /* @@ -158,8 +161,6 @@ static const struct pci_bridge_reg_behavior pci_regs_behavior[] = { .ro = (GENMASK(15, 8) | ((PCI_BRIDGE_CTL_FAST_BACK) << 16)), .w1c = BIT(10) << 16, - - .rsvd = (GENMASK(15, 12) | BIT(4)) << 16, }, }; @@ -186,13 +187,11 @@ static const struct pci_bridge_reg_behavior pcie_cap_regs_behavior[] = { */ .w1c = (BIT(6) | GENMASK(3, 0)) << 16, .ro = GENMASK(5, 4) << 16, - .rsvd = GENMASK(15, 7) << 16, }, [PCI_EXP_LNKCAP / 4] = { /* All bits are RO, except bit 23 which is reserved */ .ro = lower_32_bits(~BIT(23)), - .rsvd = BIT(23), }, [PCI_EXP_LNKCTL / 4] = { @@ -206,7 +205,6 @@ static const struct pci_bridge_reg_behavior pcie_cap_regs_behavior[] = { .rw = GENMASK(15, 14) | GENMASK(11, 3) | GENMASK(1, 0), .ro = GENMASK(13, 0) << 16, .w1c = GENMASK(15, 14) << 16, - .rsvd = GENMASK(13, 12) | BIT(2), }, [PCI_EXP_SLTCAP / 4] = { @@ -227,7 +225,6 @@ static const struct pci_bridge_reg_behavior pcie_cap_regs_behavior[] = { PCI_EXP_SLTSTA_CC | PCI_EXP_SLTSTA_DLLSC) << 16, .ro = (PCI_EXP_SLTSTA_MRLSS | PCI_EXP_SLTSTA_PDS | PCI_EXP_SLTSTA_EIS) << 16, - .rsvd = GENMASK(15) | (GENMASK(15, 9) << 16), }, [PCI_EXP_RTCTL / 4] = { @@ -241,7 +238,6 @@ static const struct pci_bridge_reg_behavior pcie_cap_regs_behavior[] = { PCI_EXP_RTCTL_SEFEE | PCI_EXP_RTCTL_PMEIE | PCI_EXP_RTCTL_CRSSVE), .ro = PCI_EXP_RTCAP_CRSVIS << 16, - .rsvd = GENMASK(15, 5) | (GENMASK(15, 1) << 16), }, [PCI_EXP_RTSTA / 4] = { @@ -251,7 +247,6 @@ static const struct pci_bridge_reg_behavior pcie_cap_regs_behavior[] = { */ .ro = GENMASK(15, 0) | PCI_EXP_RTSTA_PENDING, .w1c = PCI_EXP_RTSTA_PME, - .rsvd = GENMASK(31, 18), }, }; @@ -359,7 +354,8 @@ int pci_bridge_emul_conf_read(struct pci_bridge_emul *bridge, int where, * Make sure we never return any reserved bit with a value * different from 0. */ - *value &= ~behavior[reg / 4].rsvd; + *value &= behavior[reg / 4].ro | behavior[reg / 4].rw | + behavior[reg / 4].w1c; if (size == 1) *value = (*value >> (8 * (where & 3))) & 0xff;