linux-kernel - [PATCH v13 1/6] PCI: Introduce generic bus config read helper function

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250607161405.808585-2-18255117159@163.com>
Date: Sun,  8 Jun 2025 00:14:00 +0800
From: Hans Zhang <18255117159@....com>
To: lpieralisi@...nel.org,
	bhelgaas@...gle.com,
	mani@...nel.org,
	ilpo.jarvinen@...ux.intel.com,
	kwilczynski@...nel.org
Cc: robh@...nel.org,
	jingoohan1@...il.com,
	linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Hans Zhang <18255117159@....com>
Subject: [PATCH v13 1/6] PCI: Introduce generic bus config read helper function

The primary PCI config space accessors are tied to the size of the read
(byte/word/dword). Upcoming refactoring of PCI capability discovery logic
requires passing a config accessor function that must be able to perform
read with different sizes.

Add any size config space read accessor pci_bus_read_config() to allow
giving it as the config space accessor to the upcoming PCI capability
discovery macro.

Reconstructs the PCI function discovery logic to prepare for unified
configuration of access modes. No function changes are intended.

Signed-off-by: Hans Zhang <18255117159@....com>
---
Changes since v12:
- Optimize the function return values.

Changes since v9 ~ v11:
- None

Changes since v8:
- The new split is patch 1/6.
- The patch commit message were modified.
---
 drivers/pci/access.c | 15 +++++++++++++++
 drivers/pci/pci.h    |  2 ++
 2 files changed, 17 insertions(+)

diff --git a/drivers/pci/access.c b/drivers/pci/access.c
index b123da16b63b..ba66f55d2524 100644
--- a/drivers/pci/access.c
+++ b/drivers/pci/access.c
@@ -85,6 +85,21 @@ EXPORT_SYMBOL(pci_bus_write_config_byte);
 EXPORT_SYMBOL(pci_bus_write_config_word);
 EXPORT_SYMBOL(pci_bus_write_config_dword);
 
+int pci_bus_read_config(void *priv, unsigned int devfn, int where, u32 size,
+			u32 *val)
+{
+	struct pci_bus *bus = priv;
+
+	if (size == 1)
+		return pci_bus_read_config_byte(bus, devfn, where, (u8 *)val);
+	else if (size == 2)
+		return pci_bus_read_config_word(bus, devfn, where, (u16 *)val);
+	else if (size == 4)
+		return pci_bus_read_config_dword(bus, devfn, where, val);
+	else
+		return PCIBIOS_BAD_REGISTER_NUMBER;
+}
+
 int pci_generic_config_read(struct pci_bus *bus, unsigned int devfn,
 			    int where, int size, u32 *val)
 {
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 12215ee72afb..e7d31ed56731 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -90,6 +90,8 @@ extern bool pci_early_dump;
 bool pcie_cap_has_lnkctl(const struct pci_dev *dev);
 bool pcie_cap_has_lnkctl2(const struct pci_dev *dev);
 bool pcie_cap_has_rtctl(const struct pci_dev *dev);
+int pci_bus_read_config(void *priv, unsigned int devfn, int where, u32 size,
+			u32 *val);
 
 /* Functions internal to the PCI core code */
 
-- 
2.25.1