Commit 92cde9fc authored by Guilherme G. Piccoli's avatar Guilherme G. Piccoli Committed by Zheng Zengkai
Browse files

x86/PCI: Export find_cap() to be used in early PCI code 

maillist inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8X2RA
CVE: NA

Reference: https://lore.kernel.org/linux-pci/20181018183721.27467-2-gpiccoli@canonical.com/



-------------------------------

This patch exports (and renames) the function find_cap() to be used
in the early PCI quirk code, by the next patch.

This is being moved out from AGP code to generic early-PCI code
since it's not AGP-specific and can be used for any PCI device.
No functional changes intended.

Signed-off-by: default avatarGuilherme G. Piccoli <gpiccoli@canonical.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent 26f718c6

arch/x86/include/asm/pci-direct.h

+1 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
extern u32 read_pci_config(u8 bus, u8 slot, u8 func, u8 offset);

extern u8 read_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset);

extern u16 read_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset);

extern u32 pci_early_find_cap(int bus, int slot, int func, int cap);

extern void write_pci_config(u8 bus, u8 slot, u8 func, u8 offset, u32 val);

extern void write_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset, u8 val);

extern void write_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset, u16 val);

arch/x86/kernel/aperture_64.c

+2 −28
Original line number Diff line number Diff line
@@ -126,32 +126,6 @@ static u32 __init allocate_aperture(void) 
}





/* Find a PCI capability */

static u32 __init find_cap(int bus, int slot, int func, int cap)

{

	int bytes;

	u8 pos;



	if (!(read_pci_config_16(bus, slot, func, PCI_STATUS) &

						PCI_STATUS_CAP_LIST))

		return 0;



	pos = read_pci_config_byte(bus, slot, func, PCI_CAPABILITY_LIST);

	for (bytes = 0; bytes < 48 && pos >= 0x40; bytes++) {

		u8 id;



		pos &= ~3;

		id = read_pci_config_byte(bus, slot, func, pos+PCI_CAP_LIST_ID);

		if (id == 0xff)

			break;

		if (id == cap)

			return pos;

		pos = read_pci_config_byte(bus, slot, func,

						pos+PCI_CAP_LIST_NEXT);

	}

	return 0;

}



/* Read a standard AGPv3 bridge header */

static u32 __init read_agp(int bus, int slot, int func, int cap, u32 *order)

{
@@ -240,8 +214,8 @@ static u32 __init search_agp_bridge(u32 *order, int *valid_agp) 
				case PCI_CLASS_BRIDGE_HOST:

				case PCI_CLASS_BRIDGE_OTHER: /* needed? */

					/* AGP bridge? */

					cap = find_cap(bus, slot, func,

							PCI_CAP_ID_AGP);

					cap = pci_early_find_cap(bus, slot,

						 func, PCI_CAP_ID_AGP);

					if (!cap)

						break;

					*valid_agp = 1;

arch/x86/pci/early.c

+25 −0
Original line number Diff line number Diff line
@@ -51,6 +51,31 @@ void write_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset, u16 val) 
	outw(val, 0xcfc + (offset&2));

}



u32 pci_early_find_cap(int bus, int slot, int func, int cap)

{

	int bytes;

	u8 pos;



	if (!(read_pci_config_16(bus, slot, func, PCI_STATUS) &

						PCI_STATUS_CAP_LIST))

		return 0;



	pos = read_pci_config_byte(bus, slot, func, PCI_CAPABILITY_LIST);

	for (bytes = 0; bytes < 48 && pos >= 0x40; bytes++) {

		u8 id;



		pos &= ~3;

		id = read_pci_config_byte(bus, slot, func, pos+PCI_CAP_LIST_ID);

		if (id == 0xff)

			break;

		if (id == cap)

			return pos;

		pos = read_pci_config_byte(bus, slot, func,

						pos+PCI_CAP_LIST_NEXT);

	}

	return 0;

}



int early_pci_allowed(void)

{

	return (pci_probe & (PCI_PROBE_CONF1|PCI_PROBE_NOEARLY)) ==