Linux-PCI Archive on lore.kernel.org
 help / color / Atom feed
From: "Saheed O. Bolarinwa" <refactormyself@gmail.com>
To: helgaas@kernel.org, Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Saheed O. Bolarinwa" <refactormyself@gmail.com>,
	bjorn@helgaas.com, skhan@linuxfoundation.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v4 02/12] misc: rtsx: Check if pcie_capability_read_*() reads ~0
Date: Fri, 31 Jul 2020 13:02:30 +0200
Message-ID: <20200731110240.98326-3-refactormyself@gmail.com> (raw)
In-Reply-To: <20200731110240.98326-1-refactormyself@gmail.com>

On failure pcie_capability_read_word() sets it's last parameter, val
to 0. In which case (val & PCI_EXP_DEVCTL2_LTR_EN) evaluates to 0.
However, with Patch 12/12, it is possible that val is set to ~0 on
failure. This would introduce a bug because (x & x) == (~0 & x).

Since ~0 is an invalid value here,

Add an extra check for ~0 to the if condition to ensure success.

Suggested-by: Bjorn Helgaas <bjorn@helgaas.com>
Signed-off-by: Saheed O. Bolarinwa <refactormyself@gmail.com>
---
 drivers/misc/cardreader/rts5227.c | 2 +-
 drivers/misc/cardreader/rts5249.c | 2 +-
 drivers/misc/cardreader/rts5260.c | 2 +-
 drivers/misc/cardreader/rts5261.c | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/misc/cardreader/rts5227.c b/drivers/misc/cardreader/rts5227.c
index 3a9467aaa435..cab816639df1 100644
--- a/drivers/misc/cardreader/rts5227.c
+++ b/drivers/misc/cardreader/rts5227.c
@@ -106,7 +106,7 @@ static int rts5227_extra_init_hw(struct rtsx_pcr *pcr)
 	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, OLT_LED_CTL, 0x0F, 0x02);
 	/* Configure LTR */
 	pcie_capability_read_word(pcr->pci, PCI_EXP_DEVCTL2, &cap);
-	if (cap & PCI_EXP_DEVCTL2_LTR_EN)
+	if ((cap != (u16)~0) && (cap & PCI_EXP_DEVCTL2_LTR_EN))
 		rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, LTR_CTL, 0xFF, 0xA3);
 	/* Configure OBFF */
 	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, OBFF_CFG, 0x03, 0x03);
diff --git a/drivers/misc/cardreader/rts5249.c b/drivers/misc/cardreader/rts5249.c
index 6c6c9e95a29f..4382ac753fda 100644
--- a/drivers/misc/cardreader/rts5249.c
+++ b/drivers/misc/cardreader/rts5249.c
@@ -119,7 +119,7 @@ static void rts5249_init_from_cfg(struct rtsx_pcr *pcr)
 		u16 val;
 
 		pcie_capability_read_word(pcr->pci, PCI_EXP_DEVCTL2, &val);
-		if (val & PCI_EXP_DEVCTL2_LTR_EN) {
+		if ((val != (u16)~0) && (val & PCI_EXP_DEVCTL2_LTR_EN)) {
 			option->ltr_enabled = true;
 			option->ltr_active = true;
 			rtsx_set_ltr_latency(pcr, option->ltr_active_latency);
diff --git a/drivers/misc/cardreader/rts5260.c b/drivers/misc/cardreader/rts5260.c
index 7a9dbb778e84..3d52c86aaaa3 100644
--- a/drivers/misc/cardreader/rts5260.c
+++ b/drivers/misc/cardreader/rts5260.c
@@ -519,7 +519,7 @@ static void rts5260_init_from_cfg(struct rtsx_pcr *pcr)
 		u16 val;
 
 		pcie_capability_read_word(pcr->pci, PCI_EXP_DEVCTL2, &val);
-		if (val & PCI_EXP_DEVCTL2_LTR_EN) {
+		if ((val != (u16)~0) && (val & PCI_EXP_DEVCTL2_LTR_EN)) {
 			option->ltr_enabled = true;
 			option->ltr_active = true;
 			rtsx_set_ltr_latency(pcr, option->ltr_active_latency);
diff --git a/drivers/misc/cardreader/rts5261.c b/drivers/misc/cardreader/rts5261.c
index 195822ec858e..7e1188740194 100644
--- a/drivers/misc/cardreader/rts5261.c
+++ b/drivers/misc/cardreader/rts5261.c
@@ -440,7 +440,7 @@ static void rts5261_init_from_cfg(struct rtsx_pcr *pcr)
 		u16 val;
 
 		pcie_capability_read_word(pcr->pci, PCI_EXP_DEVCTL2, &val);
-		if (val & PCI_EXP_DEVCTL2_LTR_EN) {
+		if ((val != (u16)~0) && (val & PCI_EXP_DEVCTL2_LTR_EN)) {
 			option->ltr_enabled = true;
 			option->ltr_active = true;
 			rtsx_set_ltr_latency(pcr, option->ltr_active_latency);
-- 
2.18.4


  parent reply index

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-31 11:02 [PATCH v4 00/12] PCI: Remove '*val = 0' from pcie_capability_read_*() Saheed O. Bolarinwa
2020-07-31 11:02 ` [PATCH v4 01/12] IB/hfi1: Check if pcie_capability_read_*() reads ~0 Saheed O. Bolarinwa
2020-07-31 13:55   ` Bjorn Helgaas
2020-08-03 11:46     ` Ian Kumlien
2020-07-31 11:02 ` Saheed O. Bolarinwa [this message]
2020-07-31 11:02 ` [PATCH v4 03/12] ath9k: " Saheed O. Bolarinwa
2020-07-31 11:02 ` [PATCH v4 04/12] iwlegacy: " Saheed O. Bolarinwa
2020-07-31 11:02 ` [PATCH v4 05/12] PCI: pciehp: Set "Power On" as the default get_power_status Saheed O. Bolarinwa
2020-07-31 11:02 ` [PATCH v4 06/12] PCI: pciehp: Check if pcie_capability_read_*() reads ~0 Saheed O. Bolarinwa
2020-07-31 11:02 ` [PATCH v4 07/12] PCI/ACPI: " Saheed O. Bolarinwa

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200731110240.98326-3-refactormyself@gmail.com \
    --to=refactormyself@gmail.com \
    --cc=arnd@arndb.de \
    --cc=bjorn@helgaas.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=helgaas@kernel.org \
    --cc=linux-kernel-mentees@lists.linuxfoundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pci@vger.kernel.org \
    --cc=skhan@linuxfoundation.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-PCI Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-pci/0 linux-pci/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-pci linux-pci/ https://lore.kernel.org/linux-pci \
		linux-pci@vger.kernel.org
	public-inbox-index linux-pci

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-pci


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git