Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
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>
In-Reply-To: <20200731110240.98326-1-refactormyself@gmail.com>
References: <20200731110240.98326-1-refactormyself@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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