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>,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
linux-kernel-mentees@lists.linuxfoundation.org
Subject: [Linux-kernel-mentees] [PATCH v4 02/12] misc: rtsx: Check if pcie_capability_read_*() reads ~0
Date: Fri, 31 Jul 2020 13:02:30 +0200 [thread overview]
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
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next prev parent reply other threads:[~2020-07-31 12:02 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-31 11:02 [Linux-kernel-mentees] [PATCH v4 00/12] PCI: Remove '*val = 0' from pcie_capability_read_*() Saheed O. Bolarinwa
2020-07-31 11:02 ` [Linux-kernel-mentees] [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 ` [Linux-kernel-mentees] [PATCH v4 03/12] ath9k: " Saheed O. Bolarinwa
2020-07-31 11:02 ` [Linux-kernel-mentees] [PATCH v4 04/12] iwlegacy: " Saheed O. Bolarinwa
2020-07-31 11:02 ` [Linux-kernel-mentees] [PATCH v4 05/12] PCI: pciehp: Set "Power On" as the default get_power_status Saheed O. Bolarinwa
2020-07-31 11:02 ` [Linux-kernel-mentees] [PATCH v4 06/12] PCI: pciehp: Check if pcie_capability_read_*() reads ~0 Saheed O. Bolarinwa
2020-07-31 11:02 ` [Linux-kernel-mentees] [PATCH v4 07/12] PCI/ACPI: " Saheed O. Bolarinwa
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