* [PATCH v2 2/2] pci: imx6: support kernels built in Thumb-2 mode
2018-12-04 13:27 [PATCH v2 1/2] pci: imx6: avoid dereferencing program counter from user mode Stefan Agner
@ 2018-12-04 13:27 ` Stefan Agner
2019-02-11 16:57 ` Lucas Stach
2019-02-08 12:13 ` [PATCH v2 1/2] pci: imx6: avoid dereferencing program counter from user mode Lorenzo Pieralisi
2019-02-11 16:56 ` Lucas Stach
2 siblings, 1 reply; 5+ messages in thread
From: Stefan Agner @ 2018-12-04 13:27 UTC (permalink / raw)
To: hongxing.zhu, l.stach
Cc: lorenzo.pieralisi, andrew.smirnov, robin.murphy, linux, stefan,
linux-kernel, linux-pci, bhelgaas, leonard.crestez, festevam,
linux-arm-kernel, tpiepho
Add a fault handler which handles immediate reads in Thumb-2
mode. Install the appropriate handler depending on which mode
the kernel has been built. This avoids an "Unhandled fault:
external abort on non-linefetch (0x1008) at 0xf0a80000"
during boot on a device with a PCIe switch connected.
Link: https://lore.kernel.org/linux-pci/20181126161645.8177-1-stefan@agner.ch/
Signed-off-by: Stefan Agner <stefan@agner.ch>
---
Changes since v1:
- Added Thumb-2 32-bit instruction support (tested by inserting .w
instructions in arch/arm/include/asm/io.h)
- Avoid dereferencing if fault happened in user mode
drivers/pci/controller/dwc/pci-imx6.c | 59 ++++++++++++++++++++++++++-
1 file changed, 58 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 54a29e441303..a9bbbf176c4a 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -29,6 +29,7 @@
#include <linux/reset.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
+#include <asm/opcodes.h>
#include "pcie-designware.h"
@@ -305,6 +306,59 @@ static int imx6q_pcie_abort_handler(unsigned long addr,
return 1;
}
+static int imx6q_pcie_abort_handler_thumb2(unsigned long addr,
+ unsigned int fsr, struct pt_regs *regs)
+{
+ unsigned long pc = instruction_pointer(regs);
+ unsigned long instr;
+
+ if (user_mode(regs))
+ return 1;
+
+ instr = __mem_to_opcode_thumb32(*(unsigned long *)pc);
+
+ if (__opcode_is_thumb32(instr)) {
+ /* Load word/byte and halfword immediate offset */
+ if ((instr & 0xff100000UL) == 0xf8100000UL) {
+ int reg = (instr >> 12) & 0xf;
+ unsigned long val;
+
+ if ((instr & 0x00700000UL) == 0x00100000UL)
+ val = 0xff;
+ else if ((instr & 0x00700000UL) == 0x00300000UL)
+ val = 0xffff;
+ else
+ val = 0xffffffffUL;
+
+ regs->uregs[reg] = val;
+ regs->ARM_pc += 4;
+ return 0;
+ }
+ } else {
+ instr = __mem_to_opcode_thumb16(*(unsigned long *)pc);
+
+ /* Load word/byte and halfword immediate offset */
+ if (((instr & 0xe800) == 0x6800) ||
+ ((instr & 0xf800) == 0x8800)) {
+ int reg = instr & 0x7;
+ unsigned long val;
+
+ if (instr & 0x1000)
+ val = 0xff;
+ else if (instr & 0x8000)
+ val = 0xffff;
+ else
+ val = 0xffffffffUL;
+
+ regs->uregs[reg] = val;
+ regs->ARM_pc += 2;
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
static int imx6_pcie_attach_pd(struct device *dev)
{
struct imx6_pcie *imx6_pcie = dev_get_drvdata(dev);
@@ -1075,6 +1129,8 @@ static struct platform_driver imx6_pcie_driver = {
static int __init imx6_pcie_init(void)
{
+ bool thumb2 = IS_ENABLED(CONFIG_THUMB2_KERNEL);
+
/*
* Since probe() can be deferred we need to make sure that
* hook_fault_code is not called after __init memory is freed
@@ -1082,7 +1138,8 @@ static int __init imx6_pcie_init(void)
* we can install the handler here without risking it
* accessing some uninitialized driver state.
*/
- hook_fault_code(8, imx6q_pcie_abort_handler, SIGBUS, 0,
+ hook_fault_code(8, thumb2 ? imx6q_pcie_abort_handler_thumb2 :
+ imx6q_pcie_abort_handler, SIGBUS, 0,
"external abort on non-linefetch");
return platform_driver_register(&imx6_pcie_driver);
--
2.19.1
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^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH v2 2/2] pci: imx6: support kernels built in Thumb-2 mode
2018-12-04 13:27 ` [PATCH v2 2/2] pci: imx6: support kernels built in Thumb-2 mode Stefan Agner
@ 2019-02-11 16:57 ` Lucas Stach
0 siblings, 0 replies; 5+ messages in thread
From: Lucas Stach @ 2019-02-11 16:57 UTC (permalink / raw)
To: Stefan Agner, hongxing.zhu
Cc: lorenzo.pieralisi, andrew.smirnov, robin.murphy, linux,
linux-kernel, linux-pci, bhelgaas, leonard.crestez, festevam,
linux-arm-kernel, tpiepho
Am Dienstag, den 04.12.2018, 14:27 +0100 schrieb Stefan Agner:
> Add a fault handler which handles immediate reads in Thumb-2
> mode. Install the appropriate handler depending on which mode
> the kernel has been built. This avoids an "Unhandled fault:
> external abort on non-linefetch (0x1008) at 0xf0a80000"
> during boot on a device with a PCIe switch connected.
>
> Link: https://lore.kernel.org/linux-pci/20181126161645.8177-1-stefan@agner.ch/
> Signed-off-by: Stefan Agner <stefan@agner.ch>
Acked-by: Lucas Stach <l.stach@pengutronix.de>
> ---
> Changes since v1:
> - Added Thumb-2 32-bit instruction support (tested by inserting .w
> instructions in arch/arm/include/asm/io.h)
> - Avoid dereferencing if fault happened in user mode
>
> drivers/pci/controller/dwc/pci-imx6.c | 59 ++++++++++++++++++++++++++-
> 1 file changed, 58 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 54a29e441303..a9bbbf176c4a 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -29,6 +29,7 @@
> #include <linux/reset.h>
> #include <linux/pm_domain.h>
> #include <linux/pm_runtime.h>
> +#include <asm/opcodes.h>
>
> #include "pcie-designware.h"
>
> @@ -305,6 +306,59 @@ static int imx6q_pcie_abort_handler(unsigned long addr,
> return 1;
> }
>
> +static int imx6q_pcie_abort_handler_thumb2(unsigned long addr,
> + unsigned int fsr, struct pt_regs *regs)
> +{
> + unsigned long pc = instruction_pointer(regs);
> + unsigned long instr;
> +
> + if (user_mode(regs))
> + return 1;
> +
> + instr = __mem_to_opcode_thumb32(*(unsigned long *)pc);
> +
> + if (__opcode_is_thumb32(instr)) {
> + /* Load word/byte and halfword immediate offset */
> + if ((instr & 0xff100000UL) == 0xf8100000UL) {
> + int reg = (instr >> 12) & 0xf;
> + unsigned long val;
> +
> + if ((instr & 0x00700000UL) == 0x00100000UL)
> + val = 0xff;
> + else if ((instr & 0x00700000UL) == 0x00300000UL)
> + val = 0xffff;
> + else
> + val = 0xffffffffUL;
> +
> + regs->uregs[reg] = val;
> + regs->ARM_pc += 4;
> + return 0;
> + }
> + } else {
> + instr = __mem_to_opcode_thumb16(*(unsigned long *)pc);
> +
> + /* Load word/byte and halfword immediate offset */
> + if (((instr & 0xe800) == 0x6800) ||
> + ((instr & 0xf800) == 0x8800)) {
> + int reg = instr & 0x7;
> + unsigned long val;
> +
> + if (instr & 0x1000)
> + val = 0xff;
> + else if (instr & 0x8000)
> + val = 0xffff;
> + else
> + val = 0xffffffffUL;
> +
> + regs->uregs[reg] = val;
> + regs->ARM_pc += 2;
> + return 0;
> + }
> + }
> +
> + return 1;
> +}
> +
> static int imx6_pcie_attach_pd(struct device *dev)
> {
> struct imx6_pcie *imx6_pcie = dev_get_drvdata(dev);
> @@ -1075,6 +1129,8 @@ static struct platform_driver imx6_pcie_driver = {
>
> static int __init imx6_pcie_init(void)
> {
> + bool thumb2 = IS_ENABLED(CONFIG_THUMB2_KERNEL);
> +
> /*
> * Since probe() can be deferred we need to make sure that
> * hook_fault_code is not called after __init memory is freed
> @@ -1082,7 +1138,8 @@ static int __init imx6_pcie_init(void)
> * we can install the handler here without risking it
> * accessing some uninitialized driver state.
> */
> - hook_fault_code(8, imx6q_pcie_abort_handler, SIGBUS, 0,
> + hook_fault_code(8, thumb2 ? imx6q_pcie_abort_handler_thumb2 :
> + imx6q_pcie_abort_handler, SIGBUS, 0,
> "external abort on non-linefetch");
>
> return platform_driver_register(&imx6_pcie_driver);
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2 1/2] pci: imx6: avoid dereferencing program counter from user mode
2018-12-04 13:27 [PATCH v2 1/2] pci: imx6: avoid dereferencing program counter from user mode Stefan Agner
2018-12-04 13:27 ` [PATCH v2 2/2] pci: imx6: support kernels built in Thumb-2 mode Stefan Agner
@ 2019-02-08 12:13 ` Lorenzo Pieralisi
2019-02-11 16:56 ` Lucas Stach
2 siblings, 0 replies; 5+ messages in thread
From: Lorenzo Pieralisi @ 2019-02-08 12:13 UTC (permalink / raw)
To: Stefan Agner
Cc: hongxing.zhu, andrew.smirnov, festevam, linux-pci, linux,
linux-kernel, l.stach, bhelgaas, leonard.crestez, robin.murphy,
linux-arm-kernel, tpiepho
On Tue, Dec 04, 2018 at 02:27:32PM +0100, Stefan Agner wrote:
> The custom fault handler is currently only meant to handle kernel
> mode bus faults. Exit in case the abort happened in user mode.
>
> Signed-off-by: Stefan Agner <stefan@agner.ch>
> ---
> drivers/pci/controller/dwc/pci-imx6.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
If this series is still aimed at mainline I need Lucas' ACK to
merge it.
Lorenzo
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 69f86234f7c0..54a29e441303 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -270,8 +270,14 @@ static int imx6q_pcie_abort_handler(unsigned long addr,
> unsigned int fsr, struct pt_regs *regs)
> {
> unsigned long pc = instruction_pointer(regs);
> - unsigned long instr = *(unsigned long *)pc;
> - int reg = (instr >> 12) & 15;
> + unsigned long instr;
> + int reg;
> +
> + if (user_mode(regs))
> + return 1;
> +
> + instr = *(unsigned long *)pc;
> + reg = (instr >> 12) & 15;
>
> /*
> * If the instruction being executed was a read,
> --
> 2.19.1
>
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^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v2 1/2] pci: imx6: avoid dereferencing program counter from user mode
2018-12-04 13:27 [PATCH v2 1/2] pci: imx6: avoid dereferencing program counter from user mode Stefan Agner
2018-12-04 13:27 ` [PATCH v2 2/2] pci: imx6: support kernels built in Thumb-2 mode Stefan Agner
2019-02-08 12:13 ` [PATCH v2 1/2] pci: imx6: avoid dereferencing program counter from user mode Lorenzo Pieralisi
@ 2019-02-11 16:56 ` Lucas Stach
2 siblings, 0 replies; 5+ messages in thread
From: Lucas Stach @ 2019-02-11 16:56 UTC (permalink / raw)
To: Stefan Agner, hongxing.zhu
Cc: lorenzo.pieralisi, andrew.smirnov, robin.murphy, linux,
linux-kernel, linux-pci, bhelgaas, leonard.crestez, festevam,
linux-arm-kernel, tpiepho
Am Dienstag, den 04.12.2018, 14:27 +0100 schrieb Stefan Agner:
> The custom fault handler is currently only meant to handle kernel
> mode bus faults. Exit in case the abort happened in user mode.
>
> Signed-off-by: Stefan Agner <stefan@agner.ch>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
> ---
> drivers/pci/controller/dwc/pci-imx6.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 69f86234f7c0..54a29e441303 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -270,8 +270,14 @@ static int imx6q_pcie_abort_handler(unsigned long addr,
> unsigned int fsr, struct pt_regs *regs)
> {
> unsigned long pc = instruction_pointer(regs);
> - unsigned long instr = *(unsigned long *)pc;
> - int reg = (instr >> 12) & 15;
> + unsigned long instr;
> + int reg;
> +
> + if (user_mode(regs))
> + return 1;
> +
> + instr = *(unsigned long *)pc;
> + reg = (instr >> 12) & 15;
>
> /*
> * If the instruction being executed was a read,
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^ permalink raw reply [flat|nested] 5+ messages in thread