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In KERNEL mode, need to explicitly set the privilege in the CONTROL register on return from exceptions

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git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5757 42af7a65-404d-4744-a932-0658087f49c3
This commit is contained in:
patacongo 2013-03-19 00:16:27 +00:00
parent 854dbf19e5
commit aaa240782b
4 changed files with 58 additions and 12 deletions
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5
ChangeLog
View File

@ -4375,3 +4375,8 @@
* arch/arm/src/armv7-h/ram_vectors.h, up_ramvec_*.c, arch/arm/src/*/*_irq.c,
and Make.defs: Add support for modifiable interrupt vectors in RAM
(2013-03-18).
* arch/arm/src/armv7-m/up_exception.S, sam3u/sam3u_vectors.S, and
lpc17xx/lpc17_vectors.S: In exception handling with CONFIG_NUTTX_KERNEL,
need to explicity set and cleare the privilege bit in the CONTROL
register on return. I assumed this would be handled automatically
by the EXC_RETURN. Silly me (2013-03-18).

20
arch/arm/src/armv7-m/up_exception.S
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@ -201,10 +201,30 @@ exception_common:
/* The EXC_RETURN value tells us whether we are returning on the MSP or PSP
*/
#ifdef CONFIG_NUTTX_KERNEL
/* The EXC_RETURN value will be 0xfffffff9 (privileged thread) or 0xfffffff1
* (handler mode) if the stack is on the MSP. It can only be on the PSP if
* EXC_RETURN is 0xfffffffd (unprivileged thread)
*/
mrs r2, control /* R2=Contents of the control register */
tst r14, #EXC_RETURN_PROCESS_STACK /* nonzero if context on process stack */
beq 3f /* Branch if privileged */
orr r2, r2, #1 /* Unprivileged mode */
msr psp, r1 /* R1=The process stack pointer */
b 4f
3:
bic r2, r2, #1 /* Privileged mode */
msr msp, r1 /* R1=The main stack pointer */
4:
msr control, r2 /* Save the updated control register */
#else
tst r14, #EXC_RETURN_PROCESS_STACK /* nonzero if context on process stack */
ite eq /* next two instructions conditional */
msreq msp, r1 /* R1=The main stack pointer */
msrne psp, r1 /* R1=The process stack pointer */
#endif
/* Restore the interrupt state */

22
arch/arm/src/lpc17xx/lpc17_vectors.S
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@ -43,6 +43,7 @@
#include <arch/irq.h>
#include "chip.h"
#include "exc_return.h"
/************************************************************************************************
* Preprocessor Definitions
@ -209,7 +210,7 @@ lpc17_common:
#ifdef CONFIG_NUTTX_KERNEL
/* The EXC_RETURN value will be 0xfffffff9 (privileged thread) or 0xfffffff1
* (handler mode) if the state is on the MSP. It can only be on the PSP if
* (handler mode) if the stack is on the MSP. It can only be on the PSP if
* EXC_RETURN is 0xfffffffd (unprivileged thread)
*/
@ -351,16 +352,25 @@ lpc17_common:
* r4-r11 = restored register values
*/
2:
#ifdef CONFIG_NUTTX_KERNEL
/* The EXC_RETURN value will be 0xfffffff9 (privileged thread) or 0xfffffff1
* (handler mode) if the state is on the MSP. It can only be on the PSP if
* (handler mode) if the stack is on the MSP. It can only be on the PSP if
* EXC_RETURN is 0xfffffffd (unprivileged thread)
*/
adds r0, r14, #3 /* If R14=0xfffffffd, then r0 == 0 */
ite ne /* Next two instructions are condition */
msrne msp, r1 /* R1=The main stack pointer */
msreq psp, r1 /* R1=The process stack pointer */
mrs r2, control /* R2=Contents of the control register */
tst r14, #EXC_RETURN_PROCESS_STACK /* nonzero if context on process stack */
beq 3f /* Branch if privileged */
orr r2, r2, #1 /* Unprivileged mode */
msr psp, r1 /* R1=The process stack pointer */
b 4f
3:
bic r2, r2, #1 /* Privileged mode */
msr msp, r1 /* R1=The main stack pointer */
4:
msr control, r2 /* Save the updated control register */
#else
msr msp, r1 /* Recover the return MSP value */

23
arch/arm/src/sam3u/sam3u_vectors.S
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@ -42,6 +42,8 @@
#include <arch/irq.h>
#include "exc_return.h"
/************************************************************************************************
* Preprocessor Definitions
************************************************************************************************/
@ -236,7 +238,7 @@ sam3u_common:
#ifdef CONFIG_NUTTX_KERNEL
/* The EXC_RETURN value will be 0xfffffff9 (privileged thread) or 0xfffffff1
* (handler mode) if the state is on the MSP. It can only be on the PSP if
* (handler mode) if the stack is on the MSP. It can only be on the PSP if
* EXC_RETURN is 0xfffffffd (unprivileged thread)
*/
@ -378,16 +380,25 @@ sam3u_common:
* r4-r11 = restored register values
*/
2:
#ifdef CONFIG_NUTTX_KERNEL
/* The EXC_RETURN value will be 0xfffffff9 (privileged thread) or 0xfffffff1
* (handler mode) if the state is on the MSP. It can only be on the PSP if
* (handler mode) if the stack is on the MSP. It can only be on the PSP if
* EXC_RETURN is 0xfffffffd (unprivileged thread)
*/
adds r0, r14, #3 /* If R14=0xfffffffd, then r0 == 0 */
ite ne /* Next two instructions are condition */
msrne msp, r1 /* R1=The main stack pointer */
msreq psp, r1 /* R1=The process stack pointer */
mrs r2, control /* R2=Contents of the control register */
tst r14, #EXC_RETURN_PROCESS_STACK /* nonzero if context on process stack */
beq 3f /* Branch if privileged */
orr r2, r2, #1 /* Unprivileged mode */
msr psp, r1 /* R1=The process stack pointer */
b 4f
3:
bic r2, r2, #1 /* Privileged mode */
msr msp, r1 /* R1=The main stack pointer */
4:
msr control, r2 /* Save the updated control register */
#else
msr msp, r1 /* Recover the return MSP value */