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arch/arm/src/arm/up_fullcontextrestore.S: When performing stability test, the application would cause kernel crash. When I trace the stack, I find that register R1 has been changed, and its value is the same as register CPSR. In p_fullcontextrestore.S, the restoration of R0 and R1 is not atomic: 'msr cpsr r1 will enable interrupts and the recovery of r0 and r1 may be interrupted and the value or R1 may be changed. Fix is to use a single ldmia to restore R0, R1, and return via R15.

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Loyen Wang 2019-09-04 07:49:27 -06:00 committed by Gregory Nutt
parent ce8fb54d07
commit 0ad5bc50fb
1 changed files with 3 additions and 9 deletions
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arch/arm/src/arm/up_fullcontextrestore.S
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@ -103,16 +103,10 @@ up_fullcontextrestore:
ldr r1, [r0, #(4*REG_CPSR)] /* Fetch the stored CPSR value */
msr cpsr, r1 /* Set the CPSR */
/* Now recover r0 and r1 */
ldr r0, [sp]
ldr r1, [sp, #4]
add sp, sp, #(2*4)
/* Then return to the address at the stop of the stack,
* destroying the stack frame
/* Now recover r0 and r1. Then return to the address at the stop of
* the stack, destroying the stack frame
*/
ldr pc, [sp], #4
ldmia sp!, {r0-r1, r15}
.size up_fullcontextrestore, . - up_fullcontextrestore