armv8-m: Modify ARMv8-M registers stacking procedure

ARMv8-M TrustZone variant registers stacking
procedure is modified to be consistent with the NTZ port
variant where one `stmdb` instruction is used instead of
using 'subs' instruction along with `stmia` instruction, also,
this result in more efficient context switching
handling (lower latency).

Signed-off-by: Ahmed Ismail <Ahmed.Ismail@arm.com>
This commit is contained in:
Ahmed Ismail 2024-11-19 10:50:55 +00:00
parent 3a7b3082cf
commit c84fc7226e
10 changed files with 60 additions and 130 deletions

View file

@ -381,31 +381,24 @@ PendSV_Handler:
lsls r1, r3, #25 /* r1 = r3 << 25. Bit[6] of EXC_RETURN is 1 if secure stack was used, 0 if non-secure stack was used to store stack frame. */
bpl save_ns_context /* bpl - branch if positive or zero. If r1 >= 0 ==> Bit[6] in EXC_RETURN is 0 i.e. non-secure stack was used. */
ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
ldr r1, [r3] /* Read pxCurrentTCB. */
subs r2, r2, #12 /* Make space for xSecureContext, PSPLIM and LR on the stack. */
str r2, [r1] /* Save the new top of stack in TCB. */
mrs r1, psplim /* r1 = PSPLIM. */
mov r3, lr /* r3 = LR/EXC_RETURN. */
stmia r2!, {r0, r1, r3} /* Store xSecureContext, PSPLIM and LR on the stack. */
stmdb r2!, {r0, r1, r3} /* Store xSecureContext, PSPLIM and LR on the stack. */
b select_next_task
save_ns_context:
ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
ldr r1, [r3] /* Read pxCurrentTCB. */
#if ( ( configENABLE_FPU == 1 ) || ( configENABLE_MVE == 1 ) )
tst lr, #0x10 /* Test Bit[4] in LR. Bit[4] of EXC_RETURN is 0 if the Extended Stack Frame is in use. */
it eq
vstmdbeq r2!, {s16-s31} /* Store the additional FP context registers which are not saved automatically. */
#endif /* configENABLE_FPU || configENABLE_MVE */
subs r2, r2, #44 /* Make space for xSecureContext, PSPLIM, LR and the remaining registers on the stack. */
str r2, [r1] /* Save the new top of stack in TCB. */
adds r2, r2, #12 /* r2 = r2 + 12. */
stm r2, {r4-r11} /* Store the registers that are not saved automatically. */
stmdb r2!, {r4-r11} /* Store the registers that are not saved automatically. */
mrs r1, psplim /* r1 = PSPLIM. */
mov r3, lr /* r3 = LR/EXC_RETURN. */
subs r2, r2, #12 /* r2 = r2 - 12. */
stmia r2!, {r0, r1, r3} /* Store xSecureContext, PSPLIM and LR on the stack. */
stmdb r2!, {r0, r1, r3} /* Store xSecureContext, PSPLIM and LR on the stack. */
ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
ldr r1, [r3] /* Read pxCurrentTCB. */
str r2, [r1] /* Save the new top of stack in TCB. */
select_next_task:
mov r0, #configMAX_SYSCALL_INTERRUPT_PRIORITY

View file

@ -381,31 +381,24 @@ PendSV_Handler:
lsls r1, r3, #25 /* r1 = r3 << 25. Bit[6] of EXC_RETURN is 1 if secure stack was used, 0 if non-secure stack was used to store stack frame. */
bpl save_ns_context /* bpl - branch if positive or zero. If r1 >= 0 ==> Bit[6] in EXC_RETURN is 0 i.e. non-secure stack was used. */
ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
ldr r1, [r3] /* Read pxCurrentTCB. */
subs r2, r2, #12 /* Make space for xSecureContext, PSPLIM and LR on the stack. */
str r2, [r1] /* Save the new top of stack in TCB. */
mrs r1, psplim /* r1 = PSPLIM. */
mov r3, lr /* r3 = LR/EXC_RETURN. */
stmia r2!, {r0, r1, r3} /* Store xSecureContext, PSPLIM and LR on the stack. */
stmdb r2!, {r0, r1, r3} /* Store xSecureContext, PSPLIM and LR on the stack. */
b select_next_task
save_ns_context:
ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
ldr r1, [r3] /* Read pxCurrentTCB. */
#if ( ( configENABLE_FPU == 1 ) || ( configENABLE_MVE == 1 ) )
tst lr, #0x10 /* Test Bit[4] in LR. Bit[4] of EXC_RETURN is 0 if the Extended Stack Frame is in use. */
it eq
vstmdbeq r2!, {s16-s31} /* Store the additional FP context registers which are not saved automatically. */
#endif /* configENABLE_FPU || configENABLE_MVE */
subs r2, r2, #44 /* Make space for xSecureContext, PSPLIM, LR and the remaining registers on the stack. */
str r2, [r1] /* Save the new top of stack in TCB. */
adds r2, r2, #12 /* r2 = r2 + 12. */
stm r2, {r4-r11} /* Store the registers that are not saved automatically. */
stmdb r2!, {r4-r11} /* Store the registers that are not saved automatically. */
mrs r1, psplim /* r1 = PSPLIM. */
mov r3, lr /* r3 = LR/EXC_RETURN. */
subs r2, r2, #12 /* r2 = r2 - 12. */
stmia r2!, {r0, r1, r3} /* Store xSecureContext, PSPLIM and LR on the stack. */
stmdb r2!, {r0, r1, r3} /* Store xSecureContext, PSPLIM and LR on the stack. */
ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
ldr r1, [r3] /* Read pxCurrentTCB. */
str r2, [r1] /* Save the new top of stack in TCB. */
select_next_task:
mov r0, #configMAX_SYSCALL_INTERRUPT_PRIORITY

View file

@ -381,31 +381,24 @@ PendSV_Handler:
lsls r1, r3, #25 /* r1 = r3 << 25. Bit[6] of EXC_RETURN is 1 if secure stack was used, 0 if non-secure stack was used to store stack frame. */
bpl save_ns_context /* bpl - branch if positive or zero. If r1 >= 0 ==> Bit[6] in EXC_RETURN is 0 i.e. non-secure stack was used. */
ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
ldr r1, [r3] /* Read pxCurrentTCB. */
subs r2, r2, #12 /* Make space for xSecureContext, PSPLIM and LR on the stack. */
str r2, [r1] /* Save the new top of stack in TCB. */
mrs r1, psplim /* r1 = PSPLIM. */
mov r3, lr /* r3 = LR/EXC_RETURN. */
stmia r2!, {r0, r1, r3} /* Store xSecureContext, PSPLIM and LR on the stack. */
stmdb r2!, {r0, r1, r3} /* Store xSecureContext, PSPLIM and LR on the stack. */
b select_next_task
save_ns_context:
ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
ldr r1, [r3] /* Read pxCurrentTCB. */
#if ( ( configENABLE_FPU == 1 ) || ( configENABLE_MVE == 1 ) )
tst lr, #0x10 /* Test Bit[4] in LR. Bit[4] of EXC_RETURN is 0 if the Extended Stack Frame is in use. */
it eq
vstmdbeq r2!, {s16-s31} /* Store the additional FP context registers which are not saved automatically. */
#endif /* configENABLE_FPU || configENABLE_MVE */
subs r2, r2, #44 /* Make space for xSecureContext, PSPLIM, LR and the remaining registers on the stack. */
str r2, [r1] /* Save the new top of stack in TCB. */
adds r2, r2, #12 /* r2 = r2 + 12. */
stm r2, {r4-r11} /* Store the registers that are not saved automatically. */
stmdb r2!, {r4-r11} /* Store the registers that are not saved automatically. */
mrs r1, psplim /* r1 = PSPLIM. */
mov r3, lr /* r3 = LR/EXC_RETURN. */
subs r2, r2, #12 /* r2 = r2 - 12. */
stmia r2!, {r0, r1, r3} /* Store xSecureContext, PSPLIM and LR on the stack. */
stmdb r2!, {r0, r1, r3} /* Store xSecureContext, PSPLIM and LR on the stack. */
ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
ldr r1, [r3] /* Read pxCurrentTCB. */
str r2, [r1] /* Save the new top of stack in TCB. */
select_next_task:
mov r0, #configMAX_SYSCALL_INTERRUPT_PRIORITY

View file

@ -381,31 +381,24 @@ PendSV_Handler:
lsls r1, r3, #25 /* r1 = r3 << 25. Bit[6] of EXC_RETURN is 1 if secure stack was used, 0 if non-secure stack was used to store stack frame. */
bpl save_ns_context /* bpl - branch if positive or zero. If r1 >= 0 ==> Bit[6] in EXC_RETURN is 0 i.e. non-secure stack was used. */
ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
ldr r1, [r3] /* Read pxCurrentTCB. */
subs r2, r2, #12 /* Make space for xSecureContext, PSPLIM and LR on the stack. */
str r2, [r1] /* Save the new top of stack in TCB. */
mrs r1, psplim /* r1 = PSPLIM. */
mov r3, lr /* r3 = LR/EXC_RETURN. */
stmia r2!, {r0, r1, r3} /* Store xSecureContext, PSPLIM and LR on the stack. */
stmdb r2!, {r0, r1, r3} /* Store xSecureContext, PSPLIM and LR on the stack. */
b select_next_task
save_ns_context:
ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
ldr r1, [r3] /* Read pxCurrentTCB. */
#if ( ( configENABLE_FPU == 1 ) || ( configENABLE_MVE == 1 ) )
tst lr, #0x10 /* Test Bit[4] in LR. Bit[4] of EXC_RETURN is 0 if the Extended Stack Frame is in use. */
it eq
vstmdbeq r2!, {s16-s31} /* Store the additional FP context registers which are not saved automatically. */
#endif /* configENABLE_FPU || configENABLE_MVE */
subs r2, r2, #44 /* Make space for xSecureContext, PSPLIM, LR and the remaining registers on the stack. */
str r2, [r1] /* Save the new top of stack in TCB. */
adds r2, r2, #12 /* r2 = r2 + 12. */
stm r2, {r4-r11} /* Store the registers that are not saved automatically. */
stmdb r2!, {r4-r11} /* Store the registers that are not saved automatically. */
mrs r1, psplim /* r1 = PSPLIM. */
mov r3, lr /* r3 = LR/EXC_RETURN. */
subs r2, r2, #12 /* r2 = r2 - 12. */
stmia r2!, {r0, r1, r3} /* Store xSecureContext, PSPLIM and LR on the stack. */
stmdb r2!, {r0, r1, r3} /* Store xSecureContext, PSPLIM and LR on the stack. */
ldr r3, =pxCurrentTCB /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
ldr r1, [r3] /* Read pxCurrentTCB. */
str r2, [r1] /* Save the new top of stack in TCB. */
select_next_task:
mov r0, #configMAX_SYSCALL_INTERRUPT_PRIORITY