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Updated some comments. 

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@10318 35acf78f-673a-0410-8e92-d51de3d6d3f4
This commit is contained in:
isiora 2017-07-08 21:56:30 +00:00
parent b50e72d233
commit 79e76c130c
1 changed files with 6 additions and 6 deletions
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12
os/common/ports/ARMCMAx-TZ/compilers/GCC/chcoreasm.S
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@ -112,17 +112,16 @@ _port_switch_arm:
/*
* We are facing an architecure with security extension exploited.
* The following two monitor execution paths are taken by the execution units
* The following two monitor execution paths are followed by the execution units
* running in secure state when an irq is fired (Mon_Irq_Handler), and in non-secure
* state when a fiq interrupt is fired (Mon_Fiq_Handler).
* They originate by the monitor irq/fiq vector and run in monitor mode,
* ie in secure state.
* It assumes the following, set at boot time, or wherever it needs:
* SCR.FW == 0 and SCR.FIQ == 1 and SCR.IRQ == 0 in non-secure state,
* ie FIQs are taken to monitor mode, IRQ locally
* ie, in non-secure state, FIQs are taken to monitor mode and IRQs locally
* SCR.FW == 0 and SCR.FIQ == 0 and SCR.IRQ == 1 in secure state,
* ie the secure code takes fiq locally and the non-secure code takes irq locally
* ie the secure code takes irq to monitor and the non-secure code takes fiq to monitor
* ie, in the secure-state, FIQs are taken locally and IRQs to monitor
* MVBAR holds the address of the monitor vectors base.
* The code and the stacks memory reside both in secure memory.
*/
@ -136,8 +135,9 @@ Mon_Irq_Handler:
// current mode is monitor (so current state is secure)
//
// This procedure is challenging, because the irq must be
// executed in the context of the NT thread.
// So we shall switch to a NT thread and return into non-secure
// executed in the context of the NT thread, it must run
// in non-secure state.
// So we shall switch to a NT thread(?) and return into non-secure
// world where the IRQ will be served.
// The frame is created in the system stack,