andrius
/
arm-trusted-firmware
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

trusty: save/restore FPU registers in world switch 

Currently, Trusty OS/LK implemented FPU context switch in internal
thread switch but does not implement the proper mechanism for world
switch. This commit just simply saves/restores FPU registes in world
switch to prevent FPU context from being currupted when Trusty OS uses
VFP in its applications.

It should be noted that the macro *CTX_INCLUDE_FPREGS* must be defined
in trusty.mk if Trusty OS uses VFP

Signed-off-by: Aijun Sun <aijun.sun@spreadtrum.com>
This commit is contained in:
Aijun Sun 2017-09-19 16:52:08 +08:00
parent 1cde9b94fa
commit ab609e1a76
1 changed files with 15 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
services/spd/trusty/trusty.c
View File

@ -99,6 +99,16 @@ static struct args trusty_context_switch(uint32_t security_state, uint64_t r0,
ret.r1 = r1;
ret.r0 = r0;
/*
* To avoid the additional overhead in PSCI flow, skip FP context
* saving/restoring in case of CPU suspend and resume, asssuming that
* when it's needed the PSCI caller has preserved FP context before
* going here.
*/
#if CTX_INCLUDE_FPREGS
if (r0 != SMC_FC_CPU_SUSPEND && r0 != SMC_FC_CPU_RESUME)
fpregs_context_save(get_fpregs_ctx(cm_get_context(security_state)));
#endif
cm_el1_sysregs_context_save(security_state);
ctx->saved_security_state = security_state;
@ -107,6 +117,11 @@ static struct args trusty_context_switch(uint32_t security_state, uint64_t r0,
assert(ctx->saved_security_state == !security_state);
cm_el1_sysregs_context_restore(security_state);
#if CTX_INCLUDE_FPREGS
if (r0 != SMC_FC_CPU_SUSPEND && r0 != SMC_FC_CPU_RESUME)
fpregs_context_restore(get_fpregs_ctx(cm_get_context(security_state)));
#endif
cm_set_next_eret_context(security_state);
return ret;