This patch added additional sanity and increases an understanding for
getting proper value from the first argument for SMC call on aarch64
according to SMCC Convention.
[0] ARM DEN0028B, page 12
Signed-off-by: Roman Skakun <roman_ska...@epam.com>
---
xen/arch/arm/tee/optee.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/xen/arch/arm/tee/optee.c b/xen/arch/arm/tee/optee.c
index ee85359742..87060b52b8 100644
--- a/xen/arch/arm/tee/optee.c
+++ b/xen/arch/arm/tee/optee.c
@@ -1643,7 +1643,8 @@ static bool optee_handle_call(struct cpu_user_regs *regs)
if ( !ctx )
return false;
- switch ( get_user_reg(regs, 0) )
+ /* Only least 32 bits are significant (see ARM DEN 0028B, page 12) */
+ switch ( (uint32_t)get_user_reg(regs, 0) )
{
case OPTEE_SMC_CALLS_COUNT:
set_user_reg(regs, 0, OPTEE_MEDIATOR_SMC_COUNT);
--
2.25.1
