Hi Julien,
On 15.02.18 17:02, Julien Grall wrote:
The new SMC Calling Convention (v1.1) allows for a reduced overhead when
calling into the firmware, and provides a new feature discovery
mechanism. See "Firmware interfaces for mitigating CVE-2017-5715"
ARM DEN 00070A.
Signed-off-by: Julien Grall <julien.gr...@arm.com>
Reviewed-by: Volodymyr Babchuk <volodymyr_babc...@epam.com>
---
Changes in v3:
- Use ARM_SMCCC_NOT_SUPPORTED rather than hardcoded return
Changes in v2:
- Add a humand readable name for the specification
---
xen/arch/arm/vpsci.c | 1 +
xen/arch/arm/vsmc.c | 23 +++++++++++++++++++++++
xen/include/asm-arm/smccc.h | 18 +++++++++++++++++-
3 files changed, 41 insertions(+), 1 deletion(-)
diff --git a/xen/arch/arm/vpsci.c b/xen/arch/arm/vpsci.c
index e82b62db1a..19ee7caeb4 100644
--- a/xen/arch/arm/vpsci.c
+++ b/xen/arch/arm/vpsci.c
@@ -212,6 +212,7 @@ static int32_t do_psci_1_0_features(uint32_t psci_func_id)
case PSCI_0_2_FN32_SYSTEM_OFF:
case PSCI_0_2_FN32_SYSTEM_RESET:
case PSCI_1_0_FN32_PSCI_FEATURES:
+ case ARM_SMCCC_VERSION_FID:
return 0;
default:
return PSCI_NOT_SUPPORTED;
diff --git a/xen/arch/arm/vsmc.c b/xen/arch/arm/vsmc.c
index 3d3bd95fee..7ec492741b 100644
--- a/xen/arch/arm/vsmc.c
+++ b/xen/arch/arm/vsmc.c
@@ -81,6 +81,26 @@ static bool fill_function_call_count(struct cpu_user_regs
*regs, uint32_t cnt)
return true;
}
+/* SMCCC interface for ARM Architecture */
+static bool handle_arch(struct cpu_user_regs *regs)
+{
+ uint32_t fid = (uint32_t)get_user_reg(regs, 0);
+
+ switch ( fid )
+ {
+ case ARM_SMCCC_VERSION_FID:
+ set_user_reg(regs, 0, ARM_SMCCC_VERSION_1_1);
+ return true;
+
+ case ARM_SMCCC_ARCH_FEATURES_FID:
+ /* Nothing supported yet */
+ set_user_reg(regs, 0, ARM_SMCCC_NOT_SUPPORTED);
+ return true;
+ }
+
+ return false;
+}
+
/* SMCCC interface for hypervisor. Tell about itself. */
static bool handle_hypervisor(struct cpu_user_regs *regs)
{
@@ -188,6 +208,9 @@ static bool vsmccc_handle_call(struct cpu_user_regs *regs)
{
switch ( smccc_get_owner(funcid) )
{
+ case ARM_SMCCC_OWNER_ARCH:
+ handled = handle_arch(regs);
+ break;
case ARM_SMCCC_OWNER_HYPERVISOR:
handled = handle_hypervisor(regs);
break;
diff --git a/xen/include/asm-arm/smccc.h b/xen/include/asm-arm/smccc.h
index 62b3a8cdf5..629cc5150b 100644
--- a/xen/include/asm-arm/smccc.h
+++ b/xen/include/asm-arm/smccc.h
@@ -16,6 +16,9 @@
#ifndef __ASM_ARM_SMCCC_H__
#define __ASM_ARM_SMCCC_H__
+#define ARM_SMCCC_VERSION_1_0 0x10000
+#define ARM_SMCCC_VERSION_1_1 0x10001
+
/*
* This file provides common defines for ARM SMC Calling Convention as
* specified in
@@ -100,8 +103,21 @@ static inline uint32_t smccc_get_owner(register_t funcid)
ARM_SMCCC_OWNER_##owner, \
0xFF03)
-/* Only one error code defined in SMCCC */
+#define ARM_SMCCC_VERSION_FID \
+ ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \
+ ARM_SMCCC_CONV_32, \
+ ARM_SMCCC_OWNER_ARCH, \
+ 0x0) \
+
+#define ARM_SMCCC_ARCH_FEATURES_FID \
+ ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \
+ ARM_SMCCC_CONV_32, \
+ ARM_SMCCC_OWNER_ARCH, \
+ 0x1)
+
+/* SMCCC error codes */
#define ARM_SMCCC_ERR_UNKNOWN_FUNCTION (-1)
+#define ARM_SMCCC_NOT_SUPPORTED (-1)
/* SMCCC function identifier range which is reserved for existing APIs */
#define ARM_SMCCC_RESERVED_RANGE_START 0x0
--
Volodymyr Babchuk
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