From 4abd7fa71f3cf921aab7c2b59a838f9c5bb10bb2 Mon Sep 17 00:00:00 2001 From: Antonio Nino Diaz Date: Wed, 14 Feb 2018 14:22:29 +0000 Subject: [PATCH] Redefine SMC_UNK as -1 instead of 0xFFFFFFFF According to the SMC Calling Convention (ARM DEN0028B): The Unknown SMC Function Identifier is a sign-extended value of (-1) that is returned in R0, W0 or X0 register. The value wasn't sign-extended because it was defined as a 32-bit unsigned value (0xFFFFFFFF). SMC_PREEMPT has been redefined as -2 for the same reason. NOTE: This might be a compatibility break for some AArch64 platforms that don't follow the previous version of the SMCCC (ARM DEN0028A) correctly. That document specifies that only the bottom 32 bits of the returned value must be checked. If a platform relies on the top 32 bits of the result being 0 (so that SMC_UNK is 0x00000000FFFFFFFF), it will have to fix its code to comply with the SMCCC. Change-Id: I7f7b109f6b30c114fe570aa0ead3c335383cb54d Signed-off-by: Antonio Nino Diaz --- bl31/aarch64/runtime_exceptions.S | 4 ++-- include/lib/smcc.h | 6 +++--- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/bl31/aarch64/runtime_exceptions.S b/bl31/aarch64/runtime_exceptions.S index 57c065c6..60be9327 100644 --- a/bl31/aarch64/runtime_exceptions.S +++ b/bl31/aarch64/runtime_exceptions.S @@ -390,12 +390,12 @@ smc_unknown: * content). Either way, we aren't leaking any secure information * through them. */ - mov w0, #SMC_UNK + mov x0, #SMC_UNK b restore_gp_registers_callee_eret smc_prohibited: ldr x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR] - mov w0, #SMC_UNK + mov x0, #SMC_UNK eret rt_svc_fw_critical_error: diff --git a/include/lib/smcc.h b/include/lib/smcc.h index a273b3af..0a2d9277 100644 --- a/include/lib/smcc.h +++ b/include/lib/smcc.h @@ -35,13 +35,13 @@ #define SMC_64 U(1) #define SMC_32 U(0) #define SMC_OK U(0) -#define SMC_UNK U(0xffffffff) +#define SMC_UNK -1 #define SMC_TYPE_FAST ULL(1) #if !ERROR_DEPRECATED #define SMC_TYPE_STD ULL(0) #endif #define SMC_TYPE_YIELD U(0) -#define SMC_PREEMPTED U(0xfffffffe) +#define SMC_PREEMPTED -2 /******************************************************************************* * Owning entity number definitions inside the function id as per the SMC * calling convention @@ -99,7 +99,7 @@ */ #define DEFINE_SVC_UUID(_name, _tl, _tm, _th, _cl, _ch, \ _n0, _n1, _n2, _n3, _n4, _n5) \ - CASSERT(_tl != SMC_UNK, invalid_svc_uuid);\ + CASSERT((uint32_t)(_tl) != (uint32_t) SMC_UNK, invalid_svc_uuid);\ static const uuid_t _name = { \ _tl, _tm, _th, _cl, _ch, \ { _n0, _n1, _n2, _n3, _n4, _n5 } \ -- 2.30.2