ARM: trusted_foundations: do not use naked function

BugLink: https://bugs.launchpad.net/bugs/1836968
(commit 4ea7bdc6b5b33427bbd3f41c333e21c1825462a3 upstream)

As documented in GCC naked functions should only use basic ASM
syntax. The extended ASM or mixture of basic ASM and "C" code is
not guaranteed. Currently this works because it was hard coded
to follow and check GCC behavior for arguments and register
placement.

Furthermore with clang using parameters in Extended asm in a
naked function is not supported:
  arch/arm/firmware/trusted_foundations.c:47:10: error: parameter
          references not allowed in naked functions
                : "r" (type), "r" (arg1), "r" (arg2)
                       ^

Use a regular function to be more portable. This aligns also with
the other SMC call implementations e.g. in qcom_scm-32.c and
bcm_kona_smc.c.

Cc: Dmitry Osipenko <digetx@gmail.com>
Cc: Stephen Warren <swarren@nvidia.com>
Cc: Thierry Reding <treding@nvidia.com>
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/arch/arm/firmware/trusted_foundations.c b/arch/arm/firmware/trusted_foundations.c
index 3fb1b5a1dce968d028c8f17057c277e29302caaf..689e6565abfc4bea48e9425901387d6a096ed9d5 100644 (file)
--- a/arch/arm/firmware/trusted_foundations.c
+++ b/arch/arm/firmware/trusted_foundations.c
@@ -31,21 +31,25 @@
 
 static unsigned long cpu_boot_addr;
 
-static void __naked tf_generic_smc(u32 type, u32 arg1, u32 arg2)
+static void tf_generic_smc(u32 type, u32 arg1, u32 arg2)
 {
+       register u32 r0 asm("r0") = type;
+       register u32 r1 asm("r1") = arg1;
+       register u32 r2 asm("r2") = arg2;
+
        asm volatile(
                ".arch_extension        sec\n\t"
-               "stmfd  sp!, {r4 - r11, lr}\n\t"
+               "stmfd  sp!, {r4 - r11}\n\t"
                __asmeq("%0", "r0")
                __asmeq("%1", "r1")
                __asmeq("%2", "r2")
                "mov    r3, #0\n\t"
                "mov    r4, #0\n\t"
                "smc    #0\n\t"
-               "ldmfd  sp!, {r4 - r11, pc}"
+               "ldmfd  sp!, {r4 - r11}\n\t"
                :
-               : "r" (type), "r" (arg1), "r" (arg2)
-               : "memory");
+               : "r" (r0), "r" (r1), "r" (r2)
+               : "memory", "r3", "r12", "lr");
 }
 
 static int tf_set_cpu_boot_addr(int cpu, unsigned long boot_addr)