[PATCH 4.9 47/50] ARM: trusted_foundations: do not use naked function

Greg Kroah-Hartman
2018-12-04T11:10:02Z

From: Stefan Agner <stefan@agner.ch>

(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>
---
arch/arm/firmware/trusted_foundations.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)

--- 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)