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    Subject[PATCH v2 3/6] ARM: trusted_foundations: do not use naked function
    Date
    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>
    ---
    Changes in v2:
    - Keep stmfd/ldmfd to avoid potential ABI issues

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

    diff --git a/arch/arm/firmware/trusted_foundations.c b/arch/arm/firmware/trusted_foundations.c
    index 3fb1b5a1dce9..689e6565abfc 100644
    --- 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)
    --
    2.16.2
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