/*
 * Copyright 2012, Alex Smith, alex@alex-smith.me.uk.
 * Distributed under the terms of the MIT License.
 */


#include "x86_signals.h"

#include <string.h>

#include <KernelExport.h>

#include <commpage.h>
#include <cpu.h>
#include <elf.h>
#include <smp.h>

#include "syscall_numbers.h"


extern "C" void __attribute__((noreturn))
x86_64_user_signal_handler(signal_frame_data* data)
{
        if (data->siginfo_handler) {
                auto handler = (void (*)(int, siginfo_t*, void*, void*))data->handler;
                handler(data->info.si_signo, &data->info, &data->context, data->user_data);
        } else {
                auto handler = (void (*)(int, void*, vregs*))data->handler;
                handler(data->info.si_signo, data->user_data, &data->context.uc_mcontext);
        }

        #define TO_STRING_LITERAL_HELPER(number)        #number
        #define TO_STRING_LITERAL(number)       TO_STRING_LITERAL_HELPER(number)

        // _kern_restore_signal_frame(data)
        asm volatile(
                "movq %0, %%rdi;"
                "movq $" TO_STRING_LITERAL(SYSCALL_RESTORE_SIGNAL_FRAME) ", %%rax;"
                "syscall;"
                :: "r"(data)
        );

        #undef TO_STRING_LITERAL_HELPER
        #undef TO_STRING_LITERAL

        __builtin_unreachable();
}


static void
register_commpage_function(const char* functionName, int32 commpageIndex,
        const char* commpageSymbolName, addr_t expectedAddress)
{
        // get address and size of function
        elf_symbol_info symbolInfo;
        if (elf_lookup_kernel_symbol(functionName, &symbolInfo) != B_OK) {
                panic("register_commpage_function(): Failed to find "
                        "signal frame function \"%s\"!", functionName);
        }

        ASSERT(expectedAddress == symbolInfo.address);

        // fill in the commpage table entry
        addr_t position = fill_commpage_entry(commpageIndex,
                (void*)symbolInfo.address, symbolInfo.size);

        // add symbol to the commpage image
        image_id image = get_commpage_image();
        elf_add_memory_image_symbol(image, commpageSymbolName, position,
                symbolInfo.size, B_SYMBOL_TYPE_TEXT);
}


void
x86_initialize_commpage_signal_handler()
{
        register_commpage_function("x86_64_user_signal_handler",
                COMMPAGE_ENTRY_X86_SIGNAL_HANDLER, "commpage_signal_handler",
                (addr_t)&x86_64_user_signal_handler);
}