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IABSD.fr/src/lib/libcompiler_rt/clear_cache.c

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  • Author : patrick
    Date : 2019-09-28 13:19:19
    Hash : 46dc7675
    Message : Make compiler-rt's __clear_cache() work on 32-bit ARM by making it use sysarch(). From Josh Elsasser ok kettenis@

  • lib/libcompiler_rt/clear_cache.c
  • /* ===-- clear_cache.c - Implement __clear_cache ---------------------------===
     *
     *                     The LLVM Compiler Infrastructure
     *
     * This file is dual licensed under the MIT and the University of Illinois Open
     * Source Licenses. See LICENSE.TXT for details.
     *
     * ===----------------------------------------------------------------------===
     */
    
    #include "int_lib.h"
    #include <assert.h>
    #include <stddef.h>
    
    #if __APPLE__
      #include <libkern/OSCacheControl.h>
    #endif
    
    #if defined(_WIN32)
    /* Forward declare Win32 APIs since the GCC mode driver does not handle the
       newer SDKs as well as needed.  */
    uint32_t FlushInstructionCache(uintptr_t hProcess, void *lpBaseAddress,
                                   uintptr_t dwSize);
    uintptr_t GetCurrentProcess(void);
    #endif
    
    #if defined(__FreeBSD__) && defined(__arm__)
      #include <sys/types.h>
      #include <machine/sysarch.h>
    #endif
    
    #if defined(__NetBSD__) && defined(__arm__)
      #include <machine/sysarch.h>
    #endif
    
    #if defined(__OpenBSD__) && (defined(__arm__) || defined(__mips__))
      #include <sys/types.h>
      #include <machine/sysarch.h>
    #endif
    
    #if defined(__linux__) && defined(__mips__)
      #include <sys/cachectl.h>
      #include <sys/syscall.h>
      #include <unistd.h>
      #if defined(__ANDROID__) && defined(__LP64__)
        /*
         * clear_mips_cache - Invalidates instruction cache for Mips.
         */
        static void clear_mips_cache(const void* Addr, size_t Size) {
          __asm__ volatile (
            ".set push\n"
            ".set noreorder\n"
            ".set noat\n"
            "beq %[Size], $zero, 20f\n"          /* If size == 0, branch around. */
            "nop\n"
            "daddu %[Size], %[Addr], %[Size]\n"  /* Calculate end address + 1 */
            "rdhwr $v0, $1\n"                    /* Get step size for SYNCI.
                                                    $1 is $HW_SYNCI_Step */
            "beq $v0, $zero, 20f\n"              /* If no caches require
                                                    synchronization, branch
                                                    around. */
            "nop\n"
            "10:\n"
            "synci 0(%[Addr])\n"                 /* Synchronize all caches around
                                                    address. */
            "daddu %[Addr], %[Addr], $v0\n"      /* Add step size. */
            "sltu $at, %[Addr], %[Size]\n"       /* Compare current with end
                                                    address. */
            "bne $at, $zero, 10b\n"              /* Branch if more to do. */
            "nop\n"
            "sync\n"                             /* Clear memory hazards. */
            "20:\n"
            "bal 30f\n"
            "nop\n"
            "30:\n"
            "daddiu $ra, $ra, 12\n"              /* $ra has a value of $pc here.
                                                    Add offset of 12 to point to the
                                                    instruction after the last nop.
                                                  */
            "jr.hb $ra\n"                        /* Return, clearing instruction
                                                    hazards. */
            "nop\n"
            ".set pop\n"
            : [Addr] "+r"(Addr), [Size] "+r"(Size)
            :: "at", "ra", "v0", "memory"
          );
        }
      #endif
    #endif
    
    /*
     * The compiler generates calls to __clear_cache() when creating 
     * trampoline functions on the stack for use with nested functions.
     * It is expected to invalidate the instruction cache for the 
     * specified range.
     */
    
    void __clear_cache(void *start, void *end) {
    #if __i386__ || __x86_64__ || defined(_M_IX86) || defined(_M_X64)
    /*
     * Intel processors have a unified instruction and data cache
     * so there is nothing to do
     */
    #elif defined(_WIN32) && (defined(__arm__) || defined(__aarch64__))
        FlushInstructionCache(GetCurrentProcess(), start, end - start);
    #elif defined(__arm__) && !defined(__APPLE__)
        #if defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__)
            struct arm_sync_icache_args arg;
    
            arg.addr = (uintptr_t)start;
            arg.len = (uintptr_t)end - (uintptr_t)start;
    
            sysarch(ARM_SYNC_ICACHE, &arg);
        #elif defined(__linux__)
        /*
         * We used to include asm/unistd.h for the __ARM_NR_cacheflush define, but
         * it also brought many other unused defines, as well as a dependency on
         * kernel headers to be installed.
         *
         * This value is stable at least since Linux 3.13 and should remain so for
         * compatibility reasons, warranting it's re-definition here.
         */
        #define __ARM_NR_cacheflush 0x0f0002
             register int start_reg __asm("r0") = (int) (intptr_t) start;
             const register int end_reg __asm("r1") = (int) (intptr_t) end;
             const register int flags __asm("r2") = 0;
             const register int syscall_nr __asm("r7") = __ARM_NR_cacheflush;
             __asm __volatile("svc 0x0"
                              : "=r"(start_reg)
                              : "r"(syscall_nr), "r"(start_reg), "r"(end_reg),
                                "r"(flags));
             assert(start_reg == 0 && "Cache flush syscall failed.");
        #else
            compilerrt_abort();
        #endif
    #elif defined(__linux__) && defined(__mips__)
      const uintptr_t start_int = (uintptr_t) start;
      const uintptr_t end_int = (uintptr_t) end;
        #if defined(__ANDROID__) && defined(__LP64__)
            // Call synci implementation for short address range.
            const uintptr_t address_range_limit = 256;
            if ((end_int - start_int) <= address_range_limit) {
                clear_mips_cache(start, (end_int - start_int));
            } else {
                syscall(__NR_cacheflush, start, (end_int - start_int), BCACHE);
            }
        #else
            syscall(__NR_cacheflush, start, (end_int - start_int), BCACHE);
        #endif
    #elif defined(__mips__) && defined(__OpenBSD__)
      cacheflush(start, (uintptr_t)end - (uintptr_t)start, BCACHE);
    #elif defined(__aarch64__) && !defined(__APPLE__)
      uint64_t xstart = (uint64_t)(uintptr_t) start;
      uint64_t xend = (uint64_t)(uintptr_t) end;
      uint64_t addr;
    
      // Get Cache Type Info
      uint64_t ctr_el0;
      __asm __volatile("mrs %0, ctr_el0" : "=r"(ctr_el0));
    
      /*
       * dc & ic instructions must use 64bit registers so we don't use
       * uintptr_t in case this runs in an IPL32 environment.
       */
      const size_t dcache_line_size = 4 << ((ctr_el0 >> 16) & 15);
      for (addr = xstart & ~(dcache_line_size - 1); addr < xend;
           addr += dcache_line_size)
        __asm __volatile("dc cvau, %0" :: "r"(addr));
      __asm __volatile("dsb ish");
    
      const size_t icache_line_size = 4 << ((ctr_el0 >> 0) & 15);
      for (addr = xstart & ~(icache_line_size - 1); addr < xend;
           addr += icache_line_size)
        __asm __volatile("ic ivau, %0" :: "r"(addr));
      __asm __volatile("isb sy");
    #elif defined (__powerpc64__)
      const size_t line_size = 32;
      const size_t len = (uintptr_t)end - (uintptr_t)start;
    
      const uintptr_t mask = ~(line_size - 1);
      const uintptr_t start_line = ((uintptr_t)start) & mask;
      const uintptr_t end_line = ((uintptr_t)start + len + line_size - 1) & mask;
    
      for (uintptr_t line = start_line; line < end_line; line += line_size)
        __asm__ volatile("dcbf 0, %0" : : "r"(line));
      __asm__ volatile("sync");
    
      for (uintptr_t line = start_line; line < end_line; line += line_size)
        __asm__ volatile("icbi 0, %0" : : "r"(line));
      __asm__ volatile("isync");
    #else
        #if __APPLE__
            /* On Darwin, sys_icache_invalidate() provides this functionality */
            sys_icache_invalidate(start, end-start);
        #else
            compilerrt_abort();
        #endif
    #endif
    }