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      1 /* ===-- clear_cache.c - Implement __clear_cache ---------------------------===
      2  *
      3  *                     The LLVM Compiler Infrastructure
      4  *
      5  * This file is dual licensed under the MIT and the University of Illinois Open
      6  * Source Licenses. See LICENSE.TXT for details.
      7  *
      8  * ===----------------------------------------------------------------------===
      9  */
     10 
     11 #include "int_lib.h"
     12 #include <stddef.h>
     13 
     14 #if __APPLE__
     15   #include <libkern/OSCacheControl.h>
     16 #endif
     17 
     18 #if defined(_WIN32)
     19 /* Forward declare Win32 APIs since the GCC mode driver does not handle the
     20    newer SDKs as well as needed.  */
     21 uint32_t FlushInstructionCache(uintptr_t hProcess, void *lpBaseAddress,
     22                                uintptr_t dwSize);
     23 uintptr_t GetCurrentProcess(void);
     24 #endif
     25 
     26 #if (defined(__FreeBSD__) || defined(__Bitrig__)) && defined(__arm__)
     27   #include <sys/types.h>
     28   #include <machine/sysarch.h>
     29 #endif
     30 
     31 #if defined(__NetBSD__) && defined(__arm__)
     32   #include <machine/sysarch.h>
     33 #endif
     34 
     35 #if defined(__mips__)
     36   #include <sys/cachectl.h>
     37   #include <sys/syscall.h>
     38   #include <unistd.h>
     39   #if defined(__ANDROID__) && defined(__LP64__)
     40     /*
     41      * clear_mips_cache - Invalidates instruction cache for Mips.
     42      */
     43     static void clear_mips_cache(const void* Addr, size_t Size) {
     44       asm volatile (
     45         ".set push\n"
     46         ".set noreorder\n"
     47         ".set noat\n"
     48         "beq %[Size], $zero, 20f\n"          /* If size == 0, branch around. */
     49         "nop\n"
     50         "daddu %[Size], %[Addr], %[Size]\n"  /* Calculate end address + 1 */
     51         "rdhwr $v0, $1\n"                    /* Get step size for SYNCI.
     52                                                 $1 is $HW_SYNCI_Step */
     53         "beq $v0, $zero, 20f\n"              /* If no caches require
     54                                                 synchronization, branch
     55                                                 around. */
     56         "nop\n"
     57         "10:\n"
     58         "synci 0(%[Addr])\n"                 /* Synchronize all caches around
     59                                                 address. */
     60         "daddu %[Addr], %[Addr], $v0\n"      /* Add step size. */
     61         "sltu $at, %[Addr], %[Size]\n"       /* Compare current with end
     62                                                 address. */
     63         "bne $at, $zero, 10b\n"              /* Branch if more to do. */
     64         "nop\n"
     65         "sync\n"                             /* Clear memory hazards. */
     66         "20:\n"
     67         "bal 30f\n"
     68         "nop\n"
     69         "30:\n"
     70         "daddiu $ra, $ra, 12\n"              /* $ra has a value of $pc here.
     71                                                 Add offset of 12 to point to the
     72                                                 instruction after the last nop.
     73                                               */
     74         "jr.hb $ra\n"                        /* Return, clearing instruction
     75                                                 hazards. */
     76         "nop\n"
     77         ".set pop\n"
     78         : [Addr] "+r"(Addr), [Size] "+r"(Size)
     79         :: "at", "ra", "v0", "memory"
     80       );
     81     }
     82   #endif
     83 #endif
     84 
     85 #if defined(__linux__) && defined(__arm__)
     86   #include <asm/unistd.h>
     87 #endif
     88 
     89 /*
     90  * The compiler generates calls to __clear_cache() when creating
     91  * trampoline functions on the stack for use with nested functions.
     92  * It is expected to invalidate the instruction cache for the
     93  * specified range.
     94  */
     95 
     96 void __clear_cache(void *start, void *end) {
     97 #if __i386__ || __x86_64__
     98 /*
     99  * Intel processors have a unified instruction and data cache
    100  * so there is nothing to do
    101  */
    102 #elif defined(__arm__) && !defined(__APPLE__)
    103     #if defined(__FreeBSD__) || defined(__NetBSD__) || defined(__Bitrig__)
    104         struct arm_sync_icache_args arg;
    105 
    106         arg.addr = (uintptr_t)start;
    107         arg.len = (uintptr_t)end - (uintptr_t)start;
    108 
    109         sysarch(ARM_SYNC_ICACHE, &arg);
    110     #elif defined(__linux__)
    111          register int start_reg __asm("r0") = (int) (intptr_t) start;
    112          const register int end_reg __asm("r1") = (int) (intptr_t) end;
    113          const register int syscall_nr __asm("r7") = __ARM_NR_cacheflush;
    114          __asm __volatile("svc 0x0"
    115                           : "=r"(start_reg)
    116                           : "r"(syscall_nr), "r"(start_reg), "r"(end_reg));
    117          if (start_reg != 0) {
    118              compilerrt_abort();
    119          }
    120     #elif defined(_WIN32)
    121         FlushInstructionCache(GetCurrentProcess(), start, end - start);
    122     #else
    123         compilerrt_abort();
    124     #endif
    125 #elif defined(__mips__)
    126   const uintptr_t start_int = (uintptr_t) start;
    127   const uintptr_t end_int = (uintptr_t) end;
    128     #if defined(__ANDROID__) && defined(__LP64__)
    129         // Call synci implementation for short address range.
    130         const uintptr_t address_range_limit = 256;
    131         if ((end_int - start_int) <= address_range_limit) {
    132             clear_mips_cache(start, (end_int - start_int));
    133         } else {
    134             syscall(__NR_cacheflush, start, (end_int - start_int), BCACHE);
    135         }
    136     #else
    137         syscall(__NR_cacheflush, start, (end_int - start_int), BCACHE);
    138     #endif
    139 #elif defined(__aarch64__) && !defined(__APPLE__)
    140   uint64_t xstart = (uint64_t)(uintptr_t) start;
    141   uint64_t xend = (uint64_t)(uintptr_t) end;
    142   uint64_t addr;
    143 
    144   // Get Cache Type Info
    145   uint64_t ctr_el0;
    146   __asm __volatile("mrs %0, ctr_el0" : "=r"(ctr_el0));
    147 
    148   /*
    149    * dc & ic instructions must use 64bit registers so we don't use
    150    * uintptr_t in case this runs in an IPL32 environment.
    151    */
    152   const size_t dcache_line_size = 4 << ((ctr_el0 >> 16) & 15);
    153   for (addr = xstart; addr < xend; addr += dcache_line_size)
    154     __asm __volatile("dc cvau, %0" :: "r"(addr));
    155   __asm __volatile("dsb ish");
    156 
    157   const size_t icache_line_size = 4 << ((ctr_el0 >> 0) & 15);
    158   for (addr = xstart; addr < xend; addr += icache_line_size)
    159     __asm __volatile("ic ivau, %0" :: "r"(addr));
    160   __asm __volatile("isb sy");
    161 #else
    162     #if __APPLE__
    163         /* On Darwin, sys_icache_invalidate() provides this functionality */
    164         sys_icache_invalidate(start, end-start);
    165     #else
    166         compilerrt_abort();
    167     #endif
    168 #endif
    169 }
    170 
    171