compiler-rt: aarch64 implementation of __clear_cache

2 files changed, 158 insertions, 0 deletions

diff --git a/lib/std/special/compiler_rt.zig b/lib/std/special/compiler_rt.zig
index 9ed866f62d..4a9468fe5f 100644
--- a/lib/std/special/compiler_rt.zig
+++ b/lib/std/special/compiler_rt.zig
@@ -11,6 +11,9 @@ comptime {
 
     switch (builtin.arch) {
         .i386, .x86_64 => @export(@import("compiler_rt/stack_probe.zig").zig_probe_stack, .{ .name = "__zig_probe_stack", .linkage = linkage }),
+        .aarch64, .aarch64_be, .aarch64_32 => {
+            @export(@import("compiler_rt/clear_cache.zig").clear_cache, .{ .name = "__clear_cache", .linkage = linkage });
+        },
         else => {},
     }
 
diff --git a/lib/std/special/compiler_rt/clear_cache.zig b/lib/std/special/compiler_rt/clear_cache.zig
new file mode 100644
index 0000000000..740de34749
--- /dev/null
+++ b/lib/std/special/compiler_rt/clear_cache.zig
@@ -0,0 +1,155 @@
+const std = @import("std");
+const arch = std.builtin.cpu.arch;
+const os = std.builtin.os.tag;
+
+// Ported from llvm-project d32170dbd5b0d54436537b6b75beaf44324e0c28
+
+// 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.
+
+pub fn clear_cache(start: usize, end: usize) callconv(.C) void {
+    const x86 = switch (arch) {
+        .i386, .x86_64 => true,
+        else => false,
+    };
+    const arm32 = switch (arch) {
+        .arm, .armeb, .thumb, .thumbeb => true,
+        else => false,
+    };
+    const arm64 = switch (arch) {
+        .aarch64, .aarch64_be, .aarch64_32 => true,
+        else => false,
+    };
+    const mips = switch (arch) {
+        .mips, .mipsel, .mips64, .mips64el => true,
+        else => false,
+    };
+    const powerpc64 = switch (arch) {
+        .powerpc64, .powerpc64le => true,
+        else => false,
+    };
+    const sparc = switch (arch) {
+        .sparc, .sparcv9, .sparcel => true,
+        else => false,
+    };
+    const apple = switch (os) {
+        .ios, .macosx, .watchos, .tvos => true,
+        else => false,
+    };
+    if (x86) {
+        // Intel processors have a unified instruction and data cache
+        // so there is nothing to do
+    } else if (os == .windows and (arm32 or arm64)) {
+        @compileError("TODO");
+        // FlushInstructionCache(GetCurrentProcess(), start, end - start);
+    } else if (arm32 and !apple) {
+        @compileError("TODO");
+        //#if defined(__FreeBSD__) || defined(__NetBSD__)
+        //  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
+    } else if (os == .linux and mips) {
+        @compileError("TODO");
+        //const uintptr_t start_int = (uintptr_t)start;
+        //const uintptr_t end_int = (uintptr_t)end;
+        //syscall(__NR_cacheflush, start, (end_int - start_int), BCACHE);
+    } else if (mips and os == .openbsd) {
+        @compileError("TODO");
+        //cacheflush(start, (uintptr_t)end - (uintptr_t)start, BCACHE);
+    } else if (arm64 and !apple) {
+        // Get Cache Type Info.
+        // TODO memoize this?
+        var ctr_el0: u64 = 0;
+        asm volatile (
+            \\mrs %[x], ctr_el0
+            \\
+            : [x] "=r" (ctr_el0)
+        );
+        // The DC and IC instructions must use 64-bit registers so we don't use
+        // uintptr_t in case this runs in an IPL32 environment.
+        var addr: u64 = undefined;
+        // If CTR_EL0.IDC is set, data cache cleaning to the point of unification
+        // is not required for instruction to data coherence.
+        if (((ctr_el0 >> 28) & 0x1) == 0x0) {
+            const dcache_line_size: usize = @as(usize, 4) << @intCast(u6, (ctr_el0 >> 16) & 15);
+            addr = start & ~(dcache_line_size - 1);
+            while (addr < end) : (addr += dcache_line_size) {
+                asm volatile ("dc cvau, %[addr]"
+                    :
+                    : [addr] "r" (addr)
+                );
+            }
+        }
+        asm volatile ("dsb ish");
+        // If CTR_EL0.DIC is set, instruction cache invalidation to the point of
+        // unification is not required for instruction to data coherence.
+        if (((ctr_el0 >> 29) & 0x1) == 0x0) {
+            const icache_line_size: usize = @as(usize, 4) << @intCast(u6, (ctr_el0 >> 0) & 15);
+            addr = start & ~(icache_line_size - 1);
+            while (addr < end) : (addr += icache_line_size) {
+                asm volatile ("ic ivau, %[addr]"
+                    :
+                    : [addr] "r" (addr)
+                );
+            }
+        }
+        asm volatile ("isb sy");
+    } else if (powerpc64) {
+        @compileError("TODO");
+        //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 (sparc) {
+        @compileError("TODO");
+        //const size_t dword_size = 8;
+        //const size_t len = (uintptr_t)end - (uintptr_t)start;
+        //
+        //const uintptr_t mask = ~(dword_size - 1);
+        //const uintptr_t start_dword = ((uintptr_t)start) & mask;
+        //const uintptr_t end_dword = ((uintptr_t)start + len + dword_size - 1) & mask;
+        //
+        //for (uintptr_t dword = start_dword; dword < end_dword; dword += dword_size)
+        //  __asm__ volatile("flush %0" : : "r"(dword));
+    } else if (apple) {
+        @compileError("TODO");
+        //// On Darwin, sys_icache_invalidate() provides this functionality
+        //sys_icache_invalidate(start, end - start);
+    } else {
+        @compileError("no __clear_cache implementation available for this target");
+    }
+}