Add timer-based metering for x86

lfi-leg/amd64/amd64.c

@@ -23,6 +23,7 @@ void amd64_storespass(struct op*);
 void amd64_declpass(struct op*);
 void amd64_tlspass(struct op*);
 void amd64_syscallpass(struct op*);
+void amd64_meterpass(struct op*);
 
 void amd64_pextelim(struct op*);
 
@@ -32,6 +33,7 @@ static Pass passes[] = {
     (Pass) { .fn = &amd64_storespass },
     (Pass) { .fn = &amd64_branchpass },
     (Pass) { .fn = &amd64_declpass, .disabled = true },
+    (Pass) { .fn = &amd64_meterpass, .disabled = true },
     (Pass) { .fn = &amd64_tlspass },
     (Pass) { .fn = &amd64_syscallpass },
 };
@@ -77,6 +79,10 @@ amd64_rewrite(FILE* input, struct output* output)
             passes[i].disabled = false;
         else if (passes[i].fn == &amd64_declpass)
             passes[i].disabled = true;
+        if (args.meter != METER_NONE && passes[i].fn == &amd64_meterpass)
+            passes[i].disabled = false;
+        else if (passes[i].fn == &amd64_meterpass)
+            passes[i].disabled = true;
         if (args.allowtls && passes[i].fn == &amd64_tlspass)
             passes[i].disabled = true;
         else if (passes[i].fn == &amd64_tlspass)

lfi-leg/amd64/decl.leg

@@ -12,33 +12,33 @@
 %}
 
 ShiftInsn = (
-    (s:ShiftQ SEP r:REG COMMA x:REG) {
+    (s:ShiftQ SEP '%cl' - COMMA x1:REG COMMA x2:REG) {
         mkdirective(".bundle_lock");
-        mkinsn("andq $0x3f, %s", r.val);
-        mkinsn("%s %s, %s", s.val, r.val, x.val);
+        mkinsn("andb $0x3f, %%cl");
+        mkinsn("%s %%cl, %s, %s", s.val, x1.val, x2.val);
         mkdirective(".bundle_unlock");
-        rfree(r); rfree(x);
+        rfree(x1); rfree(x2);
     }
-    | (s:ShiftL SEP r:REG COMMA x:REG) {
+    | (s:ShiftL SEP '%cl' - COMMA x1:REG COMMA x2:REG) {
         mkdirective(".bundle_lock");
-        mkinsn("andl $0x1f, %s", r.val);
-        mkinsn("%s %s, %s", s.val, r.val, x.val);
+        mkinsn("andb $0x1f, %%cl");
+        mkinsn("%s %%cl, %s, %s", s.val, x1.val, x2.val);
         mkdirective(".bundle_unlock");
-        rfree(r); rfree(x);
+        rfree(x1); rfree(x2);
     }
-    | (s:ShiftW SEP r:REG COMMA x:REG) {
+    | (s:ShiftW SEP '%cl' - COMMA x1:REG COMMA x2:REG) {
         mkdirective(".bundle_lock");
-        mkinsn("andw $0xf, %s", r.val);
-        mkinsn("%s %s, %s", s.val, r.val, x.val);
+        mkinsn("andb $0xf, %%cl");
+        mkinsn("%s %%cl, %s, %s", s.val, x1.val, x2.val);
         mkdirective(".bundle_unlock");
-        rfree(r); rfree(x);
+        rfree(x1); rfree(x2);
     }
-    | (s:ShiftB SEP r:REG COMMA x:REG) {
+    | (s:ShiftB SEP '%cl' - COMMA x1:REG COMMA x2:REG) {
         mkdirective(".bundle_lock");
-        mkinsn("andl $0x7, %s", r.val);
-        mkinsn("%s %s, %s", s.val, r.val, x.val);
+        mkinsn("andb $0x7, %%cl");
+        mkinsn("%s %%cl, %s, %s", s.val, x1.val, x2.val);
         mkdirective(".bundle_unlock");
-        rfree(r); rfree(x);
+        rfree(x1); rfree(x2);
     }
 )
 
@@ -47,7 +47,7 @@ ShiftL = < Shift 'l' > { $$ = (Result) { .val = strndup(yytext, yyleng) } }
 ShiftW = < Shift 'w' > { $$ = (Result) { .val = strndup(yytext, yyleng) } }
 ShiftB = < Shift 'b' > { $$ = (Result) { .val = strndup(yytext, yyleng) } }
 
-Shift = ('shr' | 'shl')
+Shift = ('shrd' | 'shld')
 
 %%
 

lfi-leg/amd64/flags.c

@@ -25,6 +25,8 @@ amd64_getflags(enum flags compiler)
             flags = xasprintf("%s -mllvm -align-labels=16", flags);
         else if (args.cfi == CFI_BUNDLE32)
             flags = xasprintf("%s -mllvm -align-labels=32", flags);
+        if (args.meter != METER_NONE)
+            flags = xasprintf("%s -mllvm --reserve-r12", flags);
         break;
     case FLAGS_GCC:
         if (args.boxtype > BOX_BUNDLEJUMPS)
@@ -37,12 +39,16 @@ amd64_getflags(enum flags compiler)
             flags = xasprintf("%s -falign-labels=32 -falign-functions=32", flags);
         if (args.p2size == 0)
             flags = xasprintf("%s -ffixed-r15", flags);
+        if (args.meter != METER_NONE)
+            flags = xasprintf("%s -ffixed-r12", flags);
         break;
     default:
         assert(0);
     }
     if (!args.allowtls && compiler != FLAGS_POSTLINK) {
         flags = xasprintf("%s -mno-tls-direct-seg-refs -mtls-dialect=gnu2", flags);
     }
+    if (args.sysexternal)
+        flags = xasprintf("%s -ffixed-r13", flags);
     return flags;
 }

lfi-leg/amd64/meson.build

@@ -11,6 +11,7 @@ leg_inputs = [
   'decl.leg',
   'pextelim.leg',
   'tls.leg',
+  'meter.leg',
 ]
 
 leg_addr_inputs = [

lfi-leg/amd64/meter.leg

@@ -0,0 +1,80 @@
+%{
+#include "amd64/amd64.h"
+#include "op.h"
+#include "args.h"
+#include "util.h"
+
+#define YY_INPUT(ctx, buf, result, max_size)   \
+{                                              \
+    char yyc = ctx->op->text[ctx->idx];        \
+    ctx->idx += yyc != 0;                      \
+    result = yyc == 0 ? 0 : (*(buf) = yyc, 1); \
+}                                              \
+
+static void
+timermeter(bool indirect)
+{
+    mkinsn("leaq 0(%%r12), %%r12");
+}
+%}
+
+Top = IndBranch | Branch
+
+IndBranch = b:INDBRANCH SEP '*' r:XREG {
+    timermeter(true);
+    mkinsn("%s *%s", b.val, r.val);
+    rfree(b); rfree(r);
+}
+
+Branch = b:DIRBRANCH SEP name:NAME {
+    mkdirective(".bundle_lock");
+    timermeter(false);
+    mkinsn("%s %s", b.val, name.val);
+    mkdirective(".bundle_unlock");
+    rfree(b); rfree(name);
+}
+
+INDBRANCH = < ('notrack'? ('jmp' 'q'?) | ('call' 'q'?)) > {
+    $$ = (Result) { .val = strndup(yytext, yyleng) };
+}
+
+DIRBRANCH = < (JCC | JMP) > {
+    $$ = (Result) { .val = strndup(yytext, yyleng) };
+}
+
+JMP = 'jmp' | 'call'
+
+JCC = 'jo'
+    | 'jno'
+    | 'jc' | 'jb'
+    | 'jae' | 'jnb'
+    | 'je' | 'jz'
+    | 'jne' | 'jnz'
+    | 'jna' | 'jbe'
+    | 'ja' | 'jnbe'
+    | 'js'
+    | 'jns'
+    | 'jp' | 'jpe'
+    | 'jnp' | 'jpo'
+    | 'jl' | 'jnge'
+    | 'jge' | 'jnl'
+    | 'jle' | 'jng'
+    | 'jg' | 'jnle'
+
+%%
+
+void
+amd64_meterpass(struct op* op)
+{
+    if (!op->insn)
+        return;
+    yycontext ctx;
+    memset(&ctx, 0, sizeof(yycontext));
+    ctx.op = op;
+    oplocate(op);
+    if (yyparse(&ctx)) {
+        opremove(op);
+        opfree(op);
+    }
+    yyrelease(&ctx);
+}

lfi-leg/amd64/syscall.leg

@@ -15,15 +15,11 @@
 Top = Syscall | Retcall
 
 Syscall = 'syscall' - {
-    if (!args.decl) {
-        mkdirective(".bundle_lock");
-        mkinsn("leaq 1024f(%%rip), %%r11");
-        mkinsn("jmpq *(%%r14)");
-        mklabel("1024");
-        mkdirective(".bundle_unlock");
-    } else {
-        mkinsn("syscall");
-    }
+    mkdirective(".bundle_lock");
+    mkinsn("leaq 1024f(%%rip), %%r11");
+    mkinsn("jmpq *(%%r14)");
+    mklabel("1024");
+    mkdirective(".bundle_unlock");
 }
 
 Retcall = 'libret' - {

lfi-leg/args.h

@@ -17,11 +17,11 @@ enum boxtype {
 };
 
 enum meter {
-    METER_NONE,
-    METER_BRANCH,
-    METER_BRANCH_RESUME,
-    METER_FP,
-    METER_TIMER,
+    METER_NONE          = 0,
+    METER_BRANCH        = 1,
+    METER_BRANCH_RESUME = 2,
+    METER_FP            = 3,
+    METER_TIMER         = 4,
 };
 
 enum flags {

lfi-leg/test/amd64/decl.s

@@ -1,17 +1,17 @@
-shrq %rdi, %rax
+shrdq %cl, %rdi, %rax
 >>>
 .bundle_align_mode 4
 .bundle_lock
-andq $0x3f, %rdi
-shrq %rdi, %rax
+andb $0x3f, %cl
+shrdq %cl, %rdi, %rax
 .bundle_unlock
 ------
-shrl %edi, %eax
+shrdl %cl, %edi, %eax
 >>>
 .bundle_align_mode 4
 .bundle_lock
-andl $0x1f, %edi
-shrl %edi, %eax
+andb $0x1f, %cl
+shrdl %cl, %edi, %eax
 .bundle_unlock
 ------
 callq *(%rax)
@@ -25,8 +25,3 @@ cmpq %rax, %rax
 callq *%r11
 .bundle_unlock
 .p2align 4
-------
-syscall
->>>
-.bundle_align_mode 4
-syscall

lfi-leg/test/amd64/meter_timer.s

@@ -0,0 +1,25 @@
+jmp foo
+>>>
+.bundle_align_mode 4
+.bundle_lock
+leaq 0(%r12), %r12
+jmp foo
+.bundle_unlock
+------
+jz foo
+>>>
+.bundle_align_mode 4
+.bundle_lock
+leaq 0(%r12), %r12
+jz foo
+.bundle_unlock
+------
+jmpq *%rax
+>>>
+.bundle_align_mode 4
+.bundle_lock
+andl $0xfffffff0, %eax
+orq %r14, %rax
+leaq 0(%r12), %r12
+jmpq *%rax
+.bundle_unlock

lfi-leg/test/meson.build

@@ -29,6 +29,7 @@ tests = {
     'amd64/syscall.s',
     'amd64/variable.s',
     'amd64/tls.s',
+    'amd64/meter_timer.s',
   ],
   'riscv64': [
     'riscv64/arith.s',