[amd64] Make code patching smp safe for the case where we emit a mov …

…+ call_reg. Hopefully fixes #57959. (#5452)
mono · Aug 28, 2017 · fe214b4 · fe214b4
1 parent c843b3f
commit fe214b4
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Showing 3 changed files with 8 additions and 2 deletions.
diff --git a/mono/mini/cpu-amd64.md b/mono/mini/cpu-amd64.md
@@ -99,8 +99,8 @@ long_min_un: dest:i src1:i src2:i len:16 clob:1
 long_max: dest:i src1:i src2:i len:16 clob:1
 long_max_un: dest:i src1:i src2:i len:16 clob:1
 
-throw: src1:i len:18
-rethrow: src1:i len:18
+throw: src1:i len:24
+rethrow: src1:i len:24
 start_handler: len:16
 endfinally: len:9
 endfilter: src1:a len:9

diff --git a/mono/mini/mini-amd64.c b/mono/mini/mini-amd64.c
@@ -2869,6 +2869,11 @@ emit_call_body (MonoCompile *cfg, guint8 *code, MonoJumpInfoType patch_type, gco
 			amd64_call_code (code, 0);
 		}
 		else {
+			if (!no_patch && ((guint32)(code + 2 - cfg->native_code) % 8) != 0) {
+				guint32 pad_size = 8 - ((guint32)(code + 2 - cfg->native_code) % 8);
+				amd64_padding (code, pad_size);
+				g_assert ((guint64)(code + 2 - cfg->native_code) % 8 == 0);
+			}
 			mono_add_patch_info (cfg, code - cfg->native_code, patch_type, data);
 			amd64_set_reg_template (code, GP_SCRATCH_REG);
 			amd64_call_reg (code, GP_SCRATCH_REG);

diff --git a/mono/mini/tramp-amd64.c b/mono/mini/tramp-amd64.c
@@ -144,6 +144,7 @@ mono_arch_patch_callsite (guint8 *method_start, guint8 *orig_code, guint8 *addr)
 	if (((code [-13] == 0x49) && (code [-12] == 0xbb)) || (code [-5] == 0xe8)) {
 		if (code [-5] != 0xe8) {
 			if (can_write) {
+				g_assert ((guint64)(orig_code - 11) % 8 == 0);
 				InterlockedExchangePointer ((gpointer*)(orig_code - 11), addr);
 				VALGRIND_DISCARD_TRANSLATIONS (orig_code - 11, sizeof (gpointer));
 			}