Blame SOURCES/gcc8-harden-4.patch

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From 5a5e7890cefa112e95e1de9800d8081c2a38a1da Mon Sep 17 00:00:00 2001
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From: "H.J. Lu" <hjl.tools@gmail.com>
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Date: Wed, 5 Jan 2022 18:04:21 -0800
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Subject: [PATCH 4/4] x86: Generate INT3 for __builtin_eh_return
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Generate INT3 after indirect jmp in exception return for -fcf-protection
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with -mharden-sls=indirect-jmp.
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gcc/
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	PR target/103925
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	* config/i386/i386.c (ix86_output_indirect_function_return):
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	Generate INT3 after indirect jmp for -mharden-sls=indirect-jmp.
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gcc/testsuite/
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	PR target/103925
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	* gcc.target/i386/harden-sls-6.c: New test.
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(cherry picked from commit c2e5c4feed32c808591b5278f680bbabe63eb225)
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---
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 gcc/config/i386/i386.c                       |  9 ++++++---
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 gcc/testsuite/gcc.target/i386/harden-sls-6.c | 18 ++++++++++++++++++
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 2 files changed, 24 insertions(+), 3 deletions(-)
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 create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-6.c
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diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
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index 3bc14e20105..dbc3d462fda 100644
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--- a/gcc/config/i386/i386.c
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+++ b/gcc/config/i386/i386.c
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@@ -29083,11 +29083,14 @@ ix86_output_indirect_function_return (rtx ret_op)
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 	}
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       else
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 	output_indirect_thunk (need_prefix, regno);
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-
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-      return "";
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     }
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   else
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-    return "%!jmp\t%A0";
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+    {
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+      output_asm_insn ("%!jmp\t%A0", &ret_op);
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+      if (ix86_harden_sls & harden_sls_indirect_jmp)
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+	fputs ("\tint3\n", asm_out_file);
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+    }
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+  return "";
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 }
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 /* Split simple return with popping POPC bytes from stack to indirect
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diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-6.c b/gcc/testsuite/gcc.target/i386/harden-sls-6.c
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new file mode 100644
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index 00000000000..9068eb64008
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--- /dev/null
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+++ b/gcc/testsuite/gcc.target/i386/harden-sls-6.c
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@@ -0,0 +1,18 @@
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+/* { dg-do compile { target { ! ia32 } } } */
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+/* { dg-options "-O2 -fcf-protection -mharden-sls=indirect-jmp" } */
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+
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+struct _Unwind_Context _Unwind_Resume_or_Rethrow_this_context;
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+
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+void offset (int);
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+
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+struct _Unwind_Context {
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+  void *reg[7];
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+} _Unwind_Resume_or_Rethrow() {
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+  struct _Unwind_Context cur_contextcur_context =
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+      _Unwind_Resume_or_Rethrow_this_context;
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+  offset(0);
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+  __builtin_eh_return ((long) offset, 0);
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+}
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+
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+/* { dg-final { scan-assembler "jmp\[ \t\]+\\*%rcx" } } */
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+/* { dg-final { scan-assembler-times "int3" 1 } } */
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-- 
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2.36.1
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