latent_entropy: Fix wrong gcc code generation with 64 bit variables
The stack frame size could grow too large when the plugin used long long on 32-bit architectures when the given function had too many basic blocks. The gcc warning was: drivers/pci/hotplug/ibmphp_ebda.c: In function 'ibmphp_access_ebda': drivers/pci/hotplug/ibmphp_ebda.c:409:1: warning: the frame size of 1108 bytes is larger than 1024 bytes [-Wframe-larger-than=] This switches latent_entropy from u64 to unsigned long. Thanks to PaX Team and Emese Revfy for the patch. Signed-off-by: Kees Cook <keescook@chromium.org>
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@ -92,7 +92,7 @@ int _node_numa_mem_[MAX_NUMNODES];
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#endif
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#endif
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#ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY
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#ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY
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volatile u64 latent_entropy __latent_entropy;
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volatile unsigned long latent_entropy __latent_entropy;
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EXPORT_SYMBOL(latent_entropy);
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EXPORT_SYMBOL(latent_entropy);
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#endif
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#endif
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@ -340,7 +340,7 @@ static enum tree_code get_op(tree *rhs)
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break;
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break;
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}
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}
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if (rhs)
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if (rhs)
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*rhs = build_int_cstu(unsigned_intDI_type_node, random_const);
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*rhs = build_int_cstu(long_unsigned_type_node, random_const);
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return op;
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return op;
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}
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}
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@ -372,7 +372,7 @@ static void __perturb_latent_entropy(gimple_stmt_iterator *gsi,
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enum tree_code op;
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enum tree_code op;
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/* 1. create temporary copy of latent_entropy */
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/* 1. create temporary copy of latent_entropy */
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temp = create_var(unsigned_intDI_type_node, "tmp_latent_entropy");
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temp = create_var(long_unsigned_type_node, "temp_latent_entropy");
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/* 2. read... */
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/* 2. read... */
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add_referenced_var(latent_entropy_decl);
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add_referenced_var(latent_entropy_decl);
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@ -459,13 +459,13 @@ static void init_local_entropy(basic_block bb, tree local_entropy)
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gsi_insert_before(&gsi, call, GSI_NEW_STMT);
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gsi_insert_before(&gsi, call, GSI_NEW_STMT);
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update_stmt(call);
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update_stmt(call);
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udi_frame_addr = fold_convert(unsigned_intDI_type_node, frame_addr);
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udi_frame_addr = fold_convert(long_unsigned_type_node, frame_addr);
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assign = gimple_build_assign(local_entropy, udi_frame_addr);
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assign = gimple_build_assign(local_entropy, udi_frame_addr);
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gsi_insert_after(&gsi, assign, GSI_NEW_STMT);
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gsi_insert_after(&gsi, assign, GSI_NEW_STMT);
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update_stmt(assign);
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update_stmt(assign);
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/* 3. create temporary copy of latent_entropy */
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/* 3. create temporary copy of latent_entropy */
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tmp = create_var(unsigned_intDI_type_node, "tmp_latent_entropy");
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tmp = create_var(long_unsigned_type_node, "temp_latent_entropy");
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/* 4. read the global entropy variable into local entropy */
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/* 4. read the global entropy variable into local entropy */
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add_referenced_var(latent_entropy_decl);
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add_referenced_var(latent_entropy_decl);
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@ -480,7 +480,7 @@ static void init_local_entropy(basic_block bb, tree local_entropy)
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update_stmt(assign);
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update_stmt(assign);
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rand_cst = get_random_const();
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rand_cst = get_random_const();
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rand_const = build_int_cstu(unsigned_intDI_type_node, rand_cst);
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rand_const = build_int_cstu(long_unsigned_type_node, rand_cst);
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op = get_op(NULL);
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op = get_op(NULL);
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assign = create_assign(op, local_entropy, local_entropy, rand_const);
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assign = create_assign(op, local_entropy, local_entropy, rand_const);
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gsi_insert_after(&gsi, assign, GSI_NEW_STMT);
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gsi_insert_after(&gsi, assign, GSI_NEW_STMT);
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@ -529,7 +529,7 @@ static unsigned int latent_entropy_execute(void)
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}
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}
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/* 1. create the local entropy variable */
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/* 1. create the local entropy variable */
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local_entropy = create_var(unsigned_intDI_type_node, "local_entropy");
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local_entropy = create_var(long_unsigned_type_node, "local_entropy");
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/* 2. initialize the local entropy variable */
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/* 2. initialize the local entropy variable */
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init_local_entropy(bb, local_entropy);
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init_local_entropy(bb, local_entropy);
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@ -561,10 +561,9 @@ static void latent_entropy_start_unit(void *gcc_data __unused,
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if (in_lto_p)
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if (in_lto_p)
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return;
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return;
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/* extern volatile u64 latent_entropy */
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/* extern volatile unsigned long latent_entropy */
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gcc_assert(TYPE_PRECISION(long_long_unsigned_type_node) == 64);
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quals = TYPE_QUALS(long_unsigned_type_node) | TYPE_QUAL_VOLATILE;
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quals = TYPE_QUALS(long_long_unsigned_type_node) | TYPE_QUAL_VOLATILE;
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type = build_qualified_type(long_unsigned_type_node, quals);
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type = build_qualified_type(long_long_unsigned_type_node, quals);
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id = get_identifier("latent_entropy");
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id = get_identifier("latent_entropy");
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latent_entropy_decl = build_decl(UNKNOWN_LOCATION, VAR_DECL, id, type);
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latent_entropy_decl = build_decl(UNKNOWN_LOCATION, VAR_DECL, id, type);
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