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authorKees Cook <keescook@chromium.org>2016-10-19 00:08:04 +0200
committerKees Cook <keescook@chromium.org>2016-10-31 11:30:41 -0700
commit58bea4144d235cee5bb51203b032ddafd6d1cf8d (patch)
tree01256e5ed4f34f736e83b841ca5ef9893cc479f8 /scripts
parentda7389ac6c83e7aa8b04ebe5ba546df2a7873c5c (diff)
downloadlwn-58bea4144d235cee5bb51203b032ddafd6d1cf8d.tar.gz
lwn-58bea4144d235cee5bb51203b032ddafd6d1cf8d.zip
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>
Diffstat (limited to 'scripts')
-rw-r--r--scripts/gcc-plugins/latent_entropy_plugin.c19
1 files changed, 9 insertions, 10 deletions
diff --git a/scripts/gcc-plugins/latent_entropy_plugin.c b/scripts/gcc-plugins/latent_entropy_plugin.c
index 9d3d4adf3be8..8160f1c1b56e 100644
--- a/scripts/gcc-plugins/latent_entropy_plugin.c
+++ b/scripts/gcc-plugins/latent_entropy_plugin.c
@@ -340,7 +340,7 @@ static enum tree_code get_op(tree *rhs)
break;
}
if (rhs)
- *rhs = build_int_cstu(unsigned_intDI_type_node, random_const);
+ *rhs = build_int_cstu(long_unsigned_type_node, random_const);
return op;
}
@@ -372,7 +372,7 @@ static void __perturb_latent_entropy(gimple_stmt_iterator *gsi,
enum tree_code op;
/* 1. create temporary copy of latent_entropy */
- temp = create_var(unsigned_intDI_type_node, "tmp_latent_entropy");
+ temp = create_var(long_unsigned_type_node, "temp_latent_entropy");
/* 2. read... */
add_referenced_var(latent_entropy_decl);
@@ -459,13 +459,13 @@ static void init_local_entropy(basic_block bb, tree local_entropy)
gsi_insert_before(&gsi, call, GSI_NEW_STMT);
update_stmt(call);
- udi_frame_addr = fold_convert(unsigned_intDI_type_node, frame_addr);
+ udi_frame_addr = fold_convert(long_unsigned_type_node, frame_addr);
assign = gimple_build_assign(local_entropy, udi_frame_addr);
gsi_insert_after(&gsi, assign, GSI_NEW_STMT);
update_stmt(assign);
/* 3. create temporary copy of latent_entropy */
- tmp = create_var(unsigned_intDI_type_node, "tmp_latent_entropy");
+ tmp = create_var(long_unsigned_type_node, "temp_latent_entropy");
/* 4. read the global entropy variable into local entropy */
add_referenced_var(latent_entropy_decl);
@@ -480,7 +480,7 @@ static void init_local_entropy(basic_block bb, tree local_entropy)
update_stmt(assign);
rand_cst = get_random_const();
- rand_const = build_int_cstu(unsigned_intDI_type_node, rand_cst);
+ rand_const = build_int_cstu(long_unsigned_type_node, rand_cst);
op = get_op(NULL);
assign = create_assign(op, local_entropy, local_entropy, rand_const);
gsi_insert_after(&gsi, assign, GSI_NEW_STMT);
@@ -529,7 +529,7 @@ static unsigned int latent_entropy_execute(void)
}
/* 1. create the local entropy variable */
- local_entropy = create_var(unsigned_intDI_type_node, "local_entropy");
+ local_entropy = create_var(long_unsigned_type_node, "local_entropy");
/* 2. initialize the local entropy variable */
init_local_entropy(bb, local_entropy);
@@ -561,10 +561,9 @@ static void latent_entropy_start_unit(void *gcc_data __unused,
if (in_lto_p)
return;
- /* extern volatile u64 latent_entropy */
- gcc_assert(TYPE_PRECISION(long_long_unsigned_type_node) == 64);
- quals = TYPE_QUALS(long_long_unsigned_type_node) | TYPE_QUAL_VOLATILE;
- type = build_qualified_type(long_long_unsigned_type_node, quals);
+ /* extern volatile unsigned long latent_entropy */
+ quals = TYPE_QUALS(long_unsigned_type_node) | TYPE_QUAL_VOLATILE;
+ type = build_qualified_type(long_unsigned_type_node, quals);
id = get_identifier("latent_entropy");
latent_entropy_decl = build_decl(UNKNOWN_LOCATION, VAR_DECL, id, type);