[PATCH 02/12] firmware: declare {__start,__end}_builtin_fw as external array
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From: Vegard Nossum <hidden>
Date: 2016-10-16 15:17:16
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Subsystem:
driver core, kobjects, debugfs and sysfs, generic include/asm header files, the rest, x86 architecture (32-bit and 64-bit), x86 microcode update support · Maintainers:
Greg Kroah-Hartman, "Rafael J. Wysocki", Danilo Krummrich, Arnd Bergmann, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
The test in this loop:
for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
was getting completely compiled out by my gcc, 7.0.0 20160520. The result
was that the loop was going beyond the end of the builtin_fw array and
giving me a page fault when trying to dereference b_fw->name inside
strcmp().
By using the new external array helper macros we get the expected
behaviour.
Reported-by: Jiri Slaby <redacted>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: stable@vger.kernel.org
Signed-off-by: Vegard Nossum <redacted>
---
arch/x86/kernel/cpu/microcode/core.c | 5 ++---
drivers/base/firmware_class.c | 9 +++++----
include/asm-generic/vmlinux.lds.h | 2 +-
3 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 5ce5155..6669746 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c@@ -91,15 +91,14 @@ static bool __init check_loader_disabled_bsp(void) return *res; } -extern struct builtin_fw __start_builtin_fw[]; -extern struct builtin_fw __end_builtin_fw[]; +DECLARE_EXTARRAY(struct builtin_fw, builtin_fw); bool get_builtin_firmware(struct cpio_data *cd, const char *name) { #ifdef CONFIG_FW_LOADER struct builtin_fw *b_fw; - for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) { + ext_for_each(b_fw, builtin_fw) { if (!strcmp(name, b_fw->name)) { cd->size = b_fw->size; cd->data = b_fw->data;
diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index 22d1760..b85d943e6 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c@@ -9,6 +9,7 @@ #include <linux/capability.h> #include <linux/device.h> +#include <linux/extarray.h> #include <linux/module.h> #include <linux/init.h> #include <linux/timer.h>
@@ -43,15 +44,14 @@ MODULE_LICENSE("GPL"); #ifdef CONFIG_FW_LOADER -extern struct builtin_fw __start_builtin_fw[]; -extern struct builtin_fw __end_builtin_fw[]; +DECLARE_EXTARRAY(struct builtin_fw, builtin_fw) static bool fw_get_builtin_firmware(struct firmware *fw, const char *name, void *buf, size_t size) { struct builtin_fw *b_fw; - for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) { + ext_for_each(b_fw, builtin_fw) { if (strcmp(name, b_fw->name) == 0) { fw->size = b_fw->size; fw->data = b_fw->data;
@@ -69,9 +69,10 @@ static bool fw_is_builtin_firmware(const struct firmware *fw) { struct builtin_fw *b_fw; - for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) + ext_for_each(b_fw, builtin_fw) { if (fw->data == b_fw->data) return true; + } return false; }
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 3074796..d6121ac 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h@@ -317,7 +317,7 @@ .builtin_fw : AT(ADDR(.builtin_fw) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start_builtin_fw) = .; \ *(.builtin_fw) \ - VMLINUX_SYMBOL(__end_builtin_fw) = .; \ + VMLINUX_SYMBOL(__stop_builtin_fw) = .; \ } \ \ TRACEDATA \
--
2.10.0.479.g221bd91