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authorDaniel Vetter <daniel.vetter@ffwll.ch>2013-03-19 09:47:30 +0100
committerDaniel Vetter <daniel.vetter@ffwll.ch>2013-03-19 09:47:30 +0100
commit0d4a42f6bd298e826620585e766a154ab460617a (patch)
tree406d8f7778691d858dbe3e48e4bbb10e99c0a58a /arch/x86/include/asm/bootparam_utils.h
parentd62b4892f3d9f7dd2002e5309be10719d6805b0f (diff)
parenta937536b868b8369b98967929045f1df54234323 (diff)
Merge tag 'v3.9-rc3' into drm-intel-next-queued
Backmerge so that I can merge Imre Deak's coalesced sg entries fixes, which depend upon the new for_each_sg_page introduce in commit a321e91b6d73ed011ffceed384c40d2785cf723b Author: Imre Deak <imre.deak@intel.com> Date: Wed Feb 27 17:02:56 2013 -0800 lib/scatterlist: add simple page iterator The merge itself is just two trivial conflicts: Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'arch/x86/include/asm/bootparam_utils.h')
-rw-r--r--arch/x86/include/asm/bootparam_utils.h54
1 files changed, 54 insertions, 0 deletions
diff --git a/arch/x86/include/asm/bootparam_utils.h b/arch/x86/include/asm/bootparam_utils.h
new file mode 100644
index 000000000000..653668d140f9
--- /dev/null
+++ b/arch/x86/include/asm/bootparam_utils.h
@@ -0,0 +1,54 @@
+#ifndef _ASM_X86_BOOTPARAM_UTILS_H
+#define _ASM_X86_BOOTPARAM_UTILS_H
+
+#include <asm/bootparam.h>
+
+/*
+ * This file is included from multiple environments. Do not
+ * add completing #includes to make it standalone.
+ */
+
+/*
+ * Deal with bootloaders which fail to initialize unknown fields in
+ * boot_params to zero. The list fields in this list are taken from
+ * analysis of kexec-tools; if other broken bootloaders initialize a
+ * different set of fields we will need to figure out how to disambiguate.
+ *
+ * Note: efi_info is commonly left uninitialized, but that field has a
+ * private magic, so it is better to leave it unchanged.
+ */
+static void sanitize_boot_params(struct boot_params *boot_params)
+{
+ /*
+ * IMPORTANT NOTE TO BOOTLOADER AUTHORS: do not simply clear
+ * this field. The purpose of this field is to guarantee
+ * compliance with the x86 boot spec located in
+ * Documentation/x86/boot.txt . That spec says that the
+ * *whole* structure should be cleared, after which only the
+ * portion defined by struct setup_header (boot_params->hdr)
+ * should be copied in.
+ *
+ * If you're having an issue because the sentinel is set, you
+ * need to change the whole structure to be cleared, not this
+ * (or any other) individual field, or you will soon have
+ * problems again.
+ */
+ if (boot_params->sentinel) {
+ /* fields in boot_params are left uninitialized, clear them */
+ memset(&boot_params->olpc_ofw_header, 0,
+ (char *)&boot_params->efi_info -
+ (char *)&boot_params->olpc_ofw_header);
+ memset(&boot_params->kbd_status, 0,
+ (char *)&boot_params->hdr -
+ (char *)&boot_params->kbd_status);
+ memset(&boot_params->_pad7[0], 0,
+ (char *)&boot_params->edd_mbr_sig_buffer[0] -
+ (char *)&boot_params->_pad7[0]);
+ memset(&boot_params->_pad8[0], 0,
+ (char *)&boot_params->eddbuf[0] -
+ (char *)&boot_params->_pad8[0]);
+ memset(&boot_params->_pad9[0], 0, sizeof(boot_params->_pad9));
+ }
+}
+
+#endif /* _ASM_X86_BOOTPARAM_UTILS_H */