Re: [tip:x86/boot] x86/mm: Enable KASLR for physical mapping memory regions

[Borislav Petkov]

On Tue, Aug 16, 2016 at 08:31:28PM -0400, Brian Gerst wrote:
> These fixes work for my system.

Thanks Brian.

Ingo, please queue this into x86/urgent.

Thanks!

---
From: Borislav Petkov <bp@xxxxxxx>
Date: Wed, 17 Aug 2016 08:23:29 +0200
Subject: [PATCH] x86/microcode/AMD: Fix initrd loading with CONFIG_RANDOMIZE_MEMORY=y

Similar to

  efaad554b4ff ("x86/microcode/intel: Fix initrd loading with CONFIG_RANDOMIZE_MEMORY=y")

fix microcode loading from the initrd on AMD by adding the randomization
offset to the microcode patch container within the initrd.

Reported-and-tested-by: Brian Gerst <brgerst@xxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
---
 arch/x86/kernel/cpu/microcode/amd.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index 27a0228c9cae..f43b774d0684 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -355,6 +355,7 @@ void load_ucode_amd_ap(void)
 	unsigned int cpu = smp_processor_id();
 	struct equiv_cpu_entry *eq;
 	struct microcode_amd *mc;
+	u8 *cont;
 	u32 rev, eax;
 	u16 eq_id;
 
@@ -371,8 +372,14 @@ void load_ucode_amd_ap(void)
 	if (check_current_patch_level(&rev, false))
 		return;
 
+	cont = container;
+
+#ifdef CONFIG_RANDOMIZE_MEMORY
+	cont += PAGE_OFFSET - __PAGE_OFFSET_BASE;
+#endif
+
 	eax = cpuid_eax(0x00000001);
-	eq  = (struct equiv_cpu_entry *)(container + CONTAINER_HDR_SZ);
+	eq  = (struct equiv_cpu_entry *)(cont + CONTAINER_HDR_SZ);
 
 	eq_id = find_equiv_id(eq, eax);
 	if (!eq_id)
@@ -434,6 +441,10 @@ int __init save_microcode_in_initrd_amd(void)
 	else
 		container = cont_va;
 
+#ifdef CONFIG_RANDOMIZE_MEMORY
+	container += PAGE_OFFSET - __PAGE_OFFSET_BASE;
+#endif
+
 	eax   = cpuid_eax(0x00000001);
 	eax   = ((eax >> 8) & 0xf) + ((eax >> 20) & 0xff);
 
-- 
2.8.4

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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