- Make sure a kdump kernel with CONFIG_IMA_KEXEC enabled and booted on an AMD

SME enabled hardware properly decrypts the ima_kexec buffer information
   passed to it from the previous kernel
 
 - Fix building the kernel with Clang where a non-TLS definition of the stack
   protector guard cookie leads to bogus code generation
 
 - Clear a wrongly advertised virtualized VMLOAD/VMSAVE feature flag on some
   Zen4 client systems as those insns are not supported on client
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Merge tag 'x86_urgent_for_v6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Borislav Petkov:

 - Make sure a kdump kernel with CONFIG_IMA_KEXEC enabled and booted on
   an AMD SME enabled hardware properly decrypts the ima_kexec buffer
   information passed to it from the previous kernel

 - Fix building the kernel with Clang where a non-TLS definition of the
   stack protector guard cookie leads to bogus code generation

 - Clear a wrongly advertised virtualized VMLOAD/VMSAVE feature flag on
   some Zen4 client systems as those insns are not supported on client

* tag 'x86_urgent_for_v6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Fix a kdump kernel failure on SME system when CONFIG_IMA_KEXEC=y
  x86/stackprotector: Work around strict Clang TLS symbol requirements
  x86/CPU/AMD: Clear virtualized VMLOAD/VMSAVE on Zen4 client

arch/x86/Makefile

@@ -142,7 +142,8 @@ ifeq ($(CONFIG_X86_32),y)
 
     ifeq ($(CONFIG_STACKPROTECTOR),y)
         ifeq ($(CONFIG_SMP),y)
-			KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard
+            KBUILD_CFLAGS += -mstack-protector-guard-reg=fs \
+                             -mstack-protector-guard-symbol=__ref_stack_chk_guard
         else
             KBUILD_CFLAGS += -mstack-protector-guard=global
         endif

arch/x86/entry/entry.S

@@ -51,3 +51,19 @@ EXPORT_SYMBOL_GPL(mds_verw_sel);
 .popsection
 
 THUNK warn_thunk_thunk, __warn_thunk
+
+#ifndef CONFIG_X86_64
+/*
+ * Clang's implementation of TLS stack cookies requires the variable in
+ * question to be a TLS variable. If the variable happens to be defined as an
+ * ordinary variable with external linkage in the same compilation unit (which
+ * amounts to the whole of vmlinux with LTO enabled), Clang will drop the
+ * segment register prefix from the references, resulting in broken code. Work
+ * around this by avoiding the symbol used in -mstack-protector-guard-symbol=
+ * entirely in the C code, and use an alias emitted by the linker script
+ * instead.
+ */
+#ifdef CONFIG_STACKPROTECTOR
+EXPORT_SYMBOL(__ref_stack_chk_guard);
+#endif
+#endif

arch/x86/include/asm/asm-prototypes.h

@@ -20,3 +20,6 @@
 extern void cmpxchg8b_emu(void);
 #endif
 
+#if defined(__GENKSYMS__) && defined(CONFIG_STACKPROTECTOR)
+extern unsigned long __ref_stack_chk_guard;
+#endif

arch/x86/kernel/cpu/amd.c

@@ -924,6 +924,17 @@ static void init_amd_zen4(struct cpuinfo_x86 *c)
 {
 	if (!cpu_has(c, X86_FEATURE_HYPERVISOR))
 		msr_set_bit(MSR_ZEN4_BP_CFG, MSR_ZEN4_BP_CFG_SHARED_BTB_FIX_BIT);
+
+	/*
+	 * These Zen4 SoCs advertise support for virtualized VMLOAD/VMSAVE
+	 * in some BIOS versions but they can lead to random host reboots.
+	 */
+	switch (c->x86_model) {
+	case 0x18 ... 0x1f:
+	case 0x60 ... 0x7f:
+		clear_cpu_cap(c, X86_FEATURE_V_VMSAVE_VMLOAD);
+		break;
+	}
 }
 
 static void init_amd_zen5(struct cpuinfo_x86 *c)

arch/x86/kernel/cpu/common.c

@@ -2089,8 +2089,10 @@ void syscall_init(void)
 
 #ifdef CONFIG_STACKPROTECTOR
 DEFINE_PER_CPU(unsigned long, __stack_chk_guard);
+#ifndef CONFIG_SMP
 EXPORT_PER_CPU_SYMBOL(__stack_chk_guard);
 #endif
+#endif
 
 #endif	/* CONFIG_X86_64 */
 

arch/x86/kernel/vmlinux.lds.S

@@ -491,6 +491,9 @@ SECTIONS
 . = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE),
 	   "kernel image bigger than KERNEL_IMAGE_SIZE");
 
+/* needed for Clang - see arch/x86/entry/entry.S */
+PROVIDE(__ref_stack_chk_guard = __stack_chk_guard);
+
 #ifdef CONFIG_X86_64
 /*
  * Per-cpu symbols which need to be offset from __per_cpu_load

arch/x86/mm/ioremap.c

@@ -656,7 +656,8 @@ static bool memremap_is_setup_data(resource_size_t phys_addr,
 		paddr_next = data->next;
 		len = data->len;
 
-		if ((phys_addr > paddr) && (phys_addr < (paddr + len))) {
+		if ((phys_addr > paddr) &&
+		    (phys_addr < (paddr + sizeof(struct setup_data) + len))) {
 			memunmap(data);
 			return true;
 		}
@@ -718,7 +719,8 @@ static bool __init early_memremap_is_setup_data(resource_size_t phys_addr,
 		paddr_next = data->next;
 		len = data->len;
 
-		if ((phys_addr > paddr) && (phys_addr < (paddr + len))) {
+		if ((phys_addr > paddr) &&
+		    (phys_addr < (paddr + sizeof(struct setup_data) + len))) {
 			early_memunmap(data, sizeof(*data));
 			return true;
 		}