16 files changed, 202 insertions, 166 deletions

diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile
index 3cece19b7473..9cc0ff6e9067 100644
--- a/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile
@@ -9,19 +9,6 @@
 # Changed by many, many contributors over the years.
 #
 
-# Sanitizer runtimes are unavailable and cannot be linked for early boot code.
-KASAN_SANITIZE			:= n
-KCSAN_SANITIZE			:= n
-KMSAN_SANITIZE			:= n
-OBJECT_FILES_NON_STANDARD	:= y
-
-# Kernel does not boot with kcov instrumentation here.
-# One of the problems observed was insertion of __sanitizer_cov_trace_pc()
-# callback into middle of per-cpu data enabling code. Thus the callback observed
-# inconsistent state and crashed. We are interested mostly in syscall coverage,
-# so boot code is not interesting anyway.
-KCOV_INSTRUMENT		:= n
-
 # If you want to preset the SVGA mode, uncomment the next line and
 # set SVGA_MODE to whatever number you want.
 # Set it to -DSVGA_MODE=NORMAL_VGA if you just want the EGA/VGA mode.
@@ -69,8 +56,7 @@ KBUILD_CFLAGS	:= $(REALMODE_CFLAGS) -D_SETUP
 KBUILD_AFLAGS	:= $(KBUILD_CFLAGS) -D__ASSEMBLY__
 KBUILD_CFLAGS	+= $(call cc-option,-fmacro-prefix-map=$(srctree)/=)
 KBUILD_CFLAGS	+= -fno-asynchronous-unwind-tables
-GCOV_PROFILE := n
-UBSAN_SANITIZE := n
+KBUILD_CFLAGS	+= $(CONFIG_CC_IMPLICIT_FALLTHROUGH)
 
 $(obj)/bzImage: asflags-y  := $(SVGA_MODE)
 
@@ -129,7 +115,7 @@ targets += mtools.conf
 # genimage.sh requires bash, but it also has a bunch of other
 # external dependencies.
 quiet_cmd_genimage = GENIMAGE $3
-cmd_genimage = $(BASH) $(srctree)/$(src)/genimage.sh $2 $3 $(obj)/bzImage \
+      cmd_genimage = $(BASH) $(src)/genimage.sh $2 $3 $(obj)/bzImage \
 		$(obj)/mtools.conf '$(FDARGS)' $(FDINITRD)
 
 PHONY += bzdisk fdimage fdimage144 fdimage288 hdimage isoimage
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index f19c038409aa..243ee86cb1b1 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -17,15 +17,6 @@
 #	(see scripts/Makefile.lib size_append)
 #	compressed vmlinux.bin.all + u32 size of vmlinux.bin.all
 
-# Sanitizer runtimes are unavailable and cannot be linked for early boot code.
-KASAN_SANITIZE			:= n
-KCSAN_SANITIZE			:= n
-KMSAN_SANITIZE			:= n
-OBJECT_FILES_NON_STANDARD	:= y
-
-# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
-KCOV_INSTRUMENT		:= n
-
 targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \
 	vmlinux.bin.xz vmlinux.bin.lzo vmlinux.bin.lz4 vmlinux.bin.zst
 
@@ -59,8 +50,6 @@ KBUILD_CFLAGS += -include $(srctree)/include/linux/hidden.h
 CFLAGS_sev.o += -I$(objtree)/arch/x86/lib/
 
 KBUILD_AFLAGS  := $(KBUILD_CFLAGS) -D__ASSEMBLY__
-GCOV_PROFILE := n
-UBSAN_SANITIZE :=n
 
 KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
 KBUILD_LDFLAGS += $(call ld-option,--no-ld-generated-unwind-info)
@@ -84,7 +73,7 @@ LDFLAGS_vmlinux += -T
 hostprogs	:= mkpiggy
 HOST_EXTRACFLAGS += -I$(srctree)/tools/include
 
-sed-voffset := -e 's/^\([0-9a-fA-F]*\) [ABCDGRSTVW] \(_text\|__bss_start\|_end\)$$/\#define VO_\2 _AC(0x\1,UL)/p'
+sed-voffset := -e 's/^\([0-9a-fA-F]*\) [ABCDGRSTVW] \(_text\|__start_rodata\|__bss_start\|_end\)$$/\#define VO_\2 _AC(0x\1,UL)/p'
 
 quiet_cmd_voffset = VOFFSET $@
       cmd_voffset = $(NM) $< | sed -n $(sed-voffset) > $@
diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c
index 18d15d1ce87d..f196b1d1ddf8 100644
--- a/arch/x86/boot/compressed/acpi.c
+++ b/arch/x86/boot/compressed/acpi.c
@@ -5,6 +5,8 @@
 #include "../string.h"
 #include "efi.h"
 
+#include <asm/bootparam.h>
+
 #include <linux/numa.h>
 
 /*
diff --git a/arch/x86/boot/compressed/cmdline.c b/arch/x86/boot/compressed/cmdline.c
index c1bb180973ea..e162d7f59cc5 100644
--- a/arch/x86/boot/compressed/cmdline.c
+++ b/arch/x86/boot/compressed/cmdline.c
@@ -1,6 +1,8 @@
 // SPDX-License-Identifier: GPL-2.0
 #include "misc.h"
 
+#include <asm/bootparam.h>
+
 static unsigned long fs;
 static inline void set_fs(unsigned long seg)
 {
diff --git a/arch/x86/boot/compressed/efi.c b/arch/x86/boot/compressed/efi.c
index 6edd034b0b30..f2e50f9758e6 100644
--- a/arch/x86/boot/compressed/efi.c
+++ b/arch/x86/boot/compressed/efi.c
@@ -7,6 +7,8 @@
 
 #include "misc.h"
 
+#include <asm/bootparam.h>
+
 /**
  * efi_get_type - Given a pointer to boot_params, determine the type of EFI environment.
  *
diff --git a/arch/x86/boot/compressed/efi.h b/arch/x86/boot/compressed/efi.h
index 866c0af8b5b9..b22300970f97 100644
--- a/arch/x86/boot/compressed/efi.h
+++ b/arch/x86/boot/compressed/efi.h
@@ -97,15 +97,6 @@ typedef struct {
 	u32 tables;
 } efi_system_table_32_t;
 
-/* kexec external ABI */
-struct efi_setup_data {
-	u64 fw_vendor;
-	u64 __unused;
-	u64 tables;
-	u64 smbios;
-	u64 reserved[8];
-};
-
 struct efi_unaccepted_memory {
 	u32 version;
 	u32 unit_size;
diff --git a/arch/x86/boot/compressed/efi_mixed.S b/arch/x86/boot/compressed/efi_mixed.S
index f4e22ef774ab..876fc6d46a13 100644
--- a/arch/x86/boot/compressed/efi_mixed.S
+++ b/arch/x86/boot/compressed/efi_mixed.S
@@ -15,10 +15,12 @@
  */
 
 #include <linux/linkage.h>
+#include <asm/asm-offsets.h>
 #include <asm/msr.h>
 #include <asm/page_types.h>
 #include <asm/processor-flags.h>
 #include <asm/segment.h>
+#include <asm/setup.h>
 
 	.code64
 	.text
@@ -49,6 +51,11 @@ SYM_FUNC_START(startup_64_mixed_mode)
 	lea	efi32_boot_args(%rip), %rdx
 	mov	0(%rdx), %edi
 	mov	4(%rdx), %esi
+
+	/* Switch to the firmware's stack */
+	movl	efi32_boot_sp(%rip), %esp
+	andl	$~7, %esp
+
 #ifdef CONFIG_EFI_HANDOVER_PROTOCOL
 	mov	8(%rdx), %edx		// saved bootparams pointer
 	test	%edx, %edx
@@ -144,6 +151,7 @@ SYM_FUNC_END(__efi64_thunk)
 SYM_FUNC_START(efi32_stub_entry)
 	call	1f
 1:	popl	%ecx
+	leal	(efi32_boot_args - 1b)(%ecx), %ebx
 
 	/* Clear BSS */
 	xorl	%eax, %eax
@@ -158,6 +166,7 @@ SYM_FUNC_START(efi32_stub_entry)
 	popl	%ecx
 	popl	%edx
 	popl	%esi
+	movl	%esi, 8(%ebx)
 	jmp	efi32_entry
 SYM_FUNC_END(efi32_stub_entry)
 #endif
@@ -234,8 +243,6 @@ SYM_FUNC_END(efi_enter32)
  *
  * Arguments:	%ecx	image handle
  * 		%edx	EFI system table pointer
- *		%esi	struct bootparams pointer (or NULL when not using
- *			the EFI handover protocol)
  *
  * Since this is the point of no return for ordinary execution, no registers
  * are considered live except for the function parameters. [Note that the EFI
@@ -254,13 +261,25 @@ SYM_FUNC_START_LOCAL(efi32_entry)
 	/* Store firmware IDT descriptor */
 	sidtl	(efi32_boot_idt - 1b)(%ebx)
 
+	/* Store firmware stack pointer */
+	movl	%esp, (efi32_boot_sp - 1b)(%ebx)
+
 	/* Store boot arguments */
 	leal	(efi32_boot_args - 1b)(%ebx), %ebx
 	movl	%ecx, 0(%ebx)
 	movl	%edx, 4(%ebx)
-	movl	%esi, 8(%ebx)
 	movb	$0x0, 12(%ebx)          // efi_is64
 
+	/*
+	 * Allocate some memory for a temporary struct boot_params, which only
+	 * needs the minimal pieces that startup_32() relies on.
+	 */
+	subl	$PARAM_SIZE, %esp
+	movl	%esp, %esi
+	movl	$PAGE_SIZE, BP_kernel_alignment(%esi)
+	movl	$_end - 1b, BP_init_size(%esi)
+	subl	$startup_32 - 1b, BP_init_size(%esi)
+
 	/* Disable paging */
 	movl	%cr0, %eax
 	btrl	$X86_CR0_PG_BIT, %eax
@@ -286,8 +305,7 @@ SYM_FUNC_START(efi32_pe_entry)
 
 	movl	8(%ebp), %ecx			// image_handle
 	movl	12(%ebp), %edx			// sys_table
-	xorl	%esi, %esi
-	jmp	efi32_entry			// pass %ecx, %edx, %esi
+	jmp	efi32_entry			// pass %ecx, %edx
 						// no other registers remain live
 
 2:	popl	%edi				// restore callee-save registers
@@ -318,5 +336,6 @@ SYM_DATA_END(efi32_boot_idt)
 
 SYM_DATA_LOCAL(efi32_boot_cs, .word 0)
 SYM_DATA_LOCAL(efi32_boot_ds, .word 0)
+SYM_DATA_LOCAL(efi32_boot_sp, .long 0)
 SYM_DATA_LOCAL(efi32_boot_args, .long 0, 0, 0)
 SYM_DATA(efi_is64, .byte 1)
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index bf4a10a5794f..1dcb794c5479 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -398,6 +398,11 @@ SYM_CODE_START(startup_64)
 	call	sev_enable
 #endif
 
+	/* Preserve only the CR4 bits that must be preserved, and clear the rest */
+	movq	%cr4, %rax
+	andl	$(X86_CR4_PAE | X86_CR4_MCE | X86_CR4_LA57), %eax
+	movq	%rax, %cr4
+
 	/*
 	 * configure_5level_paging() updates the number of paging levels using
 	 * a trampoline in 32-bit addressable memory if the current number does
diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c
index d040080d7edb..dfb9c2deb77c 100644
--- a/arch/x86/boot/compressed/ident_map_64.c
+++ b/arch/x86/boot/compressed/ident_map_64.c
@@ -8,8 +8,8 @@
  * Copyright (C)      2016  Kees Cook
  */
 
-/* No PAGE_TABLE_ISOLATION support needed either: */
-#undef CONFIG_PAGE_TABLE_ISOLATION
+/* No MITIGATION_PAGE_TABLE_ISOLATION support needed either: */
+#undef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION
 
 #include "error.h"
 #include "misc.h"
@@ -284,7 +284,7 @@ static int set_clr_page_flags(struct x86_mapping_info *info,
 	pudp = pud_offset(p4dp, address);
 	pmdp = pmd_offset(pudp, address);
 
-	if (pmd_large(*pmdp))
+	if (pmd_leaf(*pmdp))
 		ptep = split_large_pmd(info, pmdp, address);
 	else
 		ptep = pte_offset_kernel(pmdp, address);
@@ -389,5 +389,5 @@ void do_boot_page_fault(struct pt_regs *regs, unsigned long error_code)
 
 void do_boot_nmi_trap(struct pt_regs *regs, unsigned long error_code)
 {
-	/* Empty handler to ignore NMI during early boot */
+	spurious_nmi_count++;
 }
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index b99e08e6815b..b70e4a21c15f 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -52,6 +52,7 @@ struct port_io_ops pio_ops;
 
 memptr free_mem_ptr;
 memptr free_mem_end_ptr;
+int spurious_nmi_count;
 
 static char *vidmem;
 static int vidport;
@@ -164,21 +165,34 @@ void __putstr(const char *s)
 	outb(0xff & (pos >> 1), vidport+1);
 }
 
-void __puthex(unsigned long value)
+static noinline void __putnum(unsigned long value, unsigned int base,
+			      int mindig)
 {
-	char alpha[2] = "0";
-	int bits;
+	char buf[8*sizeof(value)+1];
+	char *p;
 
-	for (bits = sizeof(value) * 8 - 4; bits >= 0; bits -= 4) {
-		unsigned long digit = (value >> bits) & 0xf;
+	p = buf + sizeof(buf);
+	*--p = '\0';
 
-		if (digit < 0xA)
-			alpha[0] = '0' + digit;
-		else
-			alpha[0] = 'a' + (digit - 0xA);
+	while (mindig-- > 0 || value) {
+		unsigned char digit = value % base;
+		digit += (digit >= 10) ? ('a'-10) : '0';
+		*--p = digit;
 
-		__putstr(alpha);
+		value /= base;
 	}
+
+	__putstr(p);
+}
+
+void __puthex(unsigned long value)
+{
+	__putnum(value, 16, sizeof(value)*2);
+}
+
+void __putdec(unsigned long value)
+{
+	__putnum(value, 10, 1);
 }
 
 #ifdef CONFIG_X86_NEED_RELOCS
@@ -330,6 +344,7 @@ static size_t parse_elf(void *output)
 	return ehdr.e_entry - LOAD_PHYSICAL_ADDR;
 }
 
+const unsigned long kernel_text_size = VO___start_rodata - VO__text;
 const unsigned long kernel_total_size = VO__end - VO__text;
 
 static u8 boot_heap[BOOT_HEAP_SIZE] __aligned(4);
@@ -358,6 +373,19 @@ unsigned long decompress_kernel(unsigned char *outbuf, unsigned long virt_addr,
 }
 
 /*
+ * Set the memory encryption xloadflag based on the mem_encrypt= command line
+ * parameter, if provided.
+ */
+static void parse_mem_encrypt(struct setup_header *hdr)
+{
+	int on = cmdline_find_option_bool("mem_encrypt=on");
+	int off = cmdline_find_option_bool("mem_encrypt=off");
+
+	if (on > off)
+		hdr->xloadflags |= XLF_MEM_ENCRYPTION;
+}
+
+/*
  * The compressed kernel image (ZO), has been moved so that its position
  * is against the end of the buffer used to hold the uncompressed kernel
  * image (VO) and the execution environment (.bss, .brk), which makes sure
@@ -387,6 +415,8 @@ asmlinkage __visible void *extract_kernel(void *rmode, unsigned char *output)
 	/* Clear flags intended for solely in-kernel use. */
 	boot_params_ptr->hdr.loadflags &= ~KASLR_FLAG;
 
+	parse_mem_encrypt(&boot_params_ptr->hdr);
+
 	sanitize_boot_params(boot_params_ptr);
 
 	if (boot_params_ptr->screen_info.orig_video_mode == 7) {
@@ -493,10 +523,16 @@ asmlinkage __visible void *extract_kernel(void *rmode, unsigned char *output)
 	/* Disable exception handling before booting the kernel */
 	cleanup_exception_handling();
 
+	if (spurious_nmi_count) {
+		error_putstr("Spurious early NMIs ignored: ");
+		error_putdec(spurious_nmi_count);
+		error_putstr("\n");
+	}
+
 	return output + entry_offset;
 }
 
-void fortify_panic(const char *name)
+void __fortify_panic(const u8 reason, size_t avail, size_t size)
 {
 	error("detected buffer overflow");
 }
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index bc2f0f17fb90..b353a7be380c 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -59,12 +59,15 @@ extern char _head[], _end[];
 /* misc.c */
 extern memptr free_mem_ptr;
 extern memptr free_mem_end_ptr;
+extern int spurious_nmi_count;
 void *malloc(int size);
 void free(void *where);
 void __putstr(const char *s);
 void __puthex(unsigned long value);
+void __putdec(unsigned long value);
 #define error_putstr(__x)  __putstr(__x)
 #define error_puthex(__x)  __puthex(__x)
+#define error_putdec(__x)  __putdec(__x)
 
 #ifdef CONFIG_X86_VERBOSE_BOOTUP
 
diff --git a/arch/x86/boot/compressed/pgtable_64.c b/arch/x86/boot/compressed/pgtable_64.c
index 51f957b24ba7..c882e1f67af0 100644
--- a/arch/x86/boot/compressed/pgtable_64.c
+++ b/arch/x86/boot/compressed/pgtable_64.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #include "misc.h"
+#include <asm/bootparam.h>
 #include <asm/e820/types.h>
 #include <asm/processor.h>
 #include "pgtable.h"
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index 454acd7a2daf..0457a9d7e515 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -12,6 +12,7 @@
  */
 #include "misc.h"
 
+#include <asm/bootparam.h>
 #include <asm/pgtable_types.h>
 #include <asm/sev.h>
 #include <asm/trapnr.h>
@@ -116,6 +117,9 @@ static bool fault_in_kernel_space(unsigned long address)
 #undef __init
 #define __init
 
+#undef __head
+#define __head
+
 #define __BOOT_COMPRESSED
 
 /* Basic instruction decoding support needed */
@@ -304,6 +308,10 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code)
 	if (result != ES_OK)
 		goto finish;
 
+	result = vc_check_opcode_bytes(&ctxt, exit_code);
+	if (result != ES_OK)
+		goto finish;
+
 	switch (exit_code) {
 	case SVM_EXIT_RDTSC:
 	case SVM_EXIT_RDTSCP:
@@ -327,26 +335,6 @@ finish:
 		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
 }
 
-static void enforce_vmpl0(void)
-{
-	u64 attrs;
-	int err;
-
-	/*
-	 * RMPADJUST modifies RMP permissions of a lesser-privileged (numerically
-	 * higher) privilege level. Here, clear the VMPL1 permission mask of the
-	 * GHCB page. If the guest is not running at VMPL0, this will fail.
-	 *
-	 * If the guest is running at VMPL0, it will succeed. Even if that operation
-	 * modifies permission bits, it is still ok to do so currently because Linux
-	 * SNP guests are supported only on VMPL0 so VMPL1 or higher permission masks
-	 * changing is a don't-care.
-	 */
-	attrs = 1;
-	if (rmpadjust((unsigned long)&boot_ghcb_page, RMP_PG_SIZE_4K, attrs))
-		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_NOT_VMPL0);
-}
-
 /*
  * SNP_FEATURES_IMPL_REQ is the mask of SNP features that will need
  * guest side implementation for proper functioning of the guest. If any
@@ -365,7 +353,7 @@ static void enforce_vmpl0(void)
 				 MSR_AMD64_SNP_VMPL_SSS |		\
 				 MSR_AMD64_SNP_SECURE_TSC |		\
 				 MSR_AMD64_SNP_VMGEXIT_PARAM |		\
-				 MSR_AMD64_SNP_VMSA_REG_PROTECTION |	\
+				 MSR_AMD64_SNP_VMSA_REG_PROT |		\
 				 MSR_AMD64_SNP_RESERVED_BIT13 |		\
 				 MSR_AMD64_SNP_RESERVED_BIT15 |		\
 				 MSR_AMD64_SNP_RESERVED_MASK)
@@ -405,6 +393,85 @@ void snp_check_features(void)
 	}
 }
 
+/* Search for Confidential Computing blob in the EFI config table. */
+static struct cc_blob_sev_info *find_cc_blob_efi(struct boot_params *bp)
+{
+	unsigned long cfg_table_pa;
+	unsigned int cfg_table_len;
+	int ret;
+
+	ret = efi_get_conf_table(bp, &cfg_table_pa, &cfg_table_len);
+	if (ret)
+		return NULL;
+
+	return (struct cc_blob_sev_info *)efi_find_vendor_table(bp, cfg_table_pa,
+								cfg_table_len,
+								EFI_CC_BLOB_GUID);
+}
+
+/*
+ * Initial set up of SNP relies on information provided by the
+ * Confidential Computing blob, which can be passed to the boot kernel
+ * by firmware/bootloader in the following ways:
+ *
+ * - via an entry in the EFI config table
+ * - via a setup_data structure, as defined by the Linux Boot Protocol
+ *
+ * Scan for the blob in that order.
+ */
+static struct cc_blob_sev_info *find_cc_blob(struct boot_params *bp)
+{
+	struct cc_blob_sev_info *cc_info;
+
+	cc_info = find_cc_blob_efi(bp);
+	if (cc_info)
+		goto found_cc_info;
+
+	cc_info = find_cc_blob_setup_data(bp);
+	if (!cc_info)
+		return NULL;
+
+found_cc_info:
+	if (cc_info->magic != CC_BLOB_SEV_HDR_MAGIC)
+		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
+
+	return cc_info;
+}
+
+/*
+ * Indicate SNP based on presence of SNP-specific CC blob. Subsequent checks
+ * will verify the SNP CPUID/MSR bits.
+ */
+static bool early_snp_init(struct boot_params *bp)
+{
+	struct cc_blob_sev_info *cc_info;
+
+	if (!bp)
+		return false;
+
+	cc_info = find_cc_blob(bp);
+	if (!cc_info)
+		return false;
+
+	/*
+	 * If a SNP-specific Confidential Computing blob is present, then
+	 * firmware/bootloader have indicated SNP support. Verifying this
+	 * involves CPUID checks which will be more reliable if the SNP
+	 * CPUID table is used. See comments over snp_setup_cpuid_table() for
+	 * more details.
+	 */
+	setup_cpuid_table(cc_info);
+
+	/*
+	 * Pass run-time kernel a pointer to CC info via boot_params so EFI
+	 * config table doesn't need to be searched again during early startup
+	 * phase.
+	 */
+	bp->cc_blob_address = (u32)(unsigned long)cc_info;
+
+	return true;
+}
+
 /*
  * sev_check_cpu_support - Check for SEV support in the CPU capabilities
  *
@@ -455,7 +522,7 @@ void sev_enable(struct boot_params *bp)
 		bp->cc_blob_address = 0;
 
 	/*
-	 * Do an initial SEV capability check before snp_init() which
+	 * Do an initial SEV capability check before early_snp_init() which
 	 * loads the CPUID page and the same checks afterwards are done
 	 * without the hypervisor and are trustworthy.
 	 *
@@ -470,7 +537,7 @@ void sev_enable(struct boot_params *bp)
 	 * Setup/preliminary detection of SNP. This will be sanity-checked
 	 * against CPUID/MSR values later.
 	 */
-	snp = snp_init(bp);
+	snp = early_snp_init(bp);
 
 	/* Now repeat the checks with the SNP CPUID table. */
 
@@ -501,7 +568,20 @@ void sev_enable(struct boot_params *bp)
 		if (!(get_hv_features() & GHCB_HV_FT_SNP))
 			sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
 
-		enforce_vmpl0();
+		/*
+		 * Enforce running at VMPL0.
+		 *
+		 * RMPADJUST modifies RMP permissions of a lesser-privileged (numerically
+		 * higher) privilege level. Here, clear the VMPL1 permission mask of the
+		 * GHCB page. If the guest is not running at VMPL0, this will fail.
+		 *
+		 * If the guest is running at VMPL0, it will succeed. Even if that operation
+		 * modifies permission bits, it is still ok to do so currently because Linux
+		 * SNP guests running at VMPL0 only run at VMPL0, so VMPL1 or higher
+		 * permission mask changes are a don't-care.
+		 */
+		if (rmpadjust((unsigned long)&boot_ghcb_page, RMP_PG_SIZE_4K, 1))
+			sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_NOT_VMPL0);
 	}
 
 	if (snp && !(sev_status & MSR_AMD64_SEV_SNP_ENABLED))
@@ -527,85 +607,6 @@ u64 sev_get_status(void)
 	return m.q;
 }
 
-/* Search for Confidential Computing blob in the EFI config table. */
-static struct cc_blob_sev_info *find_cc_blob_efi(struct boot_params *bp)
-{
-	unsigned long cfg_table_pa;
-	unsigned int cfg_table_len;
-	int ret;
-
-	ret = efi_get_conf_table(bp, &cfg_table_pa, &cfg_table_len);
-	if (ret)
-		return NULL;
-
-	return (struct cc_blob_sev_info *)efi_find_vendor_table(bp, cfg_table_pa,
-								cfg_table_len,
-								EFI_CC_BLOB_GUID);
-}
-
-/*
- * Initial set up of SNP relies on information provided by the
- * Confidential Computing blob, which can be passed to the boot kernel
- * by firmware/bootloader in the following ways:
- *
- * - via an entry in the EFI config table
- * - via a setup_data structure, as defined by the Linux Boot Protocol
- *
- * Scan for the blob in that order.
- */
-static struct cc_blob_sev_info *find_cc_blob(struct boot_params *bp)
-{
-	struct cc_blob_sev_info *cc_info;
-
-	cc_info = find_cc_blob_efi(bp);
-	if (cc_info)
-		goto found_cc_info;
-
-	cc_info = find_cc_blob_setup_data(bp);
-	if (!cc_info)
-		return NULL;
-
-found_cc_info:
-	if (cc_info->magic != CC_BLOB_SEV_HDR_MAGIC)
-		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
-
-	return cc_info;
-}
-
-/*
- * Indicate SNP based on presence of SNP-specific CC blob. Subsequent checks
- * will verify the SNP CPUID/MSR bits.
- */
-bool snp_init(struct boot_params *bp)
-{
-	struct cc_blob_sev_info *cc_info;
-
-	if (!bp)
-		return false;
-
-	cc_info = find_cc_blob(bp);
-	if (!cc_info)
-		return false;
-
-	/*
-	 * If a SNP-specific Confidential Computing blob is present, then
-	 * firmware/bootloader have indicated SNP support. Verifying this
-	 * involves CPUID checks which will be more reliable if the SNP
-	 * CPUID table is used. See comments over snp_setup_cpuid_table() for
-	 * more details.
-	 */
-	setup_cpuid_table(cc_info);
-
-	/*
-	 * Pass run-time kernel a pointer to CC info via boot_params so EFI
-	 * config table doesn't need to be searched again during early startup
-	 * phase.
-	 */
-	bp->cc_blob_address = (u32)(unsigned long)cc_info;
-
-	return true;
-}
-
 void sev_prep_identity_maps(unsigned long top_level_pgt)
 {
 	/*
diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index a1bbedd989e4..b5c79f43359b 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -111,11 +111,7 @@ extra_header_fields:
 	.long	salign				# SizeOfHeaders
 	.long	0				# CheckSum
 	.word	IMAGE_SUBSYSTEM_EFI_APPLICATION	# Subsystem (EFI application)
-#ifdef CONFIG_EFI_DXE_MEM_ATTRIBUTES
 	.word	IMAGE_DLL_CHARACTERISTICS_NX_COMPAT	# DllCharacteristics
-#else
-	.word	0				# DllCharacteristics
-#endif
 #ifdef CONFIG_X86_32
 	.long	0				# SizeOfStackReserve
 	.long	0				# SizeOfStackCommit
diff --git a/arch/x86/boot/main.c b/arch/x86/boot/main.c
index c4ea5258ab55..9049f390d834 100644
--- a/arch/x86/boot/main.c
+++ b/arch/x86/boot/main.c
@@ -119,8 +119,8 @@ static void init_heap(void)
 	char *stack_end;
 
 	if (boot_params.hdr.loadflags & CAN_USE_HEAP) {
-		asm("leal %P1(%%esp),%0"
-		    : "=r" (stack_end) : "i" (-STACK_SIZE));
+		asm("leal %n1(%%esp),%0"
+		    : "=r" (stack_end) : "i" (STACK_SIZE));
 
 		heap_end = (char *)
 			((size_t)boot_params.hdr.heap_end_ptr + 0x200);
diff --git a/arch/x86/boot/printf.c b/arch/x86/boot/printf.c
index 1237beeb9540..51dc14b714f6 100644
--- a/arch/x86/boot/printf.c
+++ b/arch/x86/boot/printf.c
@@ -246,6 +246,7 @@ int vsprintf(char *buf, const char *fmt, va_list args)
 
 		case 'x':
 			flags |= SMALL;
+			fallthrough;
 		case 'X':
 			base = 16;
 			break;
@@ -253,6 +254,8 @@ int vsprintf(char *buf, const char *fmt, va_list args)
 		case 'd':
 		case 'i':
 			flags |= SIGN;
+			break;
+
 		case 'u':
 			break;